Spatial Summation Effects on Lingual Vibrotactile Thresholds

Abstract

Ascending lingual vibrotactile thresholds at 250 Hz were obtained for four groups of normal-speaking adult subjects. Contactor areas were varied for each respective group. Threshold values in microns plotted as a function of the area of vibratory displacement indicated a spatial summation function for the larger contactors (greater than .02 cm2). Findings are discussed in terms of the nature of lingual-tactile mechanoreception and possible implications for neural control mechanisms subserving speech production.

Temporal resolution of successive brief stimuli for the tongue and hand

“…The contactor in the vibratory system employed by Geldard and Sherrick (1971) was even larger than that of Gescheider (1966Gescheider ( , 1967, a fact that, along with the forced-choice methodology, caused the fusion thresholds to be even lower. The fact that the fusion thresholds from the present study were twice as large as those reported by earlier investigators adds support to the observation that the peripheral and central neural mechanisms of the cutaneous system have sufficient specificity to make spatial (contactor-size) as well as temporal discriminations (Telage & Warren, 1977;Verrillo, 1966;Verrillo & Chamberlain, 1972).…”

Lingual vibrotactile sensation magnitudes: Stimulus frequency effect

“…The purpose of the present investigation was to provide further explanation of the frequency effect on subjective suprathreshold vibrotactile magnitude functions by obtaining power function curves at different frequencies from the human tongue. Exploration of the human tongue has been shown to be helpful in understanding the effect of frequency on vibrotactile threshold responses of cutaneous mechanoreceptors (Telage & Warren, 1977;Verrillo, 1966).…”

Effects of auditory interference upon observed lingual tactile thresholds

“…This discrepancy might be explained by the difference in neural receptor populations resulting from clamping the tongue. It has previously been shown that the receptors on the lingual dorsal surface differ from the more ventrally located Pacinian corpuscles in such response characteristics as frequency-sensitivity (Telage & Petrosino , 1978) and spatial summation (Telage& Warren, 1977). Additionally , clamping the tongue tends to push the Pacinian receptors toward the surface, where they may be more easily excited by vibratory stimulation .…”