Using fMRI to explore the central regulatory mechanism of swallowing initiation in the post-stroke pharyngeal phase

Abstract

Abstract Background The central mechanism of swallowing initiation during the pharyngeal phase has already been investigated but not clarified. The aim of this study is to explore the central regulatory mechanisms and the pathological mechanisms involved in swallowing disorders with delayed swallow initiation during the pharyngeal phase. The full understanding of these mechanisms would provide an experimental basis for the development of more effective swallowing treatments. Methods We selected thirteen stroke patients with delayed swallow initiation identified by Video Fluoroscopic Swallowing Study (VFSS), with nineteen healthy subjects as control group. Functional magnetic resonance scans of relevant brain sites were obtained, in order to record and analyze the differences between the two groups in activation volume and intensity in the functional areas of the brain during dry swallowing. Results The activation range of the bilateral supplementary motor areas, right dorsolateral superior frontal gyrus, left middle frontal gyrus, and right precentral gyrus increased in stroke patients after stimulation of the anterior faucial pillars with ice (P < 0.05). In addition, the activation range of the left supplementary motor area, the right lateral superior frontal gyrus, and the right posterior cingulate gyrus after treatment was even larger than what was observed in healthy subjects (P < 0.005). Conclusion The main brain areas regulating swallowing initiation include the left supplementary motor area, the right dorsolateral superior frontal gyrus, the left cuneus, and the right posterior cingulate gyrus. Amongst them, the left supplementary motor area and the right dorsolateral superior frontal gyrus are motor centers, while the left cuneus and the right posterior cingulate gyrus are sensory centers.