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Effects of remote muscle contraction on transcranial magnetic stimulation-induced motor evoked potentials and silent periods in humans.
Clin Neurophysiol. 2007 Jun; 118(6):1204-12.CN

Abstract

OBJECTIVE

To determine to what extent tonic contraction of the testing muscle modulates the effect of remote muscle contraction on motor evoked potentials (MEPs) and cortical silent periods (CSPs) in resting and active proximal and distal muscles following transcranial magnetic stimulation (TMS). In addition, we tested whether the remote effect on MEP was observable when the test MEP was small.

METHODS

While performing tonic abductions of the first dorsal interosseous (FDI), flexor carpi radialis, or anterior deltoid muscles, subjects made phasic dorsiflexions of the right ankle at various forces. MEPs and CSPs were induced by separately optimized TMS intensities and locations in the left motor cortex and recorded electromyographically.

RESULTS

Phasic dorsiflexion increased MEP amplitude and shortened CSP duration in a dorsiflexion intensity-dependent manner in all muscles tested. At test MEPs <10% of Mmax, remote effects on MEP amplitude and CSP duration were significantly attenuated while the testing muscle was active.

CONCLUSIONS

Phasic contraction of remote muscles potentiates excitatory- and suppresses inhibitory intracortical neuronal pathways converging on corticospinal tract cells innervating the upper limb muscles even when they are active. However, the magnitude of the remote effect on MEP amplitude strongly depends on the test MEP amplitude.

SIGNIFICANCE

Although remote effects on MEP amplitude and CSP duration are observed even when the test muscle is active, the magnitude of the remote effect strongly depends on TMS intensity.

Authors+Show Affiliations

Division of Health and Sport Education, United Graduate School of Education, Tokyo Gakugei University, Chiba, Japan.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

17449319

Citation

Tazoe, Toshiki, et al. "Effects of Remote Muscle Contraction On Transcranial Magnetic Stimulation-induced Motor Evoked Potentials and Silent Periods in Humans." Clinical Neurophysiology : Official Journal of the International Federation of Clinical Neurophysiology, vol. 118, no. 6, 2007, pp. 1204-12.
Tazoe T, Sakamoto M, Nakajima T, et al. Effects of remote muscle contraction on transcranial magnetic stimulation-induced motor evoked potentials and silent periods in humans. Clin Neurophysiol. 2007;118(6):1204-12.
Tazoe, T., Sakamoto, M., Nakajima, T., Endoh, T., & Komiyama, T. (2007). Effects of remote muscle contraction on transcranial magnetic stimulation-induced motor evoked potentials and silent periods in humans. Clinical Neurophysiology : Official Journal of the International Federation of Clinical Neurophysiology, 118(6), 1204-12.
Tazoe T, et al. Effects of Remote Muscle Contraction On Transcranial Magnetic Stimulation-induced Motor Evoked Potentials and Silent Periods in Humans. Clin Neurophysiol. 2007;118(6):1204-12. PubMed PMID: 17449319.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Effects of remote muscle contraction on transcranial magnetic stimulation-induced motor evoked potentials and silent periods in humans. AU - Tazoe,Toshiki, AU - Sakamoto,Masanori, AU - Nakajima,Tsuyoshi, AU - Endoh,Takashi, AU - Komiyama,Tomoyoshi, Y1 - 2007/04/20/ PY - 2006/11/24/received PY - 2007/02/23/revised PY - 2007/03/08/accepted PY - 2007/4/24/pubmed PY - 2007/7/25/medline PY - 2007/4/24/entrez SP - 1204 EP - 12 JF - Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology JO - Clin Neurophysiol VL - 118 IS - 6 N2 - OBJECTIVE: To determine to what extent tonic contraction of the testing muscle modulates the effect of remote muscle contraction on motor evoked potentials (MEPs) and cortical silent periods (CSPs) in resting and active proximal and distal muscles following transcranial magnetic stimulation (TMS). In addition, we tested whether the remote effect on MEP was observable when the test MEP was small. METHODS: While performing tonic abductions of the first dorsal interosseous (FDI), flexor carpi radialis, or anterior deltoid muscles, subjects made phasic dorsiflexions of the right ankle at various forces. MEPs and CSPs were induced by separately optimized TMS intensities and locations in the left motor cortex and recorded electromyographically. RESULTS: Phasic dorsiflexion increased MEP amplitude and shortened CSP duration in a dorsiflexion intensity-dependent manner in all muscles tested. At test MEPs <10% of Mmax, remote effects on MEP amplitude and CSP duration were significantly attenuated while the testing muscle was active. CONCLUSIONS: Phasic contraction of remote muscles potentiates excitatory- and suppresses inhibitory intracortical neuronal pathways converging on corticospinal tract cells innervating the upper limb muscles even when they are active. However, the magnitude of the remote effect on MEP amplitude strongly depends on the test MEP amplitude. SIGNIFICANCE: Although remote effects on MEP amplitude and CSP duration are observed even when the test muscle is active, the magnitude of the remote effect strongly depends on TMS intensity. SN - 1388-2457 UR - https://www.unboundmedicine.com/medline/citation/17449319/Effects_of_remote_muscle_contraction_on_transcranial_magnetic_stimulation_induced_motor_evoked_potentials_and_silent_periods_in_humans_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S1388-2457(07)00096-X DB - PRIME DP - Unbound Medicine ER -