ROLE OF THE BRAINSTEM IN VOLUNTARY GAZE SHIFTS

脑干在自愿目光转移中的作用

• 批准号: 7716347
• 负责人: ALBERT Frederick FUCHS
• 金额: $ 15.88万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-05-01 至 2009-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7716347
• 关键词: Affect; Area; Brain Stem; Computer Retrieval of Information on Scientific Projects Database; Data; Eye; Fire - disasters; Funding; Grant; Head; Head Movements; Institution; Monkeys; Motor Neurons; Movement; Neurons; Numbers; Positioning Attribute; Rate; Research; Research Personnel; Resources; Role; Saccades; Signal Transduction; Site; Source; Stimulus; Training; United States National Institutes of Health; Visual; driving force; frontal eye fields; gaze; size

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This project concerns the neuronal mechanisms involved in controlling shifts in the direction of gaze in the monkey. Such control becomes more complicated if the head also turns when the eyes move and/or if the eyes start from different initial eye positions (IPs). First, we investigated how the frontal eye fields (FEFs), a cortical area that controls eye saccades with the head restrained, behave when gaze shifts occur with the head free to rotate. Microstimulation applied for 200 ms evoked large gaze shifts with substantial head movement components from most sites in the dorsomedial FEF, but small, predominantly eye-only gaze shifts from ventrolateral sites. The size and direction of gaze movements were strongly affected by the IP prior to stimulation. Stimulus-evoked gaze shifts and their eye and head components resembled those elicited naturally by visual target steps. When stimulus train durations exceeded 200 ms, the substantial head movement often grew for the entire stimulus duration. We conclude that the dorsomedial FEF generates a gaze command signal that can produce eye, head, or combined eye-head movements depending on the IP. Second, we studied the effects of IP on the saccade-related firing of putative abducens motoneurons. The bursts accompanying ipsiversive saccades with identical velocity profiles were quite similar for IPs above the threshold for steady firing. The excess burst rate above the threshold for steady firing was either constant or decreased with ipsiversive IP, and both the number of excess spikes in the burst and burst duration were nearly constant. However, below threshold, both peak burst rate and burst duration increased substantially with ipsiversive IPs. Moreover, the pause associated with contraversive saccades shortened considerably. These data suggest that the net force driving saccades appears to be generated by a combination of saturating and non-saturating burst commands and the recruitment of additional motoneurons.

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 这个项目关注的神经元机制参与控制转移的方向在猴子的注视。如果眼睛移动时头部也转动和/或眼睛从不同的初始眼睛位置（IP）开始，则这种控制变得更加复杂。首先，我们研究了当头部自由旋转时注视转移发生时，额叶眼场（FEF）（头部受约束时控制眼球扫视的皮层区域）的行为。微刺激应用200毫秒诱发大的凝视转移与大量的头部运动组件从大多数网站的背内侧FEF，但小，主要是眼睛只凝视转移从腹外侧网站。凝视运动的大小和方向受到刺激前IP的强烈影响。刺激诱发的注视转移和他们的眼睛和头部组件类似于自然引起的视觉目标步骤。当刺激序列持续时间超过200毫秒，大量的头部运动往往增长的整个刺激持续时间。我们的结论是，背内侧FEF产生的凝视命令信号，可以产生眼睛，头部，或组合的眼头运动取决于IP。第二，我们研究了IP对假定的外展肌运动神经元的扫视相关放电的影响。爆发伴随着同向眼跳具有相同的速度配置文件是非常相似的IP以上的阈值稳定的射击。超过稳定放电阈值的过度爆发率是恒定的，或者随着同侧IP而降低，并且爆发中的过度尖峰的数量和爆发持续时间几乎是恒定的。然而，低于阈值，峰值爆发率和爆发持续时间大幅增加与ipsiversive IP。此外，与逆向扫视相关的停顿大大缩短。这些数据表明，驱动扫视的净力似乎是由饱和和非饱和突发命令和额外的运动神经元的招聘的组合产生的。