Development of direction selectivity in retina

描述（由申请人提供）：方向选择性神经节细胞对在优选方向上移动的图像响应强烈，而对在相反或零方向上移动的图像响应微弱，并且对于驱动眼运动反射至关重要，所述眼运动反射在我们移动通过视觉场景时稳定视网膜上的图像。方向选择性神经节细胞的优选方向沿着基本方向（上、下、左和右）聚集，并且对每个基本方向敏感的方向选择性神经节细胞被组织成马赛克，使得在空间中的每个点处，每个运动方向都被表示。在视网膜中产生方向选择性的主要模型是特定类别的中间神经元在方向选择性神经节细胞的树突树的无效侧上形成抑制性突触。指示马赛克的出现的机制是未知的，马赛克由在发育过程中接受抑制输入的不对称分布的细胞组成。 在这里，我们建议使用最先进的电生理和成像技术相结合，以确定这两个基本特征的方向选择性的发展背后的机制-电路的无效侧抑制和方向选择性神经节细胞马赛克的存在。特别是，我们将确定自发性视网膜活动是否在这些回路的形成中起关键作用。

DESCRIPTION (provided by applicant): Direction-selective ganglion cells respond strongly to an image moving in the preferred direction and weakly to an image moving in the opposite, or null direction, and are critical for driving ocular-motor reflexes that stabilize images on the retina as we move through a visual scene. The preferred direction of direction-selective ganglion cells cluster along the cardinal directions (up, down, left and right) and the direction-selective ganglion cells sensitive to each cardinal direction are organized into mosaics such that at each point in space, each direction of motion is represented. The predominant model for the generation of direction selectivity in the retina is that a particular class of interneurons forms inhibitory synapses on the null side of the dendritic tree of direction- selective ganglion cells. The mechanisms that instruct the emergence of mosaics comprised of cells that receive an asymmetric distribution of inhibitory inputs during development are unknown. Here we propose to use a combination of state-of-the-art electrophysiological and imaging techniques to determine the mechanisms that underlie the development of these two essential features of direction-selectivity - the circuits that underlie the null side inhibition and the existence of direction-selective ganglion cells mosaics. In particular, we will determine whether spontaneous retinal activity plays a critical role in the formation of these circuits.