Neural Basis of Saccade Preparation

描述（由申请人提供）：动眼肌功能表是由竞争网络中产生扫视和保持注视的交替活动模式控制的。当两个网络之间的运作得到适当的维持时，眼动功能是正常的。然而，活动平衡上的偏差会导致功能障碍。例如，降低固定网络的功效或增强眼跳生成网络的活性会损害延迟或抑制运动的能力。本研究旨在研究这些网络中神经元素的活动，以及扰动改变两者之间平衡时对行为的影响。重点是上丘，其吻侧极参与保持固定，尾侧区域是产生扫视的必要区域。选择的扰动是在受试者执行各种眼部运动任务时，通过向眼睛吹气来诱发眨眼。研究表明，眨眼会损害脑桥水平的跳眼抑制网络的完整性，如果眨眼是在出现跳眼目标后触发的（并允许开始运动），那么目标导向的运动伴随着眨眼的延迟会减少。具体目的1研究眨眼对上丘注视和扫视产生网络的影响。它专门测试了眨眼抑制固定网络（吻侧）活动的假设

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.