Feyerabend Michael, Witte Mirko, Möck Martin, Staiger Jochen F
Georg-August-University Göttingen, University Medical Center, Institute for Neuroanatomy, Kreuzbergring 36, 37075 Göttingen, Germany.
Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada.
iScience. 2025 Apr 28;28(6):112539. doi: 10.1016/j.isci.2025.112539. eCollection 2025 Jun 20.
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.
在感觉皮层中，对刺激的有意识感知涉及兴奋性和抑制性回路的复杂相互作用。感觉信息的皮层下来源是丘脑，在触须系统中，丘脑包含（1）“lemniscal”腹后内侧核（VPM）和（2）后核（POm）的“旁lemniscal”内侧部分。这两种互补输入通过与GABA能神经元形成突触，在多大程度上能够驱动皮层各层的前馈抑制，目前仍未完全了解。在这里，我们使用光遗传学来研究VPM和POm投射到桶状皮层中表达血管活性肠肽（VIP）和生长抑素（SST）的中间神经元的发生率。通过使用敏感的刺激和记录方法，我们表明VIP和SST神经元接受广泛的输入，很大程度上独立于层位位置或各种细胞特性。因此，丘脑介导的前馈抑制可能在所有VIP和SST中间神经元的回路模式中实现，它们可能根据特定的触须行为进行不同的利用。
