LeDoux Lab 2009 SfN Abstracts
 
Program#/Poster#: 479.23/FF124
Title: Acquisition of sidman active avoidance in rats depends on the lateral and basal, but not central, nuclei of the amygdala
Location: South Hall A
Presentation Time: Monday, Oct 19, 2009, 3:00 PM - 4:00 PM
Authors: *G. LAZARO-MUNOZ, J. E. LEDOUX, C. K. CAIN;
Ctr. Neural Sci., New York Univ., New York City, NY
Abstract: Formation, storage and expression of aversive Pavlovian CS-US associations is dependent on the amygdala, specifically the lateral (LA) and central (CE) nuclei. Pavlovian fear conditioning is an important early step in instrumental active avoidance (AA) learning. Multiple electrophysiology, pharmacology and lesion studies suggest that the amygdala is also necessary for the acquisition of AA, and plays a transient role in maintaining these responses. However, these studies have generally not distinguished between the roles of the different amygdalar nuclei. Previous work in our laboratory suggests that different outputs of the LA mediate ‘passive’ versus ‘active’ responses to aversive cues (Amorapanth et al., 2000; Choi et al., submitted). The LA and CE mediate passive defensive behaviors while the LA and the basal nucleus of the amygdala (B) seem to mediate active defensive behaviors. In this set of experiments, we examined the effects of bilateral electrolytic or sham lesions of the LA, B or CE on the acquisition of Sidman AA. Following recovery from surgeries, all rats were given 8 Sidman AA training sessions. Sidman AA was carried out in a two-way avoidance chamber in which shuttling once every 30s prevented the delivery of footshocks. A repeated measures ANOVA comparing the mean number of AA responses per training block (two training sessions/block) showed a significant effect of Group F(3, 246) = 20.87; p < 0.01. Bonferonni post-tests analysis revealed that the LA and B groups performed significantly less AA responses on blocks 2, 3, and 4 than the Sham group (ps < 0.05 for B; 0.01 for LA). Moreover, post-hoc analysis indicated that the CE group showed a significantly higher mean number of AA responses than the Sham group on block 1 (p < 0.05). Together, these results suggest that AA responses were impaired by pre-training LA or B lesions, but facilitated by pre-training CE lesions during early stages of training. These results are consistent with the hypothesis that the LA and B mediate active defensive behaviors while the CE mediates passive defensive behaviors that constrain AA.
Support: R37 MH038774
P50 MH058911
R01 MH046516
R01 MH046516
F32 MH077458