Complexity of synapse development (Introduction)
by David Turell 
, Thursday, May 08, 2014, 16:07 (3852 days ago)
That synapses are complex has been noted here. The transmission of impulses can be variously modified at each synapse. This research shows the complexity of embryologic synapse development.-http://www.the-scientist.com//?articles.view/articleNo/39914/title/Minis-Ensure-Synaptic-Maturation/-"Researchers have often focused on initial synapse formation, McCabe said, and for that, miniature neurotransmission does not appear to be essential. "But for subsequent development of those synapses, then it is required," he said. "That's a new discovery." "McCabe and his colleagues further investigated how minis influence synaptic development using Drosophila mutants in which some of the fly's postsynaptic glutamate receptors were inhibited. They found that minis regulate the growth of local synaptic terminals by activating a signaling pathway involved in presynaptic neuronal development. These experiments "beautifully dissociate the role of minis and evoked transmission in developmental maturation of the Dropsophila NMJ," Sutton wrote in an e-mail to The Scientist. "The authors very elegantly demonstrate that it is not the amount of activity at synapses that controls maturation, but rather, it is the nature of the activity (evoked versus miniature events) that is important.""
Complexity of synapse transmission
by David Turell , Tuesday, January 16, 2018, 17:17 (2503 days ago) @ David Turell
A new study finds molecules that transmit information in synapses:
https://www.the-scientist.com/?articles.view/articleNo/51342/title/Neurons-Use-Virus-Li...
"The Arc gene, which descended from an ancient group of genes that litters the eukaryotic genome, encodes a virus-like protein that transmits genetic information between neurons, according to two papers published last Thursday (January 11) in Cell.
"In prior studies, researchers have found that mice engineered to lack the Arc gene lost the ability to form long-term memories. “They can’t seem to respond or adapt to changes in their environment,” Jason Shepherd, a neuroscientist at the University of Utah and one of the studies’ coauthors, tells The Atlantic. “Arc is really key to transducing the information from those experiences into changes in the brain.”
"When Shepherd and his team took a closer look at Arc under a high-resolution microscope, they made a surprising discovery: the protein formed a capsid—a protective shell used by retroviruses to shuttle genetic information between cells—and carried messenger RNA (mRNA) that encoded itself. Another group, led by Vivian Budnik, a cell biologist at the University of Massachusetts Medical School, reported that the same was true for fly versions of Arc. In addition, both groups found that the Arc gene was similar to gag, a gene encoding a protein that helps form capsids in retroviruses.
"These discoveries are “groundbreaking,” Clive Bramham, a neuroscientist at the University of Bergen in Norway who was not involved in either study, tells Nature.
According to The Atlantic, Arc genes, which are found in multiple mammalian species (including humans), are descendants of gypsy transposons, an ancient group of genes that also gave rise to retroviruses.
"Shepherd’s group found that neurons released Arc in vesicles that fused with other neurons and ejected both proteins and mRNA. Budnik’s group uncovered a similar process in flies, which took place between neuromuscular junctions, the synapses between motor neurons and muscle cells. According to Nature, the researchers think the Arc-containing vesicles help neurons form and break connections, allowing the nervous system to adapt to new memories or environments. Because this phenomenon appears in both mice and flies, two very distantly-related species, “[t]here must be something really fundamental about it," Budnik tells Nature. "
Comment: As usual we see cells/neurons using protein molecules to present information. No full brain function required. Individual cells are not intelligent in and of themselves. They are programmed to act intelligently.
Complexity of synapse transmission
DAVID's comment: As usual we see cells/neurons using protein molecules to present information. No full brain function required. Individual cells are not intelligent in and of themselves. They are programmed to act intelligently.
You seize on the material means of presenting information, but prefer not to ask how cells/neurons came to perform such actions in the first place. If I tell you that humans use biochemical processes to pass on information, will you tell me this means they are not intelligent in and of themselves?
To expand the range, and link up with your post on DNA repair: with all new defects and diseases and threats, cells must respond. Despite every success, there is a massive failure rate. 99% of all species have died. This means the cells/cell communities did not find a solution. When humans come up with means of destroying bacteria, bacteria die and die and die, but eventually they find a solution. So did your God programme some to fail and others to succeed? Or might it be that eventually the successful ones worked it out for themselves?
Complexity of synapse transmission
by David Turell , Wednesday, January 17, 2018, 14:12 (2502 days ago) @ dhw
DAVID's comment: As usual we see cells/neurons using protein molecules to present information. No full brain function required. Individual cells are not intelligent in and of themselves. They are programmed to act intelligently.
dhw: You seize on the material means of presenting information, but prefer not to ask how cells/neurons came to perform such actions in the first place. If I tell you that humans use biochemical processes to pass on information, will you tell me this means they are not intelligent in and of themselves?
To expand the range, and link up with your post on DNA repair: with all new defects and diseases and threats, cells must respond. Despite every success, there is a massive failure rate. 99% of all species have died. This means the cells/cell communities did not find a solution. When humans come up with means of destroying bacteria, bacteria die and die and die, but eventually they find a solution. So did your God programme some to fail and others to succeed? Or might it be that eventually the successful ones worked it out for themselves?
Conflating species failure with molecules carrying information is an interesting debate subterfuge. Cells are not an equal to humans. I don't know if God dabbles in every species failure. We know He uses an evolutinary method to create advances in the complexity of living species, including sapiens.
Complexity of synapse transmission
DAVID's comment: As usual we see cells/neurons using protein molecules to present information. No full brain function required. Individual cells are not intelligent in and of themselves. They are programmed to act intelligently.
dhw: You seize on the material means of presenting information, but prefer not to ask how cells/neurons came to perform such actions in the first place. If I tell you that humans use biochemical processes to pass on information, will you tell me this means they are not intelligent in and of themselves?
dhw: To expand the range, and link up with your post on DNA repair: with all new defects and diseases and threats, cells must respond. Despite every success, there is a massive failure rate. 99% of all species have died. This means the cells/cell communities did not find a solution. When humans come up with means of destroying bacteria, bacteria die and die and die, but eventually they find a solution. So did your God programme some to fail and others to succeed? Or might it be that eventually the successful ones worked it out for themselves?
DAVID: Conflating species failure with molecules carrying information is an interesting debate subterfuge. Cells are not an equal to humans. I don't know if God dabbles in every species failure. We know He uses an evolutinary method to create advances in the complexity of living species, including sapiens.
I did not conflate species failure with molecules carrying information. I expanded the range to link up with your post on DNA repair. Nor have I ever said cells are equal to humans (and I don't know of anyone who has). If you argue that communication through biochemical processes proves that cells are not intelligent, you may as well say the same about humans. The ability to communicate, to process information, to take decisions, to solve problems is a sign of intelligence. You insist that this requires a brain and so any brainless organism that shows such intelligence must have been preprogrammed by your God 3.8 billion years ago to perform these intelligent actions. You are, of course, entitled to your opinion, but I am pointing out the flaw in your reasoning: the fact that communication and many other cellular activities require biochemical processes does NOT prove that the communicator is an automaton.
Complexity of synapse transmission
by David Turell , Thursday, January 18, 2018, 17:43 (2501 days ago) @ dhw
DAVID: Conflating species failure with molecules carrying information is an interesting debate subterfuge. Cells are not an equal to humans. I don't know if God dabbles in every species failure. We know He uses an evolutinary method to create advances in the complexity of living species, including sapiens.dhw: I did not conflate species failure with molecules carrying information. I expanded the range to link up with your post on DNA repair. Nor have I ever said cells are equal to humans (and I don't know of anyone who has). If you argue that communication through biochemical processes proves that cells are not intelligent, you may as well say the same about humans. The ability to communicate, to process information, to take decisions, to solve problems is a sign of intelligence. You insist that this requires a brain and so any brainless organism that shows such intelligence must have been preprogrammed by your God 3.8 billion years ago to perform these intelligent actions. You are, of course, entitled to your opinion, but I am pointing out the flaw in your reasoning: the fact that communication and many other cellular activities require biochemical processes does NOT prove that the communicator is an automaton.
We have never agreed on proof. My point is, as always, the cells can be programmed to appear intelligent because the responses and chemical actions are intelligently designed and programmed to make intelligent responses and actions. I pick this interpretation because cellular studies support it.
Complexity of synapse transmission
DAVID: As usual we see cells/neurons using protein molecules to present information. No full brain function required. Individual cells are not intelligent in and of themselves. They are programmed to act intelligently.
Dhw: I am pointing out the flaw in your reasoning: the fact that communication and many other cellular activities require biochemical processes does NOT prove that the communicator is an automaton.
DAVID: We have never agreed on proof. My point is, as always, the cells can be programmed to appear intelligent because the responses and chemical actions are intelligently designed and programmed to make intelligent responses and actions. I pick this interpretation because cellular studies support it.
Cellular studies by some scientists unequivocally support the concept of cellular intelligence. The sequence of comments in your first statement (cells use protein molecules...cells not intelligent) would make no sense unless you thought that cellular use of protein molecules provided evidence for your belief in your God’s 3.8 billion-year-old programme for every cellular activity in the history of life. I am simply questioning your reasoning. NB cellular intelligence does not mean that every cell is a genius, or that there are no automatic responses. It means that cellular behaviour is governed by autonomous intelligence that may determine the behaviour of a single cell or of whole communities of cells, as demonstrated most clearly when new problems arise.
Complexity of synapse transmission
by David Turell , Friday, January 19, 2018, 15:49 (2500 days ago) @ dhw
DAVID: As usual we see cells/neurons using protein molecules to present information. No full brain function required. Individual cells are not intelligent in and of themselves. They are programmed to act intelligently.
Dhw: I am pointing out the flaw in your reasoning: the fact that communication and many other cellular activities require biochemical processes does NOT prove that the communicator is an automaton.
DAVID: We have never agreed on proof. My point is, as always, the cells can be programmed to appear intelligent because the responses and chemical actions are intelligently designed and programmed to make intelligent responses and actions. I pick this interpretation because cellular studies support it.
dhw: Cellular studies by some scientists unequivocally support the concept of cellular intelligence. The sequence of comments in your first statement (cells use protein molecules...cells not intelligent) would make no sense unless you thought that cellular use of protein molecules provided evidence for your belief in your God’s 3.8 billion-year-old programme for every cellular activity in the history of life. I am simply questioning your reasoning. NB cellular intelligence does not mean that every cell is a genius, or that there are no automatic responses. It means that cellular behaviour is governed by autonomous intelligence that may determine the behaviour of a single cell or of whole communities of cells, as demonstrated most clearly when new problems arise.
Same end point. I'm impressed that you can tell from outside the cell, where we all must be as we study cells, that they are intrinsically intelligent, rather than operating with automaticity from onboard intelligent instructions. What is most interesting is how material protein molecules are seen to carry information which is immaterial, and this process is the basis of living organisms.
Complexity of synapse transmission
by David Turell , Saturday, March 31, 2018, 22:00 (2429 days ago) @ David Turell
More research into how synapses function to transmit impulses:
https://www.sciencedaily.com/releases/2018/03/180326090559.htm
"A neuron, when activated, propagates an electrical signal. But that signal cannot cross the synapse -- the junction between two neurons. So, communication from one neuron to the next is accomplished by the release of tiny membrane capsules containing signaling chemicals called neurotransmitters across the synapse.
"The electrical signal triggers these capsules, called vesicles, to fuse with membrane at the neuron's pre-synaptic terminal, thereby releasing neurotransmitters into the cleft between the two cells. The neurotransmitters travel across the cleft, then activate receptors in the post-synaptic neuron, triggering an electrical signal in that next cell.
"Because the neurotransmitter signal goes in one direction -- from the pre-synaptic neuron to the post-synaptic one -- vesicles must be re-formed for the process to continue. "Recycling is a critical process to keep synapses functional," explains Professor Takahashi,
***
"Vesicle recycling involves three steps: First, lipid membrane must be pinched off from the neuron's membrane to form vesicles, a process called endocytosis. Then, the vesicles must be refilled with neurotransmitter. Finally, filled vesicles must be transported to the release site. Although endocytosis has been well-studied, little was known about the refilling process. Prof. Takahashi, in collaboration with a former OIST researcher and colleagues at Doshisha University, now show that for at least one major type of synapse, refilling takes longer than endocytosis.
"The findings show that the refilling step can determine the rate at which vesicles are recycled and reused at the synapse. Neuroscientists have long thought that it was endocytosis that limited the speed of recycling, says Prof. Takahashi. "However, we showed that vesicle refilling rate is also an important factor."
"Neurons can form excitatory connections or inhibitory ones, depending on which neurotransmitters they release across the synapse. The neurotransmitter glutamate passes along an excitatory signal, meaning that it boosts the chance that the electrical signal from the first cell will be passed along to the second. The neurotransmitters GABA and glycine, on the other hand, transmit an inhibitory message, telling the subsequent cell not to fire.
***
"Remarkably, they showed that the time taken to refill the vesicles with GABA is nearly identical to the overall time taken for a synapse to recover from synaptic depression -- a neuron's inability to fire because the vesicles carrying the message across the synapse are used up. This implies that most of the recovery time is devoted to refilling the vesicles. In contrast, reforming the vesicles takes relatively less time. Vesicle refilling is time consuming because GABA is concentrated 10-100 times inside the vesicle, compared to the rest of the cell, using molecular pumps.
"Therefore, the researchers concluded that the slow rate of refilling vesicles with GABA can be a rate-limiting step for the neurotransmitter recycling process at inhibitory synapses.
"Since all inhibitory neurons in the brain use either GABA or glycine, a neurotransmitter which is recycled in the same way as GABA and refilled into vesicles using the same molecular pump, this principle likely applies to all inhibitory neurons in the brain. This suggests that the vesicle refilling process is crucial to maintaining many important brain functions."
Comment: Synapses obviously control the rate of transmissions across nets of neurons, which allow for a broad range of timing in how an impulse spreads. This complex arrangement strongly suggests design.