Análise por ressonância magnética funcional das áreas corticais e subcorticais da função de deglutição

Abstract

Although the act of swallowing can be considered a voluntary action of transferring food from the oral cavity to the stomach, this function of the human body can be initiated long before the presentation of food and requires extensive brain activity that allows the swallowing process to occur a coordinated, safe, effective, pleasurable way and enables the individual to behave at a social level, ensuring interaction with the environment and maintenance of his own body. However, the neurological mechanisms of swallowing are still not entirely clear and require investigation for a better definition of its normality pattern and understanding of its alterations through disorders that may affect the Central Nervous System (CNS). So, this work aims to analyze the cortical and subcortical areas activated during the swallowing function. This is a quantitative and qualitative, observational, cross-sectional and descriptive study, with a convenience sample (nonprobabilistic) of the continuous type. A total of 9 healthy men, with a minimum of 3 hours of fasting, underwent 1 Tesla Functional Magnetic Resonance Imaging (FMR) with axial T2 Flair sequences, 3D Bravo and BOLD echoplanar sequences for functional evaluation of swallowing. Each participant was asked to perform multiple swallows of saliva with a gustatory stimulus in the mouth (mint candy) for a period of 1 minute with an interval of 1 minute (ratio 1:1). During the analysis of the exams, a total of 13 brain areas activated during swallowing were identified, being the Thalamus, Cerebellum, Primary Motor Cortex, Somatosensory Cortex, Anterior Cingulate Cortex, Inferior Occiput Parietal Cortex, Inferior Frontal Cortex, Superior Temporal Cortex, Frontal Cortex Medial Cortex, Superior Parietal Cortex, Nucleus Ambiguus, Inferior Salivary Nucleus and Insular Cortex. The area of the Primary Motor Cortex, where the Motor Homunculus is characterized, was the only common area in activation among all research volunteers (100%), followed by the left Frontal Medial Cortex (77.78%), left Inferior Parietal Occipito Cortex (77.78%) and Cerebellum on the left side (77.78%). The lowest frequency of areas that were not activated in the sample of this research were the Medial Frontal Cortex (11.11%) and Lower Frontal Cortex (11.11%). Although common areas of activation in the brain are observed in the sample of this study, it is not possible to say that the central nervous system behaves in the same way for the same task of swallowing. Thus, the distributed nature of this swallowing neurological network helps to explain why so many neurological conditions result in dysphagia, and these findings are therefore of great clinical relevance, because by understanding the cortical areas for a given function, it is possible to better understand how the nature of distribution of the swallowing neurological network the synaptogenic effects that patients with neurological injuries develop in the swallowing rehabilitation process when this difficulty is impaired. Swallowing involves a very wide distribution network of neural areas, still little understood and possible to be larger than supposed.