Functions and interactions of brain areas hMT+ and hV4 in the human visual system

我们的目标是调查的颜色，形状和运动感知的视觉属性的人脑的模块化。虽然视觉图像的这些基本方面在感知上似乎是一体的，但积累的证据表明，它们在大脑的不同专门区域内分别进行处理。两个关键的大脑区域被认为是处理这些属性的基础：hMT+和hV4。人类MT复合物（hMT+）传统上被认为是背侧通路的一部分，尽管它的位置更外侧，并且已知参与运动感知，而hV4是腹侧通路的一部分，并且被认为参与形状和颜色的处理。我们对这两个领域的了解，大部分来自于对非人类灵长类动物的研究。在这里，我们的目标是通过使用脑刺激技术rTMS选择性地和暂时地损害每个人的反应来测试关于他们在人类视觉中的功能的假设。如果刺激目标大脑区域导致特定视觉任务的持续损害（或改善），则可能涉及大脑区域的功能。在使用fMRI定位相关脑区后，我们确定了每个区域的脑刺激对特定视觉任务性能的影响。每项任务都旨在测试与运动，形状或颜色感知相关的专门视觉功能。该计划旨在全面研究hMT+和hV4区域在视觉中的功能作用，同时确定这些区域之间的功能重叠和相互作用。该计划解决了关于人类大脑中视觉信息处理模块化的核心问题。该提案具有很高的影响力，因为对hV4在人脑中的作用知之甚少。这一领域很少用rTMS进行研究，但这种方法为理解其在人类视觉中的作用提供了重要的机会。此外，这些实验还专门针对两个关键区域之间的功能重叠，目的是了解背侧和腹侧通路的共同功能，而不仅仅是视觉区域如何作为独立的模块进行操作。这个项目代表了一个新的研究方向，而不是我以前支持的NSERC项目的简单延续。TMS方法将我在过去十年中从心理物理学和功能磁共振成像实验中发展起来的对颜色、形状和运动处理的理解结合到一个研究计划中，直接解决了人类大脑两个关键视觉区域的功能。

The objective is to investigate the modularity of the human brain for the visual attributes of color, form and motion perception. Although these fundamental aspects of the visual image appear perceptually integrated, accumulated evidence suggests that they are processed separately within different, specialized areas of the brain. Two key brain areas are thought to be fundamental for the processing of these attributes: hMT+ and hV4. The human MT complex (hMT+) is traditionally considered to be part of the dorsal pathway, despite its more lateral location, and is known to be involved in motion perception, whereas hV4 is part of the ventral pathway and is thought to be involved in the processing of shape and color. Much of what we know about these two areas has been acquired from work done on non-human primates. Here we aim to test hypotheses about their functions in human vision by selectively and temporarily impairing the responses of each using a brain stimulation technique, rTMS. If stimulation of the targeted brain area results in a consistent impairment (or improvement) of a specific visual task, it is likely that the brain area is functionally involved. After localizing the relevant brain areas using fMRI, we determine the effect of brain stimulation of each area on the performance of specific visual tasks. Each task is designed to test a specialized visual function relating to motion, form or color perception. The proposed program aims to provide a comprehensive investigation of the functional roles of areas hMT+ and hV4 in vision, but also to determine the functional overlap and interactions between the areas.***The program addresses core questions about the modularity of processing of visual information in the human brain. The proposal is high impact since very little known about the role of hV4 in the human brain. This area has rarely investigated with rTMS, yet the approach opens up important opportunities for understanding its role in human vision. Furthermore, the experiments specifically address the overlap of function between two key areas with the aim of understanding the common functions of the dorsal and ventral pathways rather than simply how visual areas operate as separate modules.***This program represents a new direction of research rather than a simple continuation of my previously supported NSERC program. The TMS approach combines the understanding of color, form and motion processing that I have developed in my lab over the past decade from both psychophysical and fMRI experiments into a program of research that directly addresses the function of two key visual areas of the human brain.**