White matter microstructure and volitional motor activity in schizophrenia: A diffusion kurtosis imaging study

Area of Science:

• Neuroimaging
• Psychiatry
• Neuroscience

Background:

• Avolition, a key symptom of schizophrenia, is associated with disrupted brain connectivity.
• Understanding the neural underpinnings of avolition is crucial for developing targeted interventions.

Purpose of the Study:

• To investigate the relationship between white matter (WM) microstructure and volitional motor activity in patients with schizophrenia using diffusion kurtosis imaging (DKI).
• To explore group differences in WM microstructure measures between patients and healthy controls.

Main Methods:

• Acquired multi-shell diffusion MRI and 24-h actigraphy data from 20 patients with schizophrenia and 16 healthy controls.
• Analyzed fractional anisotropy (FA), mean diffusivity (MD), and mean kurtosis (MK) in relation to motor activity levels.
• Compared WM microstructure measures between patient and control groups.

Main Results:

• In patients with schizophrenia, higher motor activity positively correlated with mean kurtosis (MK) in several WM tracts, including the longitudinal fasciculus and corpus callosum.
• These correlations between motor activity and MK were specific to DKI measures and not observed with traditional DTI measures (FA, MD).
• No significant associations were found between motor activity and WM microstructure in the healthy control group.

Conclusions:

• Reduced volitional motor activity in schizophrenia is associated with altered WM microstructure, particularly in posterior brain regions involved in cognition and motivation.
• These findings suggest that illness-related dysconnectivity or the effects of reduced physical activity may contribute to avolition in schizophrenia.
• DKI is a sensitive technique for detecting microstructural changes related to motor activity in schizophrenia.