How the brain manages fear revealed

Washington, Sept 11 : Although humans may have developed complex thought processes that can help to regulate their emotions, a new research has suggested that the processes are associated with evolutionarily older mechanisms that are common across species.

The research, which has been published in the September 11th issue of the journal Neuron, provides new insight into the way the brain manages fear.

The finding may guide exploration of novel pharmacological and therapeutic treatments for anxiety disorders.

"The ability to eliminate, control or diminish negative emotional responses is important for adaptive function and critical in the treatment of psychopathology," said study author, Dr. Mauricio Delgado from Rutgers University.

He added: "Recent research examining the neural mechanisms for diminishing fears has focused on two techniques: extinction, which has been explored across species, and cognitive emotion regulation strategies, which are unique to humans."

In earlier research on rodents and humans, the scientists attributed extinction to activity in the amygdala and ventral medial prefrontal cortex (vmPFC). On the other hand, neural circuits underlying cognitive strategies to regulate emotions are not as well understood. However, the New York University team led by Dr. Delgado and Dr. Elizabeth A. Phelps, were interested in examining the similarities and differences of diminishing fear through both techniques.

They used similar experimental paradigms with different means of controlling fear to directly compare the neural mechanisms that mediate extinction and emotional regulation.

Later, they paired a typical fear conditioning method with a measurement of physiological arousal to examine extinction. Also, they implemented a cognitive emotion regulation strategy. Functional magnetic resonance imaging (fMRI) was used to compare the neural activation patterns of extinction and emotional regulation.

It was found that the lateral prefrontal cortex regions engaged by cognitive emotion regulation strategies influenced the amygdala and diminished fear through similar vmPFC connections that are thought to inhibit the amygdala during extinction.

Overall, the findings indicate that there is overlap in the neural circuitry of diminishing learned fears through emotion regulation and extinction and that vmPFC may play a general regulatory role in diminishing fear across a range of paradigms.

"Our results suggest that even though humans may have developed unique capabilities for using complex cognitive strategies to control emotion, these strategies may influence the amygdala through phylogenetically shared mechanisms of extinction. Extinction and cognitive emotion regulation may be, in part, complementary in that they rely on a common neural circuitry and, perhaps, similar neurophysiological and neurochemical mechanisms," explained Dr. Phelps.

ANI