Rodriguez Andrea Colins, Perich Matthew G, Miller Lee, Humphries Mark D
School of Psychology, University of Nottingham, Nottingham, United Kingdom.
Département de neurosciences, Faculté de médecine, Université de Montréal, Montréal, Canada.
bioRxiv. 2024 May 17:2023.05.26.542452. doi: 10.1101/2023.05.26.542452.
The fluid movement of an arm requires multiple spatiotemporal parameters to be set independently. Recent studies have argued that arm movements are generated by the collective dynamics of neurons in motor cortex. An untested prediction of this hypothesis is that independent parameters of movement must map to independent components of the neural dynamics. Using a task where monkeys made a sequence of reaching movements to randomly placed targets, we show that the spatial and temporal parameters of arm movements are independently encoded in the low-dimensional trajectories of population activity in motor cortex: Each movement's direction corresponds to a fixed neural trajectory through neural state space and its speed to how quickly that trajectory is traversed. Recurrent neural network models show this coding allows independent control over the spatial and temporal parameters of movement by separate network parameters. Our results support a key prediction of the dynamical systems view of motor cortex, but also argue that not all parameters of movement are defined by different trajectories of population activity.
手臂的流畅运动需要多个时空参数独立设置。最近的研究认为，手臂运动是由运动皮层中神经元的集体动力学产生的。这一假设未经检验的预测是，运动的独立参数必须映射到神经动力学的独立成分上。通过一项任务，让猴子对随机放置的目标进行一系列伸手动作，我们发现手臂运动的空间和时间参数在运动皮层群体活动的低维轨迹中是独立编码的：每个动作的方向对应于通过神经状态空间的固定神经轨迹，其速度对应于该轨迹被穿越的速度。循环神经网络模型表明，这种编码允许通过单独的网络参数对运动的空间和时间参数进行独立控制。我们的结果支持了运动皮层动态系统观点的一个关键预测，但也表明并非所有运动参数都由群体活动的不同轨迹定义。
