Guangdong Key Laboratory of Mental Health and Cognitive Science, South China Normal University, Guangzhou, China; Graduate Institute of Humanities in Medicine, Taipei Medical University, Taipei, Taiwan; Brain and Consciousness Research Centre, Taipei Medical University-Shuang Ho Hospital, New Taipei City, Taiwan; Centre for Studies of Psychological Applications, South China Normal University, Guangzhou, China; School of Psychology, South China Normal University, Guangzhou, China.
Graduate Institute of Humanities in Medicine, Taipei Medical University, Taipei, Taiwan; Brain and Consciousness Research Centre, Taipei Medical University-Shuang Ho Hospital, New Taipei City, Taiwan; Centre for Cognition and Brain Disorders, Hangzhou Normal University, Hangzhou, China.
Neuroscience. 2018 May 21;379:142-151. doi: 10.1016/j.neuroscience.2018.02.041. Epub 2018 Mar 10.
Neural activity varies continually from moment to moment. Such temporal variability (TV) has been highlighted as a functionally specific brain property playing a fundamental role in cognition. We sought to investigate the mechanisms involved in TV changes between two basic behavioral states, namely having the eyes open (EO) or eyes closed (EC) in vivo in humans. To these ends we acquired BOLD fMRI, ASL, and [F]-fluoro-deoxyglucose PET in a group of healthy participants (n = 15), along with BOLD fMRI and [F]-flumazenil PET in a separate group (n = 19). Focusing on an EO- vs EC-sensitive region in the occipital cortex (identified in an independent sample), we show that TV is constrained in the EO condition compared to EC. This reduction is correlated with an increase in energy consumption and with regional GABA receptor density. This suggests that the modulation of TV by behavioral state involves an increase in overall neural activity that is related to an increased effect from GABAergic inhibition in addition to any excitatory changes. These findings contribute to our understanding of the mechanisms underlying activity variability in the human brain and its control.
神经活动时刻都在不断变化。这种时间变异性（TV）已被强调为一种具有特定功能的大脑属性，在认知中起着至关重要的作用。我们旨在研究在人类两种基本行为状态（即睁眼（EO）和闭眼（EC））之间涉及 TV 变化的机制。为此，我们在一组健康参与者（n=15）中采集了 BOLD fMRI、ASL 和 [F]-氟脱氧葡萄糖 PET，以及在另一组（n=19）中采集了 BOLD fMRI 和 [F]-氟马西尼 PET。我们关注枕叶皮层中一个对 EO 与 EC 敏感的区域（在一个独立样本中确定），结果显示，与 EC 相比，EO 条件下的 TV 受到限制。这种减少与能量消耗的增加和区域 GABA 受体密度的增加有关。这表明，行为状态对 TV 的调制涉及整体神经活动的增加，除了兴奋性变化之外，还与 GABA 能抑制的增强有关。这些发现有助于我们理解人类大脑活动变异性及其控制的机制。
