Cognition and synaptic plasticity in diabetes mellitus

Diabetes mellitus is associated with cognitive deficits and an increased ri sk of dementia, particularly in the elderly. These deficits are paralleled by neurophysiological and structural changes in the brain. In animal models of diabetes, impairments of spatial learning occur in association with dis tinct changes in hippocampal synaptic plasticity. At the molecular level th ese impairments might involve changes in glutamate-receptor subtypes, in se cond-messenger systems and in protein kinases. The multifactorial pathogene sis of diabetic encephalopathy is not yet completely understood, but clearl y shaves features with brain ageing and the pathogenesis of diabetic neurop athy. It involves both metabolic and vascular changes, related to chronic h yperglycaemia, but probably also defects in insulin action in the brain. Tr eatment with insulin might therefore not only correct hyperglycaemia, but c ould also directly affect the brain.