An impaired ability to process time in the seconds-to-minutes range is found in patients with disorders that involve dopaminergic pathways, such as Parkinson’s disease, Huntington’s disease (HD) and schizophrenia. By contrast, the failure of a neurological disorder — such as cerebellar injury — to affect the scalar property is taken to indicate that the affected structures are not essential for proper interval timing. Instead, the cerebellum might contain an internal model of the motor–effector system, so cerebellar damage could increase variability in motor and perceptual timing.