Fellow Focus: Prabhat Kunwar

A pounding heartbeat, quick breathing, sweaty palms—we all know these common responses to fearful situations. The signal that initiates fear in our bodies begins in a structure of the brain known as the amygdala. But what exactly happens between individual neurons? Recent work by JCC fellow Prabhat Kunwar begins to untangle the details.

“It is very exciting that we are in a stage where we can explain complex behaviors such as fear at the level of neurons,” says Kunwar, a postdoc in David Anderson’s lab at the California Institute of Technology. “This work is just a beginning but a very important step. In our case, we identified a microcircuit of two opposing neuronal populations in the amygdala that act like a seesaw to control learned fear.”

The work hinges on genetic markers that help distinguish different cell types within the amygdala. Kunwar fluorescently marked different populations of neurons within the mouse brain, in order to map their connectivity and manipulate their activity. The research, published in a 2010 issue of Nature, was the result of a collaboration between scientists at CalTech and the Friedrich Miescher Institute in Basel, Switzerland.

The work is part of Kunwar’s interest in the genetic dissection of neuronal circuitry underlying defensive and offensive behaviors in mice. Kunwar is originally from a small town in Nepal and moved to the United States to advance his education. “I considered scientific research early on, as I realized its power both to explain the natural world and our existence, and to bring practical benefits to society,” Kunwar says. “Soon, I became captivated by the spectacular progress in genetics and biomedical sciences.”