Beyond atrophy: Network-level functional disintegration pattern along the cognitive decline in Parkinson's disease

Area of Science:

• Neuroscience
• Neurology
• Cognitive Science

Background:

• Parkinson's disease (PD) is a neurodegenerative disorder impacting motor and cognitive functions.
• Intrinsic functional connectivity (iFC) disruptions are implicated in PD's cognitive decline.
• Understanding network-level iFC changes across PD cognitive stages is crucial.

Purpose of the Study:

• To elucidate network-level iFC disruptions in Parkinson's disease (PD).
• To characterize iFC dynamics across cognitive decline stages in PD (PD-CN, PD-MCI, PD-D).
• To identify cognition-related subnetworks and their association with cognitive performance.

Main Methods:

• Surface-based cortical thickness measurements to assess neurodegeneration.
• Network-based statistics (NBS) for mass-univariate iFC analysis across three PD cohorts.
• Interaction analysis correlating ACE-R scores with iFC alterations.

Main Results:

• iFC declines begin in the mild cognitive impairment (PD-MCI) stage, affecting default mode (DMN), somatomotor (SMN), and dorsal attention networks (DAN).
• Advanced dementia (PD-D) shows additional iFC decline in limbic and frontoparietal networks, with SMN decoupling from attention networks.
• ACE-R analysis revealed cognition-related subnetworks, with lower cognitive performance linked to reduced iFC.

Conclusions:

• iFC alterations in PD are stage-specific and network-selective.
• Early-stage disruptions involve DMN, attention, and motor networks; later stages show widespread disintegration.
• The somatomotor network's progressive decoupling highlights its role in PD cognitive impairment.