Early Path Dominance as a Principle for Neurodevelopment

Abstract

To better understand fundamental constraints on the global structural organization of the brain, we apply percolation theory as a quantitative measure of global communication across a network. The largest present sub-network across which all sets of regions are able to communicate defines a giant cluster. By novel analytic solution, we prove that if constructed tracts are constrained to emanate from those regions already in the giant cluster, a giant cluster grows smoothly without requiring a critical point. The predicted structure is highly consistent with brain data, among human diffusion MRI across adults (UK Biobank, N=19,380), adolescents (Adolescent Brain Cognitive Development Study, N=15,593) and neonates (Developing Human Connectome Project, N=758), as well as mouse viral tracing (Allen Institute). This suggests a fundamental mechanism for neurodevelopment in which the earliest tracts also become the longest and densest.

Quantifying the diverse contributions of hierarchical muscle interactions to motor function

“…The percolation threshold ( P c ) (i.e. a critical value specifying the probability of node connectivities occurring and at which large clusters and long-range connectivity begin to appear across a given network [62]) has proven to be a fundamental constraint in nervous system organization [1,6,63]. To identify the network connections in our framework that align with P c , we employed a modified percolation analysis [6].…”

Brain signaling becomes less integrated and more segregated with age

“…Diffusion MRI processing to obtain structural information such as tract length and streamline count, which we call tract density, is outlined in our previous work (Razban, Pachter, Dill, & Mujica-Parodi, 2023). Briefly, we take preprocessed dMRI scans from the UK Biobank (Sudlow et al, 2015) and calculate connectivity matrices using the Diffusion Imaging in Python software (Garyfallidis et al, 2014).…”