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

目的是研究人类大脑对颜色、形状和运动感知的视觉属性的模块化。尽管视觉图像的这些基本方面在感知上似乎是整合在一起的，但越来越多的证据表明，它们是在大脑不同的专门区域内分别处理的。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复合体（hMT+）传统上被认为是背侧通路的一部分，尽管它位于更外侧的位置，并且已知参与运动感知，而hV4是腹侧通路的一部分，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多来自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有选择地和暂时地损害每一种的反应来测试它们在人类视觉中的功能假设。如果对目标大脑区域的刺激导致特定视觉任务的持续损害（或改善），则可能是该大脑区域在功能上参与了。在使用功能磁共振成像定位相关大脑区域后，我们确定了大脑刺激每个区域对特定视觉任务表现的影响。每个任务都是为了测试与运动、形状或颜色感知相关的特殊视觉功能。该计划旨在全面研究hMT+和hV4区域在视觉中的功能作用，并确定这些区域之间的功能重叠和相互作用。

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.