Cerebral control of face,jaw, and tongue movements in awake cats: Changes in regional cerebral blood flow during lateral feeding

Mastication is achieved by cooperation among facial, masticatory, and lingual muscles. However, cortical control in cats for the masticatory performance is processed by two systems: facial movement processed by facial SI (the first somatosensory cortex), area C, and area M (motor areas), and jaw and tongue movements performed by intraoral SI, masticatory area, and area P (motor area). In particular, outputs from area P organized in the corticobulbar tract are projected bilaterally in the brainstem. In this present study, the aim is to explore changes in the regional cerebral blood flow (rCBF) in the facial SI, area M, and area P during trained lateral feeding (licking or chewing from the right or left side) of milk, fish paste, and small dry fish. The rCBF in area M showed contralateral dominance, and rCBF in area P during chewing or licking from the right or left side was almost the same value. Furthermore, activities of genioglossus and masseter muscles in the left side showed almost the same values during licking of milk and of fish paste, and chewing of small dry fish during lateral feeding. These findings suggest that the cortical process for facial, jaw, and tongue movements may be regulated by the contralateral dominance of area M and the bilateral one of area P.