# Problems when working with both fMRI and dMRI data of HCP **URL:** \ **Category:** Uncategorized\ **Tags:** tractography, preprocessing\ **Created:** [March 14, 2023, 7:43am UTC](https://community.mrtrix.org/t/problems-when-working-with-both-fmri-and-dmri-data-of-hcp/6500 "2023-03-14T07:43:39Z")\ **Posts on this page:** 1\ **Showing post:** 2
**Author:** ![fionaEyoung](https://community.mrtrix.org/user_avatar/community.mrtrix.org/fionaeyoung/32/3826_2.png) [@fionaEyoung](https://community.mrtrix.org/u/fionaEyoung)\ **Post date:** [March 15, 2023, 9:39am UTC](https://community.mrtrix.org/t/problems-when-working-with-both-fmri-and-dmri-data-of-hcp/6500/2 "2023-03-15T09:39:23Z")
Hello Zack I’m going to write my answer assuming we’re thinking of the same dataset, namely the [HCP young adult 1200 subjects release](https://www.humanconnectome.org/study/hcp-young-adult/document/1200-subjects-data-release). If not, then you should probably disregard this answer as I don’t know about all the other HCP data releases… 1. The HCP data does include a transform file for registering the dMRI data to MNI space, although it’s not completely obvious. Here are two threads ([files](https://community.mrtrix.org/t/hcp-deformation-files-for-registration-in-mni-template/6122), [transform](https://community.mrtrix.org/t/clarification-on-hcp-mni-nonlinear-warps-and-tcktransform-incorrect-scaling-on-single-axis/2857)) that should help you get your dMRI data into MNI space. 2. The diffusion data is already preprocessed (incl. motion, EPI distortion, eddy current corrections etc.; the [manual](https://www.humanconnectome.org/storage/app/media/documentation/s1200/HCP_S1200_Release_Reference_Manual.pdf) has the exact details), so you shouldn’t need to do any further preprocessing. But in general, resampling should be done after preprocessing, and definitely after `dwidenoise` and `mrdegibbs`. If you’re referring to e.g. tensor fitting or running CSD, then I would personally resample the DWI data before any model fitting, but mainly for reasons of storage and processing efficiency (in the current case of _downsampling_ high resolution data). I’ve seen [work specifically justifying _upsampling_ before model fitting](https://www.sciencedirect.com/science/article/pii/S1053811914007472) instead of after, but I don’t know of any scientific considerations about when to downsample… Hope that’s helpful! Fiona --- _[View the full topic](https://community.mrtrix.org/t/problems-when-working-with-both-fmri-and-dmri-data-of-hcp/6500)._