Swallowing Preparation and Execution: Insights from a Delayed-Response Functional Magnetic Resonance Imaging (fMRI) Study

Abstract

The present study sought to elucidate the functional contributions of sub-regions of the swallowing neural network in swallowing preparation and swallowing motor execution. Seven healthy volunteers participated in a delayed-response, go, no-go functional magnetic resonance imaging study involving four semi-randomly ordered activation tasks: (i) "prepare to swallow," (ii) "voluntary saliva swallow," (iii) "do not prepare to swallow," and (iv) "do not swallow." Results indicated that brain activation was significantly greater during swallowing preparation, than during swallowing execution, within the rostral and intermediate anterior cingulate cortex bilaterally, premotor cortex (left > right hemisphere), pericentral cortex (left > right hemisphere), and within several subcortical nuclei including the bilateral thalamus, caudate, and putamen. In contrast, activation within the bilateral insula and the left dorsolateral pericentral cortex was significantly greater in relation to swallowing execution, compared with swallowing preparation. Still other regions, including a more inferior ventrolateral pericentral area, and adjoining Brodmann area 43 bilaterally, and the supplementary motor area, were activated in relation to both swallowing preparation and execution. These findings support the view that the preparation, and subsequent execution, of swallowing are mediated by a cascading pattern of activity within the sub-regions of the bilateral swallowing neural network.

The Margins of the Language Network in the Brain

“…Ackermann and Riecker (2004) suggest that the insular contribution to speech motor control may reflect phylogenetic roots that have developed for motor coordination during swallowing. Accordingly, and in line with the authors' finding that insular activation was related to overt rather than silent speech, a more recent study found that swallowing-related insular activity was present during execution rather than preparation of swallowing (Toogood et al, 2017).…”

Motor and Sensory Cortical Processing of Neural Oscillatory Activities revealed by Human Swallowing using Intracranial Electrodes

“…Swallowing-associated high γ bursts were observed in the region along the Sylvian fissure, including the subcentral area (BA 43) and the frontal operculum (BA 44). Previous studies have reported that swallowing activated the subcentral area (Martin et al, 2004;Toogood et al, 2017) and the frontal operculum (Dziewas et al, 2003;Lowell et al, 2008). In our study, swallowing-associated high γ bursts achieved a peak at the onset time of swallowing triggers, and subsequently, the high γ power decreased.…”

Comparison of Activation Patterns in Mirror Neurons and the Swallowing Network During Action Observation and Execution: A Task-Based fMRI Study

“…Swallowing is a coordinated physiological process, involving complex neuromuscular interactions (Ertekin and Aydogdu, 2003). Extensive research has shown that the swallowing network includes the brain regions of the primary sensorimotor system, supplementary motor area (SMA), insula, cingulate cortex, IFG, IPL, temporal lobe, precuneus, cerebellum, and brain stem (Hamdy et al, 1999a;Lang, 2009;Soros et al, 2009;Lima et al, 2015;Toogood et al, 2017). When any area of the swallowing network is damaged, dysphagia occurs (Domenech and Kelly, 1999;Gonzalez-Fernandez and Daniels, 2008).…”