Structural and functional connectivity patterns of brainstem nuclei in living humans by 7 Tesla MRI

Motivation: A definitive baseline connectome of brainstem nuclei is missing. Goal(s): To improve brainstem hodology in living humans by using the similarity between functional and structural connectomes of brainstem nuclei as ground truth. Approach: In healthy subjects, we mapped 58 Brainstem Navigator atlas labels to high spatial resolution functional and diffusion-weighted 7 Tesla MRI, and computed their functional and structural connectivity, the latter computed using three probabilistic tractography methods proposed in the literature (seed-, ACT-, ACT-SIFT-based), with 148 cortical and 21 subcortical areas. Results: ACT-SIFT outperformed the other methods within the brainstem and the cortex by reducing large fiber bias. Impact: Comparison of structural and functional connectomes achieved with different methodology can improve the understanding and mapping of brainstem nuclei connections in living humans and establish a baseline connectome useful to evaluate a broad set of diseases including movement/sleep disorders.