Effects of phase-encoding on BOLD data with a positive control task

Quality assessment and quality control (QA/QC) checkpoints layered throughout the dataflow are essential to ensure the reliability of neuroimaging analyses. In the case of functional MRI, best practices recommend collecting a ‘positive control’ task with which the different layers of QA/QC can be validated. These are short and simple tasks designed to elicit robust and precisely located brain activation patterns, permitting the diagnosis of potential issues in the workflow. Here, we examine how the phase-encoding direction (PE) choice in echo-planar imaging (EPI) blood-oxygen-level-dependent (BOLD) fMRI influences the resulting activation maps using a positive control task that includes visual and motor paradigms.