![]() 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. Remarkably, the authors said, a large proportion of non-neuronal cells-almost half of all astrocytes, for example-also exhibited changes. Roughly 50 to 70 percent of excitatory neurons, for example, exhibited changes regardless of their location or function. 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. 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. They then exposed the mice to light and studied how it affected genes within the brain. Aurel Nagy, an MD-PhD student in the Greenberg lab, the researchers first housed mice in complete darkness to quiet the visual cortex, the area of the brain that controls vision. Spearheaded by co-lead authors Sinisa Hrvatin, a postdoctoral fellow in the Greenberg lab, Daniel Hochbaum, a postdoctoral fellow in the Sabatini lab and M. Moorhead III Professor of Neurobiology at HMS, and Allon Klein, assistant professor of systems biology at HMS. To build a more comprehensive picture, Greenberg teamed with co-corresponding author Bernardo Sabatini, the Alice and Rodman W. However, due to technological limitations, previous genetic studies largely focused on mixed populations of cells, obscuring critical nuances in cellular behavior. Scientists have long sought to understand how individual cells respond to various stimuli. 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.Ĭomposed of a vast array of different cells, the brain depends on a complex orchestra of cellular functions to carry out its tasks. “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. In response to visual stimulation, virtually every cell in the visual cortex is responding in a different way,” said co-senior author Michael Greenberg, the Nathan Marsh Pusey Professor of Neurobiology and chair of the Department of Neurobiology at HMS. 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. 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. 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. 21, neuroscientists and systems biologists from Harvard Medical School reveal just how inexorably interwoven nature and nurture are. In a study published in Nature Neuroscience on Jan. Yet, as biologists continue to better understand the mechanisms that underlie brain function, it is increasingly apparent that this long-debated dichotomy may be no dichotomy at all. Variations of these questions have been explored by countless philosophers and scientists across millennia. Is it nature or nurture that ultimately shapes a human? Are actions and behaviors a result of genes or environment? Nature is all that a man brings with himself into the world nurture is every influence from without that affects him after his birth.” – Francis Galton, cousin of Charles Darwin, 1874. “Nature and nurture is a convenient jingle of words, for it separates under two distinct heads the innumerable elements of which personality is composed. Harvard COVID-19 Information: Keep Harvard Healthy.Celebrating 50 Years of Diversity and Inclusion.Research Departments, Centers, Initiatives and more.
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