Abstract: Blind subjects have better tactile sensitivity than healthy subjects. The differences of texture depth recognition threshold between blind and healthy subjects are compared during tactile exploration of a biomimetic hexagonal surface, and the mechanisms of tactile sensitivity in the blind are revealed by analyzing finger-evoked frictional vibrations and cerebral tactile responses using cognitive-behavioral evaluation, tribological measurements, and electroencephalographic analysis. The results show that as the texture depth approaches the tactile threshold in both blind and healthy subjects, the proportion of deformation-related friction produced by touching is markedly increased. The dominant vibration frequency reaches the vibration perception range of the Pacinian corpuscles. Therefore, surface texture can be effectively perceived. A lower tactile depth threshold is observed in blind subjects when a hexagonal texture is touched. Moreover, deformation friction components, the maximum spectral amplitude and the amplitudes of the P100, P200, and P300 components are higher. Furthermore, a larger brain activation area, particularly in the occipital lobe, is observed compared with healthy subjects. A neuronal population model with dual channels was established, and the results indicate that touch-evoked neural pathway coupling strength and neuronal activity in blind subjects are stronger, and that the brain’s processing of tactile information is correspondingly more intensive. The results have reference value for product design and tactile perception research for the blind.

Key words: depth recognition threshold of tactile perception, blind, frictional vibration, electroencephalogram(EEG), bionic hexagonal texture