Four channels mediate vibrotaction: Facts, models, and implications

Abstract

Four separate pathways or channels apparently mediate tactile (i.e., mechanical) stimuli. Each channel, as defined psychophysically by its frequency characteristics in response to vibratory stimuli and physiologically by additional considerations such as receptive field sizes and adaptation rates to ramp‐and‐hold stimuli, operates over a wide range of frequencies and intensities. The psychophysical channels are: Pacinian or P; non‐Pacinian I or NPI; non‐Pacinian II or NPII; and non‐Pacinian III or NPIII. As defined physiologically and anatomically, the channels are hypothesized to be, respectively: Pacinian (Pacinian corpuscles) or P; rapidly adapting I (Meissner corpuscles) or RA I; slowly adapting II (Ruffini endings) or SA II; and slowly adapting I (Merkel‐cell neurite complexes) or SA I. Because the channels are overlapping in their operating ranges, it is proposed that under certain conditions (e.g., low stimulus intensities) a single channel may mediate taction, while other conditions require that more than one channel contributes to tactile sensations and to overall perceptual impressions. From the standpoint of applied aspects such as the development of tactile aids for the deaf, it should be of interest to determine if the channels can be used independently and to determine the types of interactions that may occur for the purpose of enhancing information transfer via this sensory system.