Summary:
A massive neuroimaging investigation involving 2,187 patients with multiple sclerosis reveals that grey matter atrophy does not accumulate at random; rather, it radiates outward from specific cortical and subcortical “disease epicenters.” Published by Mar Barrantes-Cepas and colleagues, the study provides strong clinical evidence for the “nodal stress hypothesis.”
The authors demonstrate that high-degree topological network hubs, such as the visual, sensorimotor, and temporal cortices, alongside the thalamus, hippocampus, and amygdala, are selectively vulnerable to neurodegenerative collapse because their intense metabolic demands exhaust local cells. The findings also document transneuronal degeneration propagating along structural connections, confirming that progressive neurodegeneration in multiple sclerosis occurs independently of acute inflammatory relapses.
Key Facts:
- Mapping Disease Epicenters: High-resolution structural MRIs from 2,187 multiple sclerosis patients demonstrate that grey matter loss originates in distinct network hubs, including the thalamus, hippocampi, amygdala, and sensorimotor, visual, and temporal cortices.
- The Nodal Stress Mechanism: The study substantiates the nodal stress hypothesis, showing that heavily connected brain hubs burn through massive energetic resources to maintain high-traffic communication, leaving them vulnerable to metabolic exhaustion, mitochondrial failure, and early tissue loss.
- Transneuronal Degeneration Across Subtypes: Rather than remaining localized, neurodegeneration cascades along structural wiring to distant connected nodes, operating as a primary engine of progression independent of acute inflammatory relapses.
Source: AAAS
Multiple sclerosis (MS) has long been defined as a chronic autoimmune disorder characterized by inflammatory demyelinating lesions scattered across the white matter of the central nervous system. Yet in recent decades, advanced neuroimaging has revealed an equally devastating, covert pathological hallmark: widespread, accelerated grey matter atrophy.
Unlike transient focal inflammation, grey matter volume loss begins during the earliest clinical stages, correlates directly with irreversible physical disability and cognitive decline, and progresses relentlessly even when disease-modifying therapies effectively suppress clinical relapses.
For years, the spatial patterning of this tissue loss remained elusive, presenting in non-random yet seemingly disparate cortical and subcortical distributions.
Now, in an extensive multicenter neuroimaging study evaluating MRI scans from 2,187 individuals diagnosed with multiple sclerosis, a research team led by Mar Barrantes-Cepas and colleagues reveals the organizational logic behind this neurodegenerative spread.
Their work substantiates the nodal stress hypothesis, demonstrating that grey matter loss originates within high-traffic, hyper-connected “disease epicenters” and propagates throughout the connectome via transneuronal degeneration.
The Cost of High Connectivity: The Nodal Stress Hypothesis
To map the spatiotemporal evolution of brain atrophy, the researchers utilized structural MRI datasets from an international cohort of 2,187 patients across various stages and clinical subtypes of multiple sclerosis, comparing localized tissue loss against normative connectome architecture.
The analysis revealed that the earliest and most severe tissue loss localized within the brain’s primary topological hubs. These “epicenters” included:
- Subcortical Relay and Limbic Structures: The thalami, hippocampi, and amygdala.
- Cortical Sensorimotor and Perceptual Networks: Primary and secondary visual cortices, sensorimotor strips, and lateral temporal cortices.
These findings provide large-scale empirical backing for the nodal stress hypothesis. In complex network topology, hubs represent the most critical communication centers, routing traffic across disparate functional modules.
However, this central positioning carries a severe bioenergetic cost. High-degree hubs maintain higher baseline firing rates, express higher densities of energy-intensive ion channels, and require disproportionate mitochondrial ATP production to preserve synaptic transmission.
In multiple sclerosis, where chronic subclinical microglial inflammation, widespread demyelination, and oxidative stress compromise mitochondrial respiratory chain efficiency, these high-demand hubs become metabolic bottlenecks. The relentless functional demand exhausts cellular energy supplies, triggering localized axonal degeneration and neuronal apoptosis.
Transneuronal Degeneration: Propagation Along the Wiring
The study demonstrated that once a disease epicenter begins to decay, the pathology does not remain confined. Instead, the scans revealed clear markers of transneuronal degeneration, a cascading process where damage in a primary hub travels anterogradely or retrogradely across anatomical white matter tracts to damage downstream connected neurons.
As high-traffic epicenters fail, their connected secondary and tertiary structural partners lose vital neurotrophic support and experience excitotoxic or disuse stress, causing neurodegeneration to systematically ripple through the structural connectome.
Crucially, the investigators tracked how these network-based degradation pathways differed across relapsing-remitting and progressive forms of the disease, finding that network-level strain drives disability accumulation across all cohorts.
“It is now clear that disease progression can occur independently of relapses and acute inflammation,” write Barrantes-Cepas and colleagues. “Network-based measures, which are easily obtainable from conventional MRI and normative datasets, could be used to explain future atrophy progression in individual patients.”
Rethinking MS Clinical Monitoring and Therapeutic Targets
The recognition that multiple sclerosis progression is driven by network-mediated metabolic exhaustion challenges the classical clinical focus on managing only acute, gadolinium-enhancing white matter lesions.
Because conventional MRI scans routinely collected in routine clinical practice can be evaluated using normative connectome templates, network-based nodal stress modeling offers a low-cost, non-invasive prognostic tool. Clinicians could potentially map an individual’s specific epicenter vulnerability early in the disease course, forecasting spatial trajectories of grey matter loss years before clinical deficits emerge.
Furthermore, these findings highlight fresh avenues for neuroprotective drug discovery: therapies designed to bolster mitochondrial bioenergetics, protect against metabolic exhaustion, or buffer high-traffic hubs from metabolic overload could provide the missing therapeutic weapon needed to halt progressive disability in multiple sclerosis.
Questions and Answers
How does grey matter atrophy spread through the brain in multiple sclerosis?
Atrophy does not spread at random. It originates in specific “disease epicenters”, the brain’s most heavily connected topological hubs, such as the thalamus, hippocampus, visual, and sensorimotor cortices. From these epicenters, damage propagates to distant brain regions along structural nerve pathways through transneuronal degeneration.
What is the “nodal stress hypothesis”?
The nodal stress hypothesis suggests that brain hubs with the highest number of connections are under constant, intense metabolic strain because they must process and route massive amounts of neural communication. In multiple sclerosis, where energy production is already impaired, these high-traffic hubs suffer metabolic exhaustion, making them the first to degenerate.
Can multiple sclerosis worsen without relapses or acute inflammation?
Yes. This study confirms that progressive neurodegeneration and brain volume loss can proceed independently of acute clinical relapses and active autoimmune lesions, driven instead by chronic network-based metabolic failure and structural disconnectivity.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this Multiple Sclerosis Research:
- Media Contact: AAAS Media
- Source: AAAS
- Image Credit: Image credited to Neuroscience News
- Original Research is Open Access: Science Advances (Nov 11, 2026). “The role of network connectivity and transcriptomic vulnerability in shaping gray matter atrophy in multiple sclerosis.” Authors: Mar Barrantes-Cepas, Mario Tranfa, David R. van Nederpelt, Ismail Koubiyr, Luigi Lorenzini, Birgit Helmlinger, Stefan Ropele, Daniela Pinter, Christian Enzinger, Tomas Uher, Manuela Vaneckova, Joep Killestein, Eva M. M. Strijbis, Martijn D. Steenwijk, Hugo Vrenken, Frederik Barkhof, Menno M. Schoonheim, and Giuseppe Pontillo.
- DOI: 10.1126/sciadv.aeg3412
Abstract
The role of network connectivity and transcriptomic vulnerability in shaping gray matter atrophy in multiple sclerosis
Clinical progression is strongly linked to gray matter atrophy in multiple sclerosis (MS), detectable early on MRI and progressing nonrandomly across the brain. However, the mechanisms driving its spatiotemporal progression and individual variability remain unclear.
Using MRIs from 2187 participants, alongside normative data, we systematically investigated network-based mechanisms underlying MS-related atrophy. Regional atrophy was associated with functional cortical hubness, supporting the nodal stress hypothesis, and was constrained by anatomical and functional connections, consistent with transneuronal degeneration. Lesional disconnection and transcriptomic vulnerability played marginal roles.
Patient- and subgroup-level analyses revealed that network-based mechanisms are specifically linked to MS-related neurodegeneration and may operate differently in distinct subtypes or disease phases. Atrophy patterns were anchored to the connectivity profiles of disease epicenters involving the visual, sensorimotor, and temporal cortices, as well as the hippocampi, amygdalae, and thalami.
Network-based measures enhanced the explanation of future atrophy progression in people with MS, providing a mechanistic framework to understand neurodegeneration in MS.
