Tao Xiaofeng, Zhang Bin, Shen Guofu, Wensveen Janice, Smith Earl L, Nishimoto Shinji, Ohzawa Izumi, Chino Yuzo M
College of Optometry, University of Houston, Houston, Texas 77204-2020.
College of Optometry, University of Houston, Houston, Texas 77204-2020, College of Optometry, NOVA Southeastern University, Fort Lauderdale, Florida 33314.
J Neurosci. 2014 Oct 8;34(41):13840-54. doi: 10.1523/JNEUROSCI.1992-14.2014.
Experiencing different quality images in the two eyes soon after birth can cause amblyopia, a developmental vision disorder. Amblyopic humans show the reduced capacity for judging the relative position of a visual target in reference to nearby stimulus elements (position uncertainty) and often experience visual image distortion. Although abnormal pooling of local stimulus information by neurons beyond striate cortex (V1) is often suggested as a neural basis of these deficits, extrastriate neurons in the amblyopic brain have rarely been studied using microelectrode recording methods. The receptive field (RF) of neurons in visual area V2 in normal monkeys is made up of multiple subfields that are thought to reflect V1 inputs and are capable of encoding the spatial relationship between local stimulus features. We created primate models of anisometropic amblyopia and analyzed the RF subfield maps for multiple nearby V2 neurons of anesthetized monkeys by using dynamic two-dimensional noise stimuli and reverse correlation methods. Unlike in normal monkeys, the subfield maps of V2 neurons in amblyopic monkeys were severely disorganized: subfield maps showed higher heterogeneity within each neuron as well as across nearby neurons. Amblyopic V2 neurons exhibited robust binocular suppression and the strength of the suppression was positively correlated with the degree of hereogeneity and the severity of amblyopia in individual monkeys. Our results suggest that the disorganized subfield maps and robust binocular suppression of amblyopic V2 neurons are likely to adversely affect the higher stages of cortical processing resulting in position uncertainty and image distortion.
出生后不久两眼体验到不同质量的图像会导致弱视，这是一种发育性视力障碍。弱视患者判断视觉目标相对于附近刺激元素的相对位置的能力下降（位置不确定性），并且经常经历视觉图像失真。尽管通常认为纹状体外皮层（V1）以外的神经元对局部刺激信息的异常整合是这些缺陷的神经基础，但弱视大脑中的纹状体外神经元很少使用微电极记录方法进行研究。正常猴子视觉区域V2中神经元的感受野（RF）由多个子区域组成，这些子区域被认为反映了V1的输入，并且能够编码局部刺激特征之间的空间关系。我们创建了屈光参差性弱视的灵长类动物模型，并使用动态二维噪声刺激和反向相关方法分析了麻醉猴子多个附近V2神经元的RF子区域图。与正常猴子不同，弱视猴子V2神经元的子区域图严重紊乱：子区域图在每个神经元内部以及附近神经元之间表现出更高的异质性。弱视V2神经元表现出强烈的双眼抑制，并且抑制强度与个体猴子的异质性程度和弱视严重程度呈正相关。我们的结果表明，弱视V2神经元紊乱的子区域图和强烈的双眼抑制可能会对皮层处理的更高阶段产生不利影响，从而导致位置不确定性和图像失真。
