Abstract
1. The ability to tell the direction of a motion across the skin deserve attention for being an easily observed function which provides a sensitive test for disturbances of the peripheral and central nervous systems. The mode of operation, on the other hand, of this tactile directional sensibility is still uncertain. 2. The dependence of directional sensibility on the contact load and distance of movement of a blunt metal tip, has now been determined for the skin of the forearm of normal subjects with the two-alternative forced-choice method. The testing was done under two conditions: elbow bent or straight. Straightening of the arm always reduced the accuracy of the directional sensibility. It also caused measurable changes of cutaneous mechanical properties, which presumably decreased the reliability of afferent information about lateral distension. 3. The average accuracy of the directional sensibility was found to be correlated linearly to the logarithm of the contact load, and straightening of the arm decreased the accuracy for each load by corresponding amounts. Similar relationships were found between the accuracy and the distance of movement. 4. Straightening of the arm did not cause any significant average reduction of the contact threshold for point stimulation of the same receptive field. A consistently lowered contact sensitivity, however, was observed for some of the subjects, which may have contributed to the reduction of the directional sensibility in these cases. 5. Correct directional estimations of the movement of the metal tip were obtained for a distance which was a fifth of the shortest distance for a corresponding estimation of the movement of a frictionless stimulus. The findings thus indicated that the friction between a moving object and the underlying skin, which can be mediated via stretch-sensitive cutaneous receptors, is critical for the determination of its direction of motion. 6. The present observations and previous observations by various authors are suggested to indicate that typical tactile directional sensibility depends on parallel processing of direction-selective data, and spatial data expressed as a function of time.
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- Bender M. B., Stacy C., Cohen J. Agraphesthesia. A disorder of directional cutaneous kinesthesia or a disorientation in cutaneous space. J Neurol Sci. 1982 Mar;53(3):531–555. doi: 10.1016/0022-510x(82)90249-0. [DOI] [PubMed] [Google Scholar]
- Berardesca E., Farinelli N., Rabbiosi G., Maibach H. I. Skin bioengineering in the noninvasive assessment of cutaneous aging. Dermatologica. 1991;182(1):1–6. doi: 10.1159/000247727. [DOI] [PubMed] [Google Scholar]
- Cua A. B., Wilhelm K. P., Maibach H. I. Elastic properties of human skin: relation to age, sex, and anatomical region. Arch Dermatol Res. 1990;282(5):283–288. doi: 10.1007/BF00375720. [DOI] [PubMed] [Google Scholar]
- Dreyer D. A., Hollins M., Whitsel B. L. Factors influencing cutaneous directional sensitivity. Sens Processes. 1978 Jun;2(2):71–79. [PubMed] [Google Scholar]
- Edin B. B., Abbs J. H. Finger movement responses of cutaneous mechanoreceptors in the dorsal skin of the human hand. J Neurophysiol. 1991 Mar;65(3):657–670. doi: 10.1152/jn.1991.65.3.657. [DOI] [PubMed] [Google Scholar]
- Gescheider G. A. Psychophysical scaling. Annu Rev Psychol. 1988;39:169–200. doi: 10.1146/annurev.ps.39.020188.001125. [DOI] [PubMed] [Google Scholar]
- Goodwin A. W., Morley J. W. Sinusoidal movement of a grating across the monkey's fingerpad: effect of contact angle and force of the grating on afferent fiber responses. J Neurosci. 1987 Jul;7(7):2192–2202. doi: 10.1523/JNEUROSCI.07-07-02192.1987. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hankey G. J., Edis R. H. The utility of testing tactile perception of direction of scratch as a sensitive clinical sign of posterior column dysfunction in spinal cord disorders. J Neurol Neurosurg Psychiatry. 1989 Mar;52(3):395–398. doi: 10.1136/jnnp.52.3.395. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Norrsell U. Defects in tactile directional sensitivity after forebrain commissurotomy in man. Nature. 1973 Sep 7;245(5419):41–42. doi: 10.1038/245041a0. [DOI] [PubMed] [Google Scholar]
- Norrsell U., Olausson H. Human, tactile, directional sensibility and its peripheral origins. Acta Physiol Scand. 1992 Feb;144(2):155–161. doi: 10.1111/j.1748-1716.1992.tb09280.x. [DOI] [PubMed] [Google Scholar]
- Pubols B. H., Jr Factors affecting cutaneous mechanoreceptor response. I. Constant-force versus constant-displacement stimulation. J Neurophysiol. 1982 Mar;47(3):515–529. doi: 10.1152/jn.1982.47.3.515. [DOI] [PubMed] [Google Scholar]
- Pubols B. H., Jr, Pubols L. M. Tactile receptor discharge and mechanical properties of glabrous skin. Fed Proc. 1983 Jun;42(9):2528–2535. [PubMed] [Google Scholar]
- Sekuler R., Nash D., Armstrong R. Sensitive, objective procedure for evaluating response to light touch. Neurology. 1973 Dec;23(12):1282–1291. doi: 10.1212/wnl.23.12.1282. [DOI] [PubMed] [Google Scholar]
- Wall P. D., Noordenbos W. Sensory functions which remain in man after complete transection of dorsal columns. Brain. 1977 Dec;100(4):641–653. doi: 10.1093/brain/100.4.641. [DOI] [PubMed] [Google Scholar]