SELENOP and selenium deficiency: Ataxia.Epilepsy.Disruption of long-term potentiation.Loss of Parvalbumin interneurons.Reactive astrogliosis.Hippocampal neurogenesis is reduced. Depletion of SELENOP and its receptor ApoER2 results in spatial memory impairment in mice as well as defects in synaptic transmission.SELENOP-deficient mice exhibit selenium deficiency in the brain and myelin sheath abnormalities in the brainstem.Genetic deletion of SELENOP results in increased release of dopamine vesicles in response to methamphetamine.