We do not understand well the mechanisms underlying the tactile perception of surface texture and object shape. The human fingertip is exceptionally good at such discriminations, particularly when it is actively moved over surfaces. This project utilizes a novel material called a "shape-memory-alloy" which is a metal that can rapidly be deformed into patterns by brief electrical heat pulses. The stimulator built with units of this material is used to deliver highly quantified spatial and temporal patterns to an array of 30 elements on the fingertip, to simulate surface roughness and edge detection as though the finger were sweeping across a surface. Manipulation of frequency, intensity, and spatial distribution will allow quantitative evaluation of perceptual discrimination, identification, and similarity ratings by subjects, comparing simulated surfaces with actual ones. Results will be important to relate to physiologically-based models of mechanoreceptor function in touch sensation, and the perception of texture and form. The potential impact extends beyond mechanosensory neuroscience into the areas of aids for the handicapped, and tactile feedback for telerobotic and virtual environment applications.
