PubMed Health⌕ Search

Biomedical subjects

G A Gescheider

Publications and source records attributed to G A Gescheider.

At least 55 records · Page 3Linked to original sources
PubMed1978

The effects of a surround on vibrotactile thresholds.

Psychophysical thresholds for the detection of vibration on the thenar eminence were measured as a function of stimulus frequency. As has been found in earlier studies, the threshold functions had two separate branches: one relatively flat branch at low frequencies and a U-shaped branch at higher frequencies. When the rigid surround which is used to confine the stimulus to the region of the vibrator contactor was removed and vibration was allowed to spread freely over the surface of the skin, thresholds along the relatively flat segment of the curve increased while thresholds along the U-shaped segment decreased. The results were interpreted in terms of the duplex model of mechanoreception.

Adult↗
PubMed1978

Psychophysical tuning curves in vibrotaction.

The frequency-response characteristics of channels used in human vibrotaction were studied by using a psychophysical tuning-curve paradigm derived from auditory research. Sinusodial 200-msec vibratory bursts delivered to the thenar eminence of the hand were detected in the presence of sinusodial maskers delivered to the same skin area either continuously or pulsed in forward masking. Psychophysical tuning curves were obtained by determining the intensity of maskers of varied frequency necessary to mask a 10-dB SL test stimulus of fixed frequency. The results support the notion that at least two independent channels operate in human vibrotaction. There was no evidence for frequency selective mechanisms other than those at the periphery. Psychophysical tuning curves were similar to neural tuning curves for individual cutaneous mechanoreceptors.

Adult↗
PubMed1977

Enhancement of vibrotactile sensation magnitude and predictions from the duplex model of mechanoreception.

The degree to which the sensation magnitude of a vibrotactile stimulus is enhanced by a prior stimulus was studied for vibration of the thenar eminence of the right hand. Enhancement was measured by a psychophysical matching procedure in which two brief stimuli separated by a variable time interval were presented to the skin and the subject adjusted a third stimulus to match the sensation magnitude of the second stimulus. By this procedure, it is possible to determine functional relationships between enhancement and the time interval between stimuli, the intensity of the stimuli, and the frequency of the stimuli. The results were consistent with the duplex model of mechanoreception.

Differential Threshold↗
PubMed1976

Evidence in support of the duplex theory of mechanoreception.

Psychophysical thresholds were measured as the frequency, size and duration of vibration on the thenar eminence was varied. The results supported the theory that there are two functionally distinct receptor systems in the skin for the perception of mechanical disturbances. Spatial and temporal summation were found for the detection of high- but not low-frequency stimuli. Furthermore, magnitude estimation data revealed that temporal summation occurs for the perception of high-frequency stimuli presented over a wide range of suprathershold values. On the other hand, temporal summation was absent for low frequency stimuli that were presented at 5, 10, 15, and 20 db above threshold.

Differential Threshold↗
PubMed1976

Effect of double ipsilateral stimulation on vibrotactile sensation magnitude.

The phenomena of enhancement and suppression of vibrotactile subjective magnitude were investigated using a matching procedure. Results support earlier reports for audition and vibrotaction suggesting that enhancement is a fundamental sensory process. The time course is described for suppression of stimuli delivered to several different to several different pats of the body. The results are consistent with earlier studies of vibrotactile masking at threshold levels.

Adult↗