Comparison of fMRI paradigms assessing visuospatial processing: Robustness and reproducibility

Area of Science:

• Neuroscience
• Cognitive Psychology
• Brain Imaging

Background:

• Functional magnetic resonance imaging (fMRI) enables non-invasive study of brain function lateralization.
• Models of hemispheric lateralization need to integrate specialization and interactions of cognitive processes.
• Reliable paradigms for right-lateralized functions like visuospatial processing are less developed than for language.

Purpose of the Study:

• To establish a robust and reliable fMRI paradigm for identifying right-hemispheric activation in visuospatial processing at the individual subject level.
• To compare the reliability of three common visuospatial processing paradigms.
• To assess the test-retest reliability of the most effective paradigm, the Landmark task.

Main Methods:

• Compared three visuospatial processing fMRI paradigms for single-subject right-lateralized activity detection.
• Assessed test-retest reliability of the Landmark task.
• Quantified hemispheric dominance using the lateralization index (LI).

Main Results:

• Single-voxel reliability for visuospatial attention activation was poor, likely due to signal-to-noise limitations.
• Hemispheric dominance (|LI| >0.4) was reliably determined in over 62% of subjects.
• Categorical hemispheric dominance (left/right) was identified in over 93% of subjects.
• The reliability of the lateralization strength (LI) was rated as 'fair' to 'good'.

Conclusions:

• The Landmark task reliably determines the degree of right-hemispheric dominance in visuospatial processing at both group and individual levels.
• Limitations in fMRI paradigms and data acquisition affect single-voxel reliability for visuospatial attention.
• Future research should focus on refining experimental paradigms and fMRI techniques for improved reliability.