From chewing to thinking: anatomical and neurophysiological links between mastication, cerebral blood flow, and cognition: a narrative review.

BACKGROUND: Mastication has increasingly been associated with cerebral blood flow (CBF) regulation and cognitive performance. Although the temporalis muscle and temporal lobe are supplied by distinct vascular territories arising from the external carotid and intracranial arterial systems, respectively, growing evidence suggests that chewing activity may indirectly modulate cerebral perfusion and higher brain functions. MATERIALS AND METHODS: This narrative review integrates anatomical, neurophysiological, neuroimaging, and epidemiological evidence regarding the relationship between mastication, cerebral blood flow, and cognition. Previously published systematic reviews, neuroimaging studies [functional magnetic resonance imaging (fMRI), positron emission tomography (PET), and near-infrared spectroscopy (NIRS)], and selected experimental studies were analyzed. The review also included recent evidence concerning neurovascular coupling and trigeminovascular mechanisms. RESULTS: Anatomically, no direct vascular anastomoses exist between vessels supplying the temporalis muscle and those supplying the temporal lobe. Nevertheless, mastication has been associated with increased regional cerebral blood flow in the frontotemporal cortex, hippocampus, and prefrontal cortex. Neuroimaging studies demonstrated increased cortical activation during chewing, whereas epidemiological studies reported associations between impaired masticatory performance, tooth loss, and cognitive decline. Proposed mechanisms include trigeminovascular reflex pathways, neurovascular coupling, and increased carotid blood flow during mastication. CONCLUSIONS: Mastication may act as a functional modulator of cerebral perfusion despite the absence of direct vascular connections between masticatory muscles and the cerebral circulation. Maintenance of effective masticatory function through preservation of dentition and oral rehabilitation may represent a potentially modifiable factor associated with cognitive health.