Stokum et al. have shown in a rodent experimental model of ischemia that subcortical white matter is much more susceptible to post-ischemic tissue swelling than cortical grey matter, and that cortical astrocytes exhibit unchanged expression in AQP-4, while white matter astrocytes exhibit a significant increase in AQP-4 expression after induced ischemia[26]. The gene discussed is AQP4; the disease is ischemia.