Negative BOLD responses (NBRs) have been associated with changes in neuronal activity, but are challenging to detect due to a lower contrast-to-noise ratio compared to positive BOLD responses (PBRs). In this work, the high sensitivity available at 7T was explored with accelerated fMRI acquisition, vein segmentation and ICA denoising techniques, to map PBRs and NBRs to visual stimulation in various brain regions beyond the visual cortex. Multiple regions with significant PBRs and NBRs could be detected, and their dependence on stimulus duration was found to differ significantly across regions, suggesting the presence of dynamic, stimulus-dependent interactions across the brain.
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