Recurrent and Concurrent Patterns of Regional BOLD Dynamics and Functional Connectivity Dynamics in Cognitive Decline

Abstract

Background: The brain’s dynamic spontaneous neural activity and dynamic functional connectivity (dFC) are both important in supporting cognition, but how these two types of brain dynamics evolve and co-evolve in subjective cognitive decline (SCD) and mild cognitive impairment (MCI) remain unclear. The aim of this study is to investigate recurrent and concurrent patterns of two types of dynamic brain states correlated with cognitive decline. Methods: the present study analyzed resting-state fMRI from 62 SCD, 75 MCI and 70 healthy controls (HC). Results: We identified a few recurrent states of dynamic regional spontaneous activity (measured as dynamic fractional amplitude of low-frequency fluctuations, dfALFF) and dFC, and further ascertained the co-occurrent patterns of two types of dynamic brain states (i.e., dfALFF and dFC states). Importantly, the occurrence frequency of a default mode network (DMN)-dominated dFC state was significantly different between HC and SCD, while the co-occurrence frequency of a DMN-dominated dFC state and a DMN-dominated dfALFF state was significantly different between SCD and MCI. These two dynamic features were both significantly positively correlated with Mini Mental State Examination scores. Conclusion: This study discovered new neural signatures of cognitive decline from recurrent and concurrent patterns of dfALFF and dFC, providing strong evidence supporting SCD as the transition phase between normal aging and MCI. This finding holds the potential to differentiate SCD from HC by using both dFC and dfALFF as objective neuroimaging biomarkers, and thus helps the early diagnosis and intervention of AD.

Exploring dynamic functional connectivity alterations in the preclinical stage of Alzheimer’s disease: an exploratory study from SICOLDE

“…However, extensive evidence suggests that FC, even at rest, should be understood as a dynamic measure. In recent years, dynamic FCs obtained from rs-fMRI time series has proven highly informative regarding the underlying brain connectivity patterns, as it enables slight changes over a short period of time to be explored (18)(19)(20). For example, research based on slidingwindow analysis found that the occurrence frequency of a default mode network (DMN)-dominated dynamic FC state was signi cantly different in SCD patients (20).…”

“…In recent years, dynamic FCs obtained from rs-fMRI time series has proven highly informative regarding the underlying brain connectivity patterns, as it enables slight changes over a short period of time to be explored (18)(19)(20). For example, research based on slidingwindow analysis found that the occurrence frequency of a default mode network (DMN)-dominated dynamic FC state was signi cantly different in SCD patients (20). However, there have been few attempts to directly compare static and dynamic FCs or to determine whether dynamic FCs could undergo stable and subtle changes in subjects with SCD.…”