Abstract
1. Electromyographic responses have been recorded from human first dorsal interosseous muscle (FDI) in response to magnetic and transcutaneous electrical stimulation of the brain. 2. Following magnetic but not electrical stimulation of the brain, the recorded EMG response was larger when FDI was active during voluntary isometric index finger abduction than during a power grip. 3. In the same experiment, cutaneous reflex responses have been recorded from FDI following electrical stimulation of the digital nerves. The long-latency excitatory component at about 60 ms (E2) was larger when recorded during voluntary finger abduction than during a power grip. This difference in size of E2 with task bore no simple relationship to the difference in size with task of the motor response to magnetic brain stimulation. 4. The results are discussed in relation to the presumed site of action of magnetic and electrical brain stimulation. It is concluded that the results may best be interpreted by assuming a higher level of cortical activity during a voluntary index finger abduction than during a grip and that this could in part explain the task-dependent changes in the long-latency response to cutaneous stimulation.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Buys E. J., Lemon R. N., Mantel G. W., Muir R. B. Selective facilitation of different hand muscles by single corticospinal neurones in the conscious monkey. J Physiol. 1986 Dec;381:529–549. doi: 10.1113/jphysiol.1986.sp016342. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Evans A. L., Harrison L. M., Stephens J. A. Task-dependent changes in cutaneous reflexes recorded from various muscles controlling finger movement in man. J Physiol. 1989 Nov;418:1–12. doi: 10.1113/jphysiol.1989.sp017825. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 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]
- Jenner J. R., Stephens J. A. Cutaneous reflex responses and their central nervous pathways studied in man. J Physiol. 1982 Dec;333:405–419. doi: 10.1113/jphysiol.1982.sp014461. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kernell D., Chien-Ping W. U. Responses of the pyramidal tract to stimulation of the baboon's motor cortex. J Physiol. 1967 Aug;191(3):653–672. doi: 10.1113/jphysiol.1967.sp008273. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lawrence D. G., Kuypers H. G. The functional organization of the motor system in the monkey. I. The effects of bilateral pyramidal lesions. Brain. 1968 Mar;91(1):1–14. doi: 10.1093/brain/91.1.1. [DOI] [PubMed] [Google Scholar]
- Muir R. B., Lemon R. N. Corticospinal neurons with a special role in precision grip. Brain Res. 1983 Feb 21;261(2):312–316. doi: 10.1016/0006-8993(83)90635-2. [DOI] [PubMed] [Google Scholar]