The characteristic patterns of dynamic network reconfiguration underlying subjective cognitive decline.

BACKGROUND

Although dynamic network reconfiguration is altered in Alzheimer's disease (AD), its pattern in subjective cognitive decline (SCD), an early preclinical stage, remains unclear.

OBJECTIVE

This study aims to identify the characteristics of dynamic network reconfiguration in SCD individuals compared to healthy controls (HCs) and AD patients.

METHODS

Time-varying multilayer network models were built for AD (n = 111), SCD (n = 115), and HC (n = 111) groups using the GenLouvain algorithm. We compared dynamic reconfiguration features across groups and examined how abnormal reconfiguration affects the relationship between amyloid-β (Aβ) pathology and cognition.

RESULTS

SCD individuals showed higher global recruitment and lower global integration than AD patients, and lower integration than HCs. At the nodal level, SCD was marked by increased recruitment and reduced integration in regions mainly within the default mode network (DMN) and somatomotor network (SMN). In SCD, recruitment in the left anterior insula and ventral frontal cortex linked Aβ pathology to memory performance. In AD, integration in the left superior frontal gyrus mediated the effects of Aβ on memory and verbal fluency. The combination of differences in nodal recruitment and integration across groups helped distinguish between healthy, SCD, and AD individuals.

CONCLUSIONS

SCD individuals show distinct patterns of dynamic network reconfiguration, high recruitment, and low integration in DMN and SMN, offering new insights into early AD pathophysiology.