Amygdala subregions differentially respond and rapidly adapt to threatening voices.

Emotional states can influence the human voice during speech utterances. Here, we tested the sensitivity and signal adaptation of functional activity located in amygdala subregions to threatening voices during high-resolution functional magnetic resonance imaging. Bilateral superficial (SF) complex and the right laterobasal (LB) complex of the amygdala were generally sensitive to emotional cues from speech prosody. Activity was stronger, however, when listeners directly focused on the emotional prosody of the voice instead of attending to a nonemotional feature. Explicit attention to prosody especially elicited activity in the right LB complex. Furthermore, the right SF specifically showed an effect of sensitization indicated by a significant signal increase in response to emotional voices which were preceded by neutral events. The bilateral SF showed signal habituation to repeated emotional voices indicated by a significant signal decrease for an emotional event preceded by another emotional event. The right SF and LB finally showed an effect of desensitization after the processing of emotional voices indicated by a signal decrease for neutral events that followed emotional events. Thus, different amygdala subregions are sensitive to threatening emotional voices, and their activity depends on the attentional focus as well as on the proximal temporal context of other neutral and emotional events.