Functional voxel hierarchy and afferent capacity revealed mental state transition on dynamic correlation resting-state fMRI

TL;DR

This study reveals how voxel hierarchy and afferent capacity in dynamic resting-state fMRI graphs can identify and quantify mental state transitions through k core percolation and directed graph analysis.

Contribution

It introduces a novel approach combining k core percolation, directed graphs, and volume entropy to analyze mental state transitions in resting-state fMRI data.

Findings

Abrupt changes in coreness k mark mental state transitions.

Transient modules of voxels exchange during state changes.

Voxel afferent capacities correlate with mental state dynamics.

Abstract

Voxel hierarchy on dynamic brain graphs is produced by k core percolation on functional dynamic amplitude correlation of resting-state fMRI. Directed graphs and their afferent/efferent capacities are produced by Markov modeling of the universal cover of undirected graphs simultaneously with the calculation of volume entropy. Positive and unsigned negative brain graphs were analyzed separately on sliding-window representation to underpin the visualization and quantitation of mental dynamic states with their transitions. Voxel hierarchy animation maps of positive graphs revealed abrupt changes in coreness k and kmaxcore, which we called mental state transitions. Afferent voxel capacities of the positive graphs also revealed transient modules composed of dominating voxels/independent components and their exchanges representing mental state transitions. Animation and quantification plots of voxel hierarchy and afferent capacity corroborated each other in underpinning mental state transitions and afferent module exchange on the positive directed functional connectivity graphs. We propose the use of spatiotemporal trajectories of voxels on positive dynamic graphs to construct hierarchical structures by k core percolation and quantified in- and out-flows of information of voxels by volume entropy/directed graphs to subserve diverse resting mental state transitions on resting-state fMRI graphs in normal human individuals.