Assessing diffusion changes in response to visual stimulation: A multi-directional MPG approach in diffusion fMRI

Motivation: To establish precise measurements that directly reflect neuronal activity, it is necessary to re-evaluate the current fMRI method. Goal(s): Evaluating the effectiveness of diffusion fMRI and its spatial specificity relative to BOLD-fMRI, with consideration of diffusion changes and perfusion effects. Approach: Utilized dfMRI with six MPG directions to obtain mean diffusivity and apparent diffusion coefficients and to suppress the perfusion effect. Results: dfMRI with six MPG directions could provide more localized activation mapping, with diffusion-driven signal changes potentially influenced by neuronal activity-related water transport mechanisms. Impact: dfMRI with multiple MPG directions enables more localized brain activity mapping compared to BOLD-fMRI, suggesting that water transport related to neuronal activity may contribute to pseudo-diffusion effects in diffusion MRI signals.