New evidence points to a more prominent role of the central amygdala in aversive learning.

Brains, according to a neuroscience team at Cold Spring Harbor Laboratory (CSHL) led by Professor Bo Li, have been wired over thousands of years of human development. However, in spite of this development, knowledge (usually cemented with pain) can only come from experience.

Learning that fire is hot and that it can hurt, said researchers, is the result of an association with sensory stimulus and the perception of threat. New research from the CSHL team in mice published recently in Nature Neuroscience suggests that one theory of fear development in the brain that was once accepted may be incorrect in many respects.

A team of neuroscientists at CSHL studied the relationship between two parts of the brain’s amygdala-the almond-shaped gland that regulates learning and memory. According to CSH, the lateral portion of the amygdala is where associations between sensory information and perceived threats are processed but the central amygdala also holds a key role that has not been fully studied.

Researcher’s conducted a series of experiments that administered a mild shock to the feet of mice, imaging the central and lateral parts of the amygdala. The mice’s response to discomfort began in the central amygdala and registered in the lateral amygdala. Researchers also blocked the activity of a set of particular neurons in the central amygdala; when mice with the blocked cells were given a shock, reduced activity in the lateral amygdala was observed.

According to their study, while experiments indicated the lateral portion of the amygdala was involved in aversive learning or fear, it is not the only area of activity. New evidence points to another source—the central amygdala. If true, CHSL researchers said it could change the way doctors treat anxiety and other fear-related disorders like post-traumatic syndrome.
 Cold_Spring_Harbor_Laboratory_PKC_cells.jpg
A subset of neurons shown here, called PKC delta-expressing cells, located in the brain's central
amygdala, drive aversive learning in mice, neuroscientists from CSHL have demonstrated.