Contribution of tactile feedback from the hand to the perception of force.

A force-matching task was used to study the influence of constraining tactile information from the hand on the perception of forces generated with the index finger flexors, the palmar prehensile grasp and with the elbow flexors. Subjects generated the same reference forces (2-10 N) with each muscle group and matched these using the corresponding muscle group in the other arm. Force perception was studied under normal conditions and when the tactile feedback from the fingertips was constrained through the use of rigid finger splints. There was no difference between the three muscle groups when matching forces under normal conditions, but when spatial tactile information from the fingertips was attenuated forces were underestimated in perceived magnitude as compared to control conditions. These results suggest that the perception of force is influenced by tactile cues that convey information about the contact surface and that distributed spatial force cues are normally used in the perception of forces generated by the hand.