Synaptic interactions in the thalamocortical system during sensory processing

11 JUIN 2018 - 11H

Ferenc Matyas, Research Centre for Natural Sciences, Budapest, Hongrie

Lieu : Salle B501

Résumé : Thalamic inputs are known to regulate amygdalar actions via transferring various brainstem and cortical information as well. Two separate thalamic regions are shown to send inputs to amygdalar subregions. Whereas the midline thalamo-amygdala pathway arising from the paraventricular thalamus (PVT) is suggested to carry arousal effects, the lateral routes originating from the suprageniculate (SG) and posterior intralaminar thalamic nucleus (PIL) mediate sensory-like information in fear learning. However, the exact neural elements and mechanisms of thalamic networks shaping amygdala-dependent behaviors are yet to be clarified. Here we identify a thalamic cell type, the calretinin-expressing (CR+) neurons in both regions, which provide exclusive thalamic input to the amygdala. These cells innervate the amygdala in a nucleus-specific fashion which is further proven byin vivoelectrophysiological recordings. Midline CR+ cells strongly project to the basolateral (BA) and central amygdala (CeA), while lateral CR+ cells innervate the lateral amygdala (LA) and the neighboring amygdalostriatal transition area (AStr). Applying the CR-Cre mouse line alongside with conditional viral vectors and optogenetics, we show an intensity-specific arousal control by the midline CR+ thalamic neuron population. Furthermore, midline CR+ cells display elevated activity prior to arousal, suggesting a causal relationship between CR+ cell activation and awakening. We also perform bidirectional optogenetic manipulation of CR+ lateral thalamic inputs in the amygdala which has revealed essential roles for this pathway in the generation and recall of cued fear memory. Finally, by performing againin vivoextracellular recordings in freely behaving mice, we show that individual CR+ lateral thalamic cells change their characteristic firing in distinct phases of associative fear learning. Placing our assumptions in a larger perspective, we suggest the existence of parallel thalamo-amygdalar circuits, namely the PVT-BA-CeA and SG/PIL-LA-AStr, which control different aspects of amygdala-related behavioral responses.

Co-authors: Barsy, B.1, Kocsis, K.1,4, Komlosi, G.2, Babiczky, A.1,2, Magyar, A.1, Kanti, V.1,5,Horváth M.1, Hillier, D.6, Yizhar, O.7,Berényi A.8, Acsády, L.2

4) Roska Tamás Doctoral School of Sciences and Technology, Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest Hungary; 5)János Szentágothai School of Neurosciences, Semmelweis University, Budapest, Hungary;6)Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland; 7)Department of Neurobiology, Weizmann Institute of Science, Rehovot, Israel; 8) Department of Physiology, University of Szeged, Szeged, Hungary.