fMRI Data

LAION-fMRI includes raw multi-echo BOLD data and preprocessed optimally-combined BOLD timeseries. Most users will start from the single-trial GLMsingle betas documented in GLMsingle Beta Estimates, but the functional data are available for users who want to inspect or rerun the preprocessing.

For acquisition parameters, see MRI Acquisition; for the preprocessing pipeline, see Preprocessing.

Raw Functional Data

The scanner DICOMs were converted with heudiconv into BIDS-style NIfTI files. Multi-echo BOLD and SBRef files live under func/, fieldmaps under fmap/, and the MEGRE anatomical scan under anat/.

A representative image-viewing run contains magnitude and phase BOLD files for all three echoes, one SBRef per echo, JSON sidecars, and the trial event file:

sub-01/ses-01/func/
├── sub-01_ses-01_task-images_run-01_echo-1_part-mag_bold.nii.gz
├── sub-01_ses-01_task-images_run-01_echo-1_part-mag_bold.json
├── sub-01_ses-01_task-images_run-01_echo-1_part-phase_bold.nii.gz
├── sub-01_ses-01_task-images_run-01_echo-1_part-phase_bold.json
├── sub-01_ses-01_task-images_run-01_echo-1_sbref.nii.gz
├── sub-01_ses-01_task-images_run-01_echo-1_sbref.json
├── sub-01_ses-01_task-images_run-01_echo-2_part-mag_bold.nii.gz
├── sub-01_ses-01_task-images_run-01_echo-2_part-mag_bold.json
├── sub-01_ses-01_task-images_run-01_echo-2_part-phase_bold.nii.gz
├── sub-01_ses-01_task-images_run-01_echo-2_part-phase_bold.json
├── sub-01_ses-01_task-images_run-01_echo-2_sbref.nii.gz
├── sub-01_ses-01_task-images_run-01_echo-2_sbref.json
├── sub-01_ses-01_task-images_run-01_echo-3_part-mag_bold.nii.gz
├── sub-01_ses-01_task-images_run-01_echo-3_part-mag_bold.json
├── sub-01_ses-01_task-images_run-01_echo-3_part-phase_bold.nii.gz
├── sub-01_ses-01_task-images_run-01_echo-3_part-phase_bold.json
├── sub-01_ses-01_task-images_run-01_echo-3_sbref.nii.gz
├── sub-01_ses-01_task-images_run-01_echo-3_sbref.json
└── sub-01_ses-01_task-images_run-01_events.tsv

Fieldmaps are stored separately:

sub-01/ses-01/fmap/
├── sub-01_ses-01_run-01_magnitude1.nii.gz
├── sub-01_ses-01_run-01_magnitude1.json
├── sub-01_ses-01_run-01_magnitude2.nii.gz
├── sub-01_ses-01_run-01_magnitude2.json
├── sub-01_ses-01_run-01_phasediff.nii.gz
└── sub-01_ses-01_run-01_phasediff.json

Preprocessed Functional Data

The final preprocessed BOLD output used for downstream analysis is stored under derivatives/tedana. Each run is a single T2*-weighted optimally-combined NIfTI in subject-native T1w space, sampled on a 1.778 mm isotropic grid with TR = 1.0 s. The sidecar JSON links the output back to the three echo BOLD files from which it was derived.

derivatives/tedana/sub-01/ses-01/func/
├── sub-01_ses-01_task-images_run-01_space-T1w_desc-optcom_bold.nii.gz
└── sub-01_ses-01_task-images_run-01_space-T1w_desc-optcom_bold.json

Most main image-viewing sessions contain 12 task-images runs. Session ses-31 is a mixed eyetracking session with fewer image-viewing runs plus localizer/deepmreye runs. Sessions ses-32 to ses-34 are supplemental sessions and are not part of the initial launch-release data.

Confounds and Behavioral Files

The raw BIDS event files and richer confound documentation will be expanded in a later documentation update. For the trial table that aligns directly with the released GLMsingle beta volumes, see GLMsingle Beta Estimates.