Sun Pei, Guo Jianfei, Guo Shichun, Chen Jingyi, He Le, Fu Shimin
Department of Psychology, School of Social Sciences, Tsinghua University, Beijing, China; Laboratory for Cognitive Brain Mapping, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama, Japan.
Department of Psychology, School of Social Sciences, Tsinghua University, Beijing, China.
PLoS One. 2014 Jun 12;9(6):e99547. doi: 10.1371/journal.pone.0099547. eCollection 2014.
It is believed that human primary visual cortex (V1) increases activity with increasing temporal frequency of a visual stimulus. Two kinds of visual stimulus were used in the previous studies, one is patterned-flash stimulus with a fixed onset period and an increasing average luminance with the increase of temporal frequency, the other is contrast reversing flickering checkerboard or grating with a constant average luminance across different temporal frequencies. That hemodynamic responses change as a function of reversal frequency of contrast reversing checkerboard is at odds with neurophysiological studies in animals and neuroimaging studies in humans. In the present study, we addressed the relationship between reversal frequency of contrast reversing checkerboard and hemodynamic response in human V1 using an event-related experimental paradigm and found that the transient characteristics of blood oxygenation level dependent response in human V1 depended very little on the reversal frequency of a contrast reversing checkerboard.
人们认为，人类初级视觉皮层（V1）会随着视觉刺激时间频率的增加而增加活动。先前的研究使用了两种视觉刺激，一种是具有固定起始期且平均亮度随时间频率增加而增加的图案闪光刺激，另一种是在不同时间频率下具有恒定平均亮度的对比度反转闪烁棋盘格或光栅。对比度反转棋盘格的血流动力学反应随反转频率而变化，这与动物神经生理学研究和人类神经影像学研究不一致。在本研究中，我们使用事件相关实验范式研究了对比度反转棋盘格的反转频率与人类V1血流动力学反应之间的关系，发现人类V1中血氧水平依赖反应的瞬态特征很少依赖于对比度反转棋盘格的反转频率。
