Visual Motor Transformation in Cortex

描述（由申请人提供）：这项工作的总体目标是了解感官刺激如何转化为运动计划，特别是，相同的感官刺激如何在不同的行为条件或背景下导致不同的运动输出。在行为猴子的单神经元记录将被用来测试一个自上而下的模型的准确性，在该模型中，更高级别的特定于上下文的处理起源于额叶皮层，然后以自上而下的方式驱动大脑其他部分的特定于上下文的处理。另一个尚未验证的假设是，特定于上下文的处理分布在许多皮层区域，特别是后顶叶皮层。 大脑中处理的分布可能取决于所执行任务的性质和复杂性。因此，将采用三种不同的实验范式。每一种范式都侧重于上下文相关处理的一个不同的重要方面。目标1侧重于如何对特定刺激做出反应的决定，例如，用眼睛或手臂运动。目标2关注于发生在短期空间记忆中的简单的上下文相关操作。目标3侧重于在两个不同的、任意的刺激-反应映射之间快速切换的能力。一般的实验方法包括提示特定的行为背景，然后测量后顶叶区域LIP和PRR，以及额叶区域FEF，SEF和DLPFC中的神经元对该纯背景线索的反应。这些反应的幅度和时间进程将在各个领域进行审查，以及这些背景驱动的反应如何与随后的刺激驱动的活动相互作用。 这些实验将提供有关视觉感官刺激如何转化为移动眼睛和手臂的计划的具体信息。他们还将讨论高级处理是否主要发生在额叶皮层，或者分布在几个大脑区域。这些结果将对我们理解不同脑区之间的相互作用具有重要意义，这将大大有助于我们治疗和康复脑损伤患者的能力。

DESCRIPTION (provided by applicant): The overall goal of this work is an understanding of how sensory stimuli are transformed into motor plans, and in particular, how identical sensory stimuli can lead to different motor outputs under different behavioral conditions, or contexts. Single neuron recordings in behaving monkeys will be used to test the accuracy of a top-down model in which higher-level, context-specific processing originates in the frontal cortex, which then drives context-specific processing in the rest of the brain in a top-down fashion. An alternative, yet-untested hypothesis is that context-specific processing is instead distributed across many cortical areas, and particularly the posterior parietal cortex. The distribution of processing in the brain is likely to depend on the nature and complexity of the task being performed. Therefore, three different experimental paradigms will be employed. Each paradigm focuses on a different, important aspect of context-dependent processing. Aim 1 focuses on decisions regarding how to respond to a particular stimulus, for example, with an eye or an arm movement. Aim 2 focuses on simple context-dependent manipulations that occur in short term spatial memory. Aim 3 focuses on the ability to rapidly switch between two different, arbitrary stimulus-response mappings. The general experimental approach involves cueing a particular behavioral context, and then measuring neuronal responses to that pure contextual cue in posterior parietal regions LIP and PRR, and in frontal regions FEF, SEF and DLPFC. Both the magnitude and the time course of these responses will be scrutinized across areas, as well as how these contextually driven responses interact with subsequent stimulus-driven activity. These experiments will provide specific information about how visual sensory stimuli are transformed into plans to move the eyes and arms. They will also address whether high level processing occurs primarily in the frontal cortex, or is distributed among several brain areas. These results will have important implications for our understanding of the interactions among different brain regions, which will contribute substantially to our ability to treat and rehabilitate brain-injured patients.