Controlling movement like a dimmer switch

New research identifies a motor pathway between the forebrain and brainstem that works like a dimmer switch to regulate swimming speed in the sea lamprey — a primitive, jawless fish with an eel-like body studied by neuroscientists as a model of the vertebrate nervous system. Dysfunction of this pathway, which is likely present in mammals potentially including humans, may contribute to the symptoms of movement disorders such as Parkinson’s disease.