Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, 12 Queen Square, London, WC1N 3BG, UK.
Cereb Cortex. 2010 Mar;20(3):694-703. doi: 10.1093/cercor/bhp140. Epub 2009 Jul 17.
People track facial expression dynamics with ease to accurately perceive distinct emotions. Although the superior temporal sulcus (STS) appears to possess mechanisms for perceiving changeable facial attributes such as expressions, the nature of the underlying neural computations is not known. Motivated by novel theoretical accounts, we hypothesized that visual and motor areas represent expressions as anticipated motion trajectories. Using magnetoencephalography, we show predictable transitions between fearful and neutral expressions (compared with scrambled and static presentations) heighten activity in visual cortex as quickly as 165 ms poststimulus onset and later (237 ms) engage fusiform gyrus, STS and premotor areas. Consistent with proposed models of biological motion representation, we suggest that visual areas predictively represent coherent facial trajectories. We show that such representations bias emotion perception of subsequent static faces, suggesting that facial movements elicit predictions that bias perception. Our findings reveal critical processes evoked in the perception of dynamic stimuli such as facial expressions, which can endow perception with temporal continuity.
人们可以轻松地跟踪面部表情动态，从而准确地感知到不同的情绪。尽管上颞叶回（STS）似乎具有感知变化的面部属性（如表情）的机制，但潜在的神经计算的本质尚不清楚。受新理论观点的启发，我们假设视觉和运动区域将表情表示为预期的运动轨迹。使用脑磁图，我们显示出在恐惧和中性表情之间的可预测转换（与随机和静态呈现相比）会在刺激开始后 165 毫秒内迅速增加视觉皮层的活动，并且稍后（237 毫秒）会涉及梭状回、STS 和运动前区。与生物运动表示的拟议模型一致，我们认为视觉区域可预测地表示连贯的面部轨迹。我们表明，这种表示会偏向后续静态面部的情绪感知，这表明面部运动引发了会影响感知的预测。我们的发现揭示了在感知动态刺激（如面部表情）时所引发的关键过程，这些过程可以使感知具有时间连续性。
