title: Magnitude estimates for electrical pulses: evidence for two neural mechanisms.
abstract: The hypothesis that there are two neural mechanisms for electrocutaneous stimulation--one that is sensitive to low current and is adaptive to repeated stimulation and another that is responsive to high current and is less adaptive--was tested in a control and four main experiments. In the main experiments, magnitude estimates obtained for single electrical pulses (of 2-msec duration) were described by a simple power function for each combination of high- and low-current levels and 10 trial blocks. The results were: (1) The slope of the power function for low current was steeper than was that for high current; (2) for low current, the intercept of the power function decreased with increasing block, whereas for high current, it remained constant over blocks; (3) this decrease of the intercept for low current disappeared when judgmental blocks were separated by a rest period of 8 min; (4) the modulus did not affect the slope; (5) for a large modulus combined with low current, the intercept decreased rapidly over trial blocks, whereas for a small modulus combined with high current, the intercept increased over trial blocks. The first four findings support the two-mechanism hypothesis, but the last one may also be interpretable in terms of the regression to absolute scale values.
authors.forename: A
authors.initials: A
authors.lastname: Higashiyama
authors.forename: T
authors.initials: T
authors.lastname: Tashiro
mesh_terms: D000293:Adolescent; D000328:Adult; D001143:Arousal / Q000502:physiology*; D004558:Electric Stimulation; D006801:Humans; D009619:Nociceptors / Q000502:physiology*; D012684:Sensory Thresholds; D012867:Skin / Q000294:innervation; D014459:Ulnar Nerve / Q000502:physiology*