Custead Rebecca, Oh Hyuntaek, Wang Yingying, Barlow Steven
Special Education and Communication Disorders, University of Nebraska, Lincoln, NE, USA; Center for Brain, Biology and Behavior, University of Nebraska, Lincoln, NE, USA.
Biological Systems Engineering, University of Nebraska, Lincoln, NE, USA; Center for Brain, Biology and Behavior, University of Nebraska, Lincoln, NE, USA.
Brain Res. 2017 Dec 15;1677:58-73. doi: 10.1016/j.brainres.2017.09.025. Epub 2017 Sep 27.
Processing dynamic tactile inputs is a primary function of the somatosensory system. Spatial velocity encoding mechanisms by the nervous system are important for skilled movement production and may play a role in recovery of sensorimotor function following neurological insult. Little is known about tactile velocity encoding in mechanosensory trigeminal networks required for speech, suck, mastication, and facial gesture. High resolution functional magnetic resonance imaging (fMRI) was used to investigate the neural substrates of velocity encoding in the human orofacial somatosensory system during unilateral saltatory pneumotactile stimulation of perioral and buccal hairy skin in 20 neurotypical adults. A custom multichannel, scalable pneumotactile array consisting of 7 TAC-Cells was used to present 5 stimulus conditions: 5cm/s, 25cm/s, 65cm/s, ALL-ON synchronous activation, and ALL-OFF. The spatiotemporal organization of whole-brain blood oxygen level-dependent (BOLD) response was analyzed with general linear modeling (GLM) and fitted response estimates of percent signal change to compare activations associated with each velocity, and the main effect of velocity alone. Sequential saltatory inputs to the right lower face produced localized BOLD responses in 6 key regions of interest (ROI) including; contralateral precentral and postcentral gyri, and ipsilateral precentral, superior temporal (STG), supramarginal gyri (SMG), and cerebellum. The spatiotemporal organization of the evoked BOLD response was highly dependent on velocity, with the greatest amplitude of BOLD signal change recorded during the 5cm/s presentation in the contralateral hemisphere. Temporal analysis of BOLD response by velocity indicated rapid adaptation via a scalability of networks processing changing pneumotactile velocity cues.
处理动态触觉输入是体感系统的主要功能。神经系统的空间速度编码机制对熟练运动的产生很重要，并且可能在神经损伤后感觉运动功能的恢复中发挥作用。对于言语、吮吸、咀嚼和面部手势所需的机械感觉三叉神经网络中的触觉速度编码知之甚少。在20名神经典型的成年人中，当对口周和颊部多毛皮肤进行单侧跳跃式气动触觉刺激时，使用高分辨率功能磁共振成像（fMRI）来研究人类口面部体感系统中速度编码的神经基质。一个由7个TAC细胞组成的定制多通道、可扩展的气动触觉阵列用于呈现5种刺激条件：5cm/s、25cm/s、65cm/s、全开启同步激活和全关闭。使用一般线性模型（GLM）分析全脑血氧水平依赖（BOLD）反应的时空组织，并对信号变化百分比的拟合反应估计值进行比较，以比较与每个速度相关的激活以及仅速度的主要效应。对右下脸的顺序跳跃式输入在6个关键感兴趣区域（ROI）产生了局部BOLD反应，包括：对侧中央前回和中央后回，以及同侧中央前回、颞上回（STG）、缘上回（SMG）和小脑。诱发的BOLD反应的时空组织高度依赖于速度，在对侧半球以5cm/s呈现期间记录到的BOLD信号变化幅度最大。按速度对BOLD反应进行时间分析表明，通过处理不断变化的气动触觉速度线索的网络的可扩展性实现了快速适应。
