Functional thalamocortical innervation of VIP- and SST-expressing GABAergic interneurons in mouse barrel cortex

Michael Feyerabend; Mirko Witte; Martin Möck; Jochen F Staiger

doi:10.1016/j.isci.2025.112539

Functional thalamocortical innervation of VIP- and SST-expressing GABAergic interneurons in mouse barrel cortex

iScience. 2025 Apr 28;28(6):112539. doi: 10.1016/j.isci.2025.112539. eCollection 2025 Jun 20.

Authors

Michael Feyerabend^{1

2

3}, Mirko Witte¹, Martin Möck¹, Jochen F Staiger¹

Affiliations

¹ Georg-August-University Göttingen, University Medical Center, Institute for Neuroanatomy, Kreuzbergring 36, 37075 Göttingen, Germany.
² Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada.
³ Robarts Research Institute, University of Western Ontario, London, ON, Canada.

Abstract

In sensory cortices, conscious perception of stimuli involves a complex interplay of excitatory and inhibitory circuits. The subcortical source of sensory information is the thalamus, which in the whisker system houses (1) the "lemniscal" ventral posteromedial nucleus (VPM) and (2) the "paralemniscal" medial part of the posterior nucleus (POm). How much these two complementary inputs can drive feedforward inhibition in cortical layers by synapsing on GABAergic neurons is still incompletely understood. Here, we used optogenetics to study the incidence of VPM and POm projections to vasoactive intestinal polypeptide (VIP)- and somatostatin (SST)-expressing interneurons in barrel cortex. By using sensitive stimulation and recording methods, we show that VIP and SST neurons receive an extensive input, largely independent of laminar location or various cellular properties. Thus, thalamus-mediated feedforward inhibition is implemented in the circuit motifs of probably all VIP and SST interneurons, which they might differentially use, dependent on specific whisking behaviors.

Keywords: Molecular biology; Neuroscience.