Recognition of facial emotion in nine individuals with bilateral amygdala damage

Abstract

Findings from several case studies have shown that bilateral amygdala damage impairs recognition of emotions in facial expressions, especially fear. However, one study did not find such an impairment, and, in general, comparison across studies has been made difficult because of the different stimuli and tasks employed. In a collaborative study to facilitate such comparisons, we report here the recognition of emotional facial expressions in nine subjects with bilateral amygdala damage, using a sensitive and quantitative assessment. Compared to controls, the subjects as a group were significantly impaired in recognizing fear, although individual performances ranged from severely impaired to essentially normal. Most subjects were impaired on several negative emotions in addition to fear, but no subject was impaired in recognizing happy expressions. An analysis of response consistency showed that impaired recognition of fear could not be attributed simply to mistaking fear for another emotion. While it remains unclear why some subjects with amygdala damage included here are not impaired on our task, the results overall are consistent with the idea that the amygdala plays an important role in triggering knowledge related to threat and danger signaled by facial expressions.