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Neuronal mechanisms in early visual stages underlying depth perception : Contribution of monocular cues and local changes in depth cues

早期视觉阶段深度感知的神经机制：单眼线索的贡献和深度线索的局部变化

基本信息

批准号：
11680796
负责人：
ITO Minami
金额：
$ 2.43万
依托单位：
Okazaki National Research Institutes
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

项目摘要

Present study aimed at exploring the contribution of monocular cues in depth perception in both levels of perception and neuronal activities. We planned both psychophysical and electrophysiological studies, while monkeys perform the depth discrimination task. We developed depth discrimination tasks, prepared new recording setup and software, and trained two monkeys with the depth discrimination task. First monkey was removed because its performance was not sufficiently improved. Second monkey showed sufficient performance in the depth discrimination task. According to accident with the eye coil, the animal showed strabismus and should be discarded. Since more than one year is necessary for the training, it is hard to complete the planned study within this project by preparing new animals. Thus, we abandoned the plan. In parallel, we explored the neuronal representation of the monocular cues by means of recording neuronal responses to angles and junctions within contour stimuli. While two monkeys performed the fixation task, we conducted extracellular recordings from the superficial layer of area V1 and V2. We made angles by combining two long straight lines and present angles and junctions at the center of neurons' receptive fields. We observed many of area V2 neurons showed moderately selective responses to a particular combination of line components. In some cases, neurons were highly specific to a particular angle. In many cases, response selectivity can be explained by linear summation ofexcitation to one or two preferred directions and inhibition to a particular direction. Inhibitory effect was dependent on both an orientation and location of line components. This result suggest the contribution ofnon-uniform inhibition around the receptive field and that area V2 is a first step to represent angles and junctions within contour stimuli.

本研究旨在从知觉水平和神经元活动两个层面探讨单眼线索对深度知觉的影响。我们计划进行心理物理学和电生理学研究，而猴子则执行深度辨别任务。我们开发了深度辨别任务，准备了新的记录设置和软件，并训练了两只猴子的深度辨别任务。第一只猴子被移除，因为它的表现没有得到充分改善。第二只猴子在深度辨别任务中表现出足够的性能。根据眼部线圈意外，该动物出现斜视，应丢弃。由于培训需要一年以上的时间，因此很难通过准备新动物来完成本项目中计划的研究。因此，我们放弃了这个计划。同时，我们通过记录神经元对轮廓刺激内的角度和连接点的反应，探索了单眼线索的神经元表征。当两只猴子进行固定任务时，我们从V1和V2区的浅层进行细胞外记录。我们通过将两条长直线组合成角度，并在神经元的感受野中心呈现角度和连接点。我们观察到许多V2区神经元对特定的线成分组合表现出中度选择性反应。在某些情况下，神经元对特定角度具有高度特异性。在许多情况下，反应的选择性可以用一个或两个优选方向的激发和一个特定方向的抑制的线性总和来解释。抑制作用依赖于线组件的方向和位置。这一结果表明，在感受野周围的非均匀抑制的贡献和V2区是第一步，代表角和连接内轮廓刺激。