Cortical Representation of Bimanual Movements
Cortical Representation of Bimanual Movements
复制标题
双手运动的皮质表征
DOI：
10.1523/jneurosci.23-37-11577.2003
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
H. Sompolinsky
中科院分区：
文献类型：
--
作者：
U. Rokni;O. Steinberg;E. Vaadia;H. Sompolinsky
灵长类动物运动皮层神经元的放电是被调节到对侧手臂的运动方向上的。有趣的是，研究发现，这些神经元也表现出对同侧手臂的定向调节，而且对双臂的偏好方向往往是相似的。最近的一项研究表明，运动皮层细胞对双手运动也有定向选择性，但双手和单手表征之间的关系尚不清楚。为了解决这个问题，我们分析了两只猕猴在单手和双手触摸运动时运动皮质神经元的反应。我们将双手运动表征分解为对侧和同侧方向调谐分量。我们的主要发现是，对侧手臂的运动改变了细胞对同侧手臂的调谐，这样：(1)调谐的偏移和调制深度被抑制；(2)优选方向随机移位。这两种影响都消除了双手运动中对侧和同侧表征之间的相关性。我们认为同侧手臂表征的改变是由在双手运动中传递胼胝体输入的局部抑制的招募引起的。这一假设得到了两个运动皮层网络模型分析的支持，该模型与再现数据中观察到的主要特征的稀疏随机半球间投影相结合。最后，我们证明了同侧手臂表示的修改减少了双臂运动之间的干扰。
It is well established that the discharge of neurons in primate motor cortex is tuned to the movement direction of the contralateral arm. Interestingly, it has been found that these neurons exhibit a directional tuning to the ipsilateral arm as well and that the preferred directions to both arms tend to be similar. A recent study showed that motor cortex cells are also directionally selective to bimanual movements, but the relationship between the bimanual and unimanual representations remains unclear. To address this issue, we analyzed the responses of motor cortical neurons recorded from two macaque monkeys during unimanual and bimanual reaching movements. We decomposed the bimanual movement representation into contralateral and ipsilateral directionally tuned components. Our major finding is that the movement of the contralateral arm modifies the tuning of the cells to the ipsilateral arm such that: (1) the offset and modulation depth of the tuning are suppressed; and (2) the preferred directions are randomly shifted. Both these effects eliminate the correlation between the contralateral and ipsilateral representations during bimanual movements. We suggest that the modification of the ipsilateral arm representation is caused by the recruitment of local inhibition that conveys callosal inputs during bimanual movements. This hypothesis is supported by the analysis of a model of two motor cortical networks, coupled with sparse random interhemispheric projections that reproduce the main features observed in the data. Finally, we show that the modification of the ipsilateral arm representation reduces the interference between the movements of both arms.
影响因子：
56.9
作者：
Martin B. Stemmler;Marius Usher;Marius Usher;Marius Usher;E. Niebur
通讯作者：
Martin B. Stemmler;Marius Usher;Marius Usher;Marius Usher;E. Niebur
DOI：
10.1073/pnas.93.18.9869
发表时间：
1996-09
影响因子：
11.1
作者：
L. Toth;S. Rao;Dae-Shik Kim;D. Somers;Mriganka Sur
通讯作者：
L. Toth;S. Rao;Dae-Shik Kim;D. Somers;Mriganka Sur
影响因子：
2.5
作者：
Moran, DW;Schwartz, AB
通讯作者：
Schwartz, AB