Genetics: brain plasticity

We know the brain can add memories and alter other functions. It can even add neurons. Here is a method using retrotransposons in the DNA of the neuron to change its function:-http://the-scientist.com/2012/07/01/brain-mosaic/

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The deaf use the auditory part of the brain for increased touch sensitivity:-http://medicalxpress.com/news/2012-07-deaf-brain-differently.html

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Further work on brain plasticity in sensory impairment:-http://www.scientificamerican.com/article.cfm?id=superpowers-for-the-blind-and-deaf

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Another study on fooling the brain:-http://medicalxpress.com/news/2012-09-youre-brain.html-I view this as showing the brain has a catalog of experience to make any determined action by the individual easier to perform. Put another way, free will gets lots of unconscious help.

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More evidence of brain plasticity:-http://www.sciencedaily.com/releases/2012/10/121008082953.htm-And newly found cells in the hippocampus guide learning:-http://medicalxpress.com/news/2012-10-discovery-gatekeeper-nerve-cells-effect.html

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Children have differing amounts of white matter, the connection fibers, early on, and this affects their reading skills and learning. It is recognized that IQ relates to active reading and being read to. A key issue in improving intelligence.- http://medicalxpress.com/news/2012-10-year-significant-differences-white-children.html

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It is all in the wiring. Two worms,same brains, different life styles:-http://www.newscientist.com/article/mg21729024.800-two-worms-same-brains--but-one-eats-the-other.html

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IQ can change:-
http://blogs.scientificamerican.com/guest-blog/2013/02/05/the-virtues-of-a-cognitive-workout-new-research-reveals-some-neurological-underpinnings-of-intelligence/?WT_mc_id=SA_CAT_MB_20130206

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Split a brain and it still will work very well. Even half a brain is better than no brain at all and works quite well:-http://www.scientificamerican.com/article.cfm?id=split-brain-patients-reveal-brains-flexibility&WT.mc_id=SA_WR_20130227

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The brain adds neurons into puberty:-http://www.sciencedaily.com/releases/2013/03/130304151847.htm-"in the past few years, researchers in MSU's neuroscience program have shown that mammalian brains also add cells during puberty in the amygdala and interconnected regions where it was thought no new growth occurred. The amygdala plays an important role in helping the brain make sense of social cues. For hamsters, it picks up signals transmitted by smell through pheromones; in humans, the amygdala evaluates facial expressions and body language.
 
"These regions are important for social behaviors, particularly mating behavior," said lead author Maggie Mohr, a doctoral student in neuroscience. 'So, we thought maybe cells that are added to those parts of the brain during puberty could be important for adult reproductive function.'"

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Yes, it happens:-http://www.the-scientist.com//?articles.view/articleNo/35902/title/Human-Adult-Neurogenesis-Revealed/

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More on growth and genomic activity of adult neurons:-http://www.the-scientist.com/?articles.view/articleNo/35902/title/Human-Adult-Neurogenesis-Revealed/-http://www.the-scientist.com/?articles.view/articleNo/36350/title/Brain-Methylation-Map-Published/-http://www.the-scientist.com/?articles.view/articleNo/34816/title/Brain-Activity-Breaks-DNA/-Our brains are extremely plastic and active in changes. Helps explain how they are able to do so much in abstractions.

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This is white matter changing as our use of the brain grows from childhood:-http://www.sciencedaily.com/releases/2014/02/140203083828.htm-Obviously IQ is more than inheritance, but teaching and use. Being an autodidact is a great idea.

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Rat study shows new neuron development after stress:-http://www.sciencedaily.com/releases/2013/04/130416204546.htm

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Rat study shows new neuron development after stress:
> 
> http://www.sciencedaily.com/releases/2013/04/130416204546.htm-Reminded me of one of my fav quotes from the movie 'The Day the World Stood Still'-"Only at the precipice do we evolve."

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The glial cells are more than just suppporting. They are active contributors and constantly working:-http://blogs.scientificamerican.com/mind-guest-blog/2013/06/24/a-secret-society-of-cells-runs-your-brain/?WT_mc_id=SA_DD_20130624

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DAVID: The glial cells are more than just supporting. They are active contributors and constantly working:-http://blogs.scientificamerican.com/mind-guest-blog/2013/06/24/a-secret-society-of-cell...-DAVID: (Under "Natures Wonders: modulating food supply") Plants manage starch consumption by feedback mechanisms akin to math formulas:-http://www.bbc.co.uk/news/health-22991838-I found these two articles fascinating, and once again would like to thank you for this constant stream of information. It's becoming clearer and clearer that organisms of all kinds comprise communities of cells which cooperate with one another to create an overall unit. I always go back to ants and bees as a visible example of such cooperation, because internal communities like brain cells remain invisible to us. (Ditto all our other organs.) These cells are not consciously controlled by us ... they do their work independently, and their work entails some form of inner "intelligence". The same applies to plants, with their intricate maths calculations.
 
Commenting on the plant research, Dr Richard Buggs of Queen Mary, University of London, said: "This is not evidence for plant intelligence. It simply suggests that plants have a mechanism designed to automatically regulate how fast they burn carbohydrates at night. Plants don't do maths voluntarily and with a purpose in mind like we do."-I don't know how Dr Buggs is able to read the mental processes of plants, although I'm sure his statement accords with what most of us believe. It certainly fits in with David's theories of design (Dr Buggs actually uses the word), but it also fits in with panpsychism if we follow the concept I quoted earlier: "there may be varying degrees in which things have inner subjective or quasi-conscious aspects, some very unlike what we experience as consciousness." This is why I prefer to put "intelligence" in inverted commas. Once we accept the idea that every organ and organism is a community or an assembly of communities, the pattern of evolution becomes very clear: a continual process of "intelligent" cells combining in different and increasingly complex ways.
 
The crunch question remains how the mechanism first came into being. No startling revelations here, I'm afraid. It's still our three equally fantastic hypotheses: design (theistic), chance (atheistic), panpsychist evolution (theistic or atheistic).

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> dhw: The crunch question remains how the mechanism first came into being. No startling revelations here, I'm afraid. It's still our three equally fantastic hypotheses: design (theistic), chance (atheistic), panpsychist evolution (theistic or atheistic).-Just remember DNA with all its levels of other codes and controls is so complex an original intelligence had to get it started. And we have no idea as yet, the further degree of complexity that will be discovered. With each level of complexity discovered the option for chance recedes.

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How the brain changes itself with changes in synapses:-"The mechanism that allows individual Purkinje cells to differentiate between the two kinds of climbing fiber signals is an open question. These signals come in bursts, so the number and spacing of the electrical impulses from climbing fiber to Purkinje cell might be significant. Medina and his colleagues also suspect that another mechanism is at play: Purkinje cells might respond differently when a signal from a climbing fiber is synchronized with signals coming elsewhere from the brain. -"Whether either or both of these explanations are confirmed, the fact that individual Purkinje cells are able to distinguish when their corresponding muscle neurons encounter an error must be taken into account in future studies of fine motor control. This understanding could lead to new research into the fundamentals of neuroplasticity and learning. -"Something that would be very useful for the brain is to have information not just about whether there was an error but how big the error wasâwhether the Purkinje cell needs to make a minor or major adjustment," Medina said. "That sort of information would seem to be necessary for us to get very good at any kind of activity that requires precise control. Perhaps climbing fiber signals are not as 'all-or-nothing' as we all thought and can provide that sort of graded information.'"-http://medicalxpress.com/news/2014-02-neurons-fine-tune-motor_1.html

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New research finds signals to produce more neurons:-"Duke researchers have found a new type of neuron in the adult brain that is capable of telling stem cells to make more new neurons. Though the experiments are in their early stages, the finding opens the tantalizing possibility that the brain may be able to repair itself from within."-http://medicalxpress.com/news/2014-06-neuron-stem-cells-neurons.html

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This guy is born without a corpus callosum, yet functions just fine. Think our consciousness is just neurons acting up? Our development controls this plasticity, and we contribute to that development with how we use our brain:-http://www.wired.com/2014/08/this-elderly-gentleman-was-born-with-his-brain-hemispheres-disconnected-how-did-it-affect-him-barely-at-all/

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Brain stimulation through sensory effects shows vascualr plasticity:-http://medicalxpress.com/news/2014-09-deprivation-vascular-brain.html

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Almost fully functional lady with no cerebellum:-http://www.newscientist.com/article/mg22329861.900-woman-of-24-found-to-have-no-cerebellum-in-her-brain.html#.VBH8u_k7eRZ

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Another example of how the brain controls itself. Curiosity increases memory:-http://www.sciencedaily.com/releases/2014/10/141002123631.htm

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"For decades, scientists thought that neurons in the brain were born only during the early development period and could not be replenished. More recently, however, they discovered cells with the ability to divide and turn into new neurons in specific brain regions. The function of these neuroprogenitor cells remains an intense area of research. Scientists at the National Institutes of Health (NIH) report that newly formed brain cells in the mouse olfactory systemthe area that processes smellsplay a critical role in maintaining proper connections. The results were published in the October 8 issue of the Journal of Neuroscience."- - ""This is a surprising new role for brain stem cells and changes the way we view them," said Leonardo Belluscio, Ph.D., a scientist at NIH's National Institute of Neurological Disorders and Stroke (NINDS) and lead author of the study"-http://medicalxpress.com/news/2014-10-scientists-unexpected-role-stem-cells.html

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How special glial cells play a role in new motor skills:-The paper shows very clearly that the ability to generate new myelin is necessary for adult mice to learn a complex motor task, said the University of Michigan's Gabriel Corfas, author of an accompanying commentary in Science and who was not involved in the research.
 
"Moreover, because myelin is produced by non-neuronal glial cells called oligodendrocytes, which myelinate axons by extending thin processes of their cell membranes to wrap around them, the study challenges the long-standing assumption that learning results exclusively from changes to neuronal anatomy or function. What this paper really does in a very compelling and elegant way is show that the glial cells . . . really perform much more important tasks than had hitherto been assigned to them, said Robin Franklin, professor at the University of Cambridge, who studies the process of remyelination and who was not involved in the work. This paper is a very significant step in a mounting body of work that shows that in fact the glial cells are not simply cells for neurons; they have, in their own right, fundamentally important roles in how the brain works."-http://www.the-scientist.com//?articles.view/articleNo/41245/title/Myelin-s-Role-in-Motor-Learning/

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Sound signals received are sent to the optical cortex, which results in better identification of what is seen in the area of the sound:-http://www.the-scientist.com/?articles.view/articleNo/40999/title/Sound-and-Light-Show/

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""We were surprised to find that there were no specialized populations among neurons in the PPC that we studied," says Churchland. Instead, the team found that PPC neurons were multitasking, each one responding to more than one stimulus. No distinct classes emerged among the more than 300 neurons they measured. "Each neuron had its own signature for how it responded - no two were alike - which means that we couldn't lump them together into categories."-"Churchland proposes that neurons such as these, which are able to multitask, may offer the brain a flexible way to combine responses. "This changes the way our team thinks about how neurons are used and work together," she says. Based on these results, Churchland says, researchers may want to question the often used method of averaging the responses of different neurons to describe their collective behavior, under the assumption that anatomically distinct groups of neurons will respond to stimuli in the same way. More broadly, the research suggests a new way of thinking about how neurons behave. In this view, "it is no longer single neurons making sense of a behavior, but the whole group, integrating multiple signals," says Churchland"-http://medicalxpress.com/news/2014-11-neurons-multitask-importance-specialization.html-Many brain areas may not be fully specialized. No computer can be like this. AI may not be possible.

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A complete article on current research. Our brains are amazingly plastic and can recover from major damage by being taught tov recruit new areas to take over lost functions:-http://www.wsj.com/articles/our-amazingly-plastic-brains-1423262095?mod=trending_now_1-"The mainstream view in neuroscience and medicine today is that the living brain is actually neuroplasticmeaning that its circuits are constantly changing in response to what we actually do out in the world. As we think, perceive, form memories or learn new skills, the connections between brain cells also change and strengthen. Far from being hard-wired, the brain has circuits that very rapidly form, unform and reform. -"This capacity is the foundation for the brain's distinctive way of healing. If an area is damaged, new neurons can often take over old tasks. Nor are we just our neurons. Our memories and experiences are also encoded in the patterns of electrical energy produced by our brain cells, like a musical score. As with an orchestra, when one member of the string section is sick, the show can still go on if a replacement has access to the musical score."

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The astronomical number of synapses (nerve connections)in the brain is mind boggling. This Catholic article gives a good simple description, and then notes not by chance:-http://www.ncregister.com/daily-news/the-half-truths-of-materialist-evolution/-"I would like to direct attention to the unsupportable notion that the human brain, to focus on a single phenomenon, could possibly have evolved by sheer chance. One of the great stumbling blocks for Darwin and other chance evolutionists is explaining how a multitude of factors simultaneously coalesce to form a unified, functioning system. The human brain could not have evolved as a result of the addition of one factor at a time. Its unity and phantasmagorical complexity defies any explanation that relies on pure chance. It would be an underestimation of the first magnitude to say that today's neurophysiologists know more about the structure and workings of the brain than did Darwin and his associates.-"Scientists in the field of brain research now inform us that a single human brain contains more molecular-scale switches than all the computers, routers and Internet connections on the entire planet! According to Stephen Smith, a professor of molecular and cellular physiology at the Stanford University School of Medicine, the brain's complexity is staggering, beyond anything his team of researchers had ever imagined, almost to the point of being beyond belief. In the cerebral cortex alone, each neuron has between 1,000 to 10,000 synapses that result, roughly, in a total of 125 trillion synapses, which is about how many stars fill 1,500 Milky Way galaxies!-"A single synapse may contain 1,000 molecular-scale switches. A synapse, simply stated, is the place where a nerve impulse passes from one nerve cell to another.-"Phantasmagorical as this level of unified complexity is, it places us merely at the doorway of the brain's even deeper mind-boggling organization. Glial cells in the brain assist in neuron speed. These cells outnumber neurons 10 times over, with 860 billion cells. All of this activity is monitored by microglia cells that not only clean up damaged cells but also prune dendrites, forming part of the learning process. The cortex alone contains 100,000 miles of myelin-covered, insulated nerve fibers.- Note 125 trillion synapses, each with up to 1,000 molecular switches. This is specified complexity at its greatest. No wonder we can think like we do. Try to invent this item one tiny Darwinian step at a time, especially from the notion of chance mutations, a theory Dawkins still favors. Or now imagine energy and matter concocting a brain without guidance or planning. Simply not possible. Still only two possibilities, chance or design.

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With more education and stimulation:-http://www.wsj.com/articles/the-questions-we-should-ask-about-intelligence-1424275812?KEYWORDS=Gopnik-"Take IQ again. James Flynn, at New Zealand's University of Otago, and others have shown that absolute IQ scores have been steadily and dramatically increasing, by as much as three points a decade. (The test designers have to keep making the questions harder to keep the average at 100).-"The best explanation is that we have consciously transformed our society into a world where schools are ubiquitous. So even though genes contribute to whatever IQ scores measure, IQ can change radically as a result of changes in environment. Abstract thinking and a thirst for knowledge might once have been a genetic quirk. In a world of schools, they become the human inheritance."

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New neurons appear all the time in adult brains, a finding not taught when I was in medical school:-http://www.sciencedaily.com/releases/2015/02/150221192244.htm-"In recent years, it has become increasingly clear that environmental influences have a profound effect on the adult brain in a wide range of mammalian species. Stressful experiences, such as restraint, social defeat, exposure to predator odors, inescapable foot shock, and sleep deprivation, have been shown to decrease the number of new neurons in the hippocampus. By contrast, more rewarding experiences, such as physical exercise and mating, tend to increase the production of new neurons in the hippocampus.-"The birth of new neurons in adulthood may have important behavioral and cognitive consequences. Stress-induced suppression of adult neurogenesis has been associated with impaired performance on hippocampus-dependent cognitive tasks, such as spatial navigation learning and object memory. Stressful experiences have also been shown to increase anxiety-like behaviors that are associated with the hippocampus. In contrast, rewarding experiences are associated with reduced anxiety-like behavior and improved performance on cognitive tasks involving the hippocampus.-"Although scientists generally agree that our day-to-day actions change our brains even in adulthood, there is some disagreement on the adaptive significance of new neurons. For instance, the literature presents mixed findings on whether new neurons generated under a specific experimental condition are geared toward the recognition of that particular experience or if they provide a more naive pool of new neurons that enable environmental adaptation in the future.-"Gould and her collaborators recently proposed that stress-induced decreases in new neuron formation might improve the chances of survival by increasing anxiety and inhibiting exploration, thereby prioritizing safety and avoidant behavior at the expense of performing optimally on cognitive tasks. On the other hand, reward-induced increases in new neuron number may reduce anxiety and facilitate exploration and learning, leading to greater reproductive success."

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Sending out new connections described:-"The filaments that make these new connections are called dendritic spines and, in a series of experiments described in the April 17 issue of the Journal of Biological Chemistry, the researchers report that a specific signaling protein, Asef2, a member of a family of proteins that regulate cell migration and adhesion, plays a critical role in spine formation. This is significant because Asef2 has been linked to autism and the co-occurrence of alcohol dependency and depression.-"'Alterations in dendritic spines are associated with many neurological and developmental disorders, such as autism, Alzheimer's disease and Down Syndrome," said Webb. "However, the formation and maintenance of spines is a very complex process that we are just beginning to understand."-"Neuron cell bodies produce two kinds of long fibers that weave through the brain: dendrites and axons. Axons transmit electrochemical signals from the cell body of one neuron to the dendrites of another neuron. Dendrites receive the incoming signals and carry them to the cell body. This is the way that neurons communicate with each other.-"As they wait for incoming signals, dendrites continually produce tiny flexible filaments called filopodia. These poke out from the surface of the dendrite and wave about in the region between the cells searching for axons. At the same time, biologists think that the axons secrete chemicals of an unknown nature that attract the filopodia.-"When one of the dendritic filaments makes contact with one of the axons, it begins to adhere and to develop into a spine. The axon and spine form the two halves of a synaptic junction. New connections like this form the basis for memory formation and storage."-http://medicalxpress.com/news/2015-04-insight-brain-memories.html

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With training:-"Elite athletes are blessed with an area of the brain that performs 82 percent faster than average under intense pressure, a study published on Wednesday claims.
 
"A series of tests commissioned by Dunlop Tyres in conjunction with University College London (UCL) found that extreme sportsmen and women performed significantly better under physical and mental duress than members of the public.-"Test subjects were given tasks that required the use of the parietal cortex, a key part of the brain that determines reaction speed. The study found that the athletes had "an exceptional advantage'".-http://medicalxpress.com/news/2015-05-elite-athletes-brains-percent-faster.html

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Students for MBA's studied for gray matter changes as they learned about business morals and ethics:-http://medicalxpress.com/news/2015-06-high-moral-correspond-gray-brain.html-"A total of 67 MBA students were administered the Defining Issue Test to determine which pattern of thought or behavior, known as cognitive schema, each student used when reasoning about moral issues. In it, students were presented with complex moral dilemmas such as medical assisted suicide and asked them to choose the relevance of each of 12 given rationales. Based on the results, subjects were then assigned to one of seven schema types which represent increasing levels of moral development. Students then underwent MRI scanning to investigate differences in gray matter volume between students who reached the post-conventional level of moral reasoning compared to those who have not reached that level yet.-"Subjects also underwent personality testing and were placed into one of the following categories: neuroticism, extraversion, openness to experience, conscientiousness, and agreeableness. Analysis showed higher scores in openness to experience and lower scores in neuroticism for participants at the more advanced levels of moral development.-"With regard to brain structure, the team observed increased gray matter in the prefrontal cortex in subjects who reached the post-conventional level of moral reasoning compared to those who are still at a pre-conventional and conventional level. In other words, gray matter volume was correlated with the subject's degree of post-conventional thinking."

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There are so many things wrong with this that it is hard to no where to start:- 
> "A total of 67 MBA students were administered the Defining Issue Test to determine which pattern of thought or behavior, known as cognitive schema, each student used when reasoning about moral issues. -The sample size is too small, which is guaranteed to produce something 'statistically significant'-
>In it, students were presented with complex moral dilemmas such as medical assisted suicide and asked them to choose the relevance of each of 12 given rationales. Based on the results, subjects were then assigned to one of seven schema types which represent increasing levels of moral development. -So they are assigned schema based on WHOSE determination of moral development? Is morality objective now? Is it measurable? Quantifiable?->Students then underwent MRI scanning to investigate differences in gray matter volume between students who reached the post-conventional level of moral reasoning compared to those who have not reached that level yet.
> -What is 'Post-conventional level of moral reasoning'?-
> "Subjects also underwent personality testing and were placed into one of the following categories: neuroticism, extraversion, openness to experience, conscientiousness, and agreeableness. Analysis showed higher scores in openness to experience and lower scores in neuroticism for participants at the more advanced levels of moral development.-There is very little correlation there, and that correlation MIGHT be more related to the fact that they are all MBA students. You know, birds of a feather and all that. Those pursuing MBA's are more likely to be the type of same type of personalities, so any correlation they may be seeing is more likely due to the nature of the participants rather than any correlation to the test.

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What is the purpose of living? How about, 'to reduce needless suffering. It seems to me to be a worthy purpose.

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> Tony: There is very little correlation there, and that correlation MIGHT be more related to the fact that they are all MBA students. You know, birds of a feather and all that. Those pursuing MBA's are more likely to be the type of same type of personalities, so any correlation they may be seeing is more likely due to the nature of the participants rather than any correlation to the test.-I agree with your objections, but the major focus of the study was a certain type of gray matter thickness that seem to have developed in these students. Again, brain plasticity. They did find it.

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But they can't prove if it was something environmental, genetic, or what. All they can really say with that study is "brains come with different gray matter thicknesses", which I don't think was ever much in question.

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What is the purpose of living? How about, 'to reduce needless suffering. It seems to me to be a worthy purpose.

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Tony: But they can't prove if it was something environmental, genetic, or what. All they can really say with that study is "brains come with different gray matter thicknesses", which I don't think was ever much in question.-There is no question stimulation increases gray matter, my only point. Read to your kid.

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When neurons divide, most don't, new histones are made along with the neuronal DNA in each new cell. Histones can modify the way DNA is expressed:-http://www.the-scientist.com/?articles.view/articleNo/43449/title/Epigenetic-Mechanism-Tunes-Brain-Cells/-"When a cell divides and copies its DNA, it also makes copies of histones, the proteins that spool DNA and regulate gene expression. Since most neurons don't typically divide, scientists have long thought that their histones also remain stagnant. A study published in Neuron yesterday (July 1) is now challenging that view, showing that neurons in mice and in humans switch out old histones for new ones, and that this process is important for brain plasticity.-"Maze and colleagues at Mount Sinai and Rockefeller University examined levels of a histone variant called H3.3 that is known to turn over in other cells, even when those cells are not dividing. They found that H3.3 accumulates with age in neurons from mouse brains and post-mortem human brain tissue. The team used a technique called 14C/12C bomb pulse dating, which takes advantage of the high levels of radioactive carbon released into the atmosphere during World War II, to determine that humans replace H3.3 throughout their lives.-"To further elucidate the turnover process, the researchers fed mice food laced with a radioactive isotope of lysine that could be detected in recently-made histone, and found that mice housed in mentally stimulating environments containing toys and wheels had more H3.3 turnover in their hippocampi, MedicalXpress reports. The scientists also demonstrated a relationship between histone replacement and neuronal plasticity in human and mouse cell lines.-'Histone turnover, shown through our work with H3.3, is essential for the behavior of brain cells, Maze said. "

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There is more grey matter in bilingual individuals, a Spanish/English study:-http://www.sciencedaily.com/releases/2015/07/150716135054.htm-"Inconsistencies in the reports about the bilingual advantage stem primarily from the variety of tasks that are used in attempts to elicit the advantage," says senior author Guinevere Eden, DPhil, director for the Center for the Study of Learning at Georgetown University Medical Center (GUMC). "Given this concern, we took a different approach and instead compared gray matter volume between adult bilinguals and monolinguals. We reasoned that the experience with two languages and the increased need for cognitive control to use them appropriately would result in brain changes in Spanish-English bilinguals when compared with English-speaking monolinguals. And in fact greater gray matter for bilinguals was observed in frontal and parietal brain regions that are involved in executive control."-"Gray matter of the brain has been shown to differ in volume as a function of people's experiences. A prominent finding of this type was a report that London taxi drivers have more gray matter in brain areas involved in spatial navigation.-***-"The researchers compared gray matter in bilinguals of American Sign Language (ASL) and spoken English with monolingual users of English. Both ASL-English and Spanish-English bilinguals share qualities associated with bilingualism, such as vocabulary size. But unlike bilinguals of two spoken languages, ASL-English bilinguals can sign and speak simultaneously, allowing the researchers to test whether the need to inhibit the other language might explain the bilingual advantage.-"'Unlike the findings for the Spanish-English bilinguals, we found no evidence for greater gray matter in the ASL-English bilinguals," Olulade says. "Thus we conclude that the management of two spoken languages in the same modality, rather than simply a larger vocabulary, leads to the differences we observed in the Spanish-English bilinguals.'"

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The result of poorly treated hydrocephalus, most white matter is missing. Is it needed?-http://www.realclearscience.com/blog/2015/08/the_normal_man_who_was_missing_a_brain.html-"In 2007, a 44-year-old happily married man with a white-collar job and two children visited a hospital in Marseille, France complaining of mild weakness in his left leg. Some time later, he concluded his hospital episode with his leg weakness cured, but with another, intriguing diagnosis in tow: he was missing most of his brain.-"A disconcerting notion to most, the condition didn't seem to trouble the man much at all. Sure, his IQ tested a tad below average, but his medical history and neurological development were otherwise normal. So how did he develop his strange, yet innocuous infirmity? -"The doctors soon learned that when he was just six months old, the man had a condition called hydrocephalus, where an excess amount of cerebrospinal fluid accumulated in the ventricles of his brain. Luckily, it was caught early, and doctors inserted a shunt -- a valve of sorts -- to ensure that the fluid drained properly. Fourteen years later, the shunt was removed.-"Perhaps it should have been left in, because over the next thirty years, the fluid gradually built up in the ventricles, ever so slowly condensing or consuming the actual brain matter until it only remained at the outer recesses of the skull.-"How the man was able to function normally remains a mystery, but then again, so do many aspects of the brain's operation. The best explanation scientists gave is that the brain is plastic and highly adaptable.-"Discover Blogs' Neuroskeptic offered another theory:-"While the enormous holes in these brains seem dramatic, the bulk of the grey matter of the cerebral cortex, around the outside of the brain, appears to be intact and in the correct place - this is visible as the dark grey shell' beneath the skull. What appears to be missing is the white matter, the nerve tracts that connect the various parts of the cerebral cortex with each other, and with the other areas of the brain.-"According to Neuroskeptic, instances like these call into question how much white matter is truly needed for the brain to function properly. Could it be that a good chunk of the 1,400-gram human brain is superfluous?"

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the blind spot can be trained to shrink 10%:-http://www.nytimes.com/2015/09/01/science/blind-spot-can-be-trained-away-a-study-says.html?emc=edit_th_20150901&nl=todaysheadlines&nlid=60788861&_r=0-"The optic nerve, which carries visual signals to the brain, passes through the retina, a light-sensitive layer of tissue. There are no so-called photoreceptors at the point where the optic nerve intersects the retina. The right eye generally compensates for the left eye's blind spot and vice versa, so the spot is hardly noticed.-"Researchers trained 10 people using a computer monitor and an eye patch. The participants were shown a waveform in the visual field of their blind spot day after day. After 20 days of this repeated stimulation, the blind spot shrunk by about 10 percent.-"The researchers believe that neurons at the periphery of the blind spot became more responsive, effectively reducing the extent of functional blindness."

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Another article covering new research:-http://www.wsj.com/articles/the-power-of-brains-to-keep-growing-1441293338-"To boost my memory, I am going for a run. My dogs' memories will get a boost, too, as they bound through the woods chasing squirrels. Over the past two decades, neuroscientists have discovered that new nerve cells (neurons) are constantly being born in one tiny area of the brain crucial for learning and memoryand that physical exercise promotes the numbers of these newborn neurons.-***-"Apart from exercise and enrichment, other factors can enhance the progression from neuron birth to full installation in the circuitryamong them, surprisingly, antidepressants such as Prozac. Berries, grapes, chocolate and teaall rich in molecules called flavonoidshave been linked to improved spatial learning behavior in rodents and humans. On the other hand, stress suppresses the proliferation of new neurons, as do alcohol and high doses of nicotine. -"Much of the data derive from rodents and nonhuman primates because the newborn neurons have to be identified by chemical tag and then counted in the postmortem brain. But Kirsty L. Spalding of Sweden's Karolinska Institute and an international team of scientists were able to exploit an unusual opportunity for quantifying numbers of newborn neurons in humans. -"As they reported in the journal Cell in June 2013, nuclear-bomb tests between 1945 and 1963 had increased levels of the carbon isotope 14 in the atmosphere. Dividing cells require carbon, so the DNA in dividing cells, including those producing new neurons, took up increased amounts of carbon 14. Based on this knowledge, the team looked at brains post mortem of people in the vicinity of the bomb tests. They found evidence for newborn neurons, but only in the dentate gyrus, and calculated that about 700 a day are added."

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A complex study of individuals comparing their personal traits to their brain wiring
finds definite patterns:-http://www.scientificamerican.com/article/how-your-brain-is-wired-reveals-the-real-you/?WT.mc_id=SA_DD_20150928-"In April, a branch of the project led by one of the HCP's co-chairs, biomedical engineer Stephen Smith at the University of Oxford, UK, released a database of resting-state connectomes from about 460 people between 22 and 35 years old. Each brain scan is supplemented by information on approximately 280 traits, such as the person's age, whether they have a history of drug use, their socioeconomic status and personality traits, and their performance on various intelligence tests.-" Smith and his colleagues ran a massive computer analysis to look at how these traits varied among the volunteers, and how the traits correlated with different brain connectivity patterns. The team was surprised to find a single, stark difference in the way brains were connected. People with more 'positive' variables, such as more education, better physical endurance and above-average performance on memory tests, shared the same patterns. Their brains seemed to be more strongly connected than those of people with 'negative' traits such as smoking, aggressive behaviour or a family history of alcohol abuse.-"Marcus Raichle, a neuroscientist at Washington University in St Louis, Missouri, is impressed that the activity and anatomy of the brains alone were enough to reveal this 'positive-negative' axis. You can distinguish people with successful traits and successful lives versus those who are not so successful, he says."-Comment: We create our personalities as we develop and age. We obviously work back and forth with our brains as partners in the project.

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A long and complex article on the appearance and function new neurons in adults:-http://www.the-scientist.com/?articles.view/articleNo/44097/title/Brain-Gain/-"The basic idea is that, because young neurons are hyperexcitable and are still establishing their connectivity, they are amenable to incorporating information about the environment. If a mouse is placed in a new cage when young neurons are still growing and making connections, they may link up with the networks that encode a memory of the environment. Just a few months ago, researchers in Germany and Argentina published a mouse study demonstrating how, during a critical period of cellular maturation, new neurons' connections with the entorhinal cortex, the main interface between the hippocampus and the cortex, and with the medial septum change in response to an enriched environment.-'The rate at which [new neurons] incorporate is dependent upon experience, Gage says. It's amazing. It means that the new neurons are encoding things when they're young and hyperexcitable that they can use as feature detectors when they're mature. It's like development is happening all the time in your brain.'

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5997 views

As neurons are used they mutate. To me this is another form of brain plasticity in somatic cells of the brain, not germ cells. This means each of us has a unique brain based on how we have used it, but those characteristics are not heritable.:-http://www.sciencedaily.com/releases/2015/10/151001153926.htm-"As we grow, our brain cells develop different genomes from one another, according to new research from Harvard Medical School and Boston Children's Hospital.-"The study, published Oct. 2 in Science, shows for the first time that mutations in somatic cells--that is, any cell in the body except sperm and eggs--are present in significant numbers in the brains of healthy people. This finding lays the foundation for exploring the role of these post-conception mutations in human development and disease.-***-"Already, the researchers have discovered that somatic mutations appear to occur more often in the genes a neuron uses most. They have also been able to trace brain cell lineages based on patterns of mutation.-"'These mutations are durable memory for where a cell came from and what it has been up to," said the study's co-senior author, Christopher A. Walsh, the HMS Bullard Professor of Pediatrics and Neurology and chief of the Division of Genetics and Genomics at Boston Children's. "This work is a proof of principle that if we wanted to, and if we had unlimited resources, we could actually decode the whole pattern of development of the human brain."-"'I believe this method will also tell us a lot about healthy and unhealthy aging as well as what makes our brains different from those of other animals," Walsh added.-***-"Walsh, Park and team studied a particular kind of somatic mutation called single nucleotide variants. Each variant may occur in just a few cells, or even just one, so they can be hard to detect with whole-genome sequencing analyses that average hundreds of thousands of cells. Sequencing individual cells brings the rare mutations to light.-***-"Many phenomena can create somatic mutations. Ultraviolet light causes them in skin cells. Errors in DNA replication cause them in rapidly dividing cancer cells.-"'What we found in the brain was neither of those things," said Walsh. "We thought the dominant source of mutation would be faulty DNA replication and were surprised to find that instead, it's faulty DNA expression."-"Park's data analysis revealed that the genes with the most mutations tended to be the ones that were used most in the brain.-"'People like to say about your brain, 'use it or lose it.' Unfortunately, we found there's a certain element of 'use it and lose it,'" said Walsh. "Every time you turn on a gene, there is at least some level of risk."-***-"'I'm full of mutations but I'm walking around, pretty healthy," said Park. "It just goes to show that there are a lot of things we don't understand.'"-Comment: He doesn't understand it because he doesn't look for purpose like I do. Romansh?

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5976 views

More on the subject:-http://www.sciencedaily.com/releases/2015/10/151001153931.htm-"A single neuron in a normal adult brain likely has more than a thousand genetic mutations that are not present in the cells that surround it, according to new research from Howard Hughes Medical Institute (HHMI) scientists. The majority of these mutations appear to arise while genes are in active use, after brain development is complete.-"'We found that the genes that the brain uses most of all are the genes that are most fragile and most likely to be mutated," says Christopher Walsh, an HHMI investigator at Boston Children's Hospital who led the research. Walsh, Peter Park, a computational biologist at Harvard Medical School, and their colleagues reported their findings in the October 2, 2015, issue of the journal Science.-"It's not yet clear how these naturally occurring mutations impact the function of a normal brain, or to what extent they contribute to disease. But by tracing the distribution of mutations among cells, Walsh and his colleagues are already learning new information about how the human brain develops. "The genome of a single neuron is like an archeological record of that cell," Walsh says. "We can read its lineage in the pattern of shared mutations. We now know that if we examined enough cells in enough brains, we could deconstruct the whole pattern of development of the human brain."-***
"What they found was that every neuron's genome was unique. Each had more than 1,000 point mutations (mutations that alter a single letter of the genetic code), and only a few mutations appeared in more than one cell. What's more, the nature of the variation was not quite what the scientists had expected.-"'We expected these mutations to look like cancer mutations," Walsh says, explaining that cancer mutations tend to arise when DNA is imperfectly copied in preparation for cell division, "but in fact they have a unique signature all their own. The mutations that occur in the brain mostly seem to occur when the cells are expressing their genes."-"Neurons don't divide, and most of the time their DNA is tightly bundled and protected from damage. When a cell needs to turn on a gene, it opens up the DNA, exposing the gene so that it can be copied into RNA, the first step in protein production. Based on the types and locations of the mutations they found in the neurons, the scientists concluded that most DNA damage had occurred during this unwinding and copying process.-"While most of the mutations in the neurons were unique, a small percentage did turn up in more than one cell. That signaled that those mutations had originated when future brain cells were still dividing, a process that is complete before birth. Those early mutations were passed on as cells divided and migrated, and the scientists were able to use them to reconstruct a partial history of the brain's development.-"'We knew that cells that shared a certain mutation were related, so we could look at how different cells in the adult were related to each other during development," explains Mollie Woodworth, a postdoctoral researcher in Walsh's lab. Their mapping revealed that closely relatedly cells could wind up quite distant from one another in the adult brain. A single patch of brain tissue might contain cells from five different lineages that diverged before the developing brain had even separated from other tissues in the fetus. "We could identify mutations that happened really early, before the brain existed, and we found that cells that had those mutations were nestled next to cells that had totally different mutations," Woodworth says. In fact, the scientists found, a particular neuron might be more closely related to a cell in the heart than to a neighboring neuron."-Comment: my conclusion is different than the researchers' confusion. Newborn brain is a clean slate, and the mutations are part of the plasticity and cooperation between the developing human person and his/her brain.

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5997 views

The hippocampus enlarges. First seen in London cabbies:-http://www.sciencedaily.com/releases/2015/10/151027123859.htm-"The researchers found that the group that practiced the same route over and over -- the spatial learning group -- increased their speed at completing the driving task more than the group practicing on different routes, indicating that they learned something specific about the spatial layout of the virtual environment. The spatial learning group also improved their ability to order a sequence of random pictures taken along the route and to draw a 2-D map representing the route.-"Importantly, only the spatial learning group showed brain structural changes in a key spatial learning part of the hippocampus, the left posterior dentate gyrus. There also were increases in the synchronization of activity -- or functional connectivity -- between this region and other cortical areas in the network of brain regions responsible for spatial cognition. And, the amount of the structural change was directly related to the amount of behavioral improvement each person showed on the task.-"'The new discovery is that microscopic changes in the hippocampus are accompanied by rapid changes in the way the structure communicates with the rest of the brain," said Just, the D.O. Hebb University Professor of Psychology in the Dietrich College of Humanities and Social Sciences and director of the CCBI. "We're excited that these results show what re-wiring as a result of learning might refer to. We now know, at least for this type of spatial learning, which area changes its structure and how it changes its communication with the rest of the brain.'"-Comment: We work the brain and the brain works for us.

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5912 views

It seems to be more than modifying circuits and synapses. Perhaps memories are stored in the molecules in neurons:-http://nautil.us/blog/heres-why-most-neuroscientists-are-wrong-about-the-brain-"Most neuroscientists accept that the brain also computes in some sense. However, they think it does so by modifying its synapses, the links between neurons. The idea is that raw sensory inputs, which initially produce incoherent actions, help the brain change its structure in order to produce behavior better suited to the experienced environment. This idea goes back to the empiricist philosophers such as Locke, Hume, and Berkeley. The new connections between neurons correspond to the associations that the empiricist philosophers thought linked together raw sensations to make the mental dust balls that constituted complex concepts. On this view, experience does not implant facts in the brain, which may be retrieved as needed; rather, experience molds the brain so that it responds to further experience more appropriately. That is why the neuroscientific term for learning is plasticity. The brain learns because experience molds it, rather than because experience implants facts.-"The problem is that experience does implant facts. We all know this, because we retrieve and make use of them throughout the day. For example, most of us can make a mental map of our environment and use it to determine our actions. We may realize that we can pick up a prescription on the way to picking up our children at school because the pharmacy is not far out of the way. Even insects make such maps. The honeybee can use its map to find its way between any two points in its foraging territory, and when a successful forager returns to the hive, it does a dance that tells other foragers where the food source is on their shared map.-From a computational point of view, directions and distances are just numbers. And numbers, rendered in binary form, are just bit strings. It's a profound truth of computer science that there is no such thing as information that is not in a deep sense numerical. Claude Shannon's famous 1948 paper, which founded the field of information theory, used a symphony concert as an example of an information-transmission problem that could be treated numerically. A consequence is that it does not make sense to say that something stores information but cannot store numbers.-"Neuroscientists have not come to terms with this truth. I have repeatedly asked roomfuls of my colleagues, first, whether they believe that the brain stores information by changing synaptic connectionsthey all say, yesand then how the brain might store a number in an altered pattern of synaptic connections. They are stumped, or refuse to answer.-***-Brains routinely remember the durations of intervalsa piece of simple numerical information if ever there was one. The Swedish research worked with the giant Purkinje cells in the cerebellum that learned the interval between the onset of stimulation to one of their inputs, and a subsequent brief stimulation of another of their inputs. The results strongly implied that the interval-duration memory was stored inside the Purkinje cell, not in its synaptic inputs. Input arriving at the synapses caused the learned information inside the cell to be read out into a nerve signal that we know controls the timing of a simple learned behavior.-"Inside neurons are molecules. Many molecules make excellent switches, and storing information in molecular switches is much more energy efficient than doing it in synapses. Learning may involve putting something like bit strings into banks of molecular switches found inside individual neuronsrather than rewiring the neural circuits. That is a profoundly different conception of learning and memory than the one currently entertained."-Comment: It acts like a computer, but the analogy is very weak.

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5921 views

Neurons control their firing speeds and make changes more quickly than previously realized:-http://www.sciencedaily.com/releases/2015/10/151029190852.htm-"Neurons communicate by passing electrical messages, known as action potentials, between each other. Each neuron has a highly specialized structural region, the axon initial segment (AIS), whose primary role is in the generation and sending of these messages. The AIS can undergo changes in size and location in response to alterations of a neuron's ongoing electrical activity. However, until now, all such 'AIS plasticity' has been exceptionally slow, occurring over a timescale of days. Work by researchers from the MRC Centre for Developmental Neurobiology (MRC CDN), has found that AIS plasticity can happen quickly, influencing the way cells fire action potentials. These results were published in the online edition of the journal Cell Reports.-***-" Using a technique called 'optogenetics', which allows precise control of neuronal activity with light, they discovered that 3 hours after elevating neuronal activity, the AIS of hippocampal neurons in culture was shortened by approximately 25%.-***-" However, to their surprise, after 3 hours of sustained neuronal activation, neurons with shorter AISs were functionally indistinguishable from their unstimulated counterparts. It turned out that a second form of plasticity was also in action at the same time as AIS shortening, involving molecular alterations to the proteins that drive action potential generation -- voltage-gated sodium channels. This sodium channel modulation acted to balance out any neuronal excitability changes caused by AIS shortening.-***-"The results suggest that brain cells can rapidly alter their structure to fine-tune their function. Since a shorter AIS is associated with decreased electrical excitability in neurons, it could represent a form of adaptation, or 'homeostasis': when neuronal activity is too high in a network, for instance during the early development of the brain, cells shorten their AIS, become less excitable, send fewer action potentials, and thereby return the network to normal levels of activity. This could prove to be an important factor in the brain's responses to perturbed activity, allowing ongoing maintenance of appropriate levels of electrical signalling, even when the inputs to a network have been significantly altered, which might happen in diseases such as epilepsy and bipolar disorder.-"'This work adds a bit of data to confirm the 'biology is messy' dictum. We saw shorter AISs and automatically assumed that our experiments would prove that this results in an excitability reduction. It took some intellectual head scratching and extra experiments to figure out that sodium channels were modulated by a separate pathway and actively counteracted the AIS shortening phenotype."-Comment: Neurons can recognize their level of activity and react to it through a series of feedback channels. The brain can self modulate. To evolve to this level of complexity requires planning, by the brain itself or by God.

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5956 views

There are complex enzymatic and chemical changes at the synaptic level which change connections and networks in response to the mental tasks we begin or use:-http://www.sciencedaily.com/releases/2015/11/151118155301.htm-"When the brain forms memories or learns a new task, it encodes the new information by tuning connections between neurons. MIT neuroscientists have discovered a novel mechanism that contributes to the strengthening of these connections, also called synapses.-"At each synapse, a presynaptic neuron sends chemical signals to one or more postsynaptic receiving cells. In most previous studies of how these connections evolve, scientists have focused on the role of the postsynaptic neurons. However, the MIT team has found that presynaptic neurons also influence connection strength.-***-"Over the past 30 years, scientists have found that strong input to a postsynaptic cell causes it to traffic more receptors for neurotransmitters to its surface, amplifying the signal it receives from the presynaptic cell. This phenomenon, known as long-term potentiation (LTP), occurs following persistent, high-frequency stimulation of the synapse.-***-"His lab has spent several years working out the mechanism for how presynaptic cells release neurotransmitter in response to spikes of electrical activity known as action potentials. When the presynaptic neuron registers an influx of calcium ions, carrying the electrical surge of the action potential, vesicles that store neurotransmitters fuse to the cell's membrane and spill their contents outside the cell, where they bind to receptors on the postsynaptic neuron.-"The presynaptic neuron also releases neurotransmitter in the absence of action potentials, in a process called spontaneous release. These 'minis' have previously been thought to represent noise occurring in the brain. However, Littleton and Cho found that minis could be regulated to drive synaptic structural plasticity.-***-"The enhancement of minis appears to provoke the postsynaptic neuron to release a signaling factor, still unidentified, that goes back to the presynaptic cell and activates an enzyme called PKA. This enzyme interacts with a vesicle protein called complexin, which normally acts as a brake, clamping vesicles to prevent release neurotransmitter until it's needed. Stimulation by PKA modifies complexin so that it releases its grip on the neurotransmitter vesicles, producing mini events. (my bold)-"When these small packets of neurotransmitter are released at elevated rates, they help stimulate growth of new connections, known as boutons, between the presynaptic and postsynaptic neurons. This makes the postsynaptic neuron even more responsive to any future communication from the presynaptic neuron."-Comment: this is a complex interplay between biochemicals which are produced to respond to specific uses of the brain. No wonder one of them is called 'complexin'. Somehow, the brain 'knows' how it is being used and responds to help the process at play. The enzymes mentioned are also very complex, giant molecules. How did evolution discover them from the vast array of potential molecules that can be manufactured? This is why the only possible way this developed is through intelligent planning. This is specified complexity, the concept of 'too complex to happen by chance'.

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5953 views

A whole journal issue devoted to helping the aging brain, noting growth of cortex thickness with activity:-http://journals.cambridge.org/download.php?file=%2FINS%2FINS21_10%2FS1355617715001149a.pdf&code=95758d08ddbfda9b8a9e7b504bdd5319-"This special issue highlights the results from three exercise
intervention studies, each using a different mode of exercise
training. In the study by Barcelos et al., the effects of an
exergaming intervention is reported to result in improved
performance on the Stoop task relative to a low attention
exercise control intervention. The structural integrity of the
brain, and possible neuroplasticity due to exercise, is reported
as greater preservation of white matter volume 12 months after
older adults performed a resistance exercise intervention (Best
et al.), suggesting durability of the protective effects in white
matter. In regard to gray matter, Reiter et al. report that an
increase in cardiorespiratory fitness after a walking exercise
intervention was associated with increased cortical thickness in
both healthy older adults and older adults diagnosed withMCI.
In the study by Basso and colleagues, the effects of acute
exercise in younger adults are shown to affect performance on
tasks of executive functionmediated by the prefrontal cortex, but
not hippocampus-related brain function measured by episodic
memory and object recognition tasks. Several papers report on
cross-sectional differences between physically active and
physically inactive, or physically fit versus unfit, participants.
The study by Schultz et al. reports that the negative relationship
between amyloid burden and cognition is attenuated in older
adults who possess greater cardiorespiratory fitness."-Comment: Keep on movin'

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7470 views

Brain plasticity depends on new neurons, new axon branch connections and synapse strength. This study in fruit flies shows synapse changes while learning:-http://www.sciencedaily.com/releases/2015/12/151202132749.htm-"The researchers exposed fruit flies to a specific test odor and a very short time later subjected them to an artificial aversive cue. To do so they fired tiny beams of laser light at dopamine-releasing neurons in the mushroom body that were genetically engineered to become active in response to the light. Just like our own neurons, dopamine-releasing neurons in the fly are involved in reward and punishment." Presenting the smell of cherries, for example, which is normally an attractive odor to flies, while at the same time stimulating a particular dopamine neuron, trains the fly to avoid cherry odor," Turner explains.-"In addition to the dopamine neurons, the team identified neurons that represented the test odor and neurons that represented the flies' behavioral response to that odor. These neurons are connected to each other, while the dopamine neurons, which represent the punishment signal, modulate that connection. The team then made recordings of the neurons representing the behavior. This enabled them to discover any changes to the synaptic inputs those neurons received from the odor-representing neurons before and after learning.-"Strikingly, the team found a dramatic reduction in the synaptic inputs upon subsequent presentations of the test odor, but not control odors. This drop reflected the decrease in the attractiveness of the odor that resulted from the learning. "The average drop in synaptic strength was around 80 percent -- that's huge," says Turner."-Comment: With several ways to change structure and function, the brain is very pliable in response to what the organism is doing.-In a related study how to follow synapse function is described:-http://medicalxpress.com/news/2015-12-neuroscientists-mind.html-"By reading fluorescent signals, the researchers could tell if a fly had been in either heat or cold for 10 minutes an entire hour after the sensory event had happened, for example. They also could see that exposure to the scent of a banana activated neural connections in the olfactory system that were different from those activated when the fly smelled jasmine.-***-"Different synapses are active during different behaviors, and we can see that in the same animal with our three distinct labels," said Gallio, the paper's corresponding author.-"The fluorescent green, yellow and blue signals enabled the researchers to label different synapses activated by the sensory experience in different colors in the same animal. The fluorescent signals persisted and could later be viewed under a relatively simple microscope.-"The researchers studied the fruit fly Drosophila melanogaster, a model animal for learning about the brain and its communication channels. They tested their newly engineered fluorescent molecules by applying them to the neural connections of the most prominent sensory systems in the fly: its sense of smell, sophisticated visual system and highly tuned thermosensory system.-"They exposed the animals to different sensory experiences, such as heat or light exposure and smelling bananas or jasmine, to see what was happening in the brain during the experience.-"To create the labels, the scientists split a fluorescent molecule in half, one half for the talking neuron and one half for the listening neuron. If those neurons talked to each other when a fly was exposed to the banana smell or heat, the two halves came together and lit up. This only happened at the site of active synaptic transmission.-"'Our results show we can detect a specific pattern of activity between neurons in the brain, recording instantaneous exchanges between them as persistent signals that can later be visualized under a microscope," Gallio said."-Comment: These synaptic changes require changes in production of acetylcholine and dopamine by a series of molecular action triggers.

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5912 views

A study in how different sources of sounds changes the brain:-http://www.sciencedaily.com/releases/2015/12/151214185800.htm-"'The sounds of our lives change our brain," said Kraus, an inventor, amateur musician and director of Northwestern's Auditory Neuroscience Lab in the School of Communication. "In our lab, we investigate how our life in sound changes the brain, and how different forms of enrichment or decline influence how our brain processes sound."-"To measure the brain's response to sound, researchers play speech or music directly into the ears of study volunteers. The scientists then measure the electricity created by the brain as it translates sound through sensors attached to participants' heads.-'Results from a series of studies involving thousands of participants from birth to age 90 suggest that the brain's ability to process sound is influenced by everything from playing music and learning a new language to aging, language disorders and hearing loss.-"Studies indicate that across the lifespan, people who actively play music (as a hobby) can hear better in noise than those who don't play music. Kraus' work also suggests that poverty and a mother's education level can affect a child's ability to process the essential parts of sound.-"'We're able to look at how the brain processes essential ingredients in sound, which are rooted in pitch and timing and timbre," Kraus said at Falling Walls. "A mixing board is a good analogy. It's very fine tuning.'"-Comment: Same as always. Our brain is built to help us.

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5799 views

Synapses change as the brain develops and different functions and experiences are demanded of it:-http://www.sciencedaily.com/releases/2016/02/160204175640.htm-"Friedlander and Saez reported that neurons whose excitatory synapses are in a certain states of plasticity, based on previous experiences, assort themselves into groups to converge onto specific individual neurons in the developing brain.-"'Individual neurons whose synapses are most likely to strengthen in response to a certain experience are more likely to connect to certain partner neurons, while those whose synapses weaken in response to a similar experience are more likely to connect to other partner neurons," Friedlander said. "The neurons whose synapses do not change at all in response to that same experience are more likely to connect to yet other partner neurons, forming a more stable but non-plastic network."-***-"When the scientists applied a pharmacological agent to the neurons that blocked synaptic inhibition, they saw that training elicited more dramatic and varied plasticity at excitatory synapses. The plasticity responses of different groups of synapses on a given neuron were more similar when inhibition was blocked, which effectively grouped together like-type neurons by their learning responses.-"'While we've known for years that neurons of similar types tend to richly interconnect, this is the first demonstration that such assortment processes apply to synaptic plasticity," Friedlander said. "Such a result has implications for enhanced learning paradigms, as well as for better understanding the dynamic network properties of the large-scale neuronal networks in the living brain.'"-Comment: More and more evidence that the brain is built to adapt to our needs.

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5801 views

Spines on dendrites can come and go based on need for contact:-http://medicalxpress.com/news/2016-02-day-life-synapse-reveals-facets.html-"A neuron is bombarded with signals from hundreds of presynaptic partners. Synapses act as conduits for these incoming signals. Excitatory neurotransmitters flow from the presynaptic to the postsynaptic neuron at synaptic locations that are on bulbous protrusions with a rounded head and thin neck, termed spines. The long branching dendrites of a single neuron can display hundreds of spines like leaves on a tree branch. -"When spines appear and disappear, a neuron can gain new connections or lose existing ones. "If spines disappear, they rarely come back to the same location; new spines seek out alternative locations," says biology graduate student Katherine Villa, co-first author on the study. "It's as if after deciding that a connection is not worth keeping neurons will try to replace it with a different contact."-***-"Directly visualizing inhibitory synapses revealed the surprising fact that while many reside on the shaft of dendritic branches, approximately 30 percent reside on dendritic spines alongside excitatory synapses. Another surprise was that when inhibitory synapses are removed, they return again and again to the same location. "Clearly, the goal here is not to change partners as we see for excitatory connections," says biology graduate student Kalen Berry, Villa's co-first author. "We think that inhibitory synapses can act as a kind of gatekeeper, flickering on and off to shut down excitatory connections as needed."-"Interestingly, the dual-purpose spines are large and extremely stable, as are the excitatory connections onto them. "This is essentially a hard-wired part of the circuit," Nedivi says. "But we still have the potential to modify it via the nearby inhibitory synapse."-"These findings raise questions about why some excitatory connections on singly innervated spines can be restructured while those on dually innervated spines cannot. How does the structural plasticity of inhibitory synapses alter excitatory circuit properties, and what enables their rapid insertion and removal at stable sites? The answers to these questions could shed light on ways to enhance plasticity in the adult brain and synapse-related disorders."-Comment: It shows how the brain has many ways to modify contacts in networks.

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5782 views

A study which looks at axon growth and how that contributes to plasticity:-http://medicalxpress.com/news/2016-02-amazing-axon-adventure.html-"For an axon in a growing embryo, the journey from retina to brain is not a straightforward one. It's a very long way for a tiny axon, through a constantly changing series of environments that it has never encountered before. So how do axons know where to go, and what can it tell us about how the brain is made and maintained?-***-"On the pathway through this patchwork quilt, there is a set of distinct beacons, breaking the axon's journey down into separate steps. Every time the growing axon reaches a new beacon, it has to make a decision about which way to go. At the tip of the axon is a growth cone, which 'sniffs out' certain chemical signals emitted from the beacons, helping it to steer in the right direction.-"The growth cones are receptive to certain signals and blind to others, so depending on what the axon encounters when it reaches a particular beacon, it will behave in a certain way. Holt's research group uses a variety of techniques to determine what the signals are at the steering points where axons alter their direction of growth or their behaviour.-***-"'It had been thought that if we built a model and took out all of the guidance molecules, there would be no topographic order whatsoever," says Eglen. "But instead we found that there is still residual order in how the neurons are wired up, so there must be extra molecules or mechanisms that we don't know about. What we're trying to do is to take biology and put it into computers so that we can really test it."-***-"Holt's group has found that the same guidance molecule can have different roles depending on what aspect of growth is going on - but the question then becomes how do you wire the brain with so few molecules?-"Adding to the complexity was another puzzling discovery - that the growth cones of axons can make proteins. Previous knowledge held that new proteins could be synthesised only within the main cellular part of each neuron, the cell body (where the nucleus is located), and then transported into axons. However, Holt's group found that the growth cones of axons are also capable of synthesising proteins 'on demand' when they encounter new guidance beacons, suggesting that messenger RNA (mRNA) molecules play a role in helping axons to navigate to their correct destinations. mRNAs are the molecules from which new proteins are synthesised, and further experiments found that axons contain hundreds or even thousands of different types of this nuclear material.-"In addition to their role in axon growth when the brain is wiring itself up during development, certain types of mRNA are also important in maintaining the connections in the adult brain, by keeping mitochondria - the energy-producing 'batteries' of cells - healthy, which, in turn, keeps axons healthy."-Comment: These axons follow automatic orders from various proteins and RNAs, and once formed, develop connections following how the individual organisms uses its brain.

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5789 views

Astroglias modify neuronal function and neurons can modify astroglias all through life, not just at the start of life:-http://www.the-scientist.com/?articles.view/articleNo/45376/title/Adjustable-Brain-Cells/&utm_campaign=NEWSLETTER_TS_The-Scientist-Daily_2016&utm_source=hs_email&utm_medium=email&utm_content=26432384&_hsenc=p2ANqtz-_vYhx6wcIDvfBLPvQokVxVFE9vU8q9BN7fiLXQYESIVB_ywTfoM6TRixdKhUo99oCyq6SsWXp6pCIKQYYX6Upl6yJfvw&_hsmi=26432385/-"Neurons in the adult mouse brain can shape the features and physiologies of nearby astroglial cells, according to a study published today (February 18) in Science. Researchers at McGill University in Montreal and their colleagues have identified a molecular signal called sonic hedgehog (Shh), secreted by neurons, that acts as the agent of change.-***-"Astroglia are non-neuronal cells in the central nervous system that generally support and modulate neuronal function. The mammalian brain has an assortment of astrocytes, which perform a variety of specialized functions. This diversity was largely thought to be established during embryogenesis and early postnatal development, said Keith Murai of McGill who led the new research. But after that, he said, the properties of these cells were thought to be solidified . . . for the rest of their lives.-"Murai and his colleagues had a different view, however. Some of these [astrocytes] are so specialized around certain neural circuits that it was hard to imagine that all of the properties of these cells could be determined by that point [in development], he said. After all, the neural circuitry itself isn't fully formed until much later.
To investigate whether astrocyte identity might continue to be shaped beyond the perinatal period, Murai's team searched for gene products in adult neurons and astrocytes that might govern continuing development. To simplify matters, the researchers focused on the cerebellar cortex, where just two types of astrocyte existBergmann glial cells (BGs), which encapsulate the impulse-receiving regions of Purkinji cell neurons (PCs), and velate astrocytes (VAs), which surround granule cell neurons (GCs). Their searches revealed many candidate factors, said Murai, but one pathway kept coming up: Shh signaling.-"Shh is a developmental morphogen known to have many important roles in the developing embryo, including the specification of cells in the brain, explained Murai. People thought that the pathway was shut down and eliminated from the brain after it developed, he said, but as it turns out, this pathway is very potent even in the adult brain.-***-"The team also found evidence that astrocytes in other brain regions were influenced by Shh manipulations, and that these cells' electrophysiologies were altered as a result.-'The key message is that astrocytes' molecular fate is not hardwired, said cell biologist Cagla Eroglu of Duke University in Durham, North Carolina, who did not participate in the study. The shapes of these cells appear to be less malleable, however. While Shh signaling influenced astrocyte expression profiles and electrical behaviors, the cells' morphologies remained largely unchanged."-Comment: Just more evidence of how dynamic is brain plasticity. By the way, astroglias are also referred as astrocytes, all part of the glial group of non-neuron cells in eh brain.

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5749 views

Mono-zygote twins start out identical but their brains are different even at birth:-http://www.wsj.com/articles/brain-mutations-guarantee-our-individuality-1455810936-"Genes directly or indirectly make the brain's chemicals, as well as the locks that these chemical keys fit. They also help assemble the brain to begin with. -"Small genetic differences help explain why each of us humans thinks, acts and feels like nobody else. Connections are forming and unforming when we memorize or forget a tune, fall in love or divorce, and write or read these paragraphs.-"The brains of identical twins are a lot more similar than those of nonidentical ones, even aside from experience. Yet each identical twin also has a unique brain; in fact, twins' brains are different halfway through pregnancy. Why? -"One reason is experience. The twins had different positions in the womb and different supplies of hormones and nutrients. -***-"Yet another way twin brains diverge: mutations after the egg and sperm unite. Every time a cell divides, errors occur; radiation and chemicals, even at very low levels, change DNA. And there are jumping genesones that duplicate themselves in different parts of the genome.-***-"New techniques make it possible to track the mutation history of a given cell line. Furthermore, most nerve cells stop dividing earlywithout which experience would not endure. Our brain cells carry their prenatal genetic signatures permanently, which means researchers can study those signatures. The scientists can map an individual nerve cell's genetic code and see where it differs from its forebears in the brain. So the researchers were able to trace the mutated cells' ancestry within each of the three people, a kind of family tree of cells inside each brainas individual as a fingerprint, but far more important.-"Since theoretically every cell in our brains (and bodies, except for eggs and sperm) should have identical genes, any differences must have resulted from mutation after the start of pregnancy. In fact, each cell on average had around 1,500 mutations. That's a minimum. Only some of these affect nerve-cell structure and function, but they guarantee the uniqueness of each brain.-"So identical twins begin with identical genes, but soon gain some changed ones. And so do we all, each minuscule mutant planting a family tree of cells within our brains, before we even meet our moms and dads. Upon which theyalong with siblings, friends, teachers and loversproceed to make each of us even more singular."-Comment: Marked plasticity is built into the brain from the beginning. The brain is our servant, not a controller. The notorious Marcus twins were in my med school class. Stewart was the leader and Marcus followed. Right and left handed, I can't remember which. Definite but subtle physical differences could tell them apart. Stewart # 2 and Marcus # 3 in rank. Review the movie with Jeremy Irons:-http://www.rogerebert.com/far-flung-correspondents/twins-playing-a-macabre-game

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5718 views

Mono-zygote twins start out identical but their brains are different even at birth:
> 
> http://www.wsj.com/articles/brain-mutations-guarantee-our-individuality-1455810936&... 
>
> Comment:... The brain is our servant, not a controller. - Our servant or the vessel in which we inhabit? It would seem to me if it were our servant we could fully control (or learn to fully control) every aspect of our being with the brain by our wishes alone.

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5770 views

Scientists have shown that areas of a migratory bird's brain are larger to handle the knowledge of travel:-https://www.sciencedaily.com/releases/2016/02/160224070056.htm-"Birds that migrate the greatest distances have more new neurons in the regions of the brain responsible for navigation and spatial orientation, suggests a new paper published in Scientific Reports.-***-" In reed warblers, birds that migrate as individuals at night, new neurons were found mainly in the hippocampus -- a region associated with navigation. In turtle doves, a species that migrates as a group, the new neurons were found mainly in the nidopallium caudolateral, an area associated with communication skills.-***-"Then, these migration distances were compared with the amount of new neurons incorporated into the birds' brains. This was done by selectively colouring brain cells in several relevant regions: once -- for identifying new cells, and then a few weeks again for identifying neuron cells. Those coloured twice were identified as new neurons. The researchers discovered that both species show a trend of increasing new neurons in line with migration distance and that different brain regions were affected.-***-"What we humans do during the day may actually make us more "brainy" as our regular activities may actually determine how our brains adapt and in which areas. In the long term, there are implications for how species evolve. For example, other research already suggests that birds that hoard food in particular periods incorporate new neurons in brain regions responsible for memory and spatial orientation. This latest paper builds on that work, suggesting that birds that need greater navigational help have more new neurons in that part of the brain while those that need to keep up with the flock incorporate new neurons in a different area.'"-Comment: Same story. Brains will develop new neurons to help with new activity. Same pattern for all animals with brain, I'll bet.

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5787 views

Teaching sighted persons braille induces marked plasticity:-https://www.sciencedaily.com/releases/2016/03/160315085940.htm-"It was already known that the brain can reorganize after a massive injury or as a result of massive sensory deprivation such as blindness. The visual cortex of the blind, deprived of its input, adapts for other tasks such as speech, memory, and reading Braille by touch. There has been speculation that this might also be possible in the normal, adult brain, but there has been no conclusive evidence.-"'For the first time we're able to show that large-scale reorganization is a viable mechanism that the sighted, adult brain is able to recruit when it is sufficiently challenged," says Szwed.-"Over nine months, 29 volunteers were taught to read Braille while blindfolded. They achieved reading speeds of between 0 and 17 words per minute. Before and after the course, they took part in a functional Magnetic Resonance Imaging (fMRI) experiment to test the impact of their learning on regions of the brain. This revealed that following the course, areas of the visual cortex, particularly the Visual Word Form Area, were activated and that connections with the tactile cortex were established.-***-"In an additional experiment using transcranial magnetic stimulation, scientists applied magnetic field from a coil to selectively suppress the Visual Word Form Area in the brains of nine volunteers. This impaired their ability to read Braille, confirming the role of this site for the task. The results also discount the hypothesis that the visual cortex could have just been activated because volunteers used their imaginations to picture Braille dots.-"'We are all capable of retuning our brains if we're prepared to put the work in," says Szwed.-"'He asserts that the findings call for a reassessment of our view of the functional organization of the human brain, which is more flexible than the brains of other primates.-"'The extra flexibility that we have uncovered might be one those features that made us human, and allowed us to create a sophisticated culture, with pianos and Braille alphabet," he says."-Comment: So much for the philosophy of determinism as it regards the brain. The brain is under our control and command to adapt to our various needs for new areas of activity and new connections. Free will survives.

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5695 views

The proof of my contention that we control our brains (Romansh take note) is shown in this study of EEG's on 50 volunteers who could be identified 100% by the patterns elicited by challenges:-https://www.sciencedaily.com/releases/2016/04/160418120608.htm-"A team of researchers has recorded the brain activity of 50 people wearing an electroencephalogram headset while they looked at a series of 500 images designed specifically to elicit unique responses from person to person, for instance, a slice of pizza, a boat, Anne Hathaway, the word 'conundrum.' They found that participants' brains reacted differently to each image, enough that a computer system was able to identify each volunteer's 'brainprint' with 100 percent accuracy.-***-"In their original study, titled "Brainprint," published in 2015 in Neurocomputing, the research team was able to identify one person out of a group of 32 by that person's responses, with only 97 percent accuracy, and that study only incorporated words, not images.-"'It's a big deal going from 97 to 100 percent because we imagine the applications for this technology being for high-security situations, like ensuring the person going into the Pentagon or the nuclear launch bay is the right person," said Laszlo. "You don't want to be 97 percent accurate for that, you want to be 100 percent accurate."-"According to Laszlo, brain biometrics are appealing because they are cancellable and cannot be stolen by malicious means the way a finger or retina can. The results suggest that brainwaves could be used by security systems to verify a person's identity."-Comment: I'm not interested in the security aspect, but the fact that we are born with malleable instrument that we fashion after ourselves as we develop.

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5678 views

In order for the brain to have plasticity new neurons must grow dendrite connections and create networks of connectivity. The genes and molecules driving this process have been found:-http://medicalxpress.com/news/2016-04-biologists-brain-cells-message-network.html-"Biologists at the University of Iowa have determined a group of genes associated with neurons help regulate dendrites' growth. But there's a catch: These genes, called gamma-protocadherins, must be an exact match for each neuron for the cells to correctly grow dendrites.-***-"Gamma-protocadherins are called "adhesion molecules" because they stick out from a cell's membrane to bind and hold cells together. The researchers learned about their role by giving a developing brain cell in a mouse the same gamma-protocadherin as in surrounding cells. When they did, the cells grew longer, more complex dendrites. But when the researchers outfitted a mouse neuron with a different gamma-protocadherin than the cells around it, dendritic growth was stunted.-***-"Gamma-protocadherins act like molecular Velcro, binding neurons together and instructing them to grow their dendrites. Weiner and his team figured out their role when they observed paltry dendritic growth in mouse brain cells where the gamma-protocadherins had been silenced.-"The researchers went further in the new study. Using mice, they expressed the same type of gamma-protocadherin (labeled either as A1 or C3) in neurons in the cerebral cortex, a region of the brain that processes language and information. After five weeks, the neurons had sizeable dendritic networks, indicative of a healthy, normally functioning brain. Likewise, when they turned on a gamma-protocadherin gene in a neuron different from the gamma-protocadherin gene with the cells surrounding it, the mice had limited dendrite growth after the same time period.-"That's important because human neurons carry up to six gamma-protocadherins, meaning there are many combinations potentially in play. Yet, it seems the "grow your dendrite" signal only happens when neurons carrying the the same gamma-protocadherin gene pair up.-"The neurons actually care who they match with," says Weiner, associate professor in the Department of Biology, part of the College of Liberal Arts and Sciences. "It takes what we knew from biochemical studies in a dish and shows that protocadherins really mediate these matching interactions in the developing brain."-"The team reports that star-looking cells called astrocytes also play a role in neurons' dendrite development. Astrocytes are glial (Greek for "glue") cells that help to bridge the gap between neurons and speed signals along. When the molecular binding between an astrocyte and neurons is an exact match, the neurons grow fully formed dendrites, the researchers report.-"'Our data indicate that g-Pcdhs (gamma-protocadherins) act locally to promote dendrite arborization via homophilic matching and confirm that connectivity in vivo depends on molecular interactions between neurons and between neurons and astrocytes," the authors write."-Comment: Again we see the controls and the complexity of these processes. Not by chance.

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5678 views

As the brain develops new networks, more neurons are produced then needed, so some are pruned back. This makes sense to me as the brain is responsive to our needs, and must be prepared to go as far as the new use is expanded, but not overextending the network which will require more energy than is necessary.-http://www.salk.edu/news-release/adult-brain-prunes-branched-connections-of-new-neurons/-"New brain cells began with a period of overgrowth, sending out a plethora of neuronal branches, before the brain pruned back the connections. The observation, described May 2, 2016 in Nature Neuroscience, suggests that new cells in the adult brain have more in common with those in the embryonic brain than scientists previously thought.-***-"While most of the brain's billions of cells are formed before birth, Gage and others previously showed that in a few select areas of the mammalian brain, stem cells develop into new neurons during adulthood. In the new study, Gage's group focused on cells in the dentate gyrus, an area deep in the brain thought to be responsible for the formation of new memories. The scientists used a new microscopy technique to observe new cells being formed in the dentate gyrus of adult mice.-"What was really surprising was that the cells that initially grew faster and became bigger were pruned back so that, in the end, they resembled all the other cells, says Gonçalves. He and his colleagues went on to show that changing signaling pathways could mimic some of the effects of the complex environmentcells grew more initially, but also pruned back earlier.-"Over a period of over a month, the Salk team kept track of each new neural branch, called a dendrite, on the growing neurons, as well as each dendrite that was pruned away. -"So why would the brain spend energy developing more dendrites than needed? The researchers suspect that the more dendrites a neuron starts with, the more flexibility it has to prune back exactly the right branches.-'The results suggest that there is significant biological pressure to maintain or retain the dendrite tree of these neurons, says Gage."-Comment: Note the last paragraph bold (mine). This will be managed by a molecular feedback loop for tight control. In this way as we try to learn new knowledge or physical maneuvers the brain carefully follows our needs.

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5655 views

The latest Kavli awards for advances:-http://www.the-scientist.com/?articles.view/articleNo/46233/title/2016-Kavli-Prize-Winners/&utm_campaign=NEWSLETTER_TS_The-Scientist-Daily_2016&utm_source=hs_email&utm_medium=email&utm_content=30231742&_hsenc=p2ANqtz-91j493wszK_68isLvQVgYyYHeKenTIZDZOBxaqIPrhK0oZSAUR4Wg1uuoPV-i_TFR-lIAO0_oeyE8yeRFn89YwIkBhdQ&_hsmi=30231742/-"Eve Marder of Brandeis University in Waltham, Massachusetts; Michael Merzenich of the University of California, San Francisco; and Carla Shatz of Stanford University have won the 2016 Kavli Prize in neuroscience in recognition of their discoveries of mechanisms that enable experience and neural activity to remodel the brain.-"Our brains have a remarkable capacity to adapt to changes in the environment, [and yet] our personality and behaviors typically remain fixed as we pass through life, Ole Petter Ottersen, chair of the Kavli neuroscience committee, said during today's prizes announcement at the Norwegian Academy of Science and Letters in Oslo. (my bold)-"Marder studies simple brain circuits in crustaceans to discover how neurotransmitters work. Merzenich has shown how circuits in the sensory cortex (known as the homunculus) are remodeled by experiencein particular, how the auditory system adapts to hearing damage and cochlear implants. Shatz has shown how visual development commences before birth."-Comment: The bolded comment is the key point. Our personalities develop on a continuum, while the working brain adapts to our needs in functional areas. We 'r us, not what the brain makes us.

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5592 views

DAVID: The latest Kavli awards for advances:-http://www.the-scientist.com/?articles.view/articleNo/46233/title/2016-Kavli-Prize-Winn... -QUOTE: "Our brains have a remarkable capacity to adapt to changes in the environment, [and yet] our personality and behaviors typically remain fixed as we pass through life. -David's comment: The bolded comment is the key point. Our personalities develop on a continuum, while the working brain adapts to our needs in functional areas. We 'r us, not what the brain makes us.-I'm not at all sure that our personality and behaviours remain fixed. Experience can change people quite drastically. And of course we all know that drugs and diseases can affect the brain and thereby change both personality and behaviour. But under normal circumstances, I also feel that I am me and not what my brain makes me, and that I use my brain and am not used by it. We have already had several discussions about the problem of identity: just what does this I/me consist of? We can see the influences of nature, nurture, heredity, experience, cells etc., but ultimately, I think it boils down to materialism versus dualism. Another endlessly fascinating question, but unless there is an afterlife, I fear we shall never know the answer!

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5563 views

David's comment: The bolded comment is the key point. Our personalities develop on a continuum, while the working brain adapts to our needs in functional areas. We 'r us, not what the brain makes us.
> 
> dhw: I'm not at all sure that our personality and behaviours remain fixed. Experience can change people quite drastically. And of course we all know that drugs and diseases can affect the brain and thereby change both personality and behaviour. But under normal circumstances, I also feel that I am me and not what my brain makes me, and that I use my brain and am not used by it. We have already had several discussions about the problem of identity: just what does this I/me consist of? We can see the influences of nature, nurture, heredity, experience, cells etc., but ultimately, I think it boils down to materialism versus dualism. Another endlessly fascinating question, but unless there is an afterlife, I fear we shall never know the answer!-No, we won't until/if the afterlife, but the key thought still remains, we are allowed to make what our brain becomes in structure and connections.

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5601 views

Any primate can take up new activities not foreseen by evolution and readily adapt to it as the brain has feedback circuits to enhance adaptation: - http://phys.org/news/2016-06-primate-brain-pre-adapted-potentially-situation.html - "Scientists have shown how the brain anticipates all of the new situations that it may encounter in a lifetime by creating a special kind of neural network that is "pre-adapted" to face any eventuality. - *** - "Human and non-human primates can learn an astonishing variety of novel behaviors that could not have been directly anticipated by evolutionwe now understand that this ability to cope with new situations is due to the "pre-adapted" nature of the primate brain. - "This study shows that this seemingly miraculous pre-adaptation comes from connections between neurons that form recurrent loops where inputs can rebound and mix in the network, like waves in a pond, thus called "reservoir" computing. This mix of the inputs allows a potentially universal representation of combinations of the inputs that can then be used to learn the right behaviour for a new situation. - "The authors demonstrate this by training a reservoir network to perform a novel problem solving task. They then compared the activity of neurons in the model with activity of neurons in the prefrontal cortex of a research primate that was trained to perform the same task. Remarkably, there were striking similarities in the activation of neurons in both the reservoir model and the primate. - "This breakthrough shows that we have taken big step towards understanding the local recurrent connectivity in the brain that prepares primates to face unlimited situations. This research shows that by allowing essentially unlimited combinations of internal representations in the network of the brain, one of them is always on hand for the given situation." - Comment: Once again we find our brain setup as readily very adequate to help us in every new physical or mental usage. Consider sports or musical instruments. Cricket for apes? Or chimps playing the violin. The brain is an instrument that is built to help us.

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5647 views

To make the brain as responsive as possible to our needs each neuron can vary its own instructions:-http://www.the-scientist.com/?articles.view/articleNo/46399/title/Single-Cell-RNA-Sequencing-Reveals-Neuronal-Diversity/&utm_campaign=NEWSLETTER_TS_The-Scientist-Daily_2016&utm_source=hs_email&utm_medium=email&utm_content=30975475&_hsenc=p2ANqtz--bFYZlFXBRhtY3gEshC8Bbq3WER9bcpJK9Gak9VTw2Sa5HbJB3b8vJLZdI7FDTTnbCSYSOQwIaOOqJh5gw7nif1PvRRg&_hsmi=30975475/-"Neurons within a single brain can differ from one another in genomic contenta phenomenon known as mosaicism. But the extent to which those differences are reflected in gene expression has remained uncertain, in large part because of the difficulty associated with analyzing transcription in individual cells. Now, a team led by researchers at the Scripps Research Institute in La Jolla, California, and the University of California, San Diego (UCSD), has developed a high-throughput pipeline to analyze the transcriptomes of thousands of single neuronal nuclei, revealing considerable variation in gene expression across the human cerebral cortex.-***-"Previous attempts to resolve differences in gene expression among neurons have been limited in scope by the small samples obtainable from fresh brains, and by the challenge of physically disentangling individual cells from one other. All these neurons in the human adult brain, they're highly, highly connected, explained UCSD's Kun Zhang, a bioengineer and collaborator on the National Institute of Health's Single Cell Analysis Program (SCAP). It's very difficult to dissociate individual neurons from human brains.-***-"By sequencing messenger RNA (mRNA) transcripts within these nuclei, the team generated 3,227 single-cell transcriptome datasets across the six regions: more than an order of magnitude more than what's been looked at previously, Chun told The Scientist. Not only did these datasets identify cells as either inhibitory or excitatory (consistent with previous work in mice), they also revealed 16 distinct neuronal subtypes divided between these two categories that tended to be localized in one or a few Brodmann areas, indicating that the composition of neuronal types varies among regions of the brain.-'One of the major findings is that the composition in the visual cortex is very different from the other five areas that we sampled, Zhang said, adding that further transcriptome differences were observable within subtypes as well as between them. With these subtypes, we can start to ask, What are the differences across these six brain areas, and do particular subtypes contribute to these differences?"-Comment: This is a human study. At some point ape brains will have this same study, and I can guess the result: no where near the variability. This is part of the reason why our brains are so helpful to our needs. One can only wonder how this developed in evolution without purposeful planning.

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5532 views

Another article on this topic discussing transposons and their role: - http://www.the-scientist.com/?articles.view/articleNo/47069/title/Sequencing-Reveals-Ge... - "Somatic mosaicismthe variation of the genome between individual cellsis particularly consequential in the brain. Neuroscientists have found that small changes to the genome of even a few neurons can have neurological consequences. In a study published in Nature Neuroscience this week (September 12), scientists set their sights on one source of this variation. Using single-cell sequencing and machine learning algorithms, they have examined the extent of long interspersed element-1 (LINE-1, or L1) retrotransposition in the healthy human brain. - "In the 1940s, Barbara McClintock and colleagues discovered transposons, or jumping genes, scraps of DNA able to move from one position in the genome to another. By 2005, Fred Rusty Gage of the Salk Institute for Biological Studies and colleagues identified L1 transposons as a source of genomic mosaicism in human neurons. Now, Gage and his colleagues have shown that L1s don't just jump around: these mobile elements can also spontaneously trigger the deletion of certain genes.
The main aspect that's new in this paper is that there seems to be increased changes in these LINE elements that may not be due to insertional changes. . . . They may be something that serve as a potential target for somatic changes, said Jerold Chun of the Scripps Research Institute in La Jolla, California, who was not involved in the present study. That's an interesting concept, and I think it will be interesting to see what that entails. - *** - "L1 transposons create unique alterations to neuronal genomes, on the order of 0.5 to one alteration per cell, and L1-associated changes can be found in 44 percent to 63 percent of cells in the healthy brain, the researchers found. But when the researchers sought to confirm these L1 insertions using direct molecular methods, they could not find around half of the supposed changes. Upon closer inspection of the stretches of DNA around where the algorithm had flagged a unique change to the genomes, the researchers instead found evidence of large genetic deletions.
L1 elements contain genes for endonucleases, proteins that cleave DNA, which are part of the toolkit they use to splice into new locations. The thought, explained Gage, is that these endonucleases sometimes continue cutting after an insertion, lopping off segments of DNA. If confirmed, this would be a previously unrecognized source of genomic mosaicism in the brain caused by L1 elements.  - *** - "The precise roles of L1 transposons in somatic mosaicism of the human brain remain unclear. Neurons are unique among the body's cells because they do not regularly turn over, but instead can stay with a person for his or her entire life. Genetic changes that occur when a neuron is formed can therefore have permanent effects." (my bold) - Comment: This is a major way brain plasticity occurs. Note these changes last a lifetime as each of us makes use of our brain to form it to our needs. There is an evolutionary aspect to this. Our DNA is 98% similar in overall appearance when total bases are counted compared to chimps, but our brains are vastly different. I think we are looking one of the reasons. Chimp brain genetic mosaic changes will be found to not be equal to this finding.

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5405 views

Mouse brain studies show how new neurons are developed in young mice and presumed to be present in humans:

http://www.the-scientist.com/?articles.view/articleNo/47364/title/How-Experience-Shapes...

"Newly made cells in the brains of mice adopt a more complex morphology and connectivity when the animals encounter an unusual environment than if their experiences are run-of-the-mill. Researchers have now figured out just how that happens. According to a study published today (October 27) in Science, a particular type of cell—called an interneuron—in the hippocampus processes the animals’ experiences and subsequently shapes the newly formed neurons.

***

"Newborn dentate gyrus neurons, which are called granule cells, take six weeks to fully develop and integrate into the mouse brain’s existing neural networks, said Schinder. To examine these cells’ development, the team labeled newborn granule cells with red fluorescent protein in the brains of mice and then either left the animals in their regular cages (controls) or exposed them to enriched environments—cages with tunnels and other unusual objects—for different 48 hour periods. Three weeks after the new cells were labeled, the team examined their morphology and activity.

"The researchers found that in animals who had been exposed to the enriched environment during a particular period (9 to 11 days after labeling), the young granule cells had longer dendrites with evidence of increased connections with other neurons. Specifically, these cells had a greater number of dendritic spines, the sites of incoming synapses, and more detectable electrical inputs.

"Granule cells receive different inputs from surrounding neurons at different stages of their development, Schinder said, which may explain why they are apparently receptive to experiential input only within a short period (day 9 to 11), rather than throughout their development.

"The team went on to analyze these neuronal inputs more closely. Through a series of optogenetic and chemogenetic experiments, the researchers showed that mature granule cells activated their younger counterparts via intermediary cells called interneurons. Artificially stimulating either the mature granule cells or the interneurons could recapitulate the effects of environmental enrichment on the young granule cells. Moreover, the team showed that blocking the activity of the interneurons during the animals’ exposure to enriched environments prevented the expected experience-induced morphology in the young granule cells.

"'The take home message is that experience can change how these young cells are incorporating into the brain and how they are contributing to brain circuitry,” said Hongjun Song, who studies neurogenesis at the Johns Hopkins University School of Medicine in Baltimore."

Comment: This shows how experience in young animals can shape the brain's function. The amazing malleable brain. The arrival of the first. It is such an unusual cell, how did it happen? The first neuron in evolution was a major event. Saltation.

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5280 views

Neurons store extra RNA so newly needed proteins to respond rapidly can be made on the quick:

https://www.sciencedaily.com/releases/2016/12/161221125505.htm

"Neurons in the brain store RNA molecules -- DNA gene copies -- in order to rapidly react to stimuli. This storage dramatically accelerates the production of proteins. This is one of the reasons why neurons in the brain can adapt quickly during learning processes.

***

"The research group of Prof. Peter Scheiffele at the Biozentrum, University of Basel, has demonstrated that neurons store a reserve stock of RNA molecules, copies of the DNA, in the cell's nucleus. These RNA molecules form the blueprint for new proteins. After a neuronal stimulus, the stored RNA molecules are mobilized in order to adjust the function of the neuron. The process of RNA synthesis (DNA copying) is very slow, especially for large genes. Thus, this newly uncovered mechanism for mobilization of stored RNAs saves time and provides new insights regarding the fast adaptation of the brain during learning processes.

"The RNA blueprint for proteins is produced by a sophisticated copying process: First, a basic RNA copy of the DNA is generated. From this copy, individual sections, so-called introns, are subsequently cut out to provide a finalized blueprint for the production of a specific protein. This process is called RNA splicing.

"So far, it was assumed, that neuronal stimuli trigger the complete process for the production of new RNA molecules. However, the team of Peter Scheiffele now discovered that neurons in the brain pre-manufacture certain immature RNA copies which are only partially spliced. These RNA molecules still contain some introns and are stored in the cell nucleus. Signals induced by neuronal stimulation trigger the splicing completion of the immature RNA molecules.

"'The copying process of the DNA, the so-called transcription, is already finalized in advance by the neurons. Hence, mature RNA molecules can be produced within minutes," explains Oriane Mauger, the first author.

"For large genes, the production of the initial version of the RNAs itself takes dozens of hours. "The fact that the RNA molecules are already available in an immature form and only need to be completed, shortens the whole process to a few minutes," says Mauger. "Since the transcription is very time-consuming, the storage of RNA means a significant time saving. This enables neurons to quickly adapt their function."

"'This study reveals a completely new regulatory mechanism for the brain," declares Scheiffele. "The results provide us with a further explanation of how neurons steer rapid plasticity processes."

Comment: Quickly learning new habits is necessary for survival in the wild. I assume this is an old mechanism in evolution, but the article does not comment. From that standpoint the process may have been implanted in the first brains since rapid adaptation is vital for survival. Saltation?

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A study of adolescents shows development of controls throughout the brain, not just the frontal cortex:

https://cosmosmagazine.com/biology/networks-form-as-brains-develop

"As children grow up – moving through adolescence and into young adulthood – their ability to control their impulses, stay organised and make decisions improves dramatically.

"According to a new study published in Current Biology, those improvements result from the development of distinct networks within the brain.

"In adolescence the brain networks become increasingly divided into distinct parts, called modules. Modules are parts of a network that are tightly connected to each other, and less connected to other parts of the network. The new evidence shows that the degree to which executive function develops during this period in part depends on the degree to which these modules are present.

"Researcher Graham Baum says the results show the brain uses “specialized units that can work together to support advanced cognitive abilities'”.

Full story: http://www.cell.com/current-biology/fulltext/S0960-9822(17)30496-7

Summary: "The human brain is organized into large-scale functional modules that have been shown to evolve in childhood and adolescence. However, it remains unknown whether the underlying white matter architecture is similarly refined during development, potentially allowing for improvements in executive function. In a sample of 882 participants (ages 8–22) who underwent diffusion imaging as part of the Philadelphia Neurodevelopmental Cohort, we demonstrate that structural network modules become more segregated with age, with weaker connections between modules and stronger connections within modules. Evolving modular topology facilitates global network efficiency and is driven by age-related strengthening of hub edges present both within and between modules. Critically, both modular segregation and network efficiency are associated with enhanced executive performance and mediate the improvement of executive functioning with age. Together, results delineate a process of structural network maturation that supports executive function in youth."

Comment: This study shows the intimate interconnection of our developing 'self' and how our brain changes to accommodate the integration of experience and responses. These changes are automatic bot also cooperative as personality develops. We do develop ourselves. Consciousness and personality are immaterial, but based on the plasticity of the brain to fully develop and experience.

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This happens all through life:

https://www.sciencedaily.com/releases/2017/06/170616102136.htm

"Stem cells persist in the adult mammalian brain and generate new neurons throughout life. A research group ...reports in the current issue of "Science" that long-distance brain connections can target discrete pools of stem cells in their niche and stimulate them to divide and produce specific subtypes of olfactory bulb neurons. This allows the "on-demand" generation of particular types of neurons in the adult brain.

"Our brain generates new neurons throughout life. A diversity of stimuli promotes stem cells in their niche to form neurons that migrate to their place of action. In an animal model Prof. Fiona Doetsch's team has now been able to show that feeding-related neurons in the hypothalamus, a brain control center for many physiological functions, stimulate a distinct type of stem cell to proliferate and mature into specific nerve cells in response to feeding.

"Stem cells reside in only a few areas of the brain. The largest reservoir is the subventricular zone, where quiescent stem cells lie closely packed together. Signals from the environment can trigger stem cells to start dividing. The stem cells in the subventricular zone supply the olfactory bulb with neurons. In rodents, almost 100,000 new neurons migrate from the stem cell niche to the olfactory bulb each day. Olfactory stimuli reaching the nose are processed in the olfactory bulb and the information is then sent to other brain regions. The closely interwoven network of diverse olfactory bulb neurons is important for distinguishing odors.

"Each stem cell has its own identity, depending on its location in the subventricular zone. While new neurons are continuously generated, whether niche signals act to control different pools of stem cells is unknown. "We have uncovered a novel long-distance and regionalized connection in the brain between the hypothalamus and the subventricular zone, and show that physiological states such as hunger and satiety can regulate the recruitment of specific pools of stem cells and in turn the formation of certain neuron subtypes in the olfactory bulb," explains Doetsch. When the animals fasted, the activity of the nerve cells in the hypothalamus decreased and with it also the rate of proliferation in the targeted stem cell population. This returns to normal levels when the animals feed again. The division of stem cells can be controlled by changing the activity of feeding-related neurons.

"The researchers reported further that the targeted stem cell subpopulation gives rise to deep granule cells in the olfactory bulb, which may provide a substrate for adaptive responses to the environment. The results of the study raise the exciting possibility that neural circuits from diverse brain regions can regulate different pools of stem cells in response to various stimuli and states."

Comment: The brain is precisely able to adapt to the animal or human activity. As an example, in the olfactory bulb new neurons are needed as odors are experienced and remembered. I assume this ability began when the first true brains formed earlier in evolution. The brain is more changeable than liver, kidney, lung, etc. It has to have this capacity in order to accommodate developing personality and thought processes handled through consciousness.

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Definite protein molecular controls have been found:

https://medicalxpress.com/news/2017-07-neurons-everyday-life.html

"Researchers from King's College London have discovered a molecular mechanism that enables neuronal connections to change through experience, thus fuelling learning and memory formation.

"One of the most remarkable features of our brain is its ability to sense and interpret the complex environment of everyday life. To accomplish this, brain circuits undergo a process that involves experience-dependent plasticity, a fundamental mechanism through which the nervous system adapts to sensory experience and which is at the root of our capacity to learn as well as encode and retain memories.

"Previous studies have shown that a special group of neurons present in the cerebral cortex called PV+ interneurons (a population of neurons that communicate with each other through deactivating chemical and electrical signals and express a protein called parvalbumin), are able to change in response to stimulus from the environment. However, until now the cellular and molecular mechanisms regulating this adaptability were largely unknown.

"In their new study, the multidisciplinary team of researchers ...found that this adaptability is shaped by a specific protein called Brevican. Moreover, loss of this protein leads to deficits in short-term spatial memory, the part of memory responsible for remembering different locations as well as spatial relations between objects.

"Most PV+ interneurons are wrapped by a mesh of proteins called perineural nets and several studies have shown that these proteins play a critical role in the regulation of experience-dependent plasticity, learning and memory. However, the mechanisms through which these proteins mediate this process remained a mystery. In this new study, the researchers found that one of these proteins called Brevican, which is also one of the most abundant proteins found in the brain, influences neuronal plasticity, orchestrating a dedicated molecular program in response to changes from the environment. The researchers also found that this protein shapes the intrinsic properties of PV+ interneurons and sculpts their connections to other neurons. These novel findings show that Brevican is dynamically regulated by experiences coming from the environment and is fundamentally required for spatial working memory and short-term memories.

"'Perineuronal net proteins regulate cortical plasticity by acting on interneurons. When we identified some of the mechanisms underlying this regulation, I was amazed by how a single protein can act as an activity sensor, orchestrate such a complex molecular program and simultaneously influence several key cellular processes', said Dr Emilia Favuzzi."

Comment: It is one thing to have brains appear as the result of evolution, but this mechanism is highly complex, could not have happened through chance. It must be designed.

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New research shows this:

https://www.newscientist.com/article/2147696-blind-people-repurpose-the-brains-visual-a...

"People who are blind use parts of their brain that normally handle for vision to process language, as well as sounds – highlighting the brain’s extraordinary ability to requisition unused real estate for new functions.

"Neurons in the part of the brain normally responsible for vision synchronise their activity to the sounds of speech in blind people, says Olivier Collignon at the Catholic University of Louvain (UCL) in Belgium. “It’s a strong argument that the organisation of the language system… is not constrained by our genetic blueprint alone,” he says.

"The finding builds on previous research showing that the parts of the brain responsible for vision can learn to process other kinds of information, including touch and sound, in people who are blind.

***

"While they were being scanned, groups of sighted and blind volunteers were played three clips from an audio book. One recording was clear and easy to understand; another was distorted but still intelligible; and the third was modified so as to be completely incomprehensible.

"Both groups showed activity in the brain’s auditory cortex, a region that processes sounds, while listening to the clips. But the volunteers who were blind showed activity in the visual cortex, too.

"The blind volunteers also appeared to have neurons in their visual cortex that fired in sync with speech in the recording – but only when the clip was intelligible. This suggests that these cells are vital for understanding language, says Collignon.

"The visual cortex contains the relevant architecture, he says, to go from sound processing to language comprehension.

“'The new finding is perhaps not surprising, but it is groundbreaking,” says Daniel-Robert Chebat at the Israeli Ariel University in the West Bank. “It shows that these parts of the brain are not only recruited [to receive new kinds of input], but can adapt and modulate their response.”

"The discovery highlights how malleable our brains are, says Collignon, but he thinks there may be a limit to this. It’s unlikely that any part of the brain can eventually learn any function, he says. Instead, there may be a set of rules, laid down in our genes, which brain regions can follow."

Comment: This is further evidence of how the human brain can modify its functional areas. It allows a highly complex organ to adapt to almost any function presented to it. The brain enlarged and developed this capacity over an eight million year period, rather speedily for evolution. It development looks designed and driven.

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An amazing case report of a seven year old with good vision but missing most of his optical cortex:

https://medicalxpress.com/news/2017-12-mysterious-case-boy-visual-cortex.html

"The boy, the researchers told the audience, suffered major damage to his visual cortex as a result of medium-chain acyl-Co-A dehydrogenase deficiency at just two weeks old—a rare condition that results in severe damage to nerve cells due to an inability to convert some types of fats into energy. That meant the boy, who the researchers referred to as B.I., wound up without most of his visual cortex, a condition that for most people would result in cortical blindness. Cortical blindness is an odd condition in which the brain can still receive visual input, but cannot process what is seen, leaving the person with the sensation of sight without being able to actually see. But oddly enough, B.I. can see almost as well as any other boy his age.

"B.I. caught the attention of the team at Monash due to his medical history—intrigued, they sought to test the boy and his vision, and find out why he could see despite his brain injury.

"In testing B.I.'s vision, the researchers found that he was somewhat near-sighted but was otherwise fine, except for the occasional lapse when faced with false-colored objects such as a blue banana. He could play soccer, for example, and video games, and make out the difference in emotions on a person's face.

"To find out why the boy could still see, the researchers observed him in an MRI machine and watched what happened as he processed images. By focusing on the middle temporal visual area, the researchers found an enlarged visual pathway of neural fibers that ran through two areas on the back of the brain where the visual cortex resides. One of the areas called the pulvinar is normally involved in managing sensory signals, the other, called the middle temporal area, is normally involved in detecting motion. In B.I.'s case, the pathway had grown larger than normal to allow it to do the work that his visual cortex was supposed to do, allowing him to see—a form of neuroplasticity.

An image of his brain is shown here:

https://www.newscientist.com/article/2155639-a-boy-is-missing-the-vision-bit-of-his-bra...

Comment: The amazing ability of the brain's neuroplasticity is shown by this boy's brain, by adapting a totally new area to receive the signals and interpret them.

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Certainly not like kids and it takes both sides:

https://cosmosmagazine.com/health/body-and-mind/how-adults-learn-a-new-language/?utm_so...

"Learning languages is a breeze for young children, but once that window of opportunity closes it becomes notoriously difficult. Now, Spanish scientists have shed more light on how we get around this.

"While it’s thought that language is specialised in the left side of the brain, the researchers found that the right side also helps out when learning a new language as an adult, providing further evidence of the brain’s remarkable flexibility.

“'The left hemisphere is widely considered to be more or less hardwired for language, but there is plenty of evidence that it is not quite as simple as that,” says Kshipra Gurunandan from the Basque Centre on Cognition, Brain and Language, lead author of a paper published in the Journal of Neurology.

***

“'Reading, listening and speaking activate common ‘language’ regions in the brain,” Gurunandan explains, “but they also involve the visual, auditory and motor regions, respectively, and we wanted to study the consequences for language learning.”

"To test this, they recruited 48 healthy native Spanish speakers aged 17 to 60 from language schools. The study consisted of two experiments: one compared basic and advanced level learners of the Basque language and the second looked at Spanish-Basque natives before and after a three-month language course in intermediate-level English.

***

"While speaking primarily activated language regions in the left hemisphere, results showed much greater variation in which hemisphere was activated while reading and, to a lesser degree, listening. The switch was most apparent in more advanced learners.

"This suggests reading and listening are more flexible throughout adulthood, which makes them easier to learn as people become more proficient, according to Gurunandan. It could also explain why adults can often understand a new language but struggle to speak it to the same skill level.

"It’s striking, she adds, that the switch from a native language to a new one that’s being actively learned recruits the brain’s left hemisphere but lateralises to both hemispheres with greater proficiency, which might also help people separate the two languages."

Comment: Makes sense since language involves eyes and ears.

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Genetics: brain plasticity (Introduction)