Differential response in the human amygdala to racial outgroup vs ingroup face stimuli

Here we describe response in the human amygdala to the presentation of raci al outgroup vs ingroup faces. Functional magnetic resonance imaging (fMRI) measures of brain activity were acquired while subjects who identified them selves as White or Black viewed photographs of both White and Black faces. Across all subjects, we observed significantly greater blood oxygen-level-d ependent (BOLD) signal in the amygdala to outgroup vs ingroup faces, but on ly during later stimulus presentations. A region of interest (ROI)-based an alysis of these voxels revealed a significant interaction between amygdala response to outgroup and ingroup faces over time. Specifically, the greater amygdala activation to outgroup faces during later stimulus presentations was the result of amygdala response habituation to repeated presentations o f ingroup faces with sustained responses to outgroup faces. The present res ults suggest that amygdala responses to human face stimuli are affected by the relationship between the perceived race of the stimulus face and that o f the subject. Results are discussed as consistent with a role for the amyg dala in encoding socially and/or biologically relevant information. We conc lude that researchers seeking to study brain responses to face stimuli in h uman subjects should consider the relationship between the race of subjects and stimuli as a significant potential source of variance. Moreover, these data provide a foundation for future related studies in the neuroscience o f social cognition and race. NeuroReport 11:2351-2355 (C) 2000 Lippincott W illiams & Wilkins.