Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA; Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA.
Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA.
Cell. 2022 Nov 23;185(24):4541-4559.e23. doi: 10.1016/j.cell.2022.10.012. Epub 2022 Nov 4.
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.
脊髓背角（DH）中触觉的编码及其对大脑中触觉表象的影响知之甚少。本研究使用一系列施加于皮肤的机械刺激、大规模的体内电生理记录和遗传操作，结果表明，小鼠脊髓 DH 中的神经元接收来自低阈值和高阈值机械感受器亚型的会聚输入，并表现出六种具有不同机械反应特征的功能之一。DH 前馈或反馈抑制基序的遗传破坏，由具有不同机械反应特征的中间神经元组成，揭示了一个广泛互联的 DH 网络，使突触后背柱（PSDC）输出神经元能够进行动态、灵活的调谐，并决定初级体感皮层中的神经元对触觉的反应。因此，机械感受器亚型的会聚和感觉层次最早阶段的非线性转换决定了皮肤触摸在大脑中的表现方式。
