Altered network stability in progressive supranuclear palsy.

Area of Science:

• Neuroscience
• Neurology
• Medical Imaging

Background:

• Clinical syndromes of Progressive Supranuclear Palsy (PSP) may involve abnormal brain network temporal dynamics.
• Atrophy, synapse loss, and neurotransmitter deficits are implicated in PSP pathophysiology.
• Altered neural signal complexity might influence brain state transitions in neurological disorders.

Purpose of the Study:

• To test if alterations in neural signal complexity impact short-latency state transitions in Progressive Supranuclear Palsy (PSP).
• To investigate the relationship between brain network dynamics, signal complexity, and clinical severity in PSP.

Main Methods:

• Utilized resting-state functional MRI (rs-fMRI) data from 94 PSP patients and 64 healthy controls across two cohorts.
• Applied hidden Markov models to assess network dynamics and multiscale entropy to measure neural signal complexity.
• Correlated network dynamics and complexity measures with clinical severity using the PSP-rating scale.

Main Results:

• PSP patients spent a greater proportion of time in brain networks associated with higher cognitive functions compared to controls.
• Reduced neural signal complexity in PSP correlated with increased time in these higher cognitive networks and clinical severity.
• Abnormal brain-state occupancy was influenced by regional atrophy but also occurred in non-atrophic areas, indicating widespread network dysfunction.

Conclusions:

• PSP pathology induces clinically significant changes in neural temporal dynamics.
• The findings demonstrate a shift towards inefficient brain states in PSP, linked to reduced neural signal complexity.
• Abnormal network dynamics in PSP are not solely confined to regions of atrophy.