Table 1.

Estimated Processing Time

	Requirements		Reproducible	Processing time
	Imaging data	Other		Template registration	DWI preprocessinga	Tractographyb	Total
Whole-brain ACT	T1w DWI	—	Yes	39 min	5 h 45 min	1 h 12 min	7 h 36 min
Manual tractography	T1w DWI	Neuroanatomical knowledge	No	39 min	5 h 45 min	Manual tracking + filtering	6 h 24 min + manual filtering
Anatomical pathway model	T1w	—	Yes	39 min	—	—	39 min

Time estimates for a single subject for the three processing pipelines using the minimum data necessary. If a T2w dataset is available then multimodal registration may improve registration accuracy but will increase processing time by ∼20 min. (T1w data for template registration and DWI for streamline generation). To provide more realistic estimates for this table we used a non-HCP unprocessed DWI dataset (2 mm isotropic resolution, 180 directions, multishell [0, 700, 1200, 2800 sec/mm²], reverse-phase-encoded b0 volumes only, acquired on a Siemens 3T Skyra Magnetom). All processing were done using a workstation equipped with a Xeon Gold 5120 CPU (14c/28t @ 2.20GHz).

^a The DWI preprocessing includes: denoising and Gibbs unringing (MRtrix), as well as correction for EPI distortions, subject motion, and Eddy currents (FSL).

^b The tractography stage includes generation of functions and for whole-brain ACT only, generation of tissue segmentation map (5TT), and 10 million streamlines (ACT).

ACT, anatomically constrained tractography; DWI, diffusion-weighted imaging; FOD, fiber orientation distribution.