Functional Organization of Visual Area MT

描述(申请人提供)：大脑皮层由许多相对离散的区域组成，这些区域专门用于各种功能。在视觉系统中，这些区域之间的连接是有序的和分层的，相对更抽象的视觉世界表示出现在层次的较高级别上。此外，不同的视觉属性，如运动和颜色，大体上是在独立的、并行的“流”中处理的。然而，视觉系统的特征也是不同处理流之间的丰富的互连集合，从而任何给定的区域将从许多其他区域接收输入。在产生一组给定神经元的特定反应属性中，各种不同输入的作用是什么？我们建议使用中颞叶视区(MT或V5)作为模型系统来解决这一问题。由于在MT神经元中已经发现了许多更高水平的视觉运动计算，并且由于不同的信息流路线是相当众所周知的，我们可以开始剖析各种输入在产生更复杂的接受场属性中所起的作用。这项建议将集中在皮质和皮质下通路之间的解剖和功能关系到MT。新的解剖学技术(多突触、逆行病毒示踪剂)、功能技术(单位记录、可逆失活、2-脱氧葡萄糖)和行为(眼球运动)将被用来阐明所谓的“间接通路”在塑造MT神经元反应特性中的作用。这些实验的结果将是更好地理解皮质回路，该回路产生MT神经元的感受场特性，以及它们在感知和视觉引导行为中所起的作用。最终，这些研究将使我们了解精神生活的生物学基础，这对治疗和治愈精神障碍至关重要。

DESCRIPTION (provided by applicant): The cerebral cortex consists of numerous, relatively discrete, areas that are specialized for various functions. In the visual system, the connections between these areas are orderly and hierarchical, with relatively more abstract representations of the visual world emerging at higher levels of the hierarchy. In addition, different visual attributes, such as motion and color, are, to a first approximation, processed in separate, parallel "streams." However, the visual system is also characterized by rich sets of interconnections between different processing streams, so that any given area will receive inputs from many other areas. What is the role of the various different inputs in generating the particular response properties of a given set of neurons? We propose to use the middle temporal visual area (MT or V5) as a model system with which to address this question. Because a number of higher-level visual motion computations have been identified in MT neurons, and because the different routes of information flow are reasonably well known, we can begin to dissect the role played by the various inputs in generating more complex receptive field properties. This proposal will focus on the anatomical and functional relationships between cortical and subcortical pathways to MT. A combination of novel anatomical techniques (multi-synaptic, retrograde viral tracers), functional techniques (single unit recording, reversible inactivation, 2-deoxyglucose) and behavior (eye movements) will be used to elucidate the role of the so-called "indirect pathways" in shaping the response properties of MT neurons. The result of these experiments will be a better understanding of the cortical circuitry that gives rise to the receptive field properties of MT neurons and of the role that they play in perception and visually guided behavior. Ultimately, these studies will inform our understanding of the biological basis of mental life, which is critical for the treatment and cure of mental disorders.