| Program#/Poster#: |
860.11/JJJ6 |
| Title: |
Physiological neural correlates of timing in the brain circuit underlying auditory threat conditioning |
| Location: |
Halls B-H |
| Presentation Time: |
Wednesday, Nov 13, 2013, 3:00 PM - 4:00 PM |
| Authors: |
*L. DIAZ-MATAIX1, M. GRAUPNER1, J. E. LEDOUX1,2, V. DOYERE3,4;
1Ctr. for Neural Sci., New York Univ., NEW YORK, NY; 2Nathan Kline Inst. for Psychiatric Res., Orangeburg, NY; 3Ctr. de Neurosciences Paris-Sud, UMR 8195, Univ. Paris-Sud, Orsay, France; 4CNRS, Orsay, France |
| Abstract: |
In auditory threat conditioning the animal not only learns that the conditioned stimulus (CS) predicts the unconditioned stimulus (US) but also when the US is supposed to arrive. The tone CS and the shock US information converge on cells of the lateral nucleus of the amygdala (LA), an area critical for learning and storing the CS-US association. The auditory CS reaches the LA after being primarily processed in the auditory thalamus, which projects directly to the LA. Among the extensive afferent and efferent connections of the amygdala, interactions with the hippocampus (CA1) are particularly important for the modulation of explicit memory. Moreover, synaptic plasticity in each of these brain regions (LA, auditory thalamus, hippocampus) occurs after threat conditioning. Using an conditioning protocol in which the US is presented in the middle of a long 60 seconds CS, we recorded local field-potentials (LFP) in the LA, auditory thalamus, and CA1 region of the hippocampus in behaving rats before and during conditioning, and during extinction. After extinction rats were re-conditioned with a different CS-US interval. This design allows differentiation of the time of arrival of the US from CS-onset or CS-offset responses. Time-frequency analyses were performed to assess power spectral density of the LFP recorded in each of these brain areas in the different frequency ranges (delta, theta, beta, gamma), as well as their functional connectivity (coherence among the LFPs). Changes in the power spectral density and in the coherence between were observed after conditioning as well as after extinction. Furthermore, we found neural activity correlated with the expected time of arrival of the US. These results provide new knowledge about the neurophysiology of the circuits responsible for threat conditioning and suggest an involvement of the threat circuit not only in processing the CS-US association but also in computing the CS-US time interval.
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| Support: |
Sevier Laboratories |
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