Individual differences in amygdala activity predict response speed during working memory

The human amygdala has classically been viewed as a brain structure primarily related to emotions and dissociated from higher cognition. We report here findings suggesting that the human amygdala also has a role in supporting working memory (WM), a canonical higher cognitive function. In a first functional magnetic resonance imaging (fMRI) study (n=53), individual differences in amygdala activity predicted behavioral performance in a 3-back WM task. Specifically, higher event-related amygdala amplitude predicted faster response time (RT; r=-0.64), with no loss of accuracy. This relationship was not contingent on mood state, task content, or personality variables. In a second fMRI study (n=21), we replicated the key finding (r=-0.47) and further showed that the correlation between the amygdala and faster RT was specific to a high working memory load condition (3-back) compared with a low working memory load condition (1-back). These results support models of amygdala function that can account for its involvement not only in emotion but also higher cognition.