State Key Laboratory of Brain and Cognitive Sciences, CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Psychology, Chinese Academy of Sciences, Beijing 100101, China; Department of Psychology, University of Chinese Academy of Sciences, Beijing 100049, China; Chinese Institute for Brain Research, Beijing 102206, China.
State Key Laboratory of Brain and Cognitive Sciences, CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Psychology, Chinese Academy of Sciences, Beijing 100101, China; Department of Psychology, University of Chinese Academy of Sciences, Beijing 100049, China; Chinese Institute for Brain Research, Beijing 102206, China.
Neuroimage. 2023 Mar;268:119893. doi: 10.1016/j.neuroimage.2023.119893. Epub 2023 Jan 21.
Biological motion (BM) perception is of great survival value to human beings. The critical characteristics of BM information lie in kinematic cues containing rhythmic structures. However, how rhythmic kinematic structures of BM are dynamically represented in the brain and contribute to visual BM processing remains largely unknown. Here, we probed this issue in three experiments using electroencephalogram (EEG). We found that neural oscillations of observers entrained to the hierarchical kinematic structures of the BM sequences (i.e., step-cycle and gait-cycle for point-light walkers). Notably, only the cortical tracking of the higher-level rhythmic structure (i.e., gait-cycle) exhibited a BM processing specificity, manifested by enhanced neural responses to upright over inverted BM stimuli. This effect could be extended to different motion types and tasks, with its strength positively correlated with the perceptual sensitivity to BM stimuli at the right temporal brain region dedicated to visual BM processing. Modeling results further suggest that the neural encoding of spatiotemporally integrative kinematic cues, in particular the opponent motions of bilateral limbs, drives the selective cortical tracking of BM information. These findings underscore the existence of a cortical mechanism that encodes periodic kinematic features of body movements, which underlies the dynamic construction of visual BM perception.
生物运动 (BM) 感知对人类具有重要的生存价值。BM 信息的关键特征在于包含节奏结构的运动学线索。然而，BM 的节奏运动结构如何在大脑中动态表示以及如何促进视觉 BM 处理在很大程度上仍是未知的。在这里，我们使用脑电图 (EEG) 在三个实验中探究了这个问题。我们发现，观察者的神经振荡与 BM 序列的分层运动结构（即点步行者的步循环和步态循环）同步。值得注意的是，只有更高层次的节奏结构（即步态循环）的皮质跟踪表现出 BM 处理的特异性，表现为对直立的 BM 刺激的神经反应增强，而对倒置的 BM 刺激的反应减弱。这种效应可以扩展到不同的运动类型和任务，其强度与专门用于视觉 BM 处理的右颞区对 BM 刺激的感知敏感性呈正相关。模型结果进一步表明，时空综合运动线索的神经编码，特别是双侧肢体的相反运动，驱动了 BM 信息的选择性皮质跟踪。这些发现强调了存在一种皮质机制，该机制对身体运动的周期性运动特征进行编码，从而构成了视觉 BM 感知的动态构建。
