Six degrees of separation: the amygdala regulates social behavior and perception.
Traditionally, the amygdala has gotten a lot of ‘bad’ press. Popular wisdom has portrayed the human amygdala as the center of an ancient animal id that drives us to rapid impulsive action before our more reasoned judgments can kick in. For a long time, it was considered to be a fear center or threat detector that is instrumental in allocating processing resources to potentially harmful events. This was in part because, thanks to research in nonhuman animals, the amygdala’s role in fear learning was extremely well mapped. More recent studies in humans suggest that it is responsive to positive and arousing rather than to strictly negative events, as well as to ambiguous events1,2. In this issue, two case studies of an individual with bilateral amygdala damage indicate that ideas about amygdala function may need even further reconsideration. The connectivity of the amygdala places it at the center of the brain, a physical hub linking numerous distant regions, and it is positioned to allow emotions to influence how the rest of the brain works, from the first stages of stimulus encoding to regulating social behavior. Adolphs and colleagues examined these two functions and found that the amygdala may be important for regulating social distance3 and influencing slower, explicit responses, as opposed to rapid automatic alerting to social signals of threat4.
Todd R.M. & Anderson A.K.