CONTROL OF VERGENCE EYE MOVEMENTS BY THE FRONTAL CORTEX

将训练警觉的恒河猴执行视神经任务，以阐明弓前皮质（8Ar）内的神经元如何编码引起聚散眼球运动的双眼刺激的视觉特征。据报道，视觉引导的聚散眼球运动由最初的瞬时聚散分量和随后的持续融合分量组成，持续融合分量足以“锁定”聚散角以使感觉融合发生。这些成分在人类中得到了广泛的研究，但在恒河猴中却没有。最初，这些组件的聚散眼球运动的特点是在猴子使用电磁搜索线圈的方法。随后，这些聚散分量和引起它们的感觉刺激将与从弓前皮质内的神经元记录的单个单元活动相关联。I.第一个目标是描述在短暂和持续的聚散成分中弓前皮质内神经元的行为。简短地呈现的二视图像或长时间呈现的不同图像将区分瞬时聚散和持续聚散。二.第二个目标将更仔细地观察由弓状前皮质内的神经元编码的视觉特征。强迫选择范例将被用来确定什么样的目标特征（例如亮度，方向，空间频率）影响瞬时聚散和神经活动。三.最终的目标是使用二视刺激，解离双目匹配的基础上，在短暂的聚散的本地和全球的线索。相关的，动态随机点立体图将测试弓前神经元如何响应这些全球差异线索。这个项目的结果将提高我们对与斜视和聚散功能障碍相关的神经功能缺损的理解。

Alert, rhesus monkeys will be trained to perform oculomotor tasks to clarify how neurons within the prearcuate cortex (8Ar) encode the visual characteristics of binocular stimuli that elicit vergence eye movements. Visually-guided vergence eye movements are reported to be composed of an initial transient vergence component and a later, sustained fusional component that "locks" vergence angle sufficiently for sensory fusion to occur. These components have been studied extensively in humans but not in the rhesus monkey. Initially, these components of vergence eye movements will be characterized in monkeys using the electromagnetic search coil method. Subsequently, these vergence components and the sensory stimuli eliciting them will be correlated with single-unit activity recorded from neurons within the prearcuate cortex. I. The first aim will characterize the behavior of neurons within the prearcuate cortex during the transient and sustained components of vergence. Briefly presented dichoptic images or long presentations of dissimilar images will separate transient vergence from sustained vergence. II. The second aim will look more closely at those visual characteristics encoded by neurons within the prearcuate cortex. A forced-choice paradigm will be used to determine what target characteristics (e.g. luminance, orientation, spatial frequency) affect transient vergence and neural activity. III. The final aim uses dichoptic stimuli that dissociate binocular matches based on local and global cues during transient vergence. Correlated, dynamic random-dot stereograms will test how prearcuate neurons respond to these global disparity cues. The results of this project will improve our understanding of neurological deficits associated with strabismus and of vergence dysfunction.