Network analysis of the human structural connectome including the brainstem

Abstract

The underlying anatomical structure is fundamental to the study of brain networks, but the role of brainstem from a structural perspective is not very well understood. We conduct a computational and graph-theoretical study of the human structural connectome incorporating a variety of subcortical structures including the brainstem. Our computational scheme involves the use of Python DIPY and Nibabel libraries to develop structural connectomes using 100 healthy adult subjects. We then compute degree, eigenvector, and betweenness centralities to identify several highly connected structures and find that the brainstem ranks highest across all examined metrics, a result that holds even when the connectivity matrix is normalized by volume. We also investigated some global topological features in the connectomes, such as the balance of integration and segregation, and found that the domination of the brainstem generally causes networks to become less integrated and segregated. Our results highlight the importance of including the brainstem in structural network analyses.

Blink-related arousal network surges are shaped by cortical vigilance states

“…The AAN is comprised of various brainstem nuclei including serotonergic (dorsal, DR; and medial raphe, MR), noradrenergic (locus coeruleus, LC), dopaminergic (substantia nigra, SN; and ventral tegmental area, VTA) and cholinergic (pontis oralis, PO; pedunculopontine, PPN) nuclei that project to thalamus, striatum and cortex (Edlow et al, 2012). AAN nuclei through their extended connections can in uence broad cortical areas through which they modulate arousal levels (Salhi et al, 2023). While the relationship between blinks, blink rates and the dopamine system has been widely investigated (Taylor et al, 1999) including clinical studies implicating D1 and D2 striatal receptors in blink rates (Demiral et al, 2022), the role of other AAN nuclei to blink events is limited.…”