The role of the periaqueductal grey in limbic and neocortical vocal fold control

The effects of a pharmacological blockade of the periaqueductal grey of the midbrain (PAG) on the elicitability of vocal fold movements from the facial motor cortex on the one hand and the anterior cingulate cortex and dorsomedial hypothalamus on the other were studied in the squirrel monkey. PAG blockade abolished vocal fold activity induced by the cingulate cortex and hypothalamus, but not that induced by the neocortex. These results point to the existence of two separate vocal fold control pathways at midbrain level: one limbic, responsible for non-verbal emotional vocal utterances, and one neocortical, responsible for the production of learned vocal patterns. The PAG represents a crucial relay station of the limbic but not the neocortical vocal control pathway.