Human Ventral Occipitotemporal Cortex

描述(由申请人提供)：腹侧枕颞叶(VO)皮质受损可导致细微的知觉问题，如色盲和失认症。因此，人们普遍认为，VO皮层的神经回路根据初级视觉皮质提供的相对较低的水平输入来计算中等水平的视觉特性。然而，人类VO皮层的视网膜组织与颜色和面部反应之间的关系还没有被仔细地测量。例如，颜色和物体信息的处理是否发生在视网膜皮质内还是在没有视网膜组织的区域，可能使用的是纯粹的平移不变计算，目前还没有确定。拟议的实验将使用功能磁共振成像来确定腹侧VO皮质的功能组织。第一组实验(目标1)将绘制VO皮层的视野反应图。这些视网膜定位图将与目标2和目标3中确定的颜色选择区域和人脸/物体选择区域进行比较。这些实验应该解决对颜色和人脸/物体有选择性反应的区域的视网膜组织问题。这些实验还将阐明VO皮层中心凹、颜色和物体反应之间的空间关系。了解这一皮质区域的正常功能组织有两个目的。首先，它将增强我们对大脑如何处理有关物体属性的中层视觉信息的了解。其次，它可能帮助我们了解VO皮质损伤导致的视觉缺陷的严重程度和恢复程度的差异性。

DESCRIPTION (provided by applicant): Damage to regions of the ventral occipitotemporal (VO) cortex can result in subtle perceptual problems, such as achromatopsia and prosopagnosia. Consequently, it is widely believed that the neural circuitry in VO cortex computes mid-level visual properties from the relatively low level input provided by primary visual cortex. However, the relationship among retinotopic organization and color and face responses in human VO cortex has not been carefully measured. For example, it has not been established whether the processing of color and object information occurs within retinotopic cortex or in areas without retinotopic organization, perhaps using a purely translation-invariant computation. The proposed experiments will determine the functional organization of the ventral VO cortex using functional magnetic resonance imaging. The first set of experiments (Aim 1) will map the visual field responses of VO cortex. These retinotopic maps will be compared with the color-selective and face/object selective regions determined in Aim 2 and Aim 3. These experiments should resolve the question of retinotopic organization in regions that respond selectively to color and faces/objects. These experiments will also clarify the spatial relationship among foveal, color, and object responses in VO cortex. Understanding the normal functional organization of this cortical region will serve two purposes. First, it will enhance our knowledge of how the brain processes mid-level visual information about object properties. Second, it may help us understand the variability in the severity and in the degree of recovery of visual deficits from VO cortical lesions.