Chandrasekaran Chandramouli, Peixoto Diogo, Newsome William T, Shenoy Krishna V
Department of Electrical Engineering, Stanford University, Stanford, CA, 94305, USA.
Department of Neurobiology, Stanford University, Stanford, CA, 94305, USA.
Nat Commun. 2017 Sep 20;8(1):614. doi: 10.1038/s41467-017-00715-0.
Dorsal premotor cortex is implicated in somatomotor decisions. However, we do not understand the temporal patterns and laminar organization of decision-related firing rates in dorsal premotor cortex. We recorded neurons from dorsal premotor cortex of monkeys performing a visual discrimination task with reaches as the behavioral report. We show that these neurons can be organized along a bidirectional visuomotor continuum based on task-related firing rates. "Increased" neurons at one end of the continuum increased their firing rates ~150 ms after stimulus onset and these firing rates covaried systematically with choice, stimulus difficulty, and reaction time-characteristics of a candidate decision variable. "Decreased" neurons at the other end of the continuum reduced their firing rate after stimulus onset, while "perimovement" neurons at the center of the continuum responded only ~150 ms before movement initiation. These neurons did not show decision variable-like characteristics. "Increased" neurons were more prevalent in superficial layers of dorsal premotor cortex; deeper layers contained more "decreased" and "perimovement" neurons. These results suggest a laminar organization for decision-related responses in dorsal premotor cortex.Dorsal premotor cortex (PMd) is thought to be involved in making somatomotor decisions. Chandrasekaran et al. investigated the temporal response dynamics of PMd neurons across cortical layers and show stronger and earlier decision-related responses in the superficial layers and more action execution-related signals in the deeper layers.
背侧运动前皮层与躯体运动决策有关。然而，我们并不了解背侧运动前皮层中与决策相关的放电率的时间模式和分层组织。我们记录了猴子背侧运动前皮层的神经元，这些猴子执行一项视觉辨别任务，并以伸手动作作为行为报告。我们发现，这些神经元可以根据与任务相关的放电率沿着双向视觉运动连续体进行组织。连续体一端的“增加型”神经元在刺激开始后约150毫秒增加其放电率，并且这些放电率与选择、刺激难度和反应时间（候选决策变量的特征）系统地协变。连续体另一端的“减少型”神经元在刺激开始后降低其放电率，而连续体中心的“运动周围型”神经元仅在运动开始前约150毫秒做出反应。这些神经元没有表现出类似决策变量的特征。“增加型”神经元在背侧运动前皮层的浅层更为普遍；深层包含更多的“减少型”和“运动周围型”神经元。这些结果表明背侧运动前皮层中与决策相关的反应存在分层组织。背侧运动前皮层（PMd）被认为参与躯体运动决策。钱德拉塞卡兰等人研究了PMd神经元跨皮层各层的时间反应动态，发现浅层有更强、更早的与决策相关的反应，深层有更多与动作执行相关的信号。
