Abstract
Regional connectivity-based parcellation (rCBP) is a widely used procedure for investigating the structural and functional differentiation within a region of interest (ROI) based on its long-range connectivity. No standardized software or guidelines currently exist for applying rCBP, making the method only accessible to those who develop their own tools. As such, there exists a discrepancy between the laboratories applying the procedure each with their own software solutions, making it difficult to compare and interpret the results. Here, we outline an rCBP procedure accompanied by an open source software package called CBPtools. CBPtools is a Python (version 3.5+) package that allows users to run an extensively evaluated rCBP analysis workflow on a given ROI. It currently supports two modalities: resting-state functional connectivity and structural connectivity based on diffusion-weighted imaging, along with support for custom connectivity matrices. Analysis parameters are customizable and the workflow can be scaled to a large number of subjects using a parallel processing environment. Parcellation results with corresponding validity metrics are provided as textual and graphical output. Thus, CBPtools provides a simple plug-and-play, yet customizable way to conduct rCBP analyses. By providing an open-source software we hope to promote reproducible and comparable rCBP analyses and, importantly, make the rCBP procedure readily available. Here, we demonstrate the utility of CBPtools using a voluminous data set on an average compute-cluster infrastructure by performing rCBP on three ROIs prominently featured in parcellation literature.
Highlights
Mapping the human brain in an effort to understand its organizational principles is a monumental task, dating back to the early 1900s with Korbinian Brodmann’s famous publication on ’Vergleichende Lokalisationslehre der Großhirnrinde’ (Localization in the cerebral cortex; Brodmann (1909))
The regional connectivity-based parcellation (CBP) (rCBP) procedure can map functional or structural subdivisions/clusters within a particular region of interest (ROI). rCBP derived parcels are known to match with histological parcellation (Bzdok et al 2013), but they may provide subdivisions pertaining to different sources of information not revealed by cytoarchitectonic mapping alone (Clos et al 2013)
For the presupplementary motor area (preSMA)–supplementary motor area (SMA) ROI we highlighted the reproducibility of histological parcellations, for the insula we focussed on the subdivisions of various k cluster solutions for the group parcellations and, lastly, for the amygdala we evaluated the cluster validity metrics provided as output by the workflow
Summary
Mapping the human brain in an effort to understand its organizational principles is a monumental task, dating back to the early 1900s with Korbinian Brodmann’s famous publication on ’Vergleichende Lokalisationslehre der Großhirnrinde’ (Localization in the cerebral cortex; Brodmann (1909)). Accompanying progress in neuroimaging data analysis techniques allow a range of connectivity measurements from various MRI modalities. Brain organization can be probed by analyzing the patterns in these measurements. One such technique is connectivity-based parcellation (CBP), an umbrella term for a widely used and diverse set of procedures to delineate whole- and regional brain organization, originally conceived by Behrens et al (2003) in their seminal work on the thalamus. A common approach to mapping the human brain through CBP is to cluster voxels/vertices into parcels. The rCBP procedure can map functional or structural subdivisions/clusters within a particular ROI. As each MRI modality yields a different aspect of brain connectivity, rCBP on each modality can yield differing parcellations with different interpretations. Due to the different interpretations that may result from each modality, a multimodal approach [e.g., Genon et al (2018) and Plachti et al (2019)] may be used to compare unimodal parcellations
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
