The brain is equally divided into grey and white matter. Grey matter contains the brain’s processing hubs, linked by an information highway — the white matter. Although white matter damage is a defining feature of multiple sclerosis and is also seen in neurodegeneration including Alzheimer’s and Parkinson’s disease, the consequences of white matter damage are not well understood.
The team created localised damage to myelin – the main component of white matter – in a well-defined brain circuit and followed what happened over time. They found that small, localised myelin damage triggered a striking response in a connected, remote grey matter region. Neuronal activity fell, microglia – the brain’s immune cells – became activated, and connections between neurons were lost.
Crucially, these changes were not permanent. After myelin was regenerated, neuronal activity recovered, connections between neurons returned, and the inflammatory response subsided.
The study also challenges a common assumption about brain inflammation. Grey matter inflammation is traditionally viewed as harmful. But here, the team found that this transient response was part of the repair process itself. When they prevented grey matter inflammation, myelin regeneration was impaired.
Conversely, when the team blocked myelin regeneration, the grey matter response did not resolve and instead became chronic. This suggests that failed myelin regeneration may help drive the persistent low-grade inflammation seen in neurodegenerative disease. ScienceMission sciencenewshighlights.
Damage to white matter in the brain can trigger features associated with neurodegenerative disease, The researchers have discovered in a new study published in the journal Nature.
