| LeDoux Lab 2008 SfN Abstracts |
|---|
| Program#/Poster#: | 591.22/UU9 |
| Title: | Lesions of the lateral and central nuclei of the amygdala disrupt aversive pavlovian-instrumental transfer in rats |
| Location: | Washington Convention Center: Hall A-C |
| Presentation Time: | Tuesday, Nov 18, 2008, 9:00 AM -10:00 AM |
| Authors: | *C. K. CAIN, G. LÁZARO-MUÑOZ,
J. E. LEDOUX; Ctr. for Neural Sci., New York Univ., New York, NY |
| Abstract: | In addition to eliciting reactions,
Pavlovian CSs can also participate in the reinforcement and motivation of
instrumental actions. Pavlovian-instrumental transfer (PIT) tasks allow
for direct assessment of conditioned motivation in the absence of contaminating
factors related to learning. In the simplest PIT tasks, rats are trained
on separate Pavlovian and instrumental protocols, then, during the PIT test,
the rate of instrumental responding is compared during CS-free and CS periods.
When the Pavlovian and instrumental associations involve USs of the same
valence (i.e. appetitive or aversive), PIT is evident as an increased response
frequency. PIT has been studied mostly with appetitive conditioning. However, aversive CSs can also facilitate responding during instrumental avoidance. We therefore developed an aversive PIT task in rats using standard fear conditioning and Sidman avoidance to begin to study the contribution of amygdala regions to fear-based instrumental actions. This study builds on the large body of research on fear reactions and uses CSs and USs that were commonly employed in mapping Pavlovian fear circuits. Rats were given 3 CS-US (tone-shock) pairings followed a day later by 15 daily Sidman avoidance training sessions where shuttling every 30s prevented shock delivery. Rats were then given bilateral electrolytic or sham lesions of the lateral (LA), basal (B) or central (CE) amgydala before PIT testing. Sham rats showed evidence for aversive PIT; shuttling was approximately 30% more frequent in CS vs. CS-free periods. Lesions of LA and CE completely abolished this effect. B lesions produced a partial blockade that will require further study to clarify. Fear conditioning findings indicate that LA is required for the formation of the CS-US association. Our results are consistent with this view since the CS-US association motivates PIT, and LA was required for PIT. Appetitive studies suggest that there are two types of PIT, where the USs in the Pavlovian and instrumental tasks are either identical (specific PIT) or different but of the same valence (general PIT). These studies also suggest that amygdala regions are differentially involved in these two forms of PIT, with LA+B mediating specific PIT and CE mediating general PIT. To the extent that our task involved specific PIT (matching USs), our results suggest that aversive PIT may differ from appetitive PIT in that LA, B and CE were each involved. Additional studies involving neurotoxic lesions and tasks designed to dissociate specific and general PIT will be performed to further elucidate the role of amygdala areas in aversive conditioned motivation. |
| Support: | F32 MH077458 |
| R37 MH038774 | |
| P50 MH058911 | |
| R01 MH046516 | |
| K05 MH067048 |