Neuroinflammation and non-motor symptoms: the dark passenger of Parkinson's disease?

Generally speaking, inflammation as a key piece to the Parkinson's disease (PD) puzzle is a relatively new concept. Acceptance of this concept has gained ground as studies by various researchers have demonstrated the potential of mitigating nigral cell death by curtailing inflammation in animal models of PD. We propose that the significance of inflammation in PD pathology may extend beyond the nigrostriatal region. In the current review, we present an argument for this based on the Braak staging and discuss how inflammation might contribute to the development of non-motor PD symptoms.