MGH McLean Adult Psychiatry Residency Program

President Obama's announcement of the BRAIN Initiative earlier this year brought public attention to key the questions of cognitive neuroscience, understand how brain activity leads to perception, decision making and behavior; and ultimately, use this knowledge to provide more effective treatments for debilitating diseases.

A new paper published in the current issue of Neuron, McLean Hospital and Harvard Medical School researchers report that increased activity in the medial prefrontal cortex (mPFC) of the brain is linked to decreased activity in the amygdala, the portion of the brain used in the creation of memories of events that scared those exposed.

According to author Vadim Bolshakov, PhD, director of the Cellular Neurobiology Laboratory at McLean and professor at Harvard Medical School, this finding is significant in that it could lead to better methods to prevent PTSD.

"A single exposure to something traumatic or scary can be enough to create a fear memory--causing someone to expect and be afraid in similar situations in the future," said Bolshakov. "What we're seeing is that we may one day be able to prevent those fear memories."

Bolshakov and his colleagues tested their theory using animal models. Dividing the mice into two groups, some were taught to fear an auditory stimulus while in others fear memory was extinguished Increased activation of mPFC in extinguished animals led to inhibition of the amygdala and significant decreases in fear responses.

"For example, if a sound ended with an extremely loud shriek, a subject would come to expect that scary noise at the end of the sound," explained Bolshakov. "What we found was when we suppressed the fear memory by decreasing activity in the amygdala, the subjects were not afraid of the end of the auditory stimulus any longer."

Bolshakov notes that this work could have serious implications for the treatment of a number of conditions including PTSD.

"While there is still a great deal of research that needs to be done before our work can be translated to clinical trials, what we are showing has the potential to ensure that individuals exposed to trauma were not haunted by the conditions surrounding their initial stressor."

Adapted from a McLean Hospital news release.

Researchers at Harvard Medical School have identified two pairs of dopaminergic neurons with links to the fly brain's central complex, suggesting that important components of aggression-related behaviors may be processed there."This is the first research to identify single dopaminergic neurons that modulate a complex behavior—aggression—in fruit flies,” said Edward Kravitz, George Packer Berry Professor of Neurobiology at HMS and lead author of the study.

Read the full story here. Source: HMS News, April 18, 2013