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. 1995 May 1;484(Pt 3):791–802. doi: 10.1113/jphysiol.1995.sp020704

Latency of effects evoked by electrical and magnetic brain stimulation in lower limb motoneurones in man.

J Nielsen 1, N Petersen 1, M Ballegaard 1
PMCID: PMC1157961  PMID: 7623293

Abstract

1. The latency of effects in the tibialis anterior (TA) and soleus (Sol) muscles evoked by electrical and magnetic stimulation of the motor cortex was evaluated in human subjects by H reflex testing. Post-stimulus time histograms (PSTHs) were established for the discharge of single voluntarily activated motor units and motor-evoked potentials (MEPs) in the surface electromyogram. 2. At rest both electrical and magnetic stimulation evoked an inhibition of the Sol H reflex at the lowest intensities of stimulation. In some subjects a facilitation with an earlier onset was seen when increasing the stimulation strength. When the anode for the electrical stimulation was placed at the vertex directly above the leg motor area, the inhibition or facilitation often had the same latency as when evoked by magnetic stimulation. However, when the anode was placed 2-3 cm lateral to the vertex, effects evoked by the electrical stimulus often occurred 1-2 ms earlier. 3. Short-latency peaks in the PSTH of the discharges of single TA motor units also tended to occur earlier when evoked by electrical stimulation with the anode lateral to the vertex than when evoked by magnetic stimulation or electrical stimulation with the anode at the vertex. 4. In one subject, near-maximal electrical stimulation evoked MEPs with a latency corresponding to that seen following stimulation of the brainstem by electrodes placed bilaterally over the mastoid processes approximately 16 cm more distal. Maximal magnetic stimulation, in contrast, never resulted in responses with a latency shorter than that seen with the weakest electrical stimuli at the vertex. 5. The initial facilitation of the Sol H reflex evoked by magnetic stimulation and by electrical anodal stimulation at the vertex increased when the subject performed a voluntary plantarflexion. In contrast, the earlier facilitation evoked by electrical anodal stimulation 2-3 cm lateral to the vertex had the same size both at rest and during contraction. 6. We suggest that magnetic stimulation and electrical anodal stimulation at the vertex may preferentially activate descending cortical cells at, or close to, the cell soma. The initial responses evoked by these two stimuli may therefore be influenced by the excitability of the cortical cells. On the other hand, electrical stimulation with the anode 2-3 cm lateral to the vertex seems to often activate the axons at a deeper level. The initial responses evoked by this type of stimulation may therefore not be influenced by the excitability of the cortical cells.

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Selected References

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  1. Amassian V. E., Quirk G. J., Stewart M. A comparison of corticospinal activation by magnetic coil and electrical stimulation of monkey motor cortex. Electroencephalogr Clin Neurophysiol. 1990 Sep-Oct;77(5):390–401. doi: 10.1016/0168-5597(90)90061-h. [DOI] [PubMed] [Google Scholar]
  2. Baker S. N., Olivier E., Lemon R. N. Recording an identified pyramidal volley evoked by transcranial magnetic stimulation in a conscious macaque monkey. Exp Brain Res. 1994;99(3):529–532. doi: 10.1007/BF00228989. [DOI] [PubMed] [Google Scholar]
  3. Burke D., Hicks R. G., Stephen J. P. Corticospinal volleys evoked by anodal and cathodal stimulation of the human motor cortex. J Physiol. 1990 Jun;425:283–299. doi: 10.1113/jphysiol.1990.sp018103. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Burke D., Hicks R., Gandevia S. C., Stephen J., Woodforth I., Crawford M. Direct comparison of corticospinal volleys in human subjects to transcranial magnetic and electrical stimulation. J Physiol. 1993 Oct;470:383–393. doi: 10.1113/jphysiol.1993.sp019864. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Datta A. K., Harrison L. M., Stephens J. A. Task-dependent changes in the size of response to magnetic brain stimulation in human first dorsal interosseous muscle. J Physiol. 1989 Nov;418:13–23. doi: 10.1113/jphysiol.1989.sp017826. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Day B. L., Dressler D., Maertens de Noordhout A., Marsden C. D., Nakashima K., Rothwell J. C., Thompson P. D. Electric and magnetic stimulation of human motor cortex: surface EMG and single motor unit responses. J Physiol. 1989 May;412:449–473. doi: 10.1113/jphysiol.1989.sp017626. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Day B. L., Riescher H., Struppler A., Rothwell J. C., Marsden C. D. Changes in the response to magnetic and electrical stimulation of the motor cortex following muscle stretch in man. J Physiol. 1991 Feb;433:41–57. doi: 10.1113/jphysiol.1991.sp018413. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Day B. L., Rothwell J. C., Thompson P. D., Dick J. P., Cowan J. M., Berardelli A., Marsden C. D. Motor cortex stimulation in intact man. 2. Multiple descending volleys. Brain. 1987 Oct;110(Pt 5):1191–1209. doi: 10.1093/brain/110.5.1191. [DOI] [PubMed] [Google Scholar]
  9. Edgley S. A., Eyre J. A., Lemon R. N., Miller S. Excitation of the corticospinal tract by electromagnetic and electrical stimulation of the scalp in the macaque monkey. J Physiol. 1990 Jun;425:301–320. doi: 10.1113/jphysiol.1990.sp018104. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Fournier E., Meunier S., Pierrot-Deseilligny E., Shindo M. Evidence for interneuronally mediated Ia excitatory effects to human quadriceps motoneurones. J Physiol. 1986 Aug;377:143–169. doi: 10.1113/jphysiol.1986.sp016179. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Hess C. W., Mills K. R., Murray N. M. Responses in small hand muscles from magnetic stimulation of the human brain. J Physiol. 1987 Jul;388:397–419. doi: 10.1113/jphysiol.1987.sp016621. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Iles J. F., Pisini J. V. Cortical modulation of transmission in spinal reflex pathways of man. J Physiol. 1992 Sep;455:425–446. doi: 10.1113/jphysiol.1992.sp019309. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Landau W. M., Bishop G. H., Clare M. H. Site of excitation in stimulation of the motor cortex. J Neurophysiol. 1965 Nov;28(6):1206–1222. doi: 10.1152/jn.1965.28.6.1206. [DOI] [PubMed] [Google Scholar]
  14. Maertens de Noordhout A., Rothwell J. C., Day B. L., Dressler D., Nakashima K., Thompson P. D., Marsden C. D. Effect of digital nerve stimuli on responses to electrical or magnetic stimulation of the human brain. J Physiol. 1992 Feb;447:535–548. doi: 10.1113/jphysiol.1992.sp019016. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Nielsen J., Petersen N., Deuschl G., Ballegaard M. Task-related changes in the effect of magnetic brain stimulation on spinal neurones in man. J Physiol. 1993 Nov;471:223–243. doi: 10.1113/jphysiol.1993.sp019899. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. PATTON H. D., AMASSIAN V. E. Single and multiple-unit analysis of cortical stage of pyramidal tract activation. J Neurophysiol. 1954 Jul;17(4):345–363. doi: 10.1152/jn.1954.17.4.345. [DOI] [PubMed] [Google Scholar]
  17. Priori A., Bertolasi L., Dressler D., Rothwell J. C., Day B. L., Thompson P. D., Marsden C. D. Transcranial electric and magnetic stimulation of the leg area of the human motor cortex: single motor unit and surface EMG responses in the tibialis anterior muscle. Electroencephalogr Clin Neurophysiol. 1993 Apr;89(2):131–137. doi: 10.1016/0168-5597(93)90095-7. [DOI] [PubMed] [Google Scholar]
  18. Saypol J. M., Roth B. J., Cohen L. G., Hallett M. A theoretical comparison of electric and magnetic stimulation of the brain. Ann Biomed Eng. 1991;19(3):317–328. doi: 10.1007/BF02584306. [DOI] [PubMed] [Google Scholar]
  19. Tofts P. S. The distribution of induced currents in magnetic stimulation of the nervous system. Phys Med Biol. 1990 Aug;35(8):1119–1128. doi: 10.1088/0031-9155/35/8/008. [DOI] [PubMed] [Google Scholar]
  20. Ugawa Y., Rothwell J. C., Day B. L., Thompson P. D., Marsden C. D. Percutaneous electrical stimulation of corticospinal pathways at the level of the pyramidal decussation in humans. Ann Neurol. 1991 Apr;29(4):418–427. doi: 10.1002/ana.410290413. [DOI] [PubMed] [Google Scholar]

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