Grey-matter microglia coordinate repair after focal white-matter demyelination

A targeted white‑matter lesion in a defined neural circuit triggers a transient grey‑matter microglial response, synapse loss, and reduced neuronal activity upstream of the lesion; these changes resolve as remyelination proceeds. Blocking microglia impairs remyelination, while aging diminishes this regenerative grey‑matter response, leading to chronic inflammation. The study reveals a circuit‑level regenerative plasticity that couples white‑matter integrity to grey‑matter function and suggests myelin‑regenerative therapies could mitigate chronic neuroinflammation in MS and related diseases.