Disrupted dynamic brain network and its functional topological underpinning in essential tremor

Area of Science:

• Neuroscience
• Neurology
• Medical Imaging

Background:

• Essential tremor (ET) is a common neurological disorder linked to neural network dysfunction.
• Previous studies using resting-state fMRI overlooked the dynamic nature of brain networks in ET.
• Investigating dynamic functional connectivity (DFC) and topology is crucial for understanding ET.

Purpose of the Study:

• To examine alterations in dynamic functional connectivity (DFC) in Essential Tremor (ET).
• To explore changes in the functional topology of brain networks within different DFC states in ET.
• To correlate DFC alterations with tremor severity in ET patients.

Main Methods:

• Resting-state fMRI data acquired from 144 ET patients and 131 healthy controls (NC).
• Sliding-window approach and K-means clustering identified dynamic functional states.
• Graph theory analysis assessed the topological organization of identified states.

Main Results:

• Two distinct DFC states identified: a 'cerebrum-dominant' state and a 'cerebellum-dominant' state.
• ET patients exhibited a higher proportion and longer duration of the cerebellum-dominant state, with fewer state transitions compared to NC.
• ET showed reduced centrality and efficiency in cerebral regions and increased betweenness centrality in cerebellar regions, particularly in the cerebellum-dominant state. These alterations correlated with tremor severity.

Conclusions:

• Essential tremor is characterized by a prolonged cerebellum-dominant state and disrupted functional topology.
• Findings provide novel insights into the neurobiological mechanisms underlying ET.
• Dynamic functional connectivity analysis offers a new perspective on ET pathophysiology.