认知与发展心理学研究室知识库

生物社会性信息对生存和适应有重要价值，个体需要皮层下加工机制快速和自动化地处理此类信息。研究这种皮层下加工机制很有意义。为此，在总结有关文献的基础上，本文选取两种生物社会性刺激——人脸和生物运动，来研究其皮层下加工机制。

研究一利用启动（或适应）情绪面孔的方式增强（或抑制）皮层下通路的活动后，用双眼竞争的方法观测随后呈现的高和低空间频率的光栅在个体视觉意识中的主导状况。研究发现，启动（或适应）的恐惧面孔，相比于中性面孔来说，可以增强（或减弱）后续呈现的低空间频率的光栅在视觉意识中的主导性。该研究的结果在一定程度上为皮层下通路假说提供了新的行为证据。

研究二使用功能磁共振成像技术观察被试加工局部生物运动时的脑活动。结果发现，上丘对局部生物运动有反应，而且这种反应存在层间的差别；并且上丘与位于大脑皮层的脑区间的连接强度受到局部生物运动的影响（相较于倒立的局部生物运动），这种影响也具有层间的差别，并且存在于从上丘到皮层区域的前馈通路上。这揭示了上丘及其不同层在局部生物运动加工中的作用，及上丘发挥这种作用参与的脑网络。

研究三用快速闪烁融合的方法将生物运动刺激抑制到意识下，把时间知觉变化作为衡量生物运动加工的指标。研究发现即使通过快速闪烁融合的方法减弱高级脑区的作用后，完整生物运动仍可延长时间知觉。这说明了完整生物运动的加工对可受抑制影响的高级脑区的依赖程度较小。

三个研究皆可直接或间接地表明，以面孔和生物运动为代表的生物社会性信息可以在皮层下得到加工，而上丘可能是其中起作用的一个重要结构。

Biosocial information is of great value to survival and adaptation. Subcortical mechanisms are needed by each individual for processing this kind of information rapidly and automatically. It is of significance to study these subcortical mechanisms. To this end, based on reviewing relevant references, two types of biosocial information, human faces and biological motion were chosen to study their subcortical processing mechanisms.

Study 1 increased (or decreased) the activities of the subcortical pathway by the priming (or adaptation) of emotional faces, and measured the dominant state of the subsequently presented Gabor patches of high and low spatial frequencies in the individual’s visual awareness with the method of binocular rivalry. It was found that fearful faces primed (or adapted to) could strengthen (or weaken) the dominance of Gabor patches with low spatial frequency in visual awareness relative to neutral faces. These results provided new behavioral evidence for the subcortical pathway hypothesis to some extent.

Study 2 used the technique of functional magnetic resonance imaging to observe brain activities of participants when the local biological motion was being processed. It was found that superior colliculus responded to local biological motion and the responses had laminar difference. And the strength of connectivities between superior colliculus and brain areas located in the cerebral cortex was affected by local biological motion (compared to inverted local biological motion), which also had laminar difference and existed in feedforward pathways from superior colliculus to brain areas located in the cerebral cortex. These results revealed the roles of superior colliculus and its layers with different depth played in local biological motion processing and demonstrated the brain networks involving superior colliculus which supported these roles.

Study 3 applied the rapid flicker fusion technique to suppress biological motion stimuli to unconsciousness and took the changes of time perception as indicators to evaluate biological motion processing. It showed that intact biological motion could still lengthen time perception though the involvement of high-level brain areas was reduced by rapid flicker fusion. This study demonstrated little dependence of intact biological motion processing on high-level areas which could be affected by suppressing.

All three studies directly or indirectly proved that biosocial information represented by faces and biological motion could be processed in subcortical areas, in which superior colliculus may be an important structure that served a function.