Lea Waller 1, , Susanne Erk 1, Elena Pozzi 2,3, Yara J. Toenders 2,3, Courtney C. Haswell 4, Marc Büttner 1, Paul M. Thompson 5, Lianne Schmaal 2,3, Rajendra A. Morey 4†, Henrik Walter 1†, Ilya M. Veer 1,6,7†
The reproducibility crisis in neuroimaging has led to an increased demand for standardized
data processing workflows. Within the ENIGMA consortium, we developed HALFpipe
(Harmonized AnaLysis Functional MRI pipeline), an open-source, containerized,
user-friendly tool that facilitates reproducible analysis of task-based and resting-state fMRI
data through uniform application of preprocessing, quality assessment, single-subject
feature extraction, and group-level statistics. It provides state-of-the-art preprocessing
using fMRIPrep without the requirement for input data in Brain Imaging Data Structure
(BIDS) format. HALFpipe extends the functionality of fMRIPrep with additional preprocessing
steps, which include spatial smoothing, grand mean scaling, temporal filtering, and
confound regression. HALFpipe generates an interactive quality assessment (QA) webpage to
assess the quality of key preprocessing outputs and raw data in general. HALFpipe features
myriad post-processing functions at the individual subject level, including calculation of
task-based activation, seed-based connectivity, network-template (or dual) regression,
atlas-based functional connectivity matrices, regional homogeneity (ReHo), and fractional
amplitude of low frequency fluctuations (fALFF), offering support to evaluate a
combinatorial number of features or preprocessing settings in one run. Finally, flexible
factorial models can be defined for mixed-effects regression analysis at the group level,
including multiple comparison correction. Here, we introduce the theoretical framework in
which HALFpipe was developed, and present an overview of the main functions of the
pipeline. HALFpipe offers the scientific community a major advance toward addressing the
reproducibility crisis in neuroimaging, providing a workflow that encompasses
preprocessing, post-processing, and QA of fMRI data, while broadening core principles of
data analysis for producing reproducible results. Instructions and code can be found at
https://github.com/HALFpipe/HALFpipe
Read the full paper here.
