CD astrocytes in the frontal white matter of post‐stroke demented (PSD) subjects occur at higher frequencies compared to post‐stroke individuals without dementia (PSND), with a loss of aquaporin 4 (AQP4) and white matter pericytes, suggesting that changes in astrocytic function and disruption of the gliovascular unit at the BBB contribute to dementia after stroke (40, 41). Here, AQP4 is linked to dementia.