Itinerary - View Abstract

Abstract View

DIFFERENCES IN INTRINSIC PROPERTIES OF DORSALLY AND VENTRALLY LOCATED LATERAL AMYGDALA NEURONS OF THE RAT.

H.H.Alphs^1*; L.R.Johnson¹; V.Doyere^1,2; P.R.Hof³; J.E.LeDoux¹

1. NIMH Ctr. for Fear and Anxiety, Ctr. for Neural Sci, NYU, NY, NY, USA

2. NAMC, CNRS-UMR8620, Univ Paris-Sud, Orsay, France

3. Mt Sinai Sch. of Med., NY, NY, USA

During Pavlovian auditory fear conditioning a previously neutral auditory stimulus (CS) gains emotional significance through pairing with a noxious unconditioned stimulus (US). These associations are believed to be formed by way of plasticity at auditory input synapses on principal neurons of the lateral nucleus of the amygdala (LA). While the LA has been implicated as a key brain structure for fear learning, how its network of cellular components performs these operations is not yet known. The LA contains three subdivisions which may play differential roles in the formation and storage of fear memories. In an effort to characterize the structural components of the LA, we compared physiological and morphological properties of LA principal neurons located in the dorsolateral subdivision (LaDL) with neurons of the ventral subdivisions (LaVM & LaVL). Neurons physiologically identified in vitro were filled, localized to LA subdivisions and reconstructed. In comparison to dorsal neurons (LaDL; n=11) ventral neurons (LaVL & LaVM; n=5) have a greater dendritic volume (7123

1311 to 3929

637

m³; P<0.05), a higher density of spines (0.54

0.15 to 0.30

0.05

m^-1, P<0.05) and a larger soma area (335

45 to 196

m², P<0.05). In addition, ventral neurons have a wider action potential half width (8.4

0.92 to 5.9

0.42 ms, P<0.05), a lower frequency of firing in response to a 500 ms, 200 nA depolarizing stimulus (8.2

0.95 to 12.3

1.0 Hz, P<0.05), and a longer membrane time constant (40.8

4.0 to 30.4

1.5 ms, P<0.01). Smaller, more rapidly responding cells of the LaDL appear better able to respond to and integrate primary sensory (CS & US) input, while larger, more slowly responding cells of the LaVL and LaVM may be better suited for integration and storage of higher order emotional information.
Support Contributed By: NARSAD, MH38774 & MH58911

Citation:
H.H. Alphs, L.R. Johnson, V. Doyere, P.R. Hof, J.E. LeDoux. DIFFERENCES IN INTRINSIC PROPERTIES OF DORSALLY AND VENTRALLY LOCATED LATERAL AMYGDALA NEURONS OF THE RAT. Program No. 623.1. 2003 Abstract Viewer/Itinerary Planner. Washington, DC: Society for Neuroscience, 2003. Online.