Sensorimotor memories influence movement kinematics but not associated tactile processing

Abstract

When interacting with objects, we often rely on visual information. However, vision is not always the most reliable sense for determining relevant object properties. For example, when the mass distribution of an object cannot be inferred visually, humans may rely on predictions about the objects dynamics. Such predictions may not only influence motor behavior but also associated somatosensory processing, as sensorimotor predictions lead to reduced tactile sensitivity during movement. We examined whether predictions based on sensorimotor memories influence grasping kinematics and associated tactile processing. Participants lifted an object of unknown mass distribution and reported whether they detected a tactile stimulus on their grasping hand during the lift. In Experiment 1, the mass distribution could change from trial to trial, whereas in Experiment 2, we intermingled longer with shorter parts of constant and variable mass distributions, while also providing implicit or explicit information about the trial structure. In both experiments, participants grasped the object by predictively choosing contact points that would compensate the mass distribution experienced in the previous trial. Tactile suppression during movement, however, was invariant across conditions. These results suggest that predictions based on sensorimotor memories can influence movement kinematics but may not affect associated tactile perception. Public significance statementTo perform a goal-directed movement, such as grasping an object, humans combine the available sensory information with predictions about the prevailing dynamics. Sensorimotor predictions also lead to a decrease of movement-related tactile signals, a phenomenon termed tactile suppression. Tactile suppression is supposed to rely on a dynamic weighting of sensory feedback and predictive signals. When sensory feedback is not reliable, reliance on memory-based predictions may be desired. Here we show that motor behavior is influenced by predictions based on sensorimotor memories, but associated tactile processing appears to be robust.