Integrating the underlying brain circuit’s structural and functional architecture is required to explore the functional organization of cognitive networks.
The Functionnectome
The researchers, including Michel Thiebaut de Schotten, member of our Executive Committee, recently introduced the Functionnectome. This structural-functional method combines an fMRI acquisition with tractography-derived white matter connectivity data to map cognitive processes onto the white matter.
However, this multimodal integration faces three significant challenges:
- the necessarily limited overlap between tractography streamlines and the grey matter, which may reduce the amount of functional signal associated with the related structural connectivity;
- the scrambling effect of crossing fibers on functional signal, as a single voxel in such regions can be structurally connected to several cognitive networks with heterogeneous functional signals; and
- the difficulty of interpretation of the resulting cognitive maps, as crossing and overlapping white matter tracts can obscure the organization of the studied network.
Improved Functionnectome
In the present study, the researchers tackled these problems by developing a streamline-extension procedure and dividing the white matter anatomical priors between association, commissural, and projection fibers.
This approach significantly improved the characterization of the white matter involvement in the studied cognitive processes.
The new Functionnectome priors produced are now readily available, and the analysis workflow highlighted here should also be generalizable to other structural-functional approaches.
The researchers improved the Functionnectome approach to better study the involvement of white matter in brain function by separating the analysis of the three classes of white matter fibers (association, commissural, and projection fibers).
This step successfully clarified the activation maps and increased their statistical significance.
Scientific publication
Nozais V, Theaud G, Descoteaux M, Thiebaut de Schotten M, Petit L. Improved Functionnectome by dissociating the contributions of white matter fiber classes to functional activation. Brain Struct Funct. 2023 Dec;228(9):2165-2177. doi: 10.1007/s00429-023-02714-y. Epub 2023 Oct 7. PMID: 37804431.
Photo credits: Photo by Alina Grubnyak on Unsplash
