CORTICOTECTAL CIRCUITS IN VISUAL PROCESSING

在哺乳动物中，视觉皮质的几乎所有区域都会发出巨大的投射 上丘，这是一种与选择性注意相关的结构 以及启动眼睛和头部的运动。虽然生理学和 对这条皮质顶盖通路的解剖已经进行了广泛的研究，其 对选择性注意和视觉运动行为的贡献实际上是 未知，因为大多数研究都使用了瘫痪、麻醉的 动物。我们建议研究反式激活的活性。 17、18、7区皮质顶盖后内侧区神经元 警觉猫的上丘脑皮层(PMLS)和额叶视野 在视觉运动任务中。我们将评估皮质顶盖细胞的活性 在使用磁搜索线圈的眼球跳动之前和期间 监控眼睛位置的技术。我们将讲述前扫视 皮质顶盖细胞对空间定向注意的活动。我们会 还要检查眼跳过程中的活动，以阐明 皮质顶盖细胞在跳动抑制等现象中， 区分真实运动和表观运动，并更新 视网膜和空间坐标。检查的响应属性 皮质不同区域的皮质顶盖细胞将提供对 多个视觉区域对丘脑功能的贡献。最后， 在先前对瘫痪、麻醉的猫的第17区的工作中，我们发现了两只 不同类型的皮质顶盖细胞参与两种不同的 大脑皮层内回路。我们将寻找他们活动中的不同之处 在扫视过程中深入了解这些功能的意义 两个皮质内回路。这个项目的长期目标是 确定视觉皮质对选择性注意的贡献 控制凝视。

In mammals, virtually all areas of visual cortex send a massive projection to the superior colliculus, a structure associated with selective attention and the initiation of eye and head movements. Although the physiology and anatomy of this corticotectal pathway have been studied extensively, its contribution to selective attention and visuomotor behavior are virtually unknown because most studies have used the paralyzed, anaesthetized animal. We propose to study the activity of antidromically-activated corticotectal neurons in areas 17, 18, 7, posteromedial lateral suprasylvian cortex (PMLS) and the frontal eye fields of alert cats trained in visuomotor tasks. We will evaluate the activity of corticotectal cells prior to and during saccadic eye movements using the magnetic search coil technique to monitor eye position. We will relate the pre-saccadic activity of corticotectal cells to spatially directed attention. We will also examine activity during the saccade to elucidate the possible role of corticotectal cells in such phenomena as saccadic suppression, distinguishing real from apparent movement, and updating relations between retinal and spatial coordinates. Examining response properties of corticotectal cells in different areas of cortex will provide insight into the contribution of multiple visual areas to collicular function. Finally, in prior work in area 17 of the paralyzed, anaesthetized cat we found two types of corticotectal cells that participate in two different intracortical circuits. We will look for differences in their activity during saccades to gain insight into the functional significance of these two intracortical circuits. The long-range goal of this project is to determine the contribution of visual cortex to selective attention and control of gaze.