Summary
In awake human subjects, electrically induced A and C fibre responses were recorded from skin nerves with percutaneously inserted tungsten microelectrodes. By studying the influence of preferential blocking manoeuvres upon the nerve response, attempts were made to correlate activity in A and C fibres with sensation. Following injection of Lidocaine of a low concentration between the stimulating and recording sites the C waves were abolished before the A deflections. When mainly A fibre activity was recorded, weak electric skin shocks were still felt as a tactile sensation. A strong stimulus was perceived as a short, sometimes sharp blow but the prolonged pain had disappeared. The reverse order of blocking of the neural peaks occurred on application of pressure on the nerve between the stimulating and recording sites. The preferential blocking of the A response was accompanied by an impaired discrimination of weak stimuli. Stronger skin stimuli evoked sensations related to pain when mainly C fibre activity was recorded. Signs of fatigue in peripheral C fibre structures were observed during high frequency stimulation, and the reduction of the C response was accompanied by a decrease in the experience of burning pain. Centripetally conducted mass-activity in C fibres was distinguished from reflex activity in sympathethic fibres by differences in latencies and response patterns to repetitive stimuli applied inside and outside the innervation zone of the fascicle recorded from.
The simultaneous recording of afferent A and C discharges together with sympathetic reflex activity seems valuable in studying reactions to cutaneous timuli in conscious man.
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References
Bessou, P., Perl, E.R.: Response of cutaneous sensory units with unmyelinated fibres to noxious stimuli. J. Neurophysiol. 32, 1025–1043 (1969).
— Burgess, P.R., Perl, E.R., Taylor, C.B.: Dynamic properties of mechanoreceptors with unmyelinated (C) fibres. J. Neurophysiol. 34, 116–131 (1971).
Bishop, G.H., Heinbecker, P., O'Leary, J.L.: The function of the non-myelinated fibers of the dorsal roots. Amer. J. Physiol. 106, 647–669 (1933).
Buchthal, F., Guld, C., Rosenfalck, P.: Innervation zone and propagation velocity in human muscle. Acta physiol. scand. 35, 174–190 (1955).
Clark, D., Hughes, J., Gasser, H.S.: Afferent function in the group of nerve fibres of slowest conduction velocity. Amer. J. Physiol. 114, 69–76 (1935).
Collins, W.F., Nulsen, F.E., Randt, C.T.: Relation of peripheral nerve fiber size and sensation in man. Arch. Neurol. 3, 381–385 (1960).
Collins, W.F., Nulsen, F.E. Shealy, C.N.: Electrophysiological studies of peripheral and central pathways conducting pain. In: R.S. Knighton and P.R. Dumke (Eds.). Pain, 33–46. Boston: 1966.
Delius, W., Hagbarth, K.-E., Hongell, A., Wallin, B.G.: Manoeuvres affecting sympathetic outflow in human skin nerves. Acta physiol. scand. 84, 177–186 (1972).
Dyck, P.J., Lambert, E.H., Nichols, P.C.: Quantitative measurements of sensation related to compound action potential and number and sizes of myelinated and unmyelinated fibres of sural nerve in health, Friedrich's ataxia, hereditary sensory neuropathy and tabes dorsalis. Handbook of E.E.G. clin. Neurophysiol. 9, 83–118 (1972).
Gasser, H.S., Erlanger, J.: The rôle of fiber size in the establishment of a nerve block by pressure or cocaine. Amer. J. Physiol. 88, 581–591 (1929).
—: Conduction in nerves in relation to fiber types. Res. Publ. Ass. nerv. ment. Dis. 15, 35–59 (1935).
—: Pain-producing impulses in peripheral nerves. Res. Publ. Ass. nerv. ment. Dis. 23, 44–62 (1943).
Hagbarth, K.-E., Hongell, A., Hallin, R.G., Torebjörk, H.E.: Afferent impulses in median nerve fascicles evoked by tactile stimuli of the human hand. Brain Res. 24, 423–442 (1970).
— Hallin, R.G., Hongell, A., Torebjörk, H.E., Wallin, B.G.: General characteristics of sympathetic activity in human skin nerves. Acta physiol. scand. 84, 164–176 (1972).
Hallin, R.G., Torebjörk, H.E.: C-fibre components in electrically evoked compound potentials recorded from human median nerve fascicles in situ. Acta Soc. Med. Upsal. 75, 77–80 (1970a).
—: Afferent and efferent C units recorded from human skin nerves in situ. Acta Soc. Med. Upsal. 75, 277–281 (1970b).
—: Electrically induced A and C fibre responses in intact human skin nerves. Exp. Brain Res. 16, 309–320 (1973).
Heinbecker, P., Bishop, G.H., O'Leary, J.L.: Pain and touch fibers in peripheral nerves. Arch. Neurol. Psychiat. (Chic.) 29, 771–789 (1933).
—: Analysis of sensation in terms of the nerve impulse. Arch. Neurol. Psychiat. (Chic.) 31, 34–53 (1934).
Iggo, A.: A single unit analysis of cutaneous receptors with C afferent fibres. In: Ciba Foundation Study Group, No 1. Pain and Itch. London: Churchill pp. 41–56. 1959.
—: Cutaneous mechanoreceptors with afferent C fibres. J. Physiol. (Lond.) 152, 337–353 (1960).
Landau, W., Bishop, G.H.: Pain from dermal, periosteal and fascial endings and from inflammation. Arch. Neurol. Psychiat. (Chic.) 69, 490–504 (1953).
Rosenfalck, P.: Intra-and extracellular potential fields of active nerve and muscle fibres. Acta physiol. scand. Suppl. 321, 165 (1969).
Talbot, W.H., Darian-Smith, I., Kornhuber, H.H., Mountcastle, V.B.: The sense of fluttervibration: comparison of the human capacity with response patterns of mechanoreceptive afferents from the monkey hand. J. Neurophysiol. 31, 301–334 (1968).
Thunberg, T.: Bidrag till kännedomen om hudens sinnesfunktioner. Uppsala Läk.-Fören. Förh. B III häft. 8, 511–555 (1898).
—: Untersuchungen über die bei einer einzelnen momentanen Hautreizung auftretenden zwei stechenden Empfindungen. Scand. Arch. Physiol. 12, 394–442 (1901).
Torebjörk, H.E., Hallin, R.G.: Activity in C fibres correlated to perception in man. In: C. Hirsch and Y. Zotterman (Eds.). Cervical Pain, pp. 171–178, 1972.
Vallbo, Å.B., Hagbarth, K.-E.: Activity from skin mechanoreceptors recorded percutaneously in awake human subjects. Exp. Neurol. 21, 270–289 (1968).
Zotterman, Y.: Studies in the peripheral nervous mechanism of pain. Acta med. scand. 80, 185–242 (1933).
—: Touch, pain and tickling: an electrophysiological investigation on cutaneous nerves. J. Physiol. (Lond.) 95, 1–28 (1939).
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Torebjörk, H.E., Hallin, R.G. Perceptual changes accompanying controlled preferential blocking of A and C fibre responses in intact human skin nerves. Exp Brain Res 16, 321–332 (1973). https://doi.org/10.1007/BF00233334
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DOI: https://doi.org/10.1007/BF00233334