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Motion During Acquisition is Associated With fMRI Brain Entropy.

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IEEE Journal of Biomedical and Health Informatics

|April 5, 2019

Summary

Head motion during fMRI scans can falsely alter brain entropy measures. This study found that greater head movement is associated with decreased brain entropy, particularly in motor cortex regions, suggesting a potential marker for motor control deficits.

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Area of Science:

Neuroimaging
Biophysics

Background:

Functional magnetic resonance imaging (fMRI) brain entropy measures neural complexity.
Age and disease can impact motor control, potentially influencing head motion during fMRI scans.
The effect of head motion on fMRI brain entropy requires careful quantification and correction to avoid spurious findings.

Purpose of the Study:

To investigate the influence of head motion on fMRI brain entropy.
To determine if head motion artifacts can be distinguished from genuine neural changes in brain entropy.
To identify brain regions where entropy may serve as a reliable marker for motor control.

Main Methods:

Analysis of resting-state and task-based fMRI data from 281 individuals.
Image realignment and nuisance regression of head motion parameters.
Calculation of fuzzy approximate entropy and fuzzy sample entropy across voxels, with comparisons of high-pass and band-pass filtering.

Main Results:

Increased head motion significantly correlated with decreased fMRI brain entropy across all tested methods.
Specific movement characteristics produced artifactual patterns, but consistent negative associations were observed in key motor regions.
Significant negative associations between motion and entropy were found in the right cerebellar crus, left precentral gyrus, left postcentral gyrus, and left inferior frontal gyrus.

Conclusions:

Head motion is a significant confounder for fMRI brain entropy measures.
Despite motion artifacts, decreased entropy in specific brain regions (motor cortex, cerebellum) may indicate impaired motor control.
These findings highlight the importance of motion correction in fMRI entropy studies and suggest potential biomarkers for neurological conditions affecting motor function.