Data from: Conservation of preparatory neural events in monkey motor cortex regardless of how movement is initiated

A time-consuming preparatory stage is hypothesized to precede voluntary movement. A putative neural substrate of motor preparation occurs when a delay separates instruction and execution cues. When readiness is sustained during the delay, sustained neural activity is observed in motor and premotor areas. Yet whether delay-period activity reflects an essential preparatory stage is controversial. In particular, it has remained ambiguous whether delay-period-like activity appears before non-delayed movements. To overcome that ambiguity, we leveraged a recently developed analysis method that parses population responses into putatively preparatory and movement-related components. We examined cortical responses when reaches were initiated after an imposed delay, at a self-chosen time, or reactively with low latency and no delay. Putatively preparatory events were conserved across all contexts. Our findings support the hypothesis that an appropriate preparatory state is consistently achieved before movement onset. However, our results reveal that this process can consume surprisingly little time.

已有假说提出，自主运动发生前存在一个耗时的准备阶段。当指令与执行提示之间存在时间延迟时，便会出现与运动准备相关的推测性神经底物。若在该延迟时段内运动准备状态持续存在，则运动皮层与运动前皮层区域会出现持续的神经活动。然而，延迟时段的神经活动是否反映了必要的准备阶段，目前仍存在争议。具体而言，无延迟运动之前是否会出现类似延迟时段的神经活动，这一问题至今仍不明确。为解决这一模糊性问题，我们采用了一种新近开发的分析方法，该方法可将神经元群体响应拆解为推测性的准备相关成分与运动相关成分。我们针对三种运动情境检测了皮层响应：分别是在强制延迟后启动伸手动作、自主选择时机启动，以及低潜伏期无延迟的反应性启动。推测性的准备相关事件在所有情境中均保持一致。本研究结果支持前述假说，即运动发起前始终会达成恰当的准备状态。但本研究结果同时表明，这一准备过程所需的时间可能意外地短。