Two distinct ipsilateral cortical representations for individuated finger movements.
Two distinct ipsilateral cortical representations for individuated finger movements.
复制标题
针对个体手指运动的两个不同的同侧皮质表示。
DOI：
10.1093/cercor/bhs120
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发表时间：
2013-06
期刊：
影响因子：
--
通讯作者：
Krakauer JW
中科院分区：
文献类型：
--
作者：
Diedrichsen J;Wiestler T;Krakauer JW
上肢的运动主要通过对侧半球控制。虽然同侧运动皮层的整体活动变化已被报道，其功能意义仍不清楚。使用人类功能成像，我们分析了神经手指表征通过研究细粒度激活模式的差异，为单等距手指按压。我们证明，皮质运动区编码同侧运动在2个根本不同的方式。在单手同侧手指按下，初级感觉和运动皮层显示，下面的全球抑制，手指特定的活动模式，几乎相同的对侧镜像对称行动引起的。当双手动作时，两个运动皮层都在功能上参与时，这个成分就消失了。我们认为，在unimanual压力出现同侧代表，因为否则功能闲置电路驱动的输入从相反的半球。第二种类型的代表成为明显的尾运动前区和前顶叶皮层在双手行动。在这些区域中，同侧动作被表示为与对侧动作相关的活动模式的非线性调制，这是一种编码方案，可以为协调双手动作提供神经基质。我们的结论是，同侧皮层代表改变其信息内容和功能的作用，这取决于行为的背景。
Movements of the upper limb are controlled mostly through the contralateral hemisphere. Although overall activity changes in the ipsilateral motor cortex have been reported, their functional significance remains unclear. Using human functional imaging, we analyzed neural finger representations by studying differences in fine-grained activation patterns for single isometric finger presses. We demonstrate that cortical motor areas encode ipsilateral movements in 2 fundamentally different ways. During unimanual ipsilateral finger presses, primary sensory and motor cortices show, underneath global suppression, finger-specific activity patterns that are nearly identical to those elicited by contralateral mirror-symmetric action. This component vanishes when both motor cortices are functionally engaged during bimanual actions. We suggest that the ipsilateral representation present during unimanual presses arises because otherwise functionally idle circuits are driven by input from the opposite hemisphere. A second type of representation becomes evident in caudal premotor and anterior parietal cortices during bimanual actions. In these regions, ipsilateral actions are represented as nonlinear modulation of activity patterns related to contralateral actions, an encoding scheme that may provide the neural substrate for coordinating bimanual movements. We conclude that ipsilateral cortical representations change their informational content and functional role, depending on the behavioral context.
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