Abstract
Both vision and proprioception operate in the planning and control of action (Touzalin-Chretien et al., 2010). However, vision has been reported as the dominant sensory modality (Heath, 2005). As such, vision is preferred over proprioception when vision is available (Touzalin-Chretien et al., 2010). Of interest, then, is the role of proprioception in motor tasks when vision is absent, and what changes in the brain may result from visual deprivation with respect to proprioception. The current study employed a 2-hour visual deprivation to differentiate proprioception from vision by removing visual input. During the visual deprivation, subjects participated in tactile discrimination tasks to promote proprioceptive plasticity. Prior to and following deprivation participants were asked to perform a grasping task under either visual (Vision) or proprioceptive (No-Vision) control (40 trials each: 160 total). For every trial, an experimenter passively moved the subject's right hand to the target and back to a set origin. In No-Vision trials, participants grasped either a small (5 cm diameter) or large (7 cm diameter) circular target at two different locations (20 or 35 cm) in response to an auditory tone. In Vision trials, vision was made available 2 s prior to the auditory tone until movement end. Participants were instructed to grasp the target as quickly and accurately as possible. PLATO goggles (Translucent Technologies, Inc.) were used to remove visual input during the deprivation and No Vision condition. Kinematic measurements (e.g. grip aperture, reaction time, movement time) were obtained using an Optotrak 3020 (Northern Digital, Inc.). Results indicated augmented use of proprioception for motor planning, but less so for motor control of reaching and grasping strategies following acute visual deprivation. Our results are consistent with findings that sensory deprivation is associated with plasticity and behavioral changes (Merabet & Pascual-Leone, 2010).