University Medical Center Göttingen, Institute for Neuroanatomy, Göttingen, Germany; and Laboratory of Sensory Processing, Faculty of Life Sciences, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
Physiol Rev. 2021 Jan 1;101(1):353-415. doi: 10.1152/physrev.00019.2019. Epub 2020 Aug 20.
The array of whiskers on the snout provides rodents with tactile sensory information relating to the size, shape and texture of objects in their immediate environment. Rodents can use their whiskers to detect stimuli, distinguish textures, locate objects and navigate. Important aspects of whisker sensation are thought to result from neuronal computations in the whisker somatosensory cortex (wS1). Each whisker is individually represented in the somatotopic map of wS1 by an anatomical unit named a 'barrel' (hence also called barrel cortex). This allows precise investigation of sensory processing in the context of a well-defined map. Here, we first review the signaling pathways from the whiskers to wS1, and then discuss current understanding of the various types of excitatory and inhibitory neurons present within wS1. Different classes of cells can be defined according to anatomical, electrophysiological and molecular features. The synaptic connectivity of neurons within local wS1 microcircuits, as well as their long-range interactions and the impact of neuromodulators, are beginning to be understood. Recent technological progress has allowed cell-type-specific connectivity to be related to cell-type-specific activity during whisker-related behaviors. An important goal for future research is to obtain a causal and mechanistic understanding of how selected aspects of tactile sensory information are processed by specific types of neurons in the synaptically connected neuronal networks of wS1 and signaled to downstream brain areas, thus contributing to sensory-guided decision-making.
鼻子上的一排胡须为啮齿动物提供了与周围环境中物体的大小、形状和质地有关的触觉感官信息。啮齿动物可以用它们的胡须来探测刺激、区分质地、定位物体和导航。胡须感觉的重要方面被认为是由于胡须体感皮层（wS1）中的神经元计算产生的。每个胡须在 wS1 的躯体感觉图谱中都由一个称为“桶状结构”（因此也称为桶状皮层）的解剖单位单独表示。这允许在定义明确的图谱中精确研究感觉处理。在这里，我们首先回顾了从胡须到 wS1 的信号通路，然后讨论了目前对存在于 wS1 内的各种兴奋性和抑制性神经元的理解。根据解剖学、电生理学和分子特征，可以定义不同的细胞类型。局部 wS1 微电路内神经元的突触连接，以及它们的长程相互作用和神经调质的影响，开始被理解。最近的技术进步使得能够将细胞类型特异性连接与与胡须相关的行为期间的细胞类型特异性活动相关联。未来研究的一个重要目标是获得因果关系和机制理解，即特定类型的神经元如何处理触觉感觉信息的特定方面，并将其信号传递到下游大脑区域，从而促进感觉引导的决策制定。
