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Interhemispheric interaction between human dorsal premotor and contralateral primary motor cortex.
J Physiol. 2004 Nov 15; 561(Pt 1):331-8.JP

Abstract

We used transcranial magnetic stimulation (TMS) in a paired pulse protocol to investigate interhemispheric interactions between the right dorsal premotor (dPM) and left primary motor cortex (M1) using interstimulus intervals of 4, 6, 8, 10, 12, 16 and 20 ms in ten healthy subjects. A conditioning stimulus over right dPM at an intensity of either 90 or 110% resting motor threshold (RMT) suppressed motor-evoked potentials (MEPs) evoked in the first dorsal interosseous (FDI) muscle by stimulation of left M1. Maximum effects occurred for interstimulus intervals (ISIs) of 8-10 ms. There was no effect if the conditioning stimulus was applied 2.5 cm lateral, anterior or medial to dPM. The effect differed from previously described M1 interhemispheric inhibition in that the threshold for the latter was greater than 90% RMT, whereas stimulation of the dPM at the same intensity led to significant inhibition. In addition, voluntary contraction of the left FDI (i.e. contralateral to the conditioning TMS) enhanced interhemispheric inhibition from right M1 but had no effect on the inhibition from right dPM. Finally, conditioning to right dPM at 90% RMT reduced short-interval intracortical inhibition (SICI; at ISI = 2 ms) in left M1 whilst there was no effect if the conditioning stimulus was applied to right M1. We conclude that conditioning TMS over dPM has effects that differ from the previous pattern of interhemispheric inhibition described between bilateral M1s. This may reflect the existence of commissural fibres between dPM and contralateral M1 that may play a role in bimanual coordination.

Authors+Show Affiliations

Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London WC1N 3BG, UK.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

15459244

Citation

Mochizuki, Hitoshi, et al. "Interhemispheric Interaction Between Human Dorsal Premotor and Contralateral Primary Motor Cortex." The Journal of Physiology, vol. 561, no. Pt 1, 2004, pp. 331-8.
Mochizuki H, Huang YZ, Rothwell JC. Interhemispheric interaction between human dorsal premotor and contralateral primary motor cortex. J Physiol (Lond). 2004;561(Pt 1):331-8.
Mochizuki, H., Huang, Y. Z., & Rothwell, J. C. (2004). Interhemispheric interaction between human dorsal premotor and contralateral primary motor cortex. The Journal of Physiology, 561(Pt 1), 331-8.
Mochizuki H, Huang YZ, Rothwell JC. Interhemispheric Interaction Between Human Dorsal Premotor and Contralateral Primary Motor Cortex. J Physiol (Lond). 2004 Nov 15;561(Pt 1):331-8. PubMed PMID: 15459244.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Interhemispheric interaction between human dorsal premotor and contralateral primary motor cortex. AU - Mochizuki,Hitoshi, AU - Huang,Ying-Zu, AU - Rothwell,John C, Y1 - 2004/09/30/ PY - 2004/10/2/pubmed PY - 2005/4/7/medline PY - 2004/10/2/entrez SP - 331 EP - 8 JF - The Journal of physiology JO - J. Physiol. (Lond.) VL - 561 IS - Pt 1 N2 - We used transcranial magnetic stimulation (TMS) in a paired pulse protocol to investigate interhemispheric interactions between the right dorsal premotor (dPM) and left primary motor cortex (M1) using interstimulus intervals of 4, 6, 8, 10, 12, 16 and 20 ms in ten healthy subjects. A conditioning stimulus over right dPM at an intensity of either 90 or 110% resting motor threshold (RMT) suppressed motor-evoked potentials (MEPs) evoked in the first dorsal interosseous (FDI) muscle by stimulation of left M1. Maximum effects occurred for interstimulus intervals (ISIs) of 8-10 ms. There was no effect if the conditioning stimulus was applied 2.5 cm lateral, anterior or medial to dPM. The effect differed from previously described M1 interhemispheric inhibition in that the threshold for the latter was greater than 90% RMT, whereas stimulation of the dPM at the same intensity led to significant inhibition. In addition, voluntary contraction of the left FDI (i.e. contralateral to the conditioning TMS) enhanced interhemispheric inhibition from right M1 but had no effect on the inhibition from right dPM. Finally, conditioning to right dPM at 90% RMT reduced short-interval intracortical inhibition (SICI; at ISI = 2 ms) in left M1 whilst there was no effect if the conditioning stimulus was applied to right M1. We conclude that conditioning TMS over dPM has effects that differ from the previous pattern of interhemispheric inhibition described between bilateral M1s. This may reflect the existence of commissural fibres between dPM and contralateral M1 that may play a role in bimanual coordination. SN - 0022-3751 UR - https://www.unboundmedicine.com/medline/citation/15459244/Interhemispheric_interaction_between_human_dorsal_premotor_and_contralateral_primary_motor_cortex_ L2 - https://doi.org/10.1113/jphysiol.2004.072843 DB - PRIME DP - Unbound Medicine ER -