Abstract
Goal-directed reaches are rapidly adapted following exposure to misaligned visual feedback of the hand. It has recently been shown that exposure to misaligned visual feedback of the hand also results in partial sensory recalibration, such that proprioceptive estimates of hand position are realigned to match visual estimates. In the present study we examined the relationship between reach (motor) adaptation and changes in sense of felt hand position (proprioceptive recalibration) by determining the influence of increasing levels of distorted visual feedback on sensory and motor recalibration. To examine proprioceptive recalibration, we determined the position at which subjects felt their hand was aligned with a reference marker after reaching to targets with a cursor that was rotated 30o, 50o or 70o clockwise relative to hand motion. Subjects exposed to the 70o rotation recalibrated the position at which they felt their hand was aligned with a reference marker the most (15o leftwards), while subjects exposed to the 30o rotation recalibrated proprioception the least (only 7o leftwards). This pattern in sensory recalibration is similar to the changes observed in subjects' reaches (reach aftereffects were 34o vs. 16o for subjects who trained with the 70o vs. 30o rotation respectively). Given the similar trend in sensory and motor recalibration, the results of the current study suggest that proprioceptive recalibration may be related to the extent that movements are adapted.Acknowledgments: DYH is an Alfred Sloan Fellow; DS is funded by an NSERC Doctoral Scholarship.