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RECONSOLIDATION OF HIGHER-ORDER AUDITORY FEAR CONDITIONING IN THE AMYGDALA.

J.Debiec^1*; V.Doyere^1,2; K.Nader³; J.E.LeDoux¹

1. Ctr. for Neural Sci., NYU, New York, NY, USA

2. Laboratoire de Neurobiologie de l'Apprentissage, de la Memoire at de la Communication, Universite Paris-Sud, Orsay, France

3. Dept. of Psychology, McGill Univ., Montreal, ON, Canada

Second-order conditioning has been a useful tool in studying neural substrates of associative learning. Evidence suggests a critical role of basolateral complex of the amygdala (BLA) in higher-order learning. BLA is also believed to be a site of memory storage in fear conditioning. Previously consolidated auditory fear memories, when reactivated, return to a labile state that requires protein synthesis in the BLA to be reconsolidated. We used reconsolidation to ask questions about the associative structure of second-order auditory fear conditioning. On two consecutive days rats with implanted intra-BLA cannulae were trained with 8 CS1-US pairings. CS1 was a tone and US was a 1.5 mA, 0.5 s footshock. On the following day another tone (CS2) was paired 4 times with the CS1. On the next day a single CS1, or US was presented. Following memory reactivation 0.5 ul of either a protein synthesis inhibitor (anisomycin; 125 ug/ul) or ACSF were infused bilaterally into the amygdala. 24 hrs later rats were presented with 4 CS2 and later 4 CS1 trials. Freezing to tone served as an index of memory retention. Rats with reactivated memories of CS1 and US demonstrated impaired response to both CSs. These data demonstrate that higher order consolidated fear memories undergo reconsolidation. In addition they are consistent with a CS2

CS1

US structure for our second-order fear conditioning paradigm. Current studies are under way to further test this possibility.
Support Contributed By: PHS grant P50MH58911, HFS grant RGP0094/2001-B and VW Foundation grant I/77376B; J.D. is a Fellow of a Polish-American Fulbright Commission.

Citation:
J. Debiec, V. Doyere, K. Nader, J.E. LeDoux. RECONSOLIDATION OF HIGHER-ORDER AUDITORY FEAR CONDITIONING IN THE AMYGDALA. Program No. 623.9. 2003 Abstract Viewer/Itinerary Planner. Washington, DC: Society for Neuroscience, 2003. Online.