Neural Basis of Saccade Preparation

描述(由申请人提供)：眼球运动曲目由竞争网络中的交替活动模式控制，这些活动模式产生眼跳并保持注视。当两个网络之间的操作得到适当维护时，眼动功能正常。然而，活动平衡的偏差可能会导致功能障碍。例如，降低注视网络的有效性或增强眼跳产生网络的活性会损害延迟或抑制运动的能力。这项提议试图检查这些网络中神经元件的活动，以及在改变两者之间平衡的扰动期间对行为的影响。焦点集中在上丘，其嘴极参与保持固定，尾部区域是产生眼跳的关键。选择的干扰是，当受试者执行各种眼球运动任务时，通过向眼睛喷气来诱导眨眼。已经证明，眨眼在脑桥水平上损害了眼跳抑制网络的完整性，如果眨眼是在展示眼跳目标(并允许启动运动)之后触发的，那么目标定向的运动伴随着眨眼的延迟减少。具体目的1研究眨眼对上丘注视和眼跳产生网络的影响。它特别测试了眨眼抑制注视网络(吻部)活动的假设 区域)，并增加眼跳产生网络(尾部区域)的兴奋性。特定目的2检查在过早触发眼跳时潜在的神经活动是否编码运动前信息。它将具体检验运动准备假说的阈值原理，以及空间注意和运动准备是否可以分离。我们预计，行为和神经生理学方法的结合将提供对神经精神障碍(例如ADHD、精神分裂症)的神经机制的洞察，这些障碍的特征是无法抑制反射性运动。

DESCRIPTION (provided by applicant): The oculomotor repertoire is governed by alternating activity patterns in competing networks that generate saccades and preserve fixation. When the operation between the two networks is properly maintained, eye movement function is normal. A bias in the balance of activity, however, can lead to dysfunction. For example, decreasing the efficacy of the fixation network or enhancing the activity of the saccade generation network compromises the ability to delay or inhibit movements. This proposal seeks to examine the activity of neural elements in these networks and the consequence on behavior during a perturbation that alters the balance between the two. The focus is specifically on the superior colliculus, whose rostral pole is involved in preserving fixation and caudal region is essential fo generating saccades. The perturbation of choice is to induce a blink by delivering an air-puff to an eye as subjects perform various oculomotor tasks. Blinks have been shown to compromise the integrity of the saccadic inhibition network at the level of the pons, and if the blink is triggered after presentation of the saccade target (and permission to initiate the movement), the goal-directed movement accompanies the blink at a reduced latency. Specific Aim 1 examines the effects of a blink on the fixation and saccade generation networks in the superior colliculus. It specifically tests the hypothesis that blinks suppress activity in the fixation network (rostral region) and increases the excitability of the saccade generation network (caudal region). Specific Aim 2 examines whether the underlying neural activity at the time of prematurely triggered saccades encodes premotor information. It will specifically test the threshold principle of the motor preparation hypothesis and whether spatial attention and motor preparation can be dissociated. We anticipate that the combination of behavioral and neurophysiological approaches will provide insights into neural mechanisms that are altered in neuropsychiatric disorders (e.g., ADHD, schizophrenia) characterized by an inability to suppress reflexive movements.