Stanley "Sandy" J. Bolanowski (22 February 1950-13 January 2005).
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Journal Article↗
Biomedical subjects
Ronald T Verrillo
Publications and source records attributed to Ronald T Verrillo.
A direct comparison of exogenous and endogenous inhibition of return and selective attention mechanisms in the somatosensory system.
The interaction of excitation and inhibition in responses due to attentional mechanisms in the visual system has been investigated. The studies reported herein use the tactile system of humans to test a specific hypothesis about the processes of attention that have never been directly addressed. Both exogenous and endogenous Inhibition of Return (IOR) reaction-time paradigms with a 100 Hz, 35 microm of peak displacement amplitude were used. In these experiments multiple Stimulus Onset Asynchronies were tested which made it difficult for subjects to learn timing patterns. We tested whether a detection time to a target which is to be attended to is a composite of at least two underlying mechanisms. These mechanisms were explored using exogenous and endogenous IOR experiments. It is hypothesized that these mechanisms work in a push-pull fashion: one deploying attention when new events occur, and the other withdrawing attention ("Disengagement") after it has been deployed. Based on the results, a new hypothesis is proposed stating that one form of attention (selective attention) competes with IOR in determining the time taken to detect a target in the tactile system.
Attention↗
Intra- and interactive touch on the face.
Experiments were performed in which the subjective size of steel balls was judged by the method of absolute magnitude estimation (AME). The balls were rolled actively ("scripting") by the right index finger pad of the subject over the passively receiving areas of the face, namely the forehead, cheek and the vermilion border of the lower lip. These areas were stimulated on the subject's own person (intra-active touch), on another person's face (interactive touch) and by another person upon the face of the subject (interactive touch). Results indicate that size perception appears to be governed primarily by the mechanical characteristics of the stimuli, including the balls and the sites on the face. When the subject's finger was used to script upon another's face, there were significant differences among or between the sites. When another person scripted upon the subject's face there were no significant differences among any of the sites. The results are discussed considering mode of stimulation and tissue mechanics.
Cheek↗
Effects of temperature on the subjective magnitude of vibration.
Absolute magnitude estimation (AME) was used to determine the effects of skin temperature on the subjective magnitude of vibration delivered to the thenar eminence of the right hand. Measurements were made at three frequencies chosen to selectively activate cutaneous mechanoreceptor channels, namely NP I and NP III (Meissner and Merkel cell-neurite receptors, respectively) at 15 Hz, Pacinian (250 Hz, 400 Hz) and NP III (Ruffini endings) at 400 Hz. Skin temperatures at 15, 20 and 40 degrees C were tested at 11 suprathreshold displacement levels. It was concluded that the subjective magnitude of vibration is influenced by temperature in the Pacinian channel, but in the NP I and NP III channels the temperature of the skin did not have an effect upon judgements of subjective magnitude. This is consistent with earlier work by Verrillo and Bolanowski (J Acoust Soc Am 80: 528-532, 1986) and Bolanowski et al. (J Acoust Soc Am 84: 1680-1694, 1988); both studies show only modest effects of temperature at threshold at frequencies below approximately 40 Hz.
Adult↗
Effect of aging on the subjective magnitude of vibration.
Two groups of subjects were tested using the method of Absolute Magnitude Estimation (AME) to determine the effect of age on the subjective intensity of vibration delivered to the skin of the hand. The mean age of the younger group was 23.5 years and that of the older group was 68.6 years. Average thresholds in the older group were higher in both the Pacinian (P) and non-Pacinian channel (NP II). The subjective magnitude of vibration was substantially lower at all intensities in the older group. Individual results clearly showed that the P channel saturates near the detection threshold of the NP II channel.
Adult↗
A four-channel analysis of the tactile sensitivity of the fingertip: frequency selectivity, spatial summation, and temporal summation.
Thresholds were measured for the detection of vibratory stimuli of variable frequency and duration applied to the index fingertip and thenar eminence through contactors of different sizes. The effects of stimulus frequency could be accounted for by the frequency characteristics of the Pacinian (P), non-Pacinian (NP) I, and NP III channels previously determined for the thenar eminence (Bolanowski et al., J Acoust Soc Am 84: 1680-1694, 1988; Gescheider et al., Somatosens Mot Res 18: 191-201, 2001). The effect of changing stimulus duration was also essentially identical for both sites, demonstrating the same amount of temporal summation in the P channel. Although the effect of changing stimulus frequency and changing stimulus duration did not differ for the two sites, the effect of varying the size of the stimulus was significantly greater for the thenar eminence than for the fingertip. The attenuated amount of spatial summation on the fingertip was interpreted as an indication that the mechanism of spatial summation consists of the operations of both neural integration and probability summation.
Adolescent↗
Effects of root or nerve destruction on vibrotactile sensitivity in trigeminal neuralgia.
Vibrotactile thresholds were determined at 7 frequencies between 25 and 300 Hz at the medial edge of the cheek in 11 patients who had been or were currently being treated for major trigeminal neuralgia, tic douloureux. A control group, comparable in age but without neural pathology, was also tested. Results indicate essentially no difference between normal and affected sides of the face prior to surgery. The drug carbamazepine (Tegretol), commonly used to control pain of trigeminal neuralgia, did not affect vibrotactile thresholds. Infraorbital neurectomy resulted in an initial loss of sensitivity at all frequencies, followed by a gradual return of sensation which reached preoperative levels at approximately one year. The return of sensitivity was followed by the return of neuralgia. Following alcoholic gasserian rhizolysis, low-frequency thresholds were elevated considerably as after neurectomy, but sensation above 100 Hz was lost completely. A return of high-frequency sensitivity accompanied the recurrence of pain in some patients who had been injected up to 13 years prior to testing. The results are discussed in terms of recent anatomical, electrophysiological, and clinical findings.
Adult↗