Department of Psychology, University of California at Berkeley Berkeley, CA, USA.
Front Psychol. 2010 Nov 12;1:186. doi: 10.3389/fpsyg.2010.00186. eCollection 2010.
A gradually fading moving object is perceived to disappear at positions beyond its luminance detection threshold, whereas abrupt offsets are usually localized accurately. What role does retinotopic activity in visual cortex play in this motion-induced mislocalization of the endpoint of fading objects? Using functional magnetic resonance imaging (fMRI), we localized regions of interest (ROIs) in retinotopic maps abutting the trajectory endpoint of a bar moving either toward or away from this position while gradually decreasing or increasing in luminance. Area V3A showed predictive activity, with stronger fMRI responses for motion toward versus away from the ROI. This effect was independent of the change in luminance. In Area V1 we found higher activity for high-contrast onsets and offsets near the ROI, but no significant differences between motion directions. We suggest that perceived final positions of moving objects are based on an interplay of predictive position representations in higher motion-sensitive retinotopic areas and offset transients in primary visual cortex.
逐渐消失的移动物体在其亮度检测阈值之外的位置被感知为消失,而突然的偏移通常可以被准确地定位。在视觉皮层的视网膜拓扑活动在这种运动引起的淡出物体端点的误定位中扮演了什么角色?我们使用功能磁共振成像(fMRI),定位了在棒向或远离该位置移动时,亮度逐渐增加或减少的轨迹端点附近的视网膜拓扑图的感兴趣区域(ROI)。V3A 区表现出预测性活动,对于朝向 ROI 的运动,fMRI 反应更强。该效应与亮度变化无关。在 V1 区,我们发现靠近 ROI 的高对比度起始和偏移的活动更高,但运动方向之间没有显著差异。我们认为,运动物体的感知最终位置是基于更高的运动敏感视网膜拓扑区域中的预测位置表示和初级视觉皮层中的偏移瞬变的相互作用。