LAUSR

Spatial perception of our hand is closely linked to our ability to move the hand accurately. We might therefore expect that reach planning would take into account any changes in perceived hand position; in other words, that perception and action relating to the hand should depend on a common sensorimotor map. However, there is evidence to suggest that changes in perceived hand position affect a body representation that functions separately from the body representation used to control movement. Here we examined target-directed reaching before and after participants either did (Mismatch group) or did not (Veridical group) experience a cue conflict known to elicit recalibration in perceived hand position. For the reaching task, participants grasped a robotic manipulandum that positioned their unseen hand for each trial. Participants then briskly moved the handle straight ahead to a visual target, receiving no performance feedback. For the perceptual calibration task, participants estimated the locations of visual, proprioceptive, or combined cues about their unseen hand. The Mismatch group experienced a gradual 70 mm forward mismatch between visual and proprioceptive cues, resulting in forward proprioceptive recalibration. Participants made significantly shorter reaches after this manipulation, consistent with feeling their hand to be further forward than it was, but reaching performance returned to baseline levels after only 10 reaches. The Veridical group, after exposure to veridically-aligned visual and proprioceptive cues about the hand, showed no change in reach distance. These results are not fully consistent with a single common sensorimotor map, but could suggest multiple, interacting body representations. NEW & NOTEWORTHY If perceived hand position changes, we might assume this affects the sensorimotor map and, in turn, reaches made with that hand. However, there is evidence for separate body representations involved in perception vs. action. After a cross-sensory conflict that results in proprioceptive recalibration in the forward direction, participants made shorter reaches as predicted, but only briefly. This is not fully consistent with a single common sensorimotor map, but could suggest multiple, interacting body representations.