Complex sentence: Nefiracetam's cytoprotective actions are mediated by enhancement of GABAergic, cholinergic, and monoaminergic neuronal systems that give antiamnesia effects to the Alzheimer's type and cerebrovascular type of dementia.
Split into simpler sentences: Nefiracetam's cytoprotective actions are mediated by enhancement of GABAergic, cholinergic, and monoaminergic neuronal systems. It has been shown to exhibit antiamnesia effects for the Alzheimer's type and cerebrovascular type of dementia.