Modeling functional dynamics of cortical gyri and sulci

Abstract

Cortical gyrification is one of the most prominent features of human brain. A variety of studies in the brain mapping field have demonstrated the specific structural and functional differences between gyral and sulcal regions. However,previous studies of gyri/sulci function analysis based on the fMRI data assume the temporal stationarity over the entire fMRI scan,while the possible temporal dynamics of gyri/sulci function is largely unknown. We present a computational framework to model the functional dynamics of cortical gyri and sulci based on task fMRI data. Specifically,the whole-brain fMRI signals’ temporal segments are derived via the sliding time window approach. The spatial overlap patterns among functional networks (SOPFNs),which are crucial for characterizing brain functions,are then measured within each time window via a group-wise sparse representation approach. Finally,the temporal dynamics of SOPFNs distribution on gyral/sulcal regions across all time windows are assessed. Experimental results based on the publicly released Human Connectome Project task fMRI data demonstrated that the proposed framework identified meaningful temporal dynamics difference of the SOPFNs distribution between gyral and sulcal regions which are reproducible across different subjects and task fMRI datasets. Our results provide novel understanding of functional dynamics mechanisms of human cerebral cortex.