Song Yongqian, Wang Qian, Fang Fang
School of Psychological and Cognitive Sciences and Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing 100871, China; IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China.
School of Psychological and Cognitive Sciences and Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing 100871, China; IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China; National Key Laboratory of General Artificial Intelligence, Peking University, Beijing 100871, China.
Neuroimage. 2024 Nov 15;302:120897. doi: 10.1016/j.neuroimage.2024.120897. Epub 2024 Oct 21.
Visual perceptual learning (VPL) refers to a long-term improvement of visual task performance through training or experience, reflecting brain plasticity even in adults. In human subjects, VPL has been mostly studied using functional magnetic resonance imaging (fMRI). However, due to the low temporal resolution of fMRI, how VPL affects the time course of visual information processing is largely unknown. To address this issue, we trained human subjects to perform a visual motion direction discrimination task. Their behavioral performance and magnetoencephalography (MEG) signals responding to the motion stimuli were measured before, immediately after, and two weeks after training. Training induced a long-lasting behavioral improvement for the trained direction. Based on the MEG signals from occipital sensors, we found that, for the trained motion direction, VPL increased the motion direction decoding accuracy, reduced the motion direction decoding latency, enhanced the direction-selective channel response, and narrowed the tuning profile. Following the MEG source reconstruction, we showed that VPL enhanced the cortical response in early visual cortex (EVC) and strengthened the feedforward connection from EVC to V3A. These VPL-induced neural changes co-occurred in 160-230 ms after stimulus onset. Complementary to previous fMRI findings on VPL, this study provides a comprehensive description on the neural mechanisms of visual motion perceptual learning from a temporal perspective and reveals how VPL shapes the time course of visual motion processing in the adult human brain.
视觉感知学习（VPL）是指通过训练或经验使视觉任务表现得到长期改善，这反映了即使在成年人中大脑也具有可塑性。在人类受试者中，VPL大多使用功能磁共振成像（fMRI）进行研究。然而，由于fMRI的时间分辨率较低，VPL如何影响视觉信息处理的时间进程在很大程度上尚不清楚。为了解决这个问题，我们训练人类受试者执行视觉运动方向辨别任务。在训练前、训练后立即以及训练后两周测量他们对运动刺激的行为表现和脑磁图（MEG）信号。训练使对训练方向的行为改善得以持久保持。基于枕叶传感器的MEG信号，我们发现，对于训练的运动方向，VPL提高了运动方向解码准确性，缩短了运动方向解码潜伏期，增强了方向选择性通道反应，并缩小了调谐曲线。在进行MEG源重建后，我们表明VPL增强了早期视觉皮层（EVC）的皮层反应，并加强了从EVC到V3A的前馈连接。这些由VPL引起的神经变化在刺激开始后160 - 230毫秒同时出现。作为先前关于VPL的fMRI研究结果的补充，本研究从时间角度对视觉运动感知学习的神经机制进行了全面描述，并揭示了VPL如何塑造成人大脑中视觉运动处理的时间进程。
