Visual motor processing in retino-collicular and cortico-collicular circuits

视觉刺激在视网膜中编码，并在皮层和皮层下回路中处理，最终指导行为。上级丘是视觉引导行为和视觉运动处理的中枢神经回路。上级丘是中脑中的分层结构，其接收传入感觉输入，从皮层神经元向下传递信息，并通过其输出投射到不同的运动结构来介导行为。例如，浅层视觉层中的神经元接收来自视网膜神经节细胞的输入，并组织成视觉运动的方向偏好图，而深层中的神经元整合来自运动皮层的输入，并介导定向扫视眼球运动。因此，上级丘作为视觉处理和视觉引导行为的关键门户。然而，一些问题仍然开放的机制方面的上级丘的功能组织和视觉运动处理的神经基础，在视网膜丘和皮质丘电路。在这里，我们将采用大规模的电生理记录使用高密度电极（神经像素探针）在头部固定的小鼠和计算建模，以解决以下目标：为了揭示视网膜丘电路的功能组织，我们将采用一种新的方法，我们最近建立，并允许记录视网膜神经节细胞和它们连接的目标，同时在体内。使用这种方法，我们将（1）表征视网膜神经节细胞传入输入如何在上级丘的视觉层中组织。此外，我们将（2）使用计算模型研究引起上级丘功能图的潜在发育机制。同时，我们将（3）研究扫视眼球运动如何调节清醒小鼠视网膜中的感觉处理，以及（4）测量皮质丘通路在导航过程中产生扫视眼球运动的因果作用。因此，我们的主要目标是研究视网膜-丘和皮质-丘回路中视觉运动加工的机制，从而揭示上级丘在视觉引导行为中的作用。

Visual stimuli are encoded in the retina and processed in cortical and subcortical circuits to ultimately guide behaviors. A neural circuit that is central for visually guided behaviors and visual motor processing is the superior colliculus. The superior colliculus is a layered structure in the midbrain that receives afferent sensory inputs, descending top-down information from cortical neurons and that mediates behavior via its output projections to different motor structures. For example, neurons in the superficial visual layer receive inputs from retinal ganglion cells and are organized in a direction preference map for visual motion, while neurons in the deeper layers integrate inputs from the motor cortex and mediate directional saccadic eye movements. Thus, the superior colliculus serves as a critical gateway for visual processing and visually guided behaviors. However, several questions remain open in regard to the mechanisms underlying the functional organization of the superior colliculus and the neural basis of visual-motor processing in retino-collicular and cortico-collicular circuits. Here we will employ large-scale electrophysiological recordings using high-density electrodes (Neuropixels probes) in head-fixed mice and computational modeling to address the following aims: To reveal the functional organization of the retino-collicular circuit we will employ a novel method that we recently established and that allows recording retinal ganglion cells and their connected targets simultaneously in vivo. Using this method, we will (1) characterize how the retinal ganglion cell afferent input is organized in the visual layers of the superior colliculus. Moreover, we will (2) study potential developmental mechanisms that give rise to the functional maps in superior colliculus using a computational model. In parallel, we will (3) investigate how saccadic eye movements modulate sensory processing in the retina in awake mice and (4) measure the causal role of the cortico-collicular pathway in generating saccadic eye movements during navigation. Thus, our major goal is to examine the mechanisms underlying visual-motor processing in retino-collicular and cortico-collicular circuits and we will thereby reveal new insights about the role of the superior colliculus in visually guided behaviors.