I’m preprocessing task-based fMRI data using fMRIPrep, and while the pipeline completes without errors, I’ve noticed a consistent issue across the majority of runs.
In nearly every subject/session, there is a spike at the begining of each run in all major confound metrics (including FD, DVARS, and GSWM). This spike appears isolated but significant. My questions are:
- What causes this?
- What will it affect down the line to have this inital spike?
- How can I clean the data either pre or post fMRIprep to ensure that this doesnt affect the results further down the pipeline?
Thank you in advance