KDR and Cognitive impairment: In the central nervous system, VEGF and VEGFR2 are expressed not only in vascular endothelial cells but also in other cells such as neurons and neural progenitor cells[56] and are involved in brain functions including enhancement of neurogenesis through the direct activation of neural progenitor cells[57], amelioration of cognitive deficits via the promotion of neurogenesis, and protection of endothelial cells and neurons during brain ischemia in adult rats[57,58].