Dynamic Adaptation of Default Mode Network in Resting state and Autobiographical Episodic Memory Retrieval State

The default mode network processes mental states involving internal representations of subjective experiences, such as autobiographical memory retrieval and resting states. A novel analysis method called one-to-many dynamic functional connectivity analysis for fMRI was developed to detect how a single brain network's dynamics adapt depending on the mental state. Applied to a single late-blind subject with advanced mental imagery ability, the method examined the default mode network during three autobiographical memory retrieval states and a resting state. The posterior cingulate cortex as the center best depicted dynamic adaptation between mental states. The correlation between the posterior cingulate cortex and the right parahippocampal cortex varied most, contributing relatively more to dynamic adaptation.

Study at a glance

Abstract

Abstract The default mode network is a brain network processing mental states featuring an internal representation of subjective experiences like autobiographical episodic memory retrieval and a resting state. If the default mode network is the common spatial domain processing such mental states, then the temporal domain might present the differences in the mental states. To detect adaptations in dynamics of a single brain network dependent on the mental states it processes, we suggested a novel analysis method called one-to-many dynamic functional connectivity analysis for fMRI. The analysis method assesses the variance in the partial correlations of a center that are time-windowed functional correlations of a brain region (a center) to the rest of the regions in a brain network, then compares the similarities in the directions of their major variance from the same or distinct mental states. We applied one-to-many dynamic functional connectivity analysis to the default mode network and measured the similarity between the major variances of the partial correlations from three autobiographical episodic memory retrieval states and a resting state. If the major direction of the variance is a configuration presenting the mental states of the brain network, we expect to see the high similarity for the same mental states and less similarity for the distinct mental states. To test our hypothesis with the new analysis method, we chose a single subject who is a late blind with advanced mental imagery ability. The results showed that the dynamic adaption in the default mode network in the two mental states could be well depicted when the posterior cingulate cortex is the center in this single case. Furthermore, we could observe that the weight of the correlation between the posterior cingulate cortex and the right parahippocampal cortex varied mostly and therefore its contribution to the dynamic adaptation was relatively higher than the other correlations.