Somatotopic Specificity of Perceptual and Neurophysiological Changes Associated with Visuo-proprioceptive Realignment
Somatotopic Specificity of Perceptual and Neurophysiological Changes Associated with Visuo-proprioceptive Realignment
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DOI：
10.1093/cercor/bhab280
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发表时间：
2021-08-23
期刊：
影响因子：
3.7
通讯作者：
Block, Hannah J.
中科院分区：
文献类型：
--
作者：
Mirdamadi, Jasmine L.;Seigel, Courtney R.;Block, Hannah J.
当手部位置的视觉和本体感受估计不一致时（例如，观察水下的手），大脑重新调整它们以减少不匹配。这种感知变化反映在初级运动皮质（M1）的兴奋性中，表明与手部运动潜在相关。在这里，我们询问指尖视觉-本体感受错位是否只影响大脑对该手指的表征（躯体位置局灶性），或者延伸到肢体的其他部位，这些部位需要移动错位的手指（躯体位置广泛）。在实验1和2中，在食指错位或真实的视觉本体感受训练之前和之后，我们使用经颅磁刺激来评估五只手和手臂肌肉的M1代表性。食指代表性表现出M1兴奋性和视觉本体感受的重新排列之间的关联，小指代表性在较小程度上。前臂屈肌、前臂伸肌和二头肌没有表现出任何这种关系。在实验3中，参与者表明他们的指尖，指关节，手腕，肘部，在指尖错位之前和之后的本体感受估计。关节处的本体感觉重新排列，而不是手腕或肘部，与指尖的重新排列相关。这些结果表明，视觉本体感受不匹配的影响是躯体定位局灶性的感觉和运动域。
When visual and proprioceptive estimates of hand position disagree (e.g., viewing the hand underwater), the brain realigns them to reduce mismatch. This perceptual change is reflected in primary motor cortex (M1) excitability, suggesting potential relevance for hand movement. Here, we asked whether fingertip visuo-proprioceptive misalignment affects only the brain's representation of that finger (somatotopically focal), or extends to other parts of the limb that would be needed to move the misaligned finger (somatotopically broad). In Experiments 1 and 2, before and after misaligned or veridical visuo-proprioceptive training at the index finger, we used transcranial magnetic stimulation to assess M1 representation of five hand and arm muscles. The index finger representation showed an association between M1 excitability and visuo-proprioceptive realignment, as did the pinkie finger representation to a lesser extent. Forearm flexors, forearm extensors, and biceps did not show any such relationship. In Experiment 3, participants indicated their proprioceptive estimate of the fingertip, knuckle, wrist, and elbow, before and after misalignment at the fingertip. Proprioceptive realignment at the knuckle, but not the wrist or elbow, was correlated with realignment at the fingertip. These results suggest the effects of visuo-proprioceptive mismatch are somatotopically focal in both sensory and motor domains.