Vibrotactile signals are produced during haptic exploration of compressible objects through a variety of contact and bulk mechanical processes. Prior studies have found that vibrotactile feedback can influence stiffness perception, but the reason for this is unknown. Here, we investigated the role of vibration in stiffness perception during object squeezing. We propose a physically motivated ex...

BACKGROUND Finger amputation may result from congenital cause, trauma, infection and tumours. The finger amputation may be rehabilitated with dental implant-retained finger prosthesis. The success of implant-retained finger prosthesis is determined by the implant loading. The type of the force is a determining factor in implant loading. OBJECTIVE To evaluate stress distributions in finger bon...

BACKGROUND The mapping from muscle activation to joint torque production can be difficult to determine for the multi-articular muscles of the fingers. This relationship was examined in vivo as a function of posture in the index finger. METHODS Five healthy adults participated in an experiment in which the seven muscles of the index finger were sequentially electrically stimulated using intram...

A hypothesis was proposed that the central nervous system controls force production by the fingers through hypothetical neural commands. The neural commands are scaled between values of 0 to 1, indicating no intentional force production or maximal voluntary contraction (MVC) force production, respectively. A matrix of interfinger connections transforms neural commands into finger forces. Two me...

To evaluate the effect of handle design characteristics on subjective ratings and pulling forces, meat-hook handles with various handle shapes, sizes, and hook positions were tested in a pulling task. Finger and phalange force data measured by force sensitive resistors and subjective ratings of discomfort were also evaluated. Generally subjects preferred 37-mm double frustum, 30-mm oval handles...

Fortier-Poisson P, Smith AM. Neuronal activity in somatosensory cortex related to tactile exploration. J Neurophysiol 115: 112–126, 2016. First published October 14, 2015; doi:10.1152/jn.00747.2014.—The very light contact forces ( 0.60 N) applied by the fingertips during tactile exploration reveal a clearly optimized sensorimotor strategy. To investigate the cortical mechanisms involved with th...

This study investigated the effects of fingertip tactile sensitivity on the structural variability of thumb and index finger forces during stable precision grip. Thirty right-handed healthy subjects participated in the experiment. Transient perturbation of tactile afferents was achieved by wrapping up the distal pads of the thumb or index finger with transparent polyethylene films. The time-dep...

The method of multidimensional scaling was applied to matrices of finger interaction (IFM) computed for individual participants for finger force production tasks. When IFMs for young controls, elderly, and persons with Down syndrome were pooled, only two dimensions described interpersonal differences; these were related to total force and to the total amount of enslaving. When IFMs for each gro...

Existing computational models of the human fingers are simplistic and do not capture the physics of interactions of the different components of the extensor mechanism. These models, though widely used in the literature to model finger mechanics have not been validated with experimental data. In this paper, we rigorously validate three index finger biomechanical models : the normative model deve...

To investigate the organization of multi-fingered grasping, we asked subjects to grasp an object using three digits: the thumb, the index finger, and the middle or ring finger. The object had three coarse flat contact surfaces, whose locations and orientations were varied systematically. Subjects were asked to grasp and lift the object and then to hold it statically. We analyzed the grasp force...