Neuronal encoding of rapid categorical decisions across primate oculomotor networks

项目摘要 在职业乒乓球比赛中，乒乓球连续击球之间的时间约为400毫秒。内 在这段时间内，球员必须迅速对球的运动和旋转进行分类，以适当地引导球的运动。 他们的球拍的持续运动，以成功地击球。虽然许多研究已经调查了 视觉系统的作用在视觉分类过程中，很少有人这样做的反应必须是 在相关的感觉信息之前启动，例如在上述示例中。因此 扫视决定的感觉调制的时间动态在很大程度上仍然没有解决。识别 视觉分类的方式通知正在进行的运动计划，我建议记录神经活动， 外侧顶内区（LIP）、额叶眼区（FEF）和上级丘（SC）中的神经元群 而猴子执行基于扫视的运动分类任务 视觉刺激的识别;因此揭示了一个分类的时间演变 以毫秒级分辨率进行判断。先前研究的结果确定了LIP和FEF中的神经元， 表现出分类调谐，当刺激属于首选类别时， 出现在屏幕上。此外，我们实验室最近的一项研究表明，LIP在视觉中的因果作用， LIP的可逆失活导致分类准确性的显著缺陷。 然而，这些研究所使用的任务结构排除了任何试图揭示的方式， 分类信号影响正在进行的运动计划，或识别时间和强度的差异， 这些大脑区域之间的分类编码。到目前为止，还没有研究调查分类编码， SC，因此，我们将是第一个确定其在视觉分类的作用。通过同时从大的记录， 在这些相互连接的大脑区域中，不同的神经元群体具有线性阵列， 研究将提供关键的洞察力的时间动态变化的感觉 把证据转化为视觉上的决定

Project Summary In a professional table tennis rally, the time between successive ping pong ball hits is around 400ms. Within this timeframe, the players must rapidly categorize the motion and spin of the ball to appropriately guide the ongoing motion of their paddle to successfully strike the ball. While numerous studies have investigated the oculomotor system’s role in the visual categorization process, few have done so where the response must be initiated in advance of relevant sensory information, such as in the aforementioned example. Thus, the temporal dynamics of sensory modulation of saccadic decisions remain largely unresolved. To identify the manner in which visual categorization informs ongoing motor plans, I propose recording neural activity from populations of neurons in the lateral intraparietal area (LIP), frontal eye field (FEF), and superior colliculus (SC) while monkeys perform a saccade-based motion categorization task in which motor planning always precedes the identification of the visual stimulus; consequently revealing the temporal evolution of a categorical judgment with millisecond resolution. Results from prior studies identified neurons in LIP and FEF that demonstrate categorical tuning, with increased firing rates when stimuli belonging to the preferred category appear on screen. Additionally, a recent study from our lab demonstrates the causal role of LIP in visual categorization in which reversible inactivation of LIP leads to significant deficits in categorization accuracy. However, the task structure utilized by these studies precludes any attempt to uncover the manner in which categorical signals influence ongoing motor plans, or identify differences in the timing and strength of categorical encoding between these brain regions. To date, no study has investigated categorical encoding in SC, thus we will be the first to identify its role in visual categorization. By simultaneously recording from large, diverse populations of neurons with linear arrays across these interconnected brain regions, the proposed research will provide critical insight into the temporal dynamics underlying the transformation of sensory evidence into oculomotor decisions.