To what extent does Tagged-MRI technique allow to infer tongue muscles' activation pattern? A modelling study

International audience`Tagged MRI' techniques have been used during the past years to predict which muscles are activated during the production tongue movements. Using this technique, inferences are based on the hypothesis that a significant strain of the anatomical region of a tongue muscle is evidence of voluntary muscle activation. In this paper, we propose to use a 3D finite-element biomechanical model of the oral cavity to study the relation between the distribution of the strains observed in the tongue body and the location of the tongue muscles activated either by the central nervous system or through reflex loops. Results showed in most cases a good correlation between the location of the tongue area that underwent high strains and the location of the muscle activated when studying single muscle activation. However, for movements involving combined muscle activations, a limited and even no correlation is measured. Hence, direct reading of Tagged MRI images would not allow inferring major tongue muscles activated in theses cases