LeDoux Lab 2005 SfN Abstracts   THE NEURAL CIRCUITS OF ACQUISITION AND EXTINCTION OF AUDITORY FEAR CONDITIONING IN HUMANS

A.M.Apergis-Schoute2*; D.Schiller1,2; L.Litman3; K.Nearing1; J.E.LeDoux2; E.A.Phelps1,2

1. Psychology, 2. Center for Neural Science, New York Univ., New York, NY, USA 3. Psychology, Brooklyn Col.-CUNY, Brooklynn, NY, USA

Studies examining the neural systems of fear conditioning in humans, mostly using visual conditioned stimuli, have been grossly consistent with data from non-human animals. Animal models of fear learning, however, have been primarily based on auditory fear conditioning. In the present study we used fMRI to examine auditory fear conditioning in humans in an effort to acquire more insight in the cross-species similarities of the neural mechanisms underlying fear acquisition and extinction. In this partial reinforcement paradigm, the CS+ and CS- were tones (170 and 800 Hz) and the US was a mild shock to the wrist. Extinction of auditory fear was tested immediately after acquisition and 24 hrs later. Consistent with previous fMRI findings of fear conditioning, our preliminary data shows differential activation in the amygdala and mPFC to the CS+ that attenuated with extinction (Phelps et al., 2004). In addition, we show that the auditory cortex has sustained increased activity specifically to the CS+, in line with plastic changes seen in the rat auditory cortex (Edeline and Weinberger, 1993). These results replicate findings of visual fMRI studies, showing the involvement of the amygdala and vmPFC in acquisition and extinction of auditory fear conditioning. In addition, these data demonstrate that changes in the auditory cortex induced by fear learning do not diminish during extinction, consistent with the pattern observed in animal studies of auditory fear conditioning. Support Contributed By: P50 MH8911 to J.E.L and MH62104 to E.A.P

Program No. 415.16 Poster presentation:Monday, Nov. 14, 11:00 AM - 12:00 PM Location: II5