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A.M.Apergis-Schoute2*; D.Schiller1,2; L.Litman3; K.Nearing1; J.E.LeDoux2; E.A.Phelps1,2 | ||
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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 |
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Program No. 415.16 Poster presentation:Monday, Nov. 14, 11:00 AM - 12:00 PM Location: II5 |
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