Program#/Poster#: |
634.14/CC43 |
Title: |
Are the auditory pathways converging in the Lateral Amygdala required for the expression of Pavlovian defense reactions? |
Location: |
Hall A |
Presentation Time: |
Tuesday, Oct 20, 2015, 1:00 PM - 5:00 PM |
Presenter at Poster |
Tue, Oct. 20, 2015, 2:00 PM - 3:00 PM |
Topics: |
++F.03.f. Motivation and emotions: Neurocircuitry |
Authors: |
*L. DIAZ-MATAIX1, N. BENABDALLAH1, S. A. SERKA1, V. DOYERE2,1, J. E. LEDOUX1,3;
1Ctr. for Neural Sci., New York Univ., New York, NY; 2Cognition and Behavior, Paris-Saclay Inst. of Neurosci. (Neuro-PSI), Orsay, France; 3Ebi, Nathan Kline Inst., Orangeburg, NY |
Abstract: |
In Pavlovian auditory threat conditioning the conditioned stimulus (CS) arrives to the Lateral Nucleus of the Amygdala (LA) through two main brain pathways: a direct thalamo-amygdala, and an indirect thalamo-cortico-amygdala connection. The acoustic stimulus arrives to the medial areas of the auditory thalamus composed by the Medial Geniculate Nucleus (MGm) and the Post Intralaminar Nucleus (PIL), and from these nuclei projections is sent to the LA. The CS can also reach the LA through a pathway from the auditory thalamus to the primary auditory cortex (Temporal Associatin Cortex area TE1) which in the rat projects to TE3, and from there to the LA. Either of these two pathways (thalamo- and cortico-amygdala) is sufficient to mediate threat conditioning (Romanski & LeDoux., 1992; LeDoux., 1995). Electrophysiological studies show that threat learning induces persistent enhanced synaptic plasticity in both cortico and thalamo-amygdala pathways (Tsvetkov et al., 2002; Rogan et al., 1997). Although the contribution of these auditory pathways to threat learning has been extensively studied, little is known about their role in the expression of threat memories. By using chemogenetics we examined the contribution of these auditory pathways to the expression of learned defense responses to a pure tone. MGm/PIL or TE3 was infected with virus carrying inhibitory Designer Receptors Exclusively Activated by Designer Drugs (DREADDs). After 6 weeks cannulae were implanted bilaterally into LA with a stainless steel recording electrode attached to the left cannula. Rats were habituated to the CS and context before conditioning them by presenting 3 tone (CS)-shock (US) pairings. Long-term memory tests were performed by presenting 5 unreinforced CSs after intra-LA infusion of the DREADD agonist CNO (Clozapine-N-oxide) or vehicle in the same animals in a counterbalanced manner to allow within animal comparison. The inactivation of the thalamic terminals in the LA by the infusion of CNO impairs freezing in parallel with a decrease in the amplitude of the LA auditory field evoked potential. Ongoing experiments are being conducted to elucidate the role of auditory cortex on threat memory expression. So far, the results suggest the necessity of an intact and functional thalamo-amygdala circuit for the expression of previously learned defense responses. |
Disclosures: |
L. Diaz-Mataix: None. N. Benabdallah: None. S.A. Serka: None. V. Doyere: None. J.E. LeDoux: None. |
Keyword
(s): |
AMYGDALA |
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MEMORY |
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ELECTROPHYSIOLOGY |
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