Changes in regional cerebral blood flow during mastication in young and old normal subjects measured with positron emission tomography

Abstract

Ten normal volunteers (ages 28-85) underwent measurement of regional cerebral blood flow using intravenous blous injection of oxygen-15 lebeld water and positron emission tomography under three different conditions: resting, chewing gums, and tasting candy. An increase in blood flow was observed in the lower part of the bilateral pre-and postcentral gyri, extending to the operculum and the insula, both in “gum” and “candy” compared to “rest” in all subjects, which suggested that the operculum-insula as well as the lower Rolandic area is responsible for the oromasticatory sensori-motor function. The blood flow increase was smaller in old subjects than in young subjects, whitch was considered to reflect a reduced muscle work and/or decreased neuronal or cerebrovascular responce.