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To study intersegmental coordination in humans performing different locomotor tasks (backward, normal, fast walking, and running), we analyzed the spatiotemporal patterns of both elevation and joint angles bilaterally in the sagittal plane. In particular, we determined the origins of the planar covariation of foot, shank, and thigh elevation angles. This(More)
A common method to explore the somatosensory function of the brain is to relate skin stimuli to neurophysiological recordings. However, interaction with the skin involves complex mechanical effects. Variability in mechanically induced spike responses is likely to be due in part to mechanical variability of the transformation of stimuli into spiking patterns(More)
The stick-to-slip transition of a fingertip in contact with a planar surface does not occur instantaneously. As the tangential load increases, portions of the skin adhere while others slip, giving rise to an evolution of the contact state, termed partial slip. We develop a quasi-static model that predicts that if the coefficient of kinetic friction is(More)
The dependency of the perceived intensity of a short stimulus on its duration is well established in vision and audition. No such phenomenon has been reported for the tactile modality. In this study naive observers were presented with pink noise vibrations enveloped in a Gabor wavelet. Characteristic durations ranging between 100 and 700 ms and intensities(More)
To explore haptic shape constancy across distance, we measured perceived curvature thresholds of cylindrical shapes, cut out of acetal resin blocks. On each trial, blindfolded observers used their bare finger to scan the surface of two of the shapes consecutively. One shape was close to the observer and the other positioned further away. This spatial(More)
Imagine you are pushing your finger against a compliant object. The change in the area of contact can provide an estimate of the relative displacement of the finger, such that the larger is the area of contact , the larger is the displacement. Does the human haptic system use this as a cue for estimating the displacement of the finger with respect to the(More)
Humans, many animals, and certain robotic hands have deformable fingertip pads [1, 2]. Deformable pads have the advantage of conforming to the objects that are being touched, ensuring a stable grasp for a large range of forces and shapes. Pad deformations change with finger displacements during touch. Pushing a finger against an external surface typically(More)
To study intersegmental coordination in humans performing different locomotor tasks (backward, normal, fast walking, and running), we analyzed the spatiotemporal pattern of both elevation and joint angles bilaterally in the sagittal plane. In particular, we determined the origins of the planar covariation of foot, shank and thigh elevation angles. This(More)
A fundamental problem faced by the brain is to estimate whether a touched object is rigidly attached to a ground reference or is movable. A simple solution to this problem would be for the brain to test whether pushing on the object with a limb is accompanied by limb displacement. The mere act of pushing excites large populations of mechanoreceptors,(More)
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