Neuronal encoding of rapid categorical decisions across primate oculomotor networks

项目摘要 在职业乒乓球拉力赛中，乒乓球连续击打之间的时间约为400毫秒。在 在这个时间范围内，球员必须迅速对球的运动和旋转进行分类，以适当地指导 他们不断的划桨动作才能成功击球。虽然许多研究已经调查了 眼球运动系统在视觉分类过程中的作用，很少有人在必须做出反应的地方这样做 在相关感官信息之前启动，例如在前述示例中。因此， 眼跳决定的感觉调节的时间动力学在很大程度上仍未解决。要确定 视觉分类通知正在进行的运动计划的方式，我建议从 顶内外侧区(LIP)、前视野区(FEF)和上丘(SC)的神经元群体 当猴子执行基于扫视的运动分类任务时，运动规划总是在前面 对视觉刺激的识别；因此揭示了类别词的时间演变 毫秒级分辨率的判断。先前的研究结果发现，LIP和FEF中的神经元 演示分类调谐，当刺激属于首选类别时，会增加激发频率 出现在屏幕上。此外，我们实验室最近的一项研究证明了嘴唇在视觉中的因果作用 分类：LIP的可逆失活导致分类准确性的严重缺陷。 然而，这些研究使用的任务结构排除了任何试图揭示 明确的信号影响正在进行的运动计划，或识别时间和强度上的差异 这些脑区之间的分类编码。到目前为止，还没有研究过分类编码在 SC，因此我们将第一个确定它在视觉分类中的作用。通过同时从大容量记录， 在这些相互连接的大脑区域中，具有线性阵列的不同神经元群体，建议 研究将提供对感官变化背后的时间动力学的批判性见解 将证据转化为动眼神经决定。

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.