Department of Bioengineering, University of Pittsburgh, Pittsburgh, United States.
Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, United States.
Elife. 2017 Sep 11;6:e29648. doi: 10.7554/eLife.29648.
The motor system prepares for movements well in advance of their execution. In the gaze control system, the dynamics of preparatory neural activity have been well described by stochastic accumulation-to-threshold models. However, it is unclear whether this activity has features indicative of a hidden movement command. We explicitly tested whether preparatory neural activity in premotor neurons of the primate superior colliculus has 'motor potential'. We removed downstream inhibition on the saccadic system using the trigeminal blink reflex, triggering saccades at earlier-than-normal latencies. Accumulating low-frequency activity was predictive of eye movement dynamics tens of milliseconds in advance of the actual saccade, indicating the presence of a latent movement command. We also show that reaching a fixed threshold level is a necessary condition for movement initiation. The results bring into question extant models of saccade generation and support the possibility of a concurrent representation for movement preparation and generation.
运动系统在执行动作之前就已经做好了充分的准备。在眼球控制系统中，预备性神经活动的动力学已经被随机累积到阈值模型很好地描述了。然而，目前尚不清楚这种活动是否具有隐藏运动指令的特征。我们明确测试了灵长类动物上丘运动神经元的预备性神经活动是否具有“运动潜能”。我们通过三叉神经眨眼反射消除了对扫视系统的下游抑制，以比正常更短的潜伏期触发扫视。积累的低频活动可提前数十毫秒预测眼球运动的动态，表明存在潜在的运动指令。我们还表明，达到固定的阈值水平是运动启动的必要条件。研究结果对现有的扫视生成模型提出了质疑，并支持运动准备和生成的同时表示的可能性。
