Improved correspondence of fMRI visual field localizer data after cortex-based macroanatomical alignment

Area of Science:

• Neuroimaging
• Visual Neuroscience
• Brain Mapping

Background:

• Functional magnetic resonance imaging (fMRI) studies of the visual system rely on localizer paradigms to define regions of interest (ROIs).
• Significant interindividual variability in cortical anatomy complicates group-level fMRI analyses.
• Cortex-based alignment (CBA) is a technique that effectively reduces macroanatomical variability between individuals.

Purpose of the Study:

• To evaluate the utility of CBA for visual field localizer paradigms in fMRI studies.
• To compare the effectiveness of CBA against traditional volume-based alignment and surface-based analyses without macroanatomical alignment.
• To assess the impact of CBA on the reliability and statistical power of group analyses for visual areas.

Main Methods:

• An attention-enhanced visual field localizer paradigm was employed in 50 participants.
• Cortex-based alignment (CBA) was applied and compared with volume-based alignment and surface-based analysis.
• The probability of activation overlap and region of interest (ROI) size and symmetry were analyzed at the group level.

Main Results:

• CBA significantly increased the probability of activation overlap, reaching up to 86%.
• Group-level analyses using CBA demonstrated the most consistent increase in ROI size.
• CBA preserved vertical ROI symmetry, indicating improved anatomical standardization.

Conclusions:

• Cortex-based alignment (CBA) substantially enhances statistical power in group fMRI studies of the visual system beyond surface-based analysis alone.
• CBA improves the signal-to-noise ratio and reliability of defining visual regions of interest (ROIs).
• CBA is particularly valuable for studying disorders with heightened interindividual anatomical variability, such as neuropsychiatric conditions.