Assessing
Résumé
An open question in speech motor control is the degree to which postural control of the tongue is accomplished through passive mechanisms - such as the mechanical and elastic properties of the tongue itself - reflexes - such as the stretch reflex - or active control mechanisms. Previously, Perrier et al. (2003) have developed a biomechanical simulation of the tongue which models the movement and configurations of the tongue resulting from muscle forces calculated using Feldman’s lambda model (Feldman & Levin, 1995) which implements the stretch reflex. In order to make progress in answering the question of the mechanisms of postural control, we modify this biomechanical simulation of the tongue to accurately model a specific external perturbation, namely one in which the tongue is pulled anteriorly using a specificforce profile exerted on the tongue body using a force effector attached to the superior part of the tongue blade. This type of perturbation was chosen as the target of our modeling efforts since it is performed on normal subjects in a separate study which provides us withphysical parameters against which we can validate our model’s performance and ensure biologically realistic results (Ito et al., 2009). Once this model is tuned to accurately represent this perturbation, we describe an experimental paradigm which we employ to compare predictions made by the model with future real data to evaluate different hypotheses regarding the importance of passive, reflex, and active strategies in postural control of the tongue.