XCP-D
Overview & Processing
XCP-D ingests minimally preprocessed fMRIPrep outputs to generate denoised BOLD images, parcellated time series, functional connectivity matrices, and quality assessment reports (Mehta et al., 2024).
ABCC data were processed using XCP-D v0.13.0 with the following parameters:
--mode abcd
Applies the ABCD-specific preprocessing workflow, including ABCD-tailored default settings for denoising, censoring, and quality control.--motion-filter-type notch
Applies a notch filter to the motion parameters to remove respiratory-frequency artifacts from head motion estimates prior to framewise displacement (FD) calculation.--create-matrices 300 600 all
Generates functional connectivity matrices (correlation matrices) using only time points with at least 300 seconds, 600 seconds, or all available uncensored data retained after motion censoring.--atlases Gordon HCP MIDB
Parcellates the BOLD signal using three atlases:Gordon— Gordon’s 333-ROI cortical parcellation derived using boundary detection on resting-state fMRI data (Gordon et al., 2016)MIDB— MIDB’s 80-ROI precision brain atlas derived from ABCD data, thresholded at 75% probability (Hermosillo et al., 2024)HCP— HCP’s 19-ROI CIFTI subcortical parcellation as defined in the HCP minimal preprocessing pipelines (Glasser et al., 2013)
--band-stop-min ${band_stop_min}/--band-stop-max ${band_stop_max}
The followingmin/maxfilter frequencies were applied to address respiratory artifacts present in ABCD multiband acquisitions, which can distort framewise alignment estimates and impact motion censoring (Fair et al., 2020):- ses-00A:
18.582/25.726 - ses-02A:
15/25 - ses-04A & ses-06A:
14.4/24
- ses-00A:
Derivatives
As with fMRIPrep, XCP-D derivatives are organized under anat/ and func/ subfolders. The derivative file contents are explained below - also see the main XCP-D documentation.
abcd/
└── derivatives/
└── abcc-xcp_d_v0.13.0/
└── sub-<SUBJECT_ID>/
└── ses-<SESSION_ID>/
├── anat/
├── func/
├── figures/
├── sub-<LABEL>_ses-<LABEL>.html
└── sub-<LABEL>_ses-<LABEL>_executive_summary.html- Denoised BOLD timeseries
Surface-based (fsLR 91k), in CIFTI format, generated per task and run - Parcellated timeseries
Atlas-based (Gordon, HCP, MIDB), in TSV and CIFTI formats - Functional connectivity matrices
Pearson correlation matrices for Gordon, HCP, and MIDB atlases, in TSV and CIFTI formats - ALFF and ReHo maps
Amplitude of low-frequency fluctuations (ALFF) and regional homogeneity (ReHo), in CIFTI format - Anatomical surfaces
fsLR 32k meshes and morphometry maps (curvature, sulcal depth, thickness) - Quality control
Motion parameters, outlier detection, ABCC QC metrics (HDF5), and visual reports
Structural Outputs
Structural derivative files are stored under anat/ as displayed below.
Note: The standard BIDS file prefix sub-<label>_ses-<label> is replaced with * below for readability. See further annotated notes following the file tree.
anat/
# Preprocessed T1w and T2w images in MNI152NLin2009cAsym standard space
├── *_space-MNI152NLin2009cAsym_desc-preproc_<T1w|T2w>.nii.gz
# fsLR 32k cortical surfaces for L/R hemispheres [1]
├── *_hemi-<L|R>_space-fsLR_den-32k_desc-hcp_inflated.surf.gii
├── *_hemi-<L|R>_space-fsLR_den-32k_desc-hcp_midthickness.surf.gii
├── *_hemi-<L|R>_space-fsLR_den-32k_desc-hcp_vinflated.surf.gii
├── *_hemi-<L|R>_space-fsLR_den-32k_pial.surf.gii
├── *_hemi-<L|R>_space-fsLR_den-32k_white.surf.gii
# Dense scalar maps (fsLR 91k grayordinate space) [2]
├── *_space-fsLR_den-91k_curv.dscalar.nii
├── *_space-fsLR_den-91k_sulc.dscalar.nii
├── *_space-fsLR_den-91k_thickness.dscalar.nii
# Atlas-based summary statistics [3]
├── *_space-fsLR_seg-<ATLAS>_stat-mean_desc-curv_morph.tsv
├── *_space-fsLR_seg-<ATLAS>_stat-mean_desc-sulc_morph.tsv
└── *_space-fsLR_seg-<ATLAS>_stat-mean_desc-thickness_morph.tsv [1] Cortical surfaces include inflated, very-inflated, midthickness, pial, white
[2] Dense scalar maps include cortical curvature, sulcal depth, thickness
[3] Atlas values (<ATLAS>) include MIDB and Gordon
Functional Outputs
Functional derivative files are stored under func/ as shown below.
Values for <TASK> in the filetrees below include:
mid: Monetary Incentive Delay tasksst: Stop Signal tasknback: N-Back working memory taskrest: Resting-state fMRI
Also note that most outputs are provided both per-run and concatenated across runs. Run-specific files include run-<LABEL> in the filename and are omitted below for readability.
Dense Timeseries & Confounds
Primary denoised BOLD outputs in fsLR grayordinate space (.dtseries.nii) accompanied by confound files (motion.tsv, outliers.tsv).
func/
├── *_task-<TASK>_space-fsLR_den-91k_desc-denoised_bold.dtseries.nii
├── *_task-<TASK>_space-fsLR_den-91k_desc-denoisedSmoothed_bold.dtseries.nii
├── *_task-<TASK>_motion.tsv
├── *_task-<TASK>_outliers.tsv
├── *_task-<TASK>_run-<label>_design.tsv- Primary input for most analyses
- Includes nuisance regression, bandpass filtering, and motion censoring
- Provided with and without surface-based spatial smoothing
- Available as both per-run and concatenated outputs
- Accompanied by run-level nuisance regressors and motion metrics used during denoising, including:
- Motion parameters and framewise displacement (
motion.tsv) - Censored timepoints (
outliers.tsv) - Nuisance regressor design matrices (
design.tsv)
- Motion parameters and framewise displacement (
Dense Scalar Maps
Voxel-wise (grayordinate-level) functional metrics derived from the denoised timeseries.
├── *_task-<TASK>_space-fsLR_den-91k_stat-alff_boldmap.dscalar.nii
├── *_task-<TASK>_space-fsLR_den-91k_stat-alff_desc-smooth_boldmap.dscalar.nii
├── *_task-<TASK>_space-fsLR_den-91k_stat-reho_boldmap.dscalar.nii- ALFF: Amplitude of low-frequency fluctuations (unsmoothed and smoothed variants)
- ReHo: Regional Homogeneity, reflecting local BOLD synchrony across neighboring grayordinates
Parcellated Outputs
Atlas-based summaries derived from dense grayordinate data.
├── *_task-<TASK>_space-fsLR_seg-<ATLAS>_den-91k_stat-mean_timeseries.ptseries.nii
├── *_task-<TASK>_space-fsLR_seg-<ATLAS>_stat-mean_timeseries.tsv
├── *_task-<TASK>_space-fsLR_seg-<ATLAS>_stat-pearsoncorrelation_relmat.tsv
├── *_task-<TASK>_space-fsLR_seg-<ATLAS>_den-91k_stat-pearsoncorrelation_boldmap.pconn.nii
├── *_task-<TASK>_space-fsLR_seg-<ATLAS>_den-91k_stat-coverage_boldmap.pscalar.nii
├── *_task-<TASK>_space-fsLR_seg-<ATLAS>_stat-coverage_bold.tsv
├── *_task-<TASK>_space-fsLR_seg-<ATLAS>_stat-alff_bold.tsv
├── *_task-<TASK>_space-fsLR_seg-<ATLAS>_stat-reho_bold.tsv Includes:
- Mean parcel timeseries (
.ptseries.nii,.tsv) - Functional connectivity (Pearson correlation matrices;
.pconn.nii,.tsv) - Parcel-wise coverage metrics (
.pscalar.nii,.tsv) - Parcel-averaged ALFF and ReHo summaries
Parcellated timeseries are extracted from dense grayordinate data using standard atlas templates. All parcellations include subcortical regions from the standard HCP 91k-grayordinate template. Available parcellations (and corresponding atlas-<ATLAS> labels) include:
Gordon— Gordon’s 333-ROI cortical parcellation, derived using boundary detection on resting-state fMRI data from 120 young adults (Gordon et al., 2016)MIDB— MIDB’s 80-ROI precision brain atlas from ABCD data and thresholded at 75% probability (Hermosillo et al., 2024)HCP— HCP’s 19-ROI CIFTI subcortical parcellation, as defined in the HCP minimal preprocessing pipelines (Glasser et al., 2013)
Quality Control Metrics
Summary metrics for assessing data quality and inclusion.
├── *_task-<TASK>_space-fsLR_den-91k_desc-linc_qc.tsv
└── *_task-<TASK>_desc-abcc_qc.hdf5- LINC QC (
.tsv): Run-level metrics (e.g., retained frames, mean FD, DVARS) - ABCC QC (
.hdf5): Aggregated metrics across tasks, including motion summaries and atlas coverage, for downstream filtering and participant exclusion
HTML QC Reports
The .html files provide subject-level visual summaries designed for rapid, systematic quality control (QC) review (source image files stored in figures/).
sub-<LABEL>_ses-<LABEL>.html- Standard XCP-D subject-level report, structured similarly to the fMRIPrep report
- Includes registration figures, BOLD carpet plots, motion summaries, and connectivity outputs
sub-<LABEL>_ses-<LABEL>_executive_summary.html- ABCC-specific executive summary report that provides a streamlined review of the most critical QC checkpoints
- Includes anatomical normalization quality, per-task BOLD pre/post-processing summaries, and motion censoring profiles