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 |
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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.
Support Contributed By: MH38774
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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. |
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