Department of Physical Medicine and Rehabilitation, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA.
J Neurosci. 2010 Jan 20;30(3):958-62. doi: 10.1523/JNEUROSCI.3742-09.2010.
Previous studies have shown that hand translation is well represented by neuronal activity in the proximal arm area of primary motor cortex (M1). However, little is known about cortical representation of hand rotation in M1. In this study, single-unit activity was recorded from monkeys while they performed a "center-out with rotation" task. When reaching for a target, subjects had to match four separate kinematic parameters: three-dimensional location and one-dimensional orientation of the target. Among the 512 neurons modulated by hand movement, 446 were tuned to hand translation, 326 were tuned to hand rotation, and 260 neurons were tuned to both hand translation and hand rotation. Approximately half of the neurons that encoded both translation and rotation did so in a nonlinear manner. This nonlinear interaction can be modeled as a gain-field type of encoding whereby hand rotational velocity modulated the hand translational cosine tuning curves in a multiplicative manner. Furthermore, this study demonstrated that both hand translation and hand rotation can be decoded simultaneously from a population of motor cortical neurons.
先前的研究表明，手部运动在初级运动皮层（M1）的近臂区的神经元活动中得到了很好的体现。然而，关于 M1 中手部旋转的皮质代表，我们知之甚少。在这项研究中，当猴子执行“中心到外周旋转”任务时，我们记录了单个神经元的活动。在到达目标时，受试者必须匹配四个独立的运动学参数：目标的三维位置和一维方向。在 512 个受手部运动调节的神经元中，446 个对手部平移敏感，326 个对手部旋转敏感，260 个对手部平移和旋转都敏感。大约一半的同时编码平移和旋转的神经元以非线性方式进行编码。这种非线性相互作用可以被建模为一种增益场类型的编码，其中手部旋转速度以乘法方式调制手部平移余弦调谐曲线。此外，这项研究还表明，手部平移和手部旋转都可以从运动皮层神经元群体中同时解码。
