Neural Representation of Features in the Human Visual Cortex

描述（由申请人提供）：灵长类动物的视觉系统根据一组稀疏的基本特征来分析输入的视觉信息。特征选择神经元提供了视觉场景中局部特征的详细分析，如刺激方向、运动方向等信息。视觉特征的神经表征已经在非人类灵长类动物中进行了广泛的研究，但由于非侵入性神经成像方法的空间分辨率有限，在人类中进行研究具有挑战性。我的实验室开发了一种新的分析技术，利用功能性磁共振成像（fMRI）来测量人类视觉系统的特征调谐特性。我们的初步研究表明，不同的刺激方向和运动方向唤起了人类视觉皮层中不同的整体fMRI活动模式，这些模式可以通过统计算法可靠地分类。本项目将应用这种新颖的模式分析方法来研究人类皮层中方向和运动方向的神经表征以及视觉注意在特征感知中的作用。拟议的研究将评估早期人类视觉区域的活动是否与刺激表面特性变化的视觉特征感知相对应。具体目标1将研究早期视觉区域的定向选择特性，并确定这些区域是否显示出线索不变的定向选择的证据，这种选择性可以有效地概括刺激形式的变化。具体目标2将评估视觉区域V1到V4和MT+的方向选择性，并测试线索不变的方向选择性和感知全局运动的敏感性。具体目标3将探讨视觉注意在选择和稳定视觉特征表征中的作用。该项目的结果将为人类视觉特征感知的神经基础提供重要的新见解，并有助于在动物和人类研究之间建立桥梁。测量个体大脑特征选择特性的能力也可能具有很高的临床意义。这种方法可能会产生有效的新工具，用于研究、表征或诊断由疾病或损伤引起的皮质视觉功能障碍，或用于评估医学治疗或功能恢复对皮质的影响。

DESCRIPTION (provided by applicant): The primate visual system analyzes incoming visual information according to a sparse set of fundamental features. Feature-selective neurons provide a detailed analysis of the local features in visual scenes, such as information about stimulus orientation, motion direction, and so forth. The neural representation of visual features has been studied extensively in non-human primates but has proven challenging to study in humans due to the limited spatial resolution of noninvasive neuroimaging methods. My lab has developed novel analysis techniques to measure the feature tuning properties of the human visual system using functional magnetic resonance imaging (fMRI). Our preliminary studies show that different stimulus orientations and motion directions evoke distinct patterns of ensemble fMRI activity in the human visual cortex that can be reliably classified by statistical algorithms. This project will apply this novel pattern analysis approach to investigate the neural representations of orientation and motion direction in the human cortex and the role of visual attention in feature perception. The proposed studies will evaluate whether activity in early human visual areas corresponds with visual feature perception across changes in the surface properties of the stimulus. Specific Aim 1 will investigate the orientation-selective properties of early visual areas, and determine whether these areas show evidence of cue-invariant orientation selectivity that can effectively generalize across changes in stimulus form. Specific Aim 2 will assess direction selectivity in visual areas V1 through V4 and MT+, and test for cue-invariant direction selectivity and sensitivity to perceived global motion. Specific Aim 3 will explore the role of visual attention in selecting and stabilizing the representations of visual features. The results from this project will provide important new insights into the human neural bases of visual feature perception, and help provide a bridge between animal and human studies. The ability to measure the feature-selective properties of an individual's brain may also have high clinical significance. This approach may lead to effective new tools to investigate, characterize, or diagnose impairments in cortical visual function resulting from disease or injury, or methods to evaluate the cortical effects of medical treatment or recovery of function.