Mini review: linkage between α-Synuclein protein and cognition

α-synuclein is a protein that plays important roles in cognitive function in the normal brain, although its exact role is not fully understood. However, current studies reveal that defects in α-synuclein function could contribute to various neurodegenerative disorders, such as Parkinson's disease (PD), a disease with symptomatic progression of deterioration in motor and cognitive function. Recent studies show that the level of α -synuclein in cerebrospinal fluid (CSF) is highly correlated with speed of cognitive decline, suggesting a potential role of α-synuclein in cognitive function. In this mini review, we will be focus on literatures of α-synuclein in cognitive function in the non-diseased brain, as well as the impact that defective α-synuclein has on cognition in disease brain. This will be accomplished by assessing the effects of soluble α-synuclein, α-synuclein oligomers, and extracellular α-synuclein transport, on neurodegeneration.