Studies in animals demonstrate a crucial role for the amygdala in emotional
and social behavior, especially as related to fear and aggression. Whereas
lesion and functional-imaging studies in humans indicate the amygdala's pa
rticipation in assessing the significance of nonverbal as well as paralingu
istic cues, direct evidence for its role in the emotional processing of lin
guistic cues is lacking. In this study, we use a modified Stroop task along
with a high-sensitivity neuroimaging technique to target the neural substr
ate engaged specifically when processing linguistic threat. Healthy volunte
er subjects were instructed to name the color of words of either threat or
neutral valence, presented in different color fonts, while neural activity
was measured by using (H2O)-O-15 positron-emission tomography, Bilateral am
ygdalar activation was significantly greater during color naming of threat
words than during color naming of neutral words. Associated activations wer
e also noted in sensory-evaluative and motor-planning areas of the brain. T
hus, our results demonstrate the amygdala's role in the processing of dange
r elicited by language. In addition, the results reinforce the amygdala's r
ole in the modulation of the perception of, and response to, emotionally sa
lient stimuli. The current study further suggests conservation of phylogene
tically older mechanisms of emotional evaluation in the context of more rec
ently evolved linguistic function.