Author/Authors :
Kasagi, Masato Department of Psychiatry and Neuroscience - Gunma University Graduate School of Medicine, Gunma, Japan , Huang, Zirui Institute of Mental Health Research - University of Ottawa, Canada , Narita, Kosuke Institute of Mental Health Research - University of Ottawa, Canada , Shitara, Hitoshi Department of Orthopaedic Surgery - Gunma University Graduate School of Medicine, Maebashi, Japan , Motegi, Tomokazu Department of Psychiatry and Neuroscience - Gunma University Graduate School of Medicine, Gunma, Japan , Suzuki, Yusuke Department of Psychiatry and Neuroscience - Gunma University Graduate School of Medicine, Gunma, Japan , Fujihara, Kazuyuki Department of Psychiatry and Neuroscience - Gunma University Graduate School of Medicine, Gunma, Japan , Tanabe, Sean Institute of Mental Health Research - University of Ottawa, Canada , Kosaka, Hirotaka Research Center for Child Mental Development - University of Fukui - Eiheiji-cho, Japan , Ujita, Koichi Department of Diagnostic Radiology and Nuclear Medicine - Gunma University Graduate School of Medicine, Japan , Fukuda, Masato Department of Psychiatry and Neuroscience - Gunma University Graduate School of Medicine, Gunma, Japan , Northoff, Georg Institute of Mental Health Research - University of Ottawa, Canada
Abstract :
The scale-free dynamics of human brain activity, characterized by an elaborate temporal structure with scale-free properties, can be quantified using the power-law exponent (PLE) as an index. Power laws are well documented in nature in general, particularly in the brain. Some previous fMRI studies have demonstrated a lower PLE during cognitive-task-evoked activity than during resting state activity. However, PLE modulation during cognitive-task-evoked activity and its relationship with an associated behavior remain unclear. In this functional fMRI study in the resting state and face processing + control task, we investigated PLE during both the resting state and task-evoked activities, as well as its relationship with behavior measured using mean reaction time (mRT) during the task. We found that (1) face discrimination-induced BOLD signal changes in the medial prefrontal cortex (mPFC), posterior cingulate cortex (PCC), amygdala, and fusiform face area; (2) PLE significantly decreased during task-evoked activity specifically in mPFC compared with resting state activity; (3) most importantly, in mPFC, mRT significantly negatively correlated with both resting state PLE and the resting-task PLE difference. These results may lead to a better understanding of the associations between task performance parameters (e.g., mRT) and the scale-free dynamics of spontaneous and task-evoked brain activities.
Keywords :
Scale-Free Brain Dynamics , Behavioral Performance , : Functional MRI Study , Resting State , Face Processing Task
