Institute of Psychology, University of Regensburg, Universitätsstrasse 31, 93053 Regensburg, Germany.
J Neurophysiol. 2010 Mar;103(3):1410-7. doi: 10.1152/jn.00582.2009. Epub 2010 Jan 13.
Prolonged exposure to complex stimuli, such as faces, biases perceptual decisions toward nonadapted, dissimilar stimuli, leading to contrastive aftereffects. Here we tested the neural correlates of this perceptual bias using a functional magnetic resonance imaging adaptation (fMRIa) paradigm. Adaptation to a face or hand stimulus led to aftereffects by biasing the categorization of subsequent ambiguous face/hand composite stimuli away from the adaptor category. The simultaneously observed fMRIa in the face-sensitive fusiform face area (FFA) and in the body-part-sensitive extrastriate body area (EBA) depended on the behavioral response of the subjects: adaptation to the preferred stimulus of the given area led to larger signal reduction during trials when it biased perception than during trials when it was less effective. Activity in two frontal areas correlated positively with the activity patterns in FFA and EBA. Based on our novel adaptation paradigm, the results suggest that the adaptation-induced aftereffects are mediated by the relative activity of category-sensitive areas of the human brain as demonstrated by fMRI.
长时间暴露于复杂刺激（如人脸）会使感知决策偏向于非适应的、不相似的刺激，从而产生对比后效。在这里，我们使用功能磁共振成像适应（fMRIa）范式来测试这种感知偏差的神经相关性。适应于人脸或手刺激会通过使后续模糊人脸/手复合刺激的分类偏向于适应器类别来产生后效。在面孔敏感的梭状回面孔区（FFA）和身体部位敏感的外梭状回区（EBA）中同时观察到的 fMRIa 取决于受试者的行为反应：适应于给定区域的首选刺激会导致在其偏向感知的试验中信号减少比在其效果较差的试验中更大。两个额区的活动与 FFA 和 EBA 中的活动模式呈正相关。基于我们新颖的适应范式，结果表明，适应诱导的后效是由人类大脑的类别敏感区域的相对活动介导的，如 fMRI 所示。
