美国哈佛医学院David D. Ginty研究小组发现，后角的机械感受器信号汇聚和转换灵活地形成对大脑输出的多样性。相关论文于2022年11月4日在线发表在《细胞》杂志上。

利用一系列施加在皮肤上的机械刺激、大规模的体内电生理记录和遗传操作，研究人员表明，小鼠脊髓后角（DH）的神经元从低阈值和高阈值的机械感受器亚型中接受汇聚的输入，并表现出六种功能不同的机械反应谱之一。

对DH前馈或反馈抑制基序（由具有不同机械反应谱的神经元组成）的遗传破坏揭示了一个广泛互联的DH网络，使突触后背柱（PSDC）输出神经元得到动态、灵活的调谐，并决定了初级体感皮层的神经元如何对触摸作出反应。因此，机械感受器亚型的融合和非线性转换在体感层次的最早阶段塑造了皮肤触摸在大脑中的表现方式。

据悉，人们对脊髓DH中触觉的编码及其对大脑中触觉表征的影响了解甚少。

附：英文原文

Title: Mechanoreceptor signal convergence and transformation in the dorsal horn flexibly shape a diversity of outputs to the brain

Author: Anda M. Chirila, Genelle Rankin, Shih-Yi Tseng, Alan J. Emanuel, Carmine L. Chavez-Martinez, Dawei Zhang, Christopher D. Harvey, David D. Ginty

Issue&Volume: 2022-11-04

Abstract: The encoding of touch in the spinal cord dorsal horn (DH) and its influence on tactile representations in the brain are poorly understood. Using a range of mechanical stimuli applied to the skin, large-scale in vivo electrophysiological recordings, and genetic manipulations, here we show that neurons in the mouse spinal cord DH receive convergent inputs from both low- and high-threshold mechanoreceptor subtypes and exhibit one of six functionally distinct mechanical response profiles. Genetic disruption of DH feedforward or feedback inhibitory motifs, comprised of interneurons with distinct mechanical response profiles, revealed an extensively interconnected DH network that enables dynamic, flexible tuning of postsynaptic dorsal column (PSDC) output neurons and dictates how neurons in the primary somatosensory cortex respond to touch. Thus, mechanoreceptor subtype convergence and non-linear transformations at the earliest stage of the somatosensory hierarchy shape how touch of the skin is represented in the brain.

DOI: 10.1016/j.cell.2022.10.012

Source: https://www.cell.com/cell/fulltext/S0092-8674(22)01327-7