A functional axis of mastication and respiration in cognitive function: A narrative review

This review presents an integrative framework of the "Mastication-Respiration Axis," proposing that the masticatory and respiratory systems interact to form a functional axis essential for the development and maintenance of cognitive health in brain circuits.

We narratively synthesized studies identified by structured searches of PubMed from inception to September 1, 2025, using predefined keywords related to mastication/chewing, nasal respiration/breathing, and cognition, and including peer-reviewed human and animal studies published in English.

Evidence shows that mastication and respiration are coordinated at the brainstem through central pattern generators. Dysfunction in this axis-such as reduced chewing or oral breathing-activates stress and inflammatory pathways. The prefrontal cortex, hippocampus, and cerebellum depend on rhythmic inputs from both systems, with nasal respiration acting as a cortical pacemaker. Animal studies demonstrate that masticatory deficiency impairs hippocampal memory, while respiratory disruption during critical developmental periods causes long-lasting cerebellar and affective-motor deficits, offering a neurobiological basis for clinical links between oral breathing and neurodevelopmental disorders.

Mastication and respiration are not merely peripheral functions but are deeply integrated with the central nervous system, forming a critical axis for brain development, plasticity, and function. Dysfunction in this axis, particularly during sensitive developmental windows, may lead to long-term impairments in memory, motor control, and affective regulation. This integrated model highlights the clinical importance of early interventions in dental, orthodontic, and respiratory health to support lifelong neurological well-being.