Modelling cognitive deficits in Parkinson's disease: Is CA2 a gateway for hippocampal synucleinopathy?

•rAAV5-h-α-synuclein injected bilaterally both into substantia nigra and dentate gyrus.•α-Synuclein overexpressing animals showed mild but significant motor and cognitive impairments.•α-Synuclein overexpression lead to TH+-neuronal loss in SN with decreased synaptophysin levels in striatum.•Despite no significant neuronal loss in hippocampus, decreased synaptophysin levels suggested synaptic degeneration.•Among hippocampal subregions CA2 was the most affected area with dense p-(Ser129)-α-synuclein accumulation.