Wang Yutong, Luo Di, Ma Lihua, Wang Luyao, Wu Jinglong, Zhang Jian, Yan Tianyi
School of Medical Technology, Beijing Institute of Technology, No. 5 South Street Zhongguancun, Beijing 100081, China.
School of Mechatronical Engineering, Beijing Institute of Technology, Beijing 100081, China.
Neuroimage. 2025 Apr 15;310:121126. doi: 10.1016/j.neuroimage.2025.121126. Epub 2025 Mar 6.
The 7T functional magnetic resonance imaging (fMRI) can provide a detailed somatotopic map. However, due to the constraints of MR-compatible applications, current tactile stimulation devices for the human hand are insufficient for precise somatotopic mapping experiments. In this study, we developed a novel 23-channel, hand-adaptive tactile stimulation device with high temporal and spatial resolution. The device consisted of an execution module and a control module. The device's output performance was measured using a laser displacement sensor. We investigated the somatotopic map of the non-dominant hand in the primary somatosensory cortex (S1) using the Bayesian population receptive field (pRF) model. The activation patterns, relative volumes, and activation center locations on S1 were assessed in somatotopic mapping experiments involving traveling wave stimulus paradigms with three stimulus orders (forward, backward, and random) in two dimensions (between-digit and within-digit). The percussive stimulation provided by the tactile stimulation device exhibited a stable displacement (2.58 mm) and a minimal output delay (4.45 milliseconds) across a wide range of vibration frequencies (0-30 Hz). The representation of digits and the palm in the between-digit dimension showed consistent somatotopic organization (D1-D2-D3-D4-D5-palm along the postcentral gyrus (poCG) from ventral to dorsal) across all three stimulation orders. Additionally, the relative volume of D1 in the random paradigm was significantly larger than in the forward and backward paradigms. The relative volume of the palm in the random paradigm was significantly larger than in the backward paradigm. The representation of the phalanges and palm in the within-digit dimension exhibited different activation patterns across different stimulation orders. These results provide new insights into the neural mechanisms in S1 and validate that the developed stimulation device can contribute to exploring the somatotopic map of the human hand.
7T功能磁共振成像（fMRI）能够提供详细的躯体感觉定位图。然而，由于磁共振兼容应用的限制，目前用于人手的触觉刺激设备不足以进行精确的躯体感觉定位映射实验。在本研究中，我们开发了一种新型的23通道、手部自适应触觉刺激设备，具有高时间和空间分辨率。该设备由执行模块和控制模块组成。使用激光位移传感器测量该设备的输出性能。我们使用贝叶斯群体感受野（pRF）模型研究了非优势手在初级躯体感觉皮层（S1）中的躯体感觉定位图。在涉及二维（指间和指内）三种刺激顺序（向前、向后和随机）的行波刺激范式的躯体感觉定位映射实验中，评估了S1上的激活模式、相对体积和激活中心位置。触觉刺激设备提供的敲击刺激在广泛的振动频率（0-30Hz）范围内表现出稳定的位移（2.58mm）和最小的输出延迟（4.45毫秒）。在所有三种刺激顺序中，指间维度上手指和手掌的表征显示出一致的躯体感觉组织（沿着中央后回（poCG）从腹侧到背侧为D1-D2-D3-D4-D5-手掌）。此外，随机范式中D1的相对体积显著大于向前和向后范式。随机范式中手掌的相对体积显著大于向后范式。指内维度上指骨和手掌的表现在不同刺激顺序下呈现出不同激活模式。这些结果为S1中的神经机制提供了新的见解，并验证了所开发的刺激设备有助于探索人手的躯体感觉定位图。
