Disparity Processing in Human Visual Cortex

描述(申请人提供)：视差调谐是灵长类皮质中几乎所有视觉区域神经元的普遍特性。我们将使用一种新的神经成像技术来检测视差信息从V1到人类大脑皮层纹外区域的流动。这项技术依赖于使用高密度脑电结合结构和功能MRI解剖测量的来源定位。我们将测量四个相隔很远的皮质区域V1、V3A、V4和HMT+对视差重复变化的神经反应-所有这些都是已知在灵长类视差处理中重要的。我们的第一个目标是检查这四个区域的皮质反应对动态随机点的敏感性，这些点受到水平或垂直差异的调制。我们还将探索对反相关随机点的反应，这些随机点已知在许多皮质区域驱动单个单位。我们的第二个目标是评估视差调制对曲面分割的贡献。我们将比较图形-背景分割中的单目调制变化所产生的响应模式和图形-背景分割中的视差调制变化所产生的响应模式。我们的第三个目标是探索立体视觉的丧失如何影响斜视观察者的大脑皮层反应。我们将特别寻找斜视抑制的皮质轨迹，以及运动不对称的轨迹，这是婴儿内斜视的一个决定性特征。与公共卫生相关的斜视是一种发育异常，影响3%-5%的人口，导致立体视丧失。这项拟议的研究将测量与斜视的两种异常相关的皮质反应：斜视抑制和之前在VEP测量中观察到的运动不对称。运动不对称是判断治疗，特别是手术疗效的一个有用的标志，因此了解其皮质起源将增强其实用性。

DESCRIPTION (provided by applicant): Disparity tuning is a pervasive property of neurons in almost all visual areas in primate cortex. We will use a novel neuroimaging technique to examine the flow of disparity information from V1 to extra- striate areas in human cortex. This technique relies on source localization using high density EEG coupled to structural and functional MRI anatomical measurements. We will measure the neural response to repetitive changes in disparity in four widely separated cortical areas, V1, V3A, V4 and hMT+ - all known to be important in primate disparity processing. Our first aim examines the sensitivity of the cortical response in these four areas to dynamic random dots, modulated by horizontal or by vertical disparity. We will also explore the response to anti-correlated random dots which are known to drive single units in many cortical areas. Our second aim evaluates the contribution of disparity-modulation to surface segmentation. We will compare the response patterns produced by monocularly modulated changes in figure-ground segmentation to those generated by disparity modulated changes in figure-ground segmentation. Our third aim explores how the loss of stereopsis affects the cortical responses of the strabismic observer. We will specifically look for the cortical locus of strabismic suppression, as well as for the locus of the motion asymmetry that is a defining characteristic of infantile esotropia. PUBLIC HEALTH RELEVANCE Strabismus is a developmental abnormality that affects 3 - 5% of the population, resulting in the loss of stereopsis. The proposed research will measure the cortical response associated with two anomalies of strabismus: strabismic suppression and the motion asymmetry previously observed in VEP measurements. The motion asymmetry is a useful marker for judging the efficacy of treatment, particularly surgery, so understanding its cortical origin will enhance its utility.