Data for: Hybrid dedicated and distributed coding in PMd/M1 provides separation and interaction of bilateral arm signals

Pronounced activity is observed in both hemispheres of the motor cortex during preparation and execution of unimanual movements. The organizational principles of bi-hemispheric signals and the functions they serve throughout motor planning remain unclear. Using an instructed-delay reaching task in monkeys, we identified two components in population responses spanning PMd and M1. A “dedicated” component, which segregated activity at the level of individual units, emerged in PMd during preparation. It was most prominent following movement when M1 became strongly engaged, and principally involved the contralateral hemisphere. In contrast to recent reports, these dedicated signals solely accounted for divergence of arm-specific neural subspaces. The other “distributed” component mixed signals for each arm within units, and the subspace containing it did not discriminate between arms at any stage. The statistics of the population response suggest two functional aspects of the cortical network: one that spans both hemispheres for supporting preparatory and ongoing processes, and another that is predominantly housed in the contralateral hemisphere and specifies unilateral output.

在单肢运动的准备与执行阶段，运动皮层双侧半球均会出现显著的神经活动。但双侧半球信号的组织原则，以及其在整个运动规划过程中所承担的功能，目前仍不明确。本研究通过猕猴的指令延迟伸手任务（instructed-delay reaching task），在背侧运动前皮层（PMd）与初级运动皮层（M1）的群体响应中识别出两种成分。其一为"专属"成分：在准备阶段，该成分于背侧运动前皮层中显现，且以单个神经元单元层面的活动分离为特征；在运动执行阶段，当初级运动皮层被强烈激活时，该成分最为显著，且主要集中于对侧半球。与近期研究结论相悖的是，这些专属信号仅能解释肢体特异性神经子空间的分化。另一种为"分布式"成分：该成分在单个神经元单元内混合了双侧肢体的相关信号，且其所对应的子空间在任何阶段均无法区分不同肢体。群体响应的统计学特征揭示了皮层网络的两项功能属性：其一跨双侧半球，用于支持运动准备与执行中的神经过程；其二主要集中于对侧半球，负责调控单侧肢体的运动输出。