The cartoon shows the rostral and caudal progression of the brainstem monoamine disorder (BMD) which characterises Parkinson’s disease (PD) in its novel re-definition. In the micrograph at the electron microscopy it is shown the molecular mechanism of interneuronal spreading of alpha-synuclein which appears to underlie disease progression and produces non-motor symptoms in PD. Immunogold particles = 10 nm. Original magnification = x25000.