Bursts of neuronal activity that last only milliseconds trigger lasting changes in the brain
https://hms.harvard.edu/news/nature-meet-nurture#.Wn2PtNBMUEU.twitterExcerpt: "Using novel technologies developed at HMS, the team looked at how a single sensory experience affects gene expression in the brain by analyzing more than 114,000 individual cells in the mouse visual cortex before and after exposure to light.
Their findings revealed a dramatic and diverse landscape of gene expression changes across all cell types, involving 611 different genes, many linked to neural connectivity and the brain’s ability to rewire itself to learn and adapt.
The results offer insights into how bursts of neuronal activity that last only milliseconds trigger lasting changes in the brain, and open new fields of exploration for efforts to understand how the brain works.
“This in essence addresses the long-asked question about nature and nurture: Is it genes or environment? It’s both, and this is how they come together,” he said.
Neuroscientists have known that stimuli—sensory experiences such as touch or sound, metabolic changes, injury and other environmental experiences—can trigger the activation of genetic programs within the brain.
They then exposed the mice to light and studied how it affected genes within the brain. Using technology developed by the Klein lab known as inDrops, they tracked which genes got turned on or off in tens of thousands of individual cells before and after light exposure.
The team found significant changes in gene expression after light exposure in all cell types in the visual cortex—both neurons and, unexpectedly, non-neuronal cells such as astrocytes, macrophages and muscle cells that line blood vessels in the brain.
Roughly 50 to 70 percent of excitatory neurons, for example, exhibited changes regardless of their location or function. Remarkably, the authors said, a large proportion of non-neuronal cells—almost half of all astrocytes, for example—also exhibited changes.
The team identified thousands of genes with altered expression patterns after light exposure, and 611 genes that had at least two-fold increases or decreases.
These findings open a wide range of avenues for further study, the authors said. For example, how genetic programs affect the function of specific cell types, how they vary early or later in life and how dysfunction in these programs might contribute to disease, all of which could help scientists learn more about the fundamental workings of the brain.
“Experience and environmental stimuli appear to almost constantly affect gene expression and function throughout the brain. This may help us to understand how processes such as learning and memory formation, which require long-term changes in the brain, arise from the short bursts of electrical activity through which neurons signal to each other,” Greenberg said.One especially interesting area of inquiry, according to Greenberg, includes the regulatory elements that control the expression of genes in response to sensory experience. In a paper published earlier this year in Molecular Cell, he and his team explored the activity of the FOS/JUN protein complex, which is expressed across many different cell types in the brain but appears to regulate unique programs in each different cell type."
My comment: Sensory experiences affect gene expression patterns in the brain that controls gene expression patterns and epigenetic information layers in other parts of the body. This is why a fish in a dark environment is able to rapidly alter its gene expression patterns and become blind. Nothing to do with random mutations or selection. All kind of visual stimulation affects the brain and after that, overall inheritable epigenetic information layers in the body. Any change in organisms is based on epigenetic regulation of existing biological information OR loss of it.
