Abstract View
LESIONS OF THE LATERAL/BASAL BUT NOT THE CENTRAL NUCLEUS OF THE AMYGDALA IMPAIR POST-TRAINING PERFORMANCE OF FEAR-INDUCED 2-WAY ACTIVE AVOIDANCE SIGNALED BY A CONDITIONED STIMULUS.
J.Choi*; J.E.LeDoux
Ctr. for Neural Sci., NYU, New York, NY, USA
It has been proposed that different fear responses are mediated by different subnuclei within the amygala (Amoranpath, LeDoux and Nader, 2000). We tested contributions of the lateral and basal (LA/B) and the Central (CE) nuclei using 2-way active avoidance learning where concurrently acquired conditioned fear motivates an instrumental response.
Rats were trained in a shuttlebox composed of two adjoining chambers. They were presented with a 5-KHz, 70-dB tone (conditional stimulus: CS) that signaled the upcoming footshock (unconditional stimulus: US; 0.6mA). The rat had 15 s to move to the other side to terminate the CS and avoid the US (conditional response: CR); otherwise a footshock (0.6mA) was delivered and remained on until the rat escaped to the other side. A daily training session was composed of 30 trials with an average of 2-min inter-trial intervals. Training continued until successful avoidance responses were achieved on more than 80% of the trials. Delivery of stimuli and movement detection were fully automated. Rats were then divided into 4 groups and received bilateral electrolytic lesions of the designated structure: Entire Amygdala (AMG), LA/B, CE or sham-operated control (S). After 7-10 days of recovery, rats were tested for 2 days using the same training procedure. Both AMG and LA/B showed significant decline in CR rate and CR latency. In contrast, CE showed no decline in their response performance when compared to S. These results suggest that LA or B is an essential component in the expression of active avoidance learning.
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Citation:
J. Choi, J.E. LeDoux. LESIONS OF THE LATERAL/BASAL BUT NOT THE CENTRAL NUCLEUS OF THE AMYGDALA IMPAIR POST-TRAINING PERFORMANCE OF FEAR-INDUCED 2-WAY ACTIVE AVOIDANCE SIGNALED BY A CONDITIONED STIMULUS. Program No. 623.5. 2003 Abstract Viewer/Itinerary Planner. Washington, DC: Society for Neuroscience, 2003. Online.