EFFECT OF MASTICATION ON REGIONAL CEREBRAL BLOOD-FLOW IN HUMANS EXAMINED BY POSITRON-EMISSION TOMOGRAPHY WITH O-15-LABELED WATER AND MAGNETIC-RESONANCE-IMAGING

The interaction between mastication and cerebral blood flow was studie d in 12 healthy volunteers (five males and seven females) aged 18-40 y ears. Positron-emission tomography (PET)-auto-radiography was carried out after bolus injection of 1.5 GBq (H2O)-O-15 (O-15-labelled water) with a half life of 2 min. The PET images were superimposed on magneti c resonance images of each participant. The regional cerebral blood fl ow images were normalized by the global cerebral blood flow value, and subtraction images (those during gum-chewing minus those during resti ng) were created and recut at the magnetic resonance image slice posit ions. Gum specially designed for chewing training was used. Masticatio n increased regional cerebral blood flow in the primary sensorimotor a reas by 25-28%, in the supplementary motor areas and insulae by 9-17%, and in the cerebellum and striatum by 8-11%. These increases demonstr ate that chewing activates widespread regions of the brain. (C) 1997 E lsevier Science Ltd.