5-HT AND MOTOR CONTROL - A HYPOTHESIS

The activity of 5-HT-containing neurons in the brain is activated pref erentially in association with motor output in cats. This is especiall y apparent during changes in muscle tone and during responses mediated by central pattern generators; such as chewing, locomotion and respir ation. These and other data support the hypothesis that the primary fu nctions of the 5-HT system in the brain are to facilitate motor output and concurrently inhibit sensory information processing. This hypothe sis is applicable phylogenetically, from invertebrates to mammals.