Population Dynamics in the Oculomotor System

项目摘要 感觉运动转换是由前运动脑网络介导的，其中单个神经元代表 感觉、认知和运动相关的信息。在上级丘（SC）中， 产生视觉引导的扫视眼球运动，许多神经元在所有三个阶段都是活跃的， 在感觉和运动事件期间短暂的、高频率的尖峰脉冲，并表现出持续的、较低的 爆发之间的发射率活动。对多个信息维度的混合选择性 这是神经系统表达信息的一种潜在有效模式，但它也提出了至关重要的问题。 问题：两个脉冲串有什么不同，解码器如何精确地知道何时启动 移动如果其输入在不期望移动时是活动的（例如，响应于感官 刺激）？什么信息被编码在低频活动中，以及它是如何被调制的。 不同的认知需求我们认为这些问题的答案不在于个人的活动 神经元，而是跨活跃神经元的群体和时间动态。具体目标1测试 运动启动的各种神经机制，通过量化区分感觉和 在SC人群中的运动爆发。具体目标2侧重于干预的低频活动 在两次爆发之间。我们将使用动力系统方法来描述神经轨迹如何 在感觉运动转换过程中演变，以及它在具有不同认知负荷的任务中如何不同。的能力 根据任务要求区分神经轨迹表明了一种潜在的机制， 不同维度的信息可以多路复用到同一群神经元中。

PROJECT SUMMARY Sensorimotor transformations are mediated by premotor brain networks where individual neurons represent sensory, cognitive, and movement-related information. In the superior colliculus (SC), a central hub for producing visually-guided saccadic eye movements, many neurons are active during all three stages, emitting transient, high-frequency bursts of spikes during the sensory and motor events and exhibiting persistent, lower firing rate activity in-between the bursts. The mixed-selectivity to multiple dimensions of information exemplifies a potentially efficient mode of information representation by the nervous system, but it also raises crucial questions: What features differentiate the two bursts, and how does a decoder know precisely when to initiate a movement if its inputs are active at times when a movement is not desired (e.g., in response to sensory stimulation)? What information is encoded in the low-frequency activity, and how is it modulated during different cognitive demands? We reason that the answers to these questions lie not in the activity of individual neurons but rather across the population of active neurons and in the temporal dynamics. Specific Aim 1 tests various neural mechanisms of movement initiation by quantifying features that differentiate the sensory and motor bursts across the SC population. Specific Aim 2 focuses on the low-frequency activity that intervenes between the two bursts. We will use a dynamical systems approach to characterize how the neural trajectory evolves during sensorimotor transformation and how it differs for tasks with different cognitive loads. The ability to discriminate neural trajectories according to task demands indicates a potential mechanism by which different dimensions of information can be multiplexed into the same population of neurons.