Control of Muscle Synergies by Cortical Ensembles
Control of Muscle Synergies by Cortical Ensembles
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DOI：
10.1007/978-0-387-77064-2_9
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发表时间：
2009-01-01
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影响因子：
--
通讯作者：
Miller, Lee E.
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文献类型：
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作者：
Morrow, Michelle M.;Pohlmeyer, Eric A.;Miller, Lee E.
自20世纪80年代初引入以来，神经元放电的“首选方向”概念已被证明是研究大脑运动区单个神经元不同特性的有力手段。最近，从神经元集合记录的活动（每个神经元具有所有识别的优选方向）已被用于预测手部运动，离线地、实时地发现。我们最近的实验也解决了类似的问题，但重点是初级运动皮层放电和肌肉活动之间的关系，而不是肢体运动学。我们最近引入了“肌肉空间”首选方向（PDM）的概念，这类似于熟悉的手空间首选方向（PDH）。在这份手稿中，我们表明，有相当大的变化，这些PDM向量的方向跨神经元，但对于一个给定的任务和神经元，两个连续的测量PDM是非常相似的。我们发现这些向量倾向于在肌肉空间的特定区域形成簇，这可能反映了协同控制重要肌肉群的神经元，我们还表明，从神经集合测量的放电可以用来预测单个肌肉的活动，在很大程度上，运动学信号已经被其他群体预测。事实上，这些预测的准确性与运动学信号的准确性相似，尽管EMG信号具有随机性和更大的带宽。PDMS表示从一个神经元到多个肌肉的发散，而肌肉活动的预测表示从多个神经元到单个肌肉的收敛。我们正在继续调查这个复杂的功能互连矩阵的性质。
Since its introduction in the early 1980s, the concept of a "preferred direction" for neuronal discharge has proven to be a powerful means of Studying diverse properties of individual neurons in the motor areas of the brain. More recently, the activity recorded from ensembles of neurons, each with ail identified preferred direction, has been used to predict hand movement, both off-line, find in real-time. Our recent experiments]have addressed similar issues, but have focused oil the relation between primary motor cortical discharge and muscle activity, rather than limb kinematics.We recently introduced the concept of a "muscle-space" preferred direction (PDM), that is analogous to the familiar hand-space preferred direction (PDH). In this manuscript, we show that there is considerable variety in the direction of these PDM vectors across neurons, but that for a given task and neuron, two successive measurements of PDM are very similar. We found that these vectors tend to form clusters in particular regions of the muscle space that may reflect neurons that control synergistically important groups of muscles.We have also shown that the discharge measured froth neural ensembles can he used to predict the activity of individual muscles, in much the way that kinematic signals have been predicted by other groups. In fact, the accuracy of these predictions is similar to that of kinematic signals, despite the stochastic nature and greater bandwidth of the EMG signals. PDMS represent a divergence from one neuron to numerous muscles, while the prediction of muscle activity represents convergence from many neurons to individual muscles. We are continuing to investigate the nature of this complex matrix of functional interconnections.