CORTICAL SUBSTRATES OF VISUAL MOTION PERCEPTION

活跃观察者的视觉环境是不断变化的，甚至 尽管它的个别特征可能保持不变。保存 视觉刺激的连续性，观察者不仅要编码 视觉信息，但也在短时间内保存它。这 研究的目的是检查这种临时存储的属性 机制。我们还将探索选定的纹外生物的作用 大脑皮质区域存储视觉的基本特征之一 刺激，它的运动方向。我们选择此功能是因为它 神经编码是很好理解的，一些皮质区域参与了ITS 已确定正在处理中。这些研究将提供重要的新的 有关视觉皮质可能参与的信息 辅助视觉短期记忆的回路中的区域。 拟议的实验将使用心理物理手段、微刺激 以及选定的生理识别区域的损害 纹状体外皮质区域以调查临时存储(即 短期记忆)方向信息。 I.调节短期记忆的机制的心理物理特性 对于刺激运动-第一组实验将探索 运动信息存储的基本过程的性质，在 特别是它的时空和定向调整，视网膜复制，以及 不同类型的刺激噪声对降级储存的效果。 猴子将在一项视觉任务中接受测试，在这项任务中，两个视觉刺激， 在时间上分开的样品和测试将被判定为相同或 不一样。这些研究将使我们更好地了解 调节运动信息保持的机制，有助于确定 存储视觉信息的皮质处理水平 并为后续的神经基质研究奠定了基础 视觉记忆。 二.MT、V3和V4区在区分和储存 刺激方向和方向-这部分的目标是 项目是确定与运动识别的视觉区域的角色 信息处理和存储方面的分析，V3和MT 关于刺激方向。我们将使用皮质内微刺激 生理上确定的部位和损伤入路。要确定 这些操作产生的影响的特殊性，我们将 还可以使用需要区分和保留的非运动任务 刺激方向，并将相同的操作应用于本地化 区域V4的一部分，已通过表单处理识别。这 将有助于阐明分层和平行皮质流如何调节 包括对刺激特征的感知和回忆。

The visual environment of an active observer is constantly changing, even though its individual features may remain constant. To preserve continuity of visual stimulation, the observer has to not only encode visual information, but also preserve it over brief periods of time. This research is aimed at examining properties of this temporary storage mechanism. We will also explore the role of selected extrastriate cortical areas in storing one of the fundamental features of the visual stimulus, its direction of motion. We chose this feature because its neural coding is well understood and some cortical areas involved in its processing have been identified. These studies will provide important new information concerning the possible participation of visual cortical areas in circuitry subserving visual short-term memory. Proposed experiments will use psychophysical measures, microstimulation and lesions of physiologically identified regions in selected extrastriate cortical areas to investigate the temporary storage (i.e. short-term memory) of directional information. I. Psychophysical properties of mechanisms mediating short-term memory for stimulus motion - The first group of experiments will explore the nature of the process underlying the storage of motion information, in particular its spatio-temporal and directional tuning, retinotopy, and the efficacy of different types of stimulus noise in degrading storage. The monkeys will be tested in a visual task in which two visual stimuli, the sample and the test, separated in time will be judged as the same or different. These studies will provide a better understanding of the mechanisms mediating the retention of motion information, help determine the level of cortical processing at which visual information is stored and set the stage for subsequent studies of neural substrates underlying visual memory. II. The role of areas MT, V3 and V4 in discrimination and storage of stimulus direction and orientation - The goal of this portion of the project is to determine the role of visual areas identified with motion analysis, areas V3 and MT, in the processing and storage of information about stimulus direction. We will use intracortical microstimulation of physiologically identified sites and the lesion approach. To determine the specificity of the effects produced by these manipulations, we will also use non-motion tasks requiring discrimination and retention of stimulus orientation, and apply the same manipulations to localized portions of area V4, which has been identified with form processing. This will help clarify how hierarchical and parallel cortical streams mediate both perception and recall of stimulus features.