HUMAN THERMAL SENSATION - FREQUENCY-RESPONSE TO SINUSOIDAL STIMULI ATTHE SURFACE OF THE SKIN

The question of how the human organism perceives changing thermal stim uli has been recently studied and reported in experiments where these stimuli were either ramps and plateaux or simply step changes. Other e xperiments have been done in which the stimuli have been periodically varying airflows. A psychosensory intensity (PSI) model. has been deve loped to relate experimentally derived sensation data to simulated cut aneous thermoreceptor responses to the temperature ramp-plateaux and s tep stimuli applied to the skin surface by thermodes. From the point o f view of signal processing, a natural extension of this approach is t o ask what the response would be to sinusoidally varying stimuli of di ffering frequencies, or, in other words, what would be the frequency r esponse of this skin system? The purpose of this paper is to extend th e PSI model and apply these sinusoids to it and hence find the frequen cy response function. This function is then compared with the function al form found in two experiments where the stimuli were pulsating airf lows of differing frequency. The PSI model seems to simulate well the form of the response of the human skin system to varying temperature c hanges of a whole range of frequencies as well as the response to ramp s and plateaux of differing periods, ramp inclines and intensities.