Parallel neural responses in amygdala subregions and sensory cortex duringimplicit fear conditioning

We used event-related fMRI to measure neural activity in volunteer subjects during acquisition of an implicit association between a visual conditioned stimulus (CS+) (angry face) and an auditory unconditioned stimulus (UCS) ( aversive, loud noise). Three distinct functional regions were identified wi thin left amygdala: a UCS (noise)-related lateral region, a CS+-related ven tral region, and a dorsal region where CS+-related responses changed progre ssively across the learning session. Differential neural responses to the v isual CS+ were also evoked in extrastriate and auditory cortices, Our resul ts indicate that learning an association between biologically salient stimu li of different sensory modalities involves parallel changes of neural acti vity in segregated amygdala subregions and unimodal sensory cortices, (C) 2 001 Academic Press.