LeDoux Lab 2004 SfN Abstracts

PROPRANOLOL IMPAIRS RECONSOLIDATION OF CONDITIONED FEAR IN HUMANS
M.M.Miller1,4*; M.Altemus2; J.Debiec3; J.E.LeDoux3; E.A.Phelps4
1. Lab. of Neuroendocrinology, Rockefeller Univ, New York, NY, USA 2. Dept of Psychiatry, Weill Med. Col., Cornell Univ, New York, NY, USA 3. Ctr for Neural Sci, 4. Dept of Psychology, New York Univ, New York, NY, USA
Recent studies in rats suggest that previously stable, long-term memories of fear conditioning return to a labile state after re-exposure to the conditioned stimulus. In the present study, we examined whether reconsolidation occurs for a conditioned fear memory in humans, and whether it might be blocked by the beta-adrenergic receptor antagonist propranolol. The experiment consisted of 3 phases (training, re-exposure, and extinction) performed on 3 consecutive days. On Day 1, all subjects viewed colored squares, which served as the CS+ and CS-, on a computer screen. The CS+ was intermittently paired with a shock to the wrist on Day 1, and Galvanic Skin Response (GSR) was recorded as a measure of conditioning. On Day 2, two groups of subjects were briefly re-exposed to the CS+ and CS-. Immediately after re-exposure, subjects received either 40mg propranolol (oral dose) or placebo. A third group of subjects received propranolol in a novel environment without exposure to the stimuli. On Day 3, all subjects were exposed to the CS+ and CS- without shock, and GSR was recorded. During the Day 3 extinction test, the placebo group showed higher GSR to the CS+ than to the CS-. Similarly, the group that received propranolol with no re-exposure showed higher GSR to the CS+ than CS-. However, the group that received propranolol immediately after re-exposure did not show a differential response to CS+ vs. CS-. These results suggest that propranolol impairs the reconsolidation of fear memory in humans. Support Contributed By: MH58911, MH62104, M01RR0047
Program No. 208.2 Poster presentation:Sunday, Oct. 24, 9:00 AM - 10:00 PM Location: NN17