Does behavioral dissociation of real vs. pantomime movements only apply to visually guided action?

Abstract

Pantomime reaching movements to imagined objects differ kinematically from real reaching movements to visual objects. It has been proposed that these differences may be related to the availability of online visual input. Specifically, real reaches are proposed to rely on online visual information localized largely in the left dorsal stream whereas pantomime reaches are proposed to rely on perceptual information processed in more widespread areas including the ventral stream and the right dorsal stream. Withdrawing the hand to place an object in the mouth is a natural and common movement; yet, it differs from other reaching movements in that it relies almost entirely on somatosensory guidance and may be mediated by a ‘hard-wired’ cortical motor representation that controls the arm, hand, and mouth. Given these differences, it could be hypothesized that hand-to-mouth movements might not be subject to the same real vs. pantomime dissociation as visually guided reaching. The present study used frame-by-frame video analysis and linear kinematics to analyze hand and mouth movements as participants withdrew the arm and hand to place either real or imagined food items into the mouth for eating. Pantomime hand-to-mouth movements were characterized by longer movement durations, lower peak velocities, and smaller openings of the mouth aperture to receive the food item than real hand-to-mouth movements. Nonetheless, mouth opening scaled to object size regardless of whether the food item was real or imagined. The results are discussed in relation to the idea that neurobehavioral dissociation of real vs. pantomime actions is a general feature of movement control that applies to both visually and nonvisually guided actions.

Meeting abstract presented at VSS 2015