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Pathways mediating orienting and visual discrimination and their roles in information processing in cats

介导定向和视觉辨别的通路及其在猫信息处理中的作用

基本信息

批准号：
07458258
负责人：
SASAKI Shigeto
金额：
$ 0.45万
依托单位：
Tokyo Metropolitan Institute for Neuroscience
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

Effects of moving visual stimulus (100-4500*/s) and of interrupted light stimulus (gap) on orienting and neuronal activities in the pontomedullary reticular formation were examined. Cats were trained to fixate a light spot on center of a flat panel and then to pursuit the moving light spot with the head and eyes. For visual stimuli of 450-1000*/s, cats oriented to a trarget with a single saccade and a saccade-like head movement (head saccade), but with 2-4 eye and head saccades for other stimulus seed. Gaze and head velocities were maximal between 300-600*/s of visual stimuli but decreased for the other range of stimuli, while eye velocities changed little with these stimuli. Head movements preceded eye saccades by 10-40 ms and their latencies were shortest (about 60ms) for the stimulus range 450-1000*/s but prolonged in the other range of stimulus speed. The gap (30ms) inserted in the early part of the visual stimuli prolonged latencies of orienting with little effects on velocities, while a gap inserted in the later part of the stimuli reduced the head velocity without affecting latencies. Eye velocities were little affected by gap stimulation. These results suggested that head and eye movements are controlled differentially and circuitry controlling head movements is very sensitive to the velocity and gap of visual stimuli. In the pontomedullary reticular formation, two major types of neurons have been differentiated, phasic sustained neurons (PSNs) and phasic neurons (PNs). PSNs fired maximally (best tuned) around 450-700*/s and decreased in the other range. Firing of PNs were a little affected by these stimuli. These results suggested that the velocity tuning of orienting movements are chiefly mediated by PSNs while velocity independent head movements are controlled by PNs.

研究了移动视觉刺激（100-4500*/s）和间断光刺激（间隙）对桥脑延髓网状结构中定向和神经元活动的影响。猫被训练将光点固定在平板的中心，然后用头和眼睛追踪移动的光点。对于450-1000*/s的视觉刺激，猫以单次扫视和扫视样头部运动（头部扫视）定向到目标，但对于其他刺激种子以2-4次眼睛和头部扫视。在300-600*/s的视觉刺激下，注视速度和头部速度最大，但在其他刺激范围内下降，而眼速度变化不大。在450-1000*/s的刺激速度范围内，头部运动先于眼扫视10-40 ms，其潜伏期最短（约60 ms），但在其他刺激速度范围内，其潜伏期延长。在视觉刺激的前半部分插入差距（30 ms）可延长定向的潜伏期，但对速度影响不大，而在刺激的后半部分插入间隙可降低头部速度，但对潜伏期无影响。眼速度的影响不大间隙刺激。这些结果表明，头部和眼睛的运动是不同的控制和电路控制头部运动是非常敏感的速度和间隙的视觉刺激。在脑桥延髓网状结构中，已经分化出两种主要类型的神经元，相位维持神经元（PSNs）和相位神经元（PNs）。PSN在450-700*/s左右发射最大（最佳调谐），并在其他范围内下降。这些刺激对PNs的放电有一定的影响。这些结果表明，定向运动的速度调谐主要由PSN介导，而速度无关的头部运动由PNs控制。