Liu Yuqi, Halfen Elizabeth J, Yau Jeffrey M, Fischer-Baum Simon, Kohler Peter J, Faseyitan Olufunsho, Coslett H Branch, Medina Jared
CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, PR China; Department of Psychological and Brain Sciences, University of Delaware, USA.
Department of Neuroscience, Baylor College of Medicine, USA.
Neuroimage. 2025 Aug 15;317:121336. doi: 10.1016/j.neuroimage.2025.121336. Epub 2025 Jun 17.
Somatosensory inputs are critical to motor control. Animal studies have shown that primary somatosensory lesions cause sensorimotor deficits along with disrupted organization in primary motor cortex (M1). How does damage in primary somatosensory cortex (S1) influence motor networks in humans? Using fMRI, we examined two individuals, LS and RF, who had extensive damage to left somatosensory cortex, but primarily intact motor cortex and preserved motor abilities. Given left S1 damage, tactile detection and localization were impaired for the contralesional hand in both individuals. When moving the contralesional hand, LS, with near complete damage to S1 hand area, showed increased activation in ipsilesional putamen and deactivation in contralesional cerebellum relative to age-matched controls. These findings demonstrate influences of S1 damage to subcortical sensorimotor areas that are distant from the lesion site, and a potential reweighting of the motor network with increased action selection in putamen and inhibition of sensory prediction in cerebellum in the face of sensory loss. In contrast, RF, who had a small island of spared S1 in the hand area, showed greater activation in contralesional S1 for movement versus rest. This same region was also activated by pure somatosensory stimulation in a second experiment, suggesting that the spared S1 area in RF still subserves sensorimotor processing. Finally, the right middle occipital gyrus was more strongly activated in both individuals compared with controls, suggesting the potential reliance on visual imagery in the face of degraded sensory feedback.
体感输入对运动控制至关重要。动物研究表明，原发性体感损伤会导致感觉运动缺陷，同时初级运动皮层（M1）的组织也会受到破坏。原发性体感皮层（S1）的损伤如何影响人类的运动网络？我们使用功能磁共振成像（fMRI）对两名个体LS和RF进行了检查，他们的左侧体感皮层受到广泛损伤，但主要运动皮层完好且运动能力保留。鉴于左侧S1损伤，两名个体对侧手的触觉检测和定位均受损。当对侧手移动时，S1手部区域几乎完全受损的LS相对于年龄匹配的对照组，同侧壳核激活增加，对侧小脑失活。这些发现表明S1损伤对远离病变部位的皮层下感觉运动区域有影响，并且在面对感觉丧失时，运动网络可能会重新加权，增加壳核中的动作选择并抑制小脑中的感觉预测。相比之下，手部区域有一小片S1保留区的RF在运动与静息状态下，对侧S1的激活更强。在第二个实验中，同一区域也被纯体感刺激激活，这表明RF中保留的S1区域仍然参与感觉运动处理。最后，与对照组相比，两名个体的右侧枕中回激活更强，这表明在感觉反馈退化的情况下可能依赖视觉意象。
