Corticotectal transmission for express saccades

描述（由申请人提供）：灵长类动眼肌系统是理解反射和意志运动产生的首要模型系统。人类和猴子都有两种类型的眼球扫视运动：“规律扫视”和“快速扫视”。有规律的扫视有很长的潜伏期，并且被认为涉及到信息从视觉皮层转移到额叶皮层，再到上丘。表达性扫视具有较短的潜伏期，被认为是由视觉皮层到上丘的直接通路介导的，绕过额叶皮层。重要的是，在某些条件下，快速扫视和正常扫视的比例大致相等；在一些试验中出现了快速扫视，而在另一些看似相同的试验中出现了规律扫视。如果像假设的那样，表达性扫视是由视觉皮层到上丘的投射介导的，那么如果这些投射在它们没有自然强烈激活的条件下受到刺激，那么表达性扫视发生的可能性应该会增加。直到最近，这样的操作在技术上是不可能的，但是光遗传学改变了这一点。光遗传学是一套相对较新的利用光操纵神经活动的工具，这些工具在转基因小鼠的研究中已经非常有价值。通过在清醒的灵长类动物身上使用这些工具，将实现两个具体目标和一个更广泛的目标。第一个目的是验证从视觉皮层到上丘的投影促进表达性扫视的假设。第二个目的是验证一个假设，即在快速扫视期间，上丘两个通常不相连的隔室之间的电活动会短暂连接。更大的目标是通过改进用于清醒行为的猴子的光遗传学工具来催化系统神经生理学的进展。灵长类动物神经生理学界对这些技术的广泛采用和改进将有助于揭示大脑区域之间的信号传递如何介导行为。这样的理解对于神经和精神疾病的诊断和治疗将是重要的，这些疾病的病因可能涉及大脑区域之间的异常通信。

DESCRIPTION (provided by applicant): The primate oculomotor system is a premier model system for understanding the production of reflexive and volitional movements. Two types of saccadic eye movements are made by humans and monkeys: "regular" and "express" saccades. Regular saccades have long latencies and are thought to involve the transfer of information from the visual cortex, to the frontal cortex, to the superior colliculus. Express saccades have shorter latencies and are thought to be mediated by a direct pathway from visual cortex to the superior colliculus, bypassing the frontal cortex. Importantly, under some conditions both express and regular saccades are made in roughly equal proportion; express saccades occur on some trials, regular saccades on other, seemingly identical, trials. If, as hypothesized, express saccades are mediated by projections from the visual cortex to the superior colliculus, the probability of express saccade occurrence should increase if these projections are stimulated under conditions in which they are not naturally strongly activated. Such a manipulation was technically impossible until recently, but optogenetics has changed this. Optogenetics is a relatively new set of tools for manipulating neural activity with light, an these tools have already been extremely valuable in the study of transgenic mice. By using these tools in the awake, behaving primate, two specific aims and one broader objective will be achieved. The first aim is to test the hypothesis that the projections from visual cortex to the superior colliculus facilitate express saccades. The second aim is to test the hypothesis that electrical activity between two usually disconnected compartments in the superior colliculus become transiently connected during express saccades. The larger objective is to catalyze progress in systems neurophysiology by refining optogenetic tools for use in the awake, behaving monkey. Widespread adoption and refinement of these techniques by the primate neurophysiology community will help to reveal how signal transmission between brain areas mediates behavior. Such an understanding will be important for the diagnosis and treatment of neurological and psychiatric diseases, whose etiology may involve aberrant communication between brain areas.