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Four channels mediate the mechanical aspects of touch
S J Bolanowski1, G A Gescheider, R T Verrillo
1Center for Brain Research, University of Rochester Medical School, New York 14642.
The Journal of the Acoustical Society of America
|November 1, 1988
Summary
Four tactile sensation channels (P, NP I, NP II, and NP III) are identified in human skin, expanding our understanding of mechanoreception. These channels, corresponding to specific nerve fiber types, collectively enable vibration perception across a wide frequency range.
Area of Science:
- Neuroscience
- Somatosensory System
- Psychophysics
Background:
- Previous research identified four afferent fiber types (PC, RA, SA II, SA I) in glabrous skin.
- Only three fiber types were previously known to mediate tactile sensation.
Purpose of the Study:
- To present psychophysical evidence for four distinct tactile sensation channels (P, NP I, NP II, NP III).
- To define the fourth psychophysical channel (NP III) and its role in tactile perception.
- To correlate psychophysical channels with specific physiological nerve fiber types.
Main Methods:
- Selective masking of psychophysical channels.
- Modification of skin-surface temperature.
- Testing cutaneous sensitivity at low vibratory frequencies.
Main Results:
- The fourth psychophysical channel (NP III) was defined through experimentation.
- Four channels (P, NP I, NP II, NP III) work together to perceive vibrations from 0.4 to over 500 Hz.
- Each channel mediates specific frequency ranges and is linked to distinct nerve fiber types (P-PC, NP I-RA, NP II-SA II, NP III-SA I).
Conclusions:
- The four psychophysical channels have distinct physiological substrates in specific nerve fiber types.
- Partial overlap in channel sensitivities suggests simultaneous activation by suprathreshold stimuli.
- The combined input from these four channels likely determines the perceptual qualities of touch.