Diffusion-weighted MRI (dMRI) is a widely used neuroimaging modality that permits the in vivo exploration of white matter connections in the human brain. Normative structural connectomics – the application of large-scale, group-derived dMRI datasets to out-of-sample cohorts – have increasingly been leveraged to study the network correlates of focal brain interventions, insults, and other regions-of-interest (ROIs). Here, we provide a normative, whole-brain connectome in MNI space that enables researchers to interrogate fiber streamlines that are likely perturbed by given ROIs, even in the absence of subject-specific dMRI data. Assembled from multi-shell dMRI data of 985 healthy Human Connectome Project subjects using generalized Q-sampling imaging and multispectral normalization techniques, this connectome comprises ~12 million unique streamlines, the largest to date. It has been already utilized in at least 18 peer-reviewed publications, most frequently in the context of neuromodulatory interventions like deep brain stimulation and focused ultrasound. This connectome constitute a useful tool for understanding the wider impact of focal brain perturbations on white matter architecture going forward and it will be publicly available shortly.
The files (including the MATLAB scripts provided here) necessary to use the connectome are available on FigShare (https://figshare.com/s/0dcf57e9946c8ee5e74f). This repository contains the two custom-built matlab scripts created for this project:
These scripts are to be run one after the other to identify and output fiber streamlines that overlap a given region-of-interest (ROI). The freely available SPM software package (https://www.fil.ion.ucl.ac.uk/spm/software/spm12/) must be downloaded and added to the matlab path before use. The first script (‘dTOR_compute_fiber_weights.m’) takes an ROI input file in nifti format and uses this to seed the structural connectome, identifying streamlines that intersect the ROI and ascribing them a weight. To convert the information saved in the matlab data file to a viewable form, the second script (‘dTOR_create_trk.m’) must be run. This script takes the .mat file created by the first script as an input and generates a tractogram file (.trk) that can be opened in a streamline viewing/editing software such as MI-Brain (https://github.com/imeka/mi-brain) or TrackVis (https://trackvis.org).