The effect of skin temperature on vibrotactile sensitivity

Abstract

The effect of skin temperature on detection of vibrotactile stimuli was measured for vibrations of 30 and 250 Hz. Data for the 250-Hz stimulus supported the results of Weitz (1941), who found that thresholds for 100-, 256-, and 900-Hz vibration varied as a U-shape function of skin temperature with a minimum at about 37°C. Temperature had a negligible effect on sensitivity at 30 Hz. A second experiment examined a range of frequencies between 30 and 250 Hz. Cooling greatly lowered sensitivity only to 150-and 250-Hz stimuli. Warming reduced sensitivity less, but more uniformly across frequencies. I t was concluded that cooling may affect vibrotactile thresholds by decreasing the sensitivity of Pacinian corpuscles; the reason for the decrease in sensitivity due to warming is unclear.Severe cold numbs the sense of touch. Despite the commonplace nature of this experience, relatively little has been done to quantify it. Early studies by Allers and Halpern (1922) and Moore (1910) seemed to reveal that the threshold for punctiform touch varies as a V-shaped function of skin temperature, with a minimum at about 37°C. But in both studies stimulus control and measurement left much to be desired. Later, Weitz (1941) seemed to corroborate the earlier findings. He noted that on hairy skin pressure-sensitive and vibration-sensitive "spots" coincided, and found that thresholds for punctiform vibration also varied as a V-shaped function of skin temperature, with a minimum at 37°C. Weitz concluded that temperature affected detection by altering biochemical processes in mechanoreceptors sensitive to both pressure and vibrotactile stimulation.But recent findings in electrophysiology and vibrotactile psychophysics have challenged the view that punctiform pressure and vibration are always mediated by the same receptors. Pressure receptors tend to be slowly adapting and amplitude-sensitive, vibration receptors quickly adapting and velocitysensitive (Harrington & Merzenich, 1970;Merzenich & Harrington, 1969). Since these different response properties undoubtedly derive from different biophysical processes, it seems questionable that temperature would affect the different receptors in identical ways.One can find out indirectly by psychophysical experiment. At least two receptor populations seem Reprint requests may be sent to: Barry G. Green, John B. Pierce Foundation Laboratory, 290 Congress Avenue, New Haven, CT 06519.to mediate the perception of vibrotactile stimuli: One, composed of so-called low-frequency receptors, reacts most readily to vibrations below about 80 Hz; the other, a high-frequency system, reacts to vibrations above 80 Hz. The high-frequency system is believed to be composed of Pacinian corpuscles (Merzenich & Harrington, 1969; Mountcastle, Talbot, Darian-Smith, & Kornhuber, 1967;Talbot, Darian-Smith, Kornhuber, & Mountcastle, 1968;Verrillo, 1963Verrillo, , 1968, whereas no specific receptor has been identified for the low-frequency system. The obvious question is: Since different receptors may be involved, does ski...

The effect of cooling on the vibrotactile sensitivity of the tongue

“…This pattern of results is the same as has been found on the skin of the hand and the arm for threshold-level stimuli (Bolanowski & Verrillo, 1982;Green, 1977;Verrillo & Bolanowski, 1986), although there is evidence that more extreme cooling (to 15°C and below) may affect the sensitivity to low-frequency vibration as well (Bolanowski & Verrillo, 1982).…”

“…Exposing the tongue to ambient air without further temperature rinses undoubtedly reduced the impact of the rinses; the warmed tongue would tend to cool by evaporation and the cooled tongue would tend to warm due to normal blood flow. It may have been because of this procedure that cooling the tongue with 17°rinses produced an effect that was much smaller (2.4 dB vs. 17.5 dB) than an effect that had been obtained in a study on the hand in which the skin had seemingly been cooled less severely (to 20°C;Green, 1977). Fucci et al also investigated only one frequency of vibration, leaving unanswered the question of whether the weak thermal effect they found would extend to lowfrequency vibration.…”

“…The present study examined one such property: the effect of skin temperature on the sensitivity to vibration. Because it was known that cooling the skin of either the hand or the arm could significantly reduce its sensitivity to high-frequency vibration (Bolanowski & Verrillo, 1982;Green, 1977;Koradecka, 1974;Weitz, 1941) and, to a much lesser extent, its sensitivity to low-frequency vibration (Bolanowski & Verrillo, 1982), it seemed likely that cooling might also reduce the sensitivity to vibration on the tongue.…”

Vibrotactile localization on the arm: Effects of place, space, and age

“…Circumaural headphones were worn, through which white noise was presented to mask distracting ambient or cuing sounds from the stimulators. Skin temperature was measured at a central location on each site to be examined and was maintained within the range of 31º-37º C for this and the following experiments, in order to stabilize sensitivity (e.g., Green, 1977;Stevens, 1990;Verrillo & Bolanowski, 1986). The left hand and volar forearm were exposed and oriented so as to be available for stimulation.…”

Frequency-dependence of Psychophysical and Physiological Responses to Hand-transmitted Vibration

“…[8][9][10] ). The greatest effect seems to be on thresholds mediated by the Pacinian channel ( 10) ; Fig.…”