| Program#/Poster#: |
860.13/JJJ8 |
| Title: |
Central amygdala as the gateway for defense reactions |
| Location: |
Halls B-H |
| Presentation Time: |
Wednesday, Nov 13, 2013, 1:00 PM - 2:00 PM |
| Authors: |
*Y. GU, R. M. SEARS, J. E. LEDOUX;
Ctr. for Neural Sci., New York Univ., New York, NY |
| Abstract: |
Expression of conditioned defense responses involves much more complex circuits than initially thought, including coordinated interactions between excitatory and inhibitory intra-amygdala microcircuits. In particular, recent work has begun to uncover the microcircuitry of the central nucleus of the amygdala (CeA), the major amygdalar output nucleus responsible for the expression of conditioned responses. We therefore tested the balance of excitatory and inhibitory drive within the CeA on conditioned responses using designer receptors exclusively activated by designer drugs (DREADD). Following injection of excitatory (hM3Dq) or inhibitory (hM4Di) receptors, animals were trained using a Pavlovian auditory threat conditioning paradigm. To test the role of CeA inhibition or excitation during the expression of conditioned defense responses, 24 hrs after conditioning, DREADD receptors were specifically activated by systemic clozapine-N-oxide injections, followed by exposure to conditioned stimuli (tones). The excitatory (hM3Dq) DREADD group showed decreased freezing compared to the control (saline) group in the long-term memory test. In contrast, the inhibitory (hM4Di) DREADD group showed significantly enhanced freezing compared to the control (saline) group. Forty-eight hours following this test, rats were re-tested under drug-free conditions and showed normal freezing levels. These data confirm previous studies demonstrating the involvement of CeA in the expression of conditioned reactions. Work is ongoing to understand the circuit mechanisms responsible for our findings.
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| Support: |
Sevier Laboratories |
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