Brain complexity: gene changes add to complexity (Introduction)

by David Turell , Wednesday, October 14, 2015, 20:57 (3328 days ago) @ David Turell

Epigenetic gene changes compound the complex actions of the brain with 100 billion neurons and trillions of connections:-http://medicalxpress.com/news/2015-10-brains-genes-neurons.html- "Genomics examines the entire set of genetic information contained within cells, the activities of genes and the interactions between them. Genomics revealed that the brain's genes are considerably more involved in regulating behavior than ever imagined.-"Genes direct the production of the above-mentioned brain molecules via intermediaries made of RNA. RNA molecules tell the machinery of the cell when and how to make the proteins it needs to grow and function. Technologies developed over the last 20 years have allowed researchers to monitor the ebbs and flows of RNA produced by every gene in the brain with increasing precision. These studies have unveiled a surprisingly close relationship between behavior and gene activity in the brain.-***
"Why is there such a close coupling of brain gene activity and behavior? One hint comes from another bee study. Honeybees respond aggressively and immediately to a threat to their hive; in nature any prolonged delay could prove fatal. This behavioral response is much faster than the time it takes to produce new molecules of RNA, suggesting the initial response is more dependent on the neural system than the genomic one. Nevertheless, my laboratory found changes in the activity of hundreds of genes in the brains of individual bees in response to an intruder in the hive, hours after the threat was neutralized. The threatening experience changed them, in both molecular and behavioral terms.-"Coincident with the persistent changes in brain gene activity, which we could see via changes in amounts of each individual type of RNA molecule, was a persistent increase in the vigilance of the once-agitated bees. This makes good sense; while past performance does not necessarily predict future results on Wall Street, it is a safe bet in nature to remain vigilant after experiencing a threat. Experimental manipulations that simulated the gene activity profile of the post-intruder brain made naïve bees more aggressive, demonstrating a causal relationship between brain gene activity and behavior. The bee brain, confronted with a threat that might be recurring, has genomic apps that help it respond more effectively.-"My colleagues and I also showed that the same kinds of changes occur after stickleback fish and mice are threatened, suggesting that this slow, persistent, genomic response to experience is a universal property of brains.-***-"The brain's neurons and the genomes within them, the hardware and the software, together orchestrate one's response to a new situation, which can vary from person to person. The same dramatic event - a challenge at school or work, a new person in one's social circle - might cause a great deal of stress in one person, and very little in another. We now think that the neural systems of two such people are likely tuned differently by their genomic systems, perhaps as a consequence of differentially stressful past experiences. In the living brain, unlike a computer, the software can help modify the hardware, and as new situations are encountered, the functioning of the neural hardware continues to modify the genomic software. Nature has come up with a "smart" system in which hardware and software are adaptable and interact dynamically!-"This reciprocity between genes and neurons continually builds on an interwoven history that stretches all the way back to inherited individual differences in temperament, which also influence gene activity. And while an acute stress might cause genomic changes that provoke fear and anger for a few hours, chronic stress due to deprivation or violence can cause debilitating health effects because it activates genomic changes in the brain that do not dissipate. In some cases, it induces long-lasting changes to the chemical structure of DNA; these changes, referred to as epigenetic, might even be passed down from one generation to the next."-Comment: No computer will ever match it.