Center for Information and Neural Networks (CiNet), National Institute of Information and Communications Technology (NICT), 1-4 Yamadaoka, Suita, Osaka, 565-0871, Japan.
Institute for Open and Transdisciplinary Research Initiatives, Osaka University, 1-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.
Brain Imaging Behav. 2021 Apr;15(2):656-676. doi: 10.1007/s11682-020-00275-w.
In people with normal sight, mental simulation (motor imagery) of an experienced action involves a multisensory (especially kinesthetic and visual) emulation process associated with the action. Here, we examined how long-term blindness influences sensory experience during motor imagery and its neuronal correlates by comparing data obtained from blind and sighted people. We scanned brain activity with functional magnetic resonance imaging (fMRI) while 16 sighted and 14 blind male volunteers imagined either walking or jogging around a circle of 2 m radius. In the training before fMRI, they performed these actions with their eyes closed. During scanning, we explicitly instructed the blindfolded participants to generate kinesthetic motor imagery. After the experimental run, they rated the degree to which their motor imagery became kinesthetic or spatio-visual. The imagery of blind people was more kinesthetic as per instructions, while that of the sighted group became more spatio-visual. The imagery of both groups commonly activated bilateral frontoparietal cortices including supplementary motor areas (SMA). Despite the lack of group differences in degree of brain activation, we observed stronger functional connectivity between the SMA and cerebellum in the blind group compared to that in the sighted group. To conclude, long-term blindness likely changes sensory emulation during motor imagery to a more kinesthetic mode, which may be associated with stronger functional coupling in kinesthetic brain networks compared with that in sighted people. This study adds valuable knowledge on motor cognition and mental imagery processes in the blind.
在视力正常的人群中，对经历过的动作的心理模拟（运动想象）涉及与该动作相关的多感觉（特别是动觉和视觉）模拟过程。在这里，我们通过比较盲人（n=14）和视力正常者（n=16）的数据，研究了长期失明如何影响运动想象过程中的感觉体验及其神经相关性。我们使用功能磁共振成像（fMRI）扫描大脑活动，16 名视力正常的男性志愿者和 14 名盲人男性志愿者分别想象围绕半径为 2 米的圆圈行走或慢跑。在 fMRI 扫描之前的训练中，他们闭上眼睛完成这些动作。在扫描过程中，我们明确要求蒙住眼睛的参与者产生动觉运动想象。实验结束后，他们对运动想象变得动觉或空间视觉的程度进行评分。根据指令，盲人的想象更具动觉性，而视力正常者的想象更具空间视觉性。两组的想象通常都会激活双侧额顶叶皮质，包括辅助运动区（SMA）。尽管两组在大脑激活程度上没有差异，但我们观察到盲人组 SMA 与小脑之间的功能连接强度大于视力正常者组。总之，长期失明可能会使运动想象过程中的感觉模拟转变为更具动觉的模式，这可能与动觉脑网络的功能连接比视力正常者更强有关。这项研究为盲人的运动认知和心理意象过程增加了有价值的知识。
