*L. OSTROFF, M. H. MONFILS, N. JINDAL, J. LEDOUX; Ctr. Neural Sci., New York Univ., New York, NY

Synapses in the lateral amygdala (LA) are involved in the acquisition, storage, and retrieval of fear memories. The frequency and spatial relationship between elements of amygdala neuropil, and in particular learning-induced changes in these relationships, may provide valuable insight into the structural mechanisms of information storage. Using serial electron microscopy, we have reconstructed three-dimensional volumes of LA tissue from adult rats and examined the synapses, dendrites, and presynaptic boutons. The majority of excitatory synapses occur on dendritic spines, while most, but not all, inhibitory synapses occur on dendritic shafts. Spines occur with a frequency of about two per micron, and generally have long, very thin necks ending in bulbous heads with one or more synapses. Presynaptic boutons also may have one or several postsynaptic partners. Polyribosomes are present in dendritic shafts and spine heads, but not in axons. Future ultrastructural studies in fear conditioned animals should provide insight into the structural basis of amygdala-dependent learning

Support Contributed By: NIH R01 MH46516; NIH R37 MH38774; NIH K05 MH067048;NIH P50 MH58911
NIH P50 MH58911

Program No. 307.6/BBB19
Poster presentation:Sunday, Nov 04, 2007, 2:00 PM - 3:00 PM
Location: San Diego Convention Center: Halls B-H