THE CONTRIBUTION OF PROPRIOCEPTION AND TOUCH TO THE PERCEPTION OF WEAK FORCES: PRELIMINARY RESULTS
The general objective of this study was to test the contribution of touch to identifying the direction of a weak force (0.08 N) transmitted by a hand-held object. In the first experiment, we found that the performance did not vary when participants held the object with a distal or a proximal grasp. This negative result suggests that cutaneous receptor types that are unequally distributed between the phalanges involved in the two grasps played a limited role in this task. In a second experiment, we found that an ischemic block of the hand led to a marked decrease in performance. This observation suggests that signals originating in the hand provide important information about the direction of the force though it is difficult to know whether these signals have a cutaneous or proprioceptive origin since the block also affected the intrinsic muscles of the hand.