Calibrating grasp size and reach distance: interactions reveal integral organization of reaching-to-grasp movements.
Feedback is a central feature of neural systems and of crucial importance to human behaviour as shown in goal directed actions such as reaching-to-grasp. One important source of feedback in reach-to-grasp behaviour arises from the haptic information obtained after grasping an object. We manipulated the felt distance and/or size of a visually constant object to explore the role of haptic information in the calibration of reaching and grasping. Crucially, our design explored post-adaptation effects rather than the previously documented role of haptic information in movement organisation. A post-adaptation reach-to-grasp task showed: (1) distorted haptic feedback caused recalibration; (2) reach distance and grasp size could be calibrated separately but, if calibrated simultaneously, then (3) recalibration was greater when distance and size changed in a consistent (e.g. reaching for a larger object at a greater distance) rather than an inconsistent (e.g. a smaller object at a greater distance) fashion. These interactions reveal the integral nature of reach-to-grasp organization, that is, that reaching and grasping are integrated components of a single action system.
Coats
Rachel
R
School of Psychology, University of Aberdeen, AB242UB Aberdeen, Scotland, UK.
Bingham
Geoffrey P
GP
Mon-Williams
Mark
M
D000328:Adult; D002138:Calibration; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D009068:Movement / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011597:Psychomotor Performance / Q000502:physiology*