Breaking News
August 14, 2018 - American Heart Association Urges Screen Time Limits for Youth
August 14, 2018 - Brief interventions during routine care reduce alcohol use among men with HIV
August 14, 2018 - New genome analysis could identify people at higher risk of common deadly diseases
August 14, 2018 - NIH grant for Mount Sinai to study use of inhaled corticosteroids for treatment of sickle cell disease
August 14, 2018 - Daicel supplies free nanodiamond samples to international researchers
August 14, 2018 - Switching anti-psychotic drugs in first-episode schizophrenia patients does not improve clinical outcomes
August 14, 2018 - Study to examine whether modulating gut bacteria can improve cardiac function in heart failure patients
August 14, 2018 - One out of two children not getting enough nutrients needed for their health
August 14, 2018 - Mono-antiplatelet therapy after aortic heart valve replacements may work as well as two drugs
August 14, 2018 - Aid-in-dying patient chooses his last day
August 14, 2018 - Exercise Really Can Chase Away the Blues, to a Point
August 14, 2018 - Surgical mesh implants may cause autoimmune disorders
August 14, 2018 - Researchers develop revolutionary zebrafish model to gain more insight into bone diseases
August 14, 2018 - Researchers discover secret communication hotline between breast cancers and normal cells
August 14, 2018 - Study examines how a person adapts to visual field loss after stroke
August 14, 2018 - Researchers show how specialized nucleic acid-based nanostructures could help target cancer cells
August 14, 2018 - Reducing opioid prescriptions for one operation can also spill over to other procedures
August 14, 2018 - E-cigarettes not so safe but still better than cigarettes
August 14, 2018 - Researchers find link between common ‘harmless’ virus and cardiovascular damage
August 14, 2018 - Initiation of PIMs associated with higher risk of fracture-specific hospitalizations and mortality
August 14, 2018 - Genetically modified mosquitoes and special bed nets help tackle deadly diseases
August 14, 2018 - Advances in treating hep C lead to new option for transplant patients
August 14, 2018 - Study finds quality of doctor-patient discussions about lung cancer screening to be ‘poor’
August 14, 2018 - MSU researchers uncover the effects of aging on regenerative ability of kidneys
August 14, 2018 - Better conditioning, throwing mechanics can help reduce elbow injuries in young baseball pitchers
August 14, 2018 - Brain game doesn’t offer brain gain
August 14, 2018 - Reproductive choices facing women with disabilities require careful consideration
August 14, 2018 - Scientists pinpoint the cause of a rare childhood seizure disorder
August 14, 2018 - Lumpectomy plus radiation associated with reduced risk of breast cancer death, study finds
August 14, 2018 - UAB study shows how ion channel differentiates newborn and mature neurons in the brain
August 14, 2018 - Experts highlight key knowledge gaps that need to be addressed in Ebola vaccine research
August 14, 2018 - Discovery could lead to new drugs against infection and inflammation
August 14, 2018 - Infection Prevention Differs Between Small, Large Hospitals
August 14, 2018 - Mom still matters—In study, young adults tended to prioritize parents over friends
August 14, 2018 - Deep brain stimulation might benefit those with severe alcoholism, preliminary studies show
August 14, 2018 - Study finds increased rate of repeat pregnancies in women with intellectual and developmental disabilities
August 14, 2018 - Lighter sedation fails to reduce risk of postoperative delirium in older patients
August 13, 2018 - Asking better questions about person’s memory could improve doctors’ understanding of patients
August 13, 2018 - U.S. Trauma Doctors Push for Stricter Gun Controls
August 13, 2018 - Asthma and flu: a double whammy
August 13, 2018 - 5 Questions: Donna Zulman on engaging high-need patients in intensive outpatient programs | News Center
August 13, 2018 - Behavioral Nudges Lead to Drop in Prescriptions of Potent Antipsychotic
August 13, 2018 - Potential New Class of Drugs May Reduce Cardiovascular Risk by Targeting Gut Microbes
August 13, 2018 - How to get your kids to eat better
August 13, 2018 - The importance of hearing your patients
August 13, 2018 - Transmission of F. tularensis unlikely to happen through the food chain
August 13, 2018 - Researchers discover epigenetic mechanism underlying ischemic cardiomyopathy
August 13, 2018 - Adolescent health programs receive only a tiny share of international aid, finds research
August 13, 2018 - Fracture risk increases by 30% after gastric bypass, study shows
August 13, 2018 - Quality-improvement project to standardize feeding practices helps micro preemies gain weight
August 13, 2018 - Long-term cannabinoid exposure impairs memory, study shows
August 13, 2018 - New intervention to reduce risk of HIV in young transgender women
August 13, 2018 - Japan human trial tests iPS cell treatment for Parkinson’s
August 13, 2018 - Altered nitrogen metabolism may contribute to emergence of new cancer mutations
August 13, 2018 - Cycling provides greatest health benefits, study finds
August 13, 2018 - Scientists discover biomarker for kidney cancer
August 13, 2018 - New test predicts the risk of serious disease before symptoms appear
August 13, 2018 - Cianna Medical receives FDA 510(k) clearance to extend indication of SCOUT reflector for use in soft tissue localization
August 13, 2018 - Ground-breaking discovery offers new hope for treatment of Alzheimer’s, other neurological diseases
August 13, 2018 - Medical nutrition therapy provided by RDNs benefits patients with chronic kidney disease
August 13, 2018 - Prenatal Tdap vaccination not linked with increased risk of autism in children, study shows
August 13, 2018 - One-Third of Canadian Patients Get Hip Fx Repair Within 24 Hours
August 13, 2018 - ANA (Antinuclear Antibody) Test: MedlinePlus Lab Test Information
August 13, 2018 - Traffic jams in the brain
August 13, 2018 - NIH awards $6.5 million to establish multi-institution biomedical technology resource center
August 13, 2018 - New marker in the blood could help predict person’s risk of developing kidney cancer
August 13, 2018 - New biomarker may provide clues to create diagnostic tool for hypoglycemia-associated autonomic failure
August 13, 2018 - Oxidative Stress Hampers Blood Vessel Dilation in Men
August 13, 2018 - Parents’ Religious Beliefs May Affect Kids’ Suicide Risk: Study
August 13, 2018 - Measure of belly fat in older adults is linked with cognitive impairment
August 13, 2018 - FDA permits marketing of first mobile medical app for contraceptive use to prevent pregnancy
August 13, 2018 - NUS scientists develop new technology to customize optimal drug ‘cocktail’ for myeloma patients
August 13, 2018 - Disordered eating behaviors up for overweight young adults
August 13, 2018 - Connection between Alzheimer’s disease and degenerative eye diseases
August 13, 2018 - Employer expectation of checking email during nonwork hours affects health of workers and families
August 13, 2018 - Rotavirus vaccination reduces infant diarrhea deaths by 34% in rural Malawi
August 13, 2018 - Approval of drug derived from cannabis not necessarily a win for weed
August 13, 2018 - Study shows COPD risk in women with asthma can be reduced
August 13, 2018 - FIND and genedrive announce study agreement to evaluate HCV ID Kit
August 13, 2018 - One in two people putting their eye health at risk during summer, says eye research charity
Findings reveal dramatic landscape of genetic changes in the brain in response to visual stimulation

Findings reveal dramatic landscape of genetic changes in the brain in response to visual stimulation

image_pdfDownload PDFimage_print

“Nature and nurture is a convenient jingle of words, for it separates under two distinct heads the innumerable elements of which personality is composed. 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.

Is it nature or nurture that ultimately shapes a human? Are actions and behaviors a result of genes or environment? Variations of these questions have been explored by countless philosophers and scientists across millennia. 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.

In a study published in Nature Neuroscience on Jan. 21, neuroscientists and systems biologists from Harvard Medical School reveal just how inexorably interwoven nature and nurture are in the mouse brain. 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.

“What we found is, in a sense, amazing. 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.

“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.

One out of many

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.

Composed of a vast array of different cells, the brain depends on a complex orchestra of cellular functions to carry out its tasks. Scientists have long sought to understand how individual cells respond to various stimuli. However, due to technological limitations, previous genetic studies largely focused on mixed populations of cells, obscuring critical nuances in cellular behavior.

To build a more comprehensive picture, Greenberg teamed with co-corresponding author Bernardo Sabatini, the Alice and Rodman W. Moorhead III Professor of Neurobiology at HMS, and Allon Klein, assistant professor of systems biology at HMS.

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. 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.

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, nonneuronal 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.

Many of these genes have been previously linked to structural remodeling in the brain, suggesting that virtually the entire visual cortex, including the vasculature and muscle cell types, may undergo genetically controlled rewiring in response to a sensory experience.

There has been some controversy among neuroscientists over whether gene expression could functionally control plasticity or connectivity between neurons.

“I think our study strongly suggests that this is the case, and that each cell has a unique genetic program that’s tailored to the function of a given cell within a neural circuit,” Greenberg said.

Question goldmine

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.

Identifying the regulatory elements that control gene expression is critical because they may account for differences in brain function from one human to another, and may also underlie disorders such as autism, schizophrenia and bipolar disease, the researchers said.

“We’re sitting on a goldmine of questions that can help us better understand how the brain works,” Greenberg said. “And there is a whole field of exploration waiting to be tapped.”

Source:

https://hms.harvard.edu/news/nature-meet-nurture

Tagged with:

About author

Related Articles