Busier Brain Regions May Become MS Atrophy Epicenters

Analyses of MRI scans from 2,187 patients with multiple sclerosis reveal that grey matter atrophy spreads from specific cortical "disease epicenters." The work supports an emergent hypothesis arguing that the metabolic stress from highly active regions of the brain wears down local cells, causing dysfunction that culminates in atrophy. One hallmark of multiple sclerosis is grey matter atrophy, which appears early in MRIs and then spreads throughout the brain in seemingly non-random patterns. Now, Mar Barrantes-Cepas and colleagues have explored how these patterns develop and how they differ in people over time. Evaluating MRIs from 2,187 participants, they observed evidence for a theory called the nodal stress hypothesis. It suggests that neural hubs with more connectivity are also more vulnerable to multiple sclerosis atrophy. Essentially, these hubs – found here in the visual, sensorimotor, and temporal cortices; as well as the hippocampi, thalami, and amygdala – act as disease epicenters because their elevated metabolic needs exhaust cells. The scans also showed evidence for transneuronal degeneration, or when epicenter neurodegeneration spreads to more distant, connected neurons. Barrantes-Cepas et al. also characterized how network-based processes manifested differently across disease phases and subtypes. "It is now clear that disease progression can occur independently of relapses and acute inflammation," they write. "Network-based measures, which are easily obtainable from conventional MRI and normative datasets, could be used to explain future atrophy progression in individual patients."