Brain functional activity of swallowing: a meta-analysis of functional magnetic resonance imaging.

OBJECTIVE: Swallowing is one of the most important activities in our life, and serves the dual roles of nutritional intake and eating enjoyment. The study aimed to conduct a meta-analysis to investigate the brain activity of swallowing. METHODS: Studies of swallowing using functional magnetic resonance imaging were reviewed in PubMed, Web of Science, China National Knowledge Infrastructure (CNKI), Chinese Science and Technology Periodical Database (VIP), and Wan Fang before November 30, 2021. Two authors analyzed the studies for eligibility criteria. The final inclusion of studies was decided by consensus. An activation likelihood estimation (ALE) meta-analysis of these studies was performed with GingerALE, including 16 studies. RESULTS: For swallowing, clusters with high activation likelihood were found in the bilateral insula, bilateral precentral gyrus, bilateral postcentral gyrus, left transverse temporal gyrus, right medial front gyrus, bilateral inferior frontal gyrus, bilateral cingulate gyrus. For water swallowing, clusters with high activation likelihood were found in the bilateral inferior frontal gyrus and the left precentral gyrus. For saliva swallowing, clusters with high activation likelihood were found in the bilateral cingulate gyrus, bilateral precentral gyrus, left postcentral gyrus, left transverse gyrus. CONCLUSION: This meta-analysis reflects that swallowing is regulated by both sensory and motor cortex, and saliva swallowing activates more brain areas than water swallowing, which would promote our knowledge of swallowing and provide some direction for clinical and other research.