早期人类视觉皮层对明度变化的反应。
Responses to lightness variations in early human visual cortex.
作者信息
Boyaci Huseyin, Fang Fang, Murray Scott O, Kersten Daniel
机构信息
Department of Psychology, University of Minnesota, Minneapolis, Minnesota 55455, USA.
出版信息
Curr Biol. 2007 Jun 5;17(11):989-93. doi: 10.1016/j.cub.2007.05.005.
Lightness is the apparent reflectance of a surface, and it depends not only on the actual luminance of the surface but also on the context in which the surface is viewed [1-10]. The cortical mechanisms of lightness processing are largely unknown, and the role of early cortical areas is still a matter of debate [11-17]. We studied the cortical responses to lightness variations in early stages of the human visual system with functional magnetic resonance imaging (fMRI) while observers were performing a demanding fixation task. The set of dynamically presented visual stimuli included the rectangular version of the classic Craik-O'Brien stimulus [3, 18, 19] and a variant that led to a weaker lightness effect, as well as a pattern with actual luminance variations. We found that the cortical activity in retinotopic areas, including the primary visual cortex (V1), is correlated with context-dependent lightness variations.
明度是表面的表观反射率，它不仅取决于表面的实际亮度，还取决于观察该表面的环境[1 - 10]。明度处理的皮层机制在很大程度上尚不清楚，早期皮层区域的作用仍存在争议[11 - 17]。我们利用功能磁共振成像（fMRI）研究了人类视觉系统早期阶段对明度变化的皮层反应，同时观察者执行一项要求较高的注视任务。动态呈现的视觉刺激集包括经典Craik - O'Brien刺激的矩形版本[3, 18, 19]以及导致较弱明度效应的变体，还有具有实际亮度变化的图案。我们发现，包括初级视觉皮层（V1）在内的视网膜拓扑区域的皮层活动与依赖于环境的明度变化相关。
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