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Different Fear States Engage Distinct Networks within the Intercalated Cell Clusters of the Amygdala

Authors :
Nicolas Singewald
Francesco Ferraguti
Raffaella Geracitano
Daniela Busti
Mirosława Mańko
Marco Capogna
Yannis Dalezios
Nigel Whittle
Walter E. Kaufmann
Kurt Sätzler
Source :
Busti, D, Geracitano, R, Whittle, N, Dalezios, Y, Mańko, M, Kaufmann, W, Sätzler, K, Singewald, N, Capogna, M & Ferraguti, F 2011, ' Different fear states engage distinct networks within the intercalated cell clusters of the amygdala ', The Journal of neuroscience : the official journal of the Society for Neuroscience, vol. 31, no. 13, pp. 5131-44 . https://doi.org/10.1523/JNEUROSCI.6100-10.2011
Publication Year :
2011
Publisher :
Society for Neuroscience, 2011.

Abstract

Although extinction-based therapies are among the most effective treatments for anxiety disorders, the neural bases of fear extinction remain still essentially unclear. Recent evidence suggests that the intercalated cell masses of the amygdala (ITCs) are critical structures for fear extinction. However, the neuronal organization of ITCs and how distinct clusters contribute to different fear states are still entirely unknown. Here, by combining whole-cell patch-clamp recordings and biocytin labeling with full anatomical reconstruction of the filled neurons and ultrastructural analysis of their synaptic contacts, we have elucidated the cellular organization and efferent connections of one of the main ITC clusters in mice. Our data showed an unexpected heterogeneity in the axonal pattern of medial paracapsular ITC (Imp) neurons and the presence of three distinct neuronal subtypes. Functionally, we observed that the Imp was preferentially activated during fear expression, whereas extinction training and extinction retrieval activated the main ITC nucleus (IN), as measured by quantifying Zif268 expression. This can be explained by the IPSPs evoked in the IN after Imp stimulation, most likely through the GABAergic monosynaptic innervation of IN neurons by one subtype of Imp cells, namely the medial capsular-projecting (MCp)–Imp neurons. MCp–Imp neurons also target large ITC cells that surround ITC clusters and express the metabotropic glutamate receptor 1α. These findings reveal a distinctive participation of ITC clusters to different fear states and the underlying anatomical circuitries, hence shedding new light on ITC networks and providing a novel framework to elucidate their role in fear expression and extinction.

Details

ISSN :
15292401 and 02706474
Volume :
31
Database :
OpenAIRE
Journal :
The Journal of Neuroscience
Accession number :
edsair.doi.dedup.....2b270c13a0443cc272ac7b1a3c5faaa3
Full Text :
https://doi.org/10.1523/jneurosci.6100-10.2011