Disparity Processing in Human Visual Cortex

描述（由申请人提供）：视差调节是灵长类动物皮层中几乎所有视觉区域的神经元普遍存在的特性。我们将使用一种新的神经成像技术来检查视差信息从V1到皮层外区域的流动。该技术依赖于使用高密度脑电图与结构和功能MRI解剖测量相结合的源定位。我们将测量四个广泛分离的皮层区域，V1, V3A， V4和hMT+对视差重复变化的神经反应，这些区域在灵长类动物的视差处理中都很重要。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，由水平或垂直视差调节。我们还将探索对反相关随机点的响应，这些点已知在许多皮质区域驱动单个单元。我们的第二个目标是评估差分调制对表面分割的贡献。我们将比较单眼调制的图像-地面分割变化和视差调制的图像-地面分割变化产生的响应模式。我们的第三个目的是探讨立体视觉的丧失如何影响斜视观察者的皮层反应。我们将专门寻找斜视抑制的皮质位点，以及运动不对称的位点，这是婴儿内斜视的一个决定性特征。斜视是一种发育异常，影响3 - 5%的人口，导致立体视觉丧失。该研究将测量与斜视两种异常相关的皮层反应：斜视抑制和先前在VEP测量中观察到的运动不对称。运动不对称是判断治疗效果的有用标志，特别是手术，因此了解其皮层起源将提高其实用性。

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.