Cortical reorganization (in recovery)

After injury the cortical maps and the areas recruited for a function change — perilesional tissue can take over, the contralesional hemisphere may become more involved, and somatotopic borders shift with use. Recovery is accompanied by, and partly mediated by, such reorganization, which is itself activity-dependent: what the patient does, and what a BCI pairs with what, shapes which reorganization occurs. Plasticity-driven rehabilitation tries to bias this toward adaptive patterns — for example re-engaging spared ipsilesional motor cortex rather than relying on compensatory contralesional or non-corticospinal routes.

Honesty: reorganization is real and measurable (with TMS mapping, fMRI, MEG), but its relationship to good outcome is not simply 'more is better.' Some contralesional recruitment reflects compensation or maladaptation rather than true recovery, and the field has moved from celebrating any reorganization to asking whether the specific, function-restoring pattern is being promoted.