| LeDoux Lab 2012 SfN Abstracts |
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| Program#/Poster#: | 603.08/EEE11 |
| Title: | The role of nucleus accumbens in the expression of auditory signaled two-way active avoidance in rats. |
| Location: | Hall F-J |
| Presentation Time: | Tuesday, Oct 16, 2012, 11:00 AM -12:00 PM |
| Authors: | *F. RAMIREZ1,
R. M. SEARS1, J. M. MOCARELLO1, J. E. LEDOUX1,2;
1Ctr. for Neural Sci., New York Univ., New York, NY; 2Emotional Brain Inst., Nathan Kline Inst. For Psychiatric Res., Orangeburg, FL |
| Abstract: | The neural circuitry underlying
Pavlovian defense conditioning (fear conditioning) has been thoroughly investigated.
By contrast, the neural substrates underlying aversively motivated instrumental
behaviors have been studied far less. Recent work indicates that the basal amygdala (B) is essential for performing previously learned avoidance responses in a rodent model of aversive instrumental conditioning. To confirm previous anatomical findings, we performed anterograde-tracing studies and found that the nucleus accumbens (NAc) is highly innervated with afferents from B. NAc is considered an interface between systems that detect emotionally salient events and those which drive motor action plans. The intent of this study is to characterize the neural circuitry driving SigAA, a task in which rats learn to shuttle across a divided chamber during a tone (CS) in order to avoid a foot shock (US). We propose that NAc is essential for mediating active responses to such stimuli that predict harm. To test this hypothesis we silenced neural activity in the shell (NAcSh) or core (NAcCo) subregions of NAc by microinfusion of the GABA-A receptor-specific agonist muscimol (100ng/0.3μl) prior to testing SigAA. Inactivation of NAcSh during SigAA significantly impaired avoidance responding. The following day, when the drug was no longer active, rats returned to asymptotic levels of performance. In contrast, we found that temporary manipulation of NAcCo had no affect on avoidance responses. Following these experiments, fluorescently labeled retrograde tracer beads were microinfused into our drug manipulation sites in the NAcSh, revealing labeled cell bodies in B. Our SigAA data suggest that NAcSh, but not NAcCo, is necessary for successful avoidance responses to previously learned response contingencies. Studies are underway in which we dissect the role of NAc subregions during different phases of learning and expression of avoidance responses during SigAA. |
| Support: | RO1 DA029053 |
| 0920153 | |
| MH38774 | |