Cathodal transcranial direct current stimulation suppresses ipsilateral projections to presumed propriospinal neurons of the proximal upper limb

Bradnam, LV; Stinear, CM; Byblow, WD

Cathodal transcranial direct current stimulation suppresses ipsilateral projections to presumed propriospinal neurons of the proximal upper limb

Bradnam, LV

Stinear, CM Byblow, WD

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Publication Type:: Journal Article
Citation:: Journal of Neurophysiology, 2011, 105 (5), pp. 2582 - 2589
Issue Date:: 2011-05-01

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Field	Value	Language
dc.contributor.author	Bradnam, LV https://orcid.org/0000-0002-3067-0326	en_US
dc.contributor.author	Stinear, CM	en_US
dc.contributor.author	Byblow, WD	en_US
dc.date.issued	2011-05-01	en_US
dc.identifier.citation	Journal of Neurophysiology, 2011, 105 (5), pp. 2582 - 2589	en_US
dc.identifier.issn	0022-3077	en_US
dc.identifier.uri	http://hdl.handle.net/10453/110368
dc.description.abstract	This study investigated whether cathodal transcranial direct current stimulation (c-tDCS) of left primary motor cortex (M1) modulates excitability of ipsilateral propriospinal premotoneurons (PNs) in healthy humans. Transcranial magnetic stimulation (TMS) of the right motor cortex was used to obtain motor evoked potentials (MEPs) from the left biceps brachii (BB) while participants maintained contraction of the left BB. To examine presumed PN excitability, left BB MEPs were compared with those conditioned by median nerve stimulation (MNS) at the left elbow. Interstimulus intervals between TMS and MNS were set to produce summation at the C3-C4 level of the spinal cord. MNS facilitated BB MEPs elicited at TMS intensities near active motor threshold but inhibited BB MEPs at slightly higher intensities, indicative of putative PN modulation. c-tDCS suppressed the facilitatory and inhibitory effects of MNS. Sham tDCS did not alter either component. There was no effect of c-tDCS and sham tDCS on nonconditioned left BB MEPs or on the ipsilateral silent period of left BB. Right first dorsal interosseous MEPs were suppressed by c-tDCS. These results indicate that M1 c-tDCS can be used to modulate excitability of ipsilateral projections to presumed PNs controlling the proximal arm muscle BB. This technique may hold promise for promoting motor recovery of proximal upper limb function after stroke. © 2011 the American Physiological Society.	en_US
dc.relation.ispartof	Journal of Neurophysiology	en_US
dc.relation.isbasedon	10.1152/jn.01084.2010	en_US
dc.subject.classification	Neurology & Neurosurgery	en_US
dc.subject.mesh	Arm	en_US
dc.subject.mesh	Motor Cortex	en_US
dc.subject.mesh	Spinal Nerves	en_US
dc.subject.mesh	Humans	en_US
dc.subject.mesh	Electromyography	en_US
dc.subject.mesh	Electrodes	en_US
dc.subject.mesh	Proprioception	en_US
dc.subject.mesh	Evoked Potentials, Motor	en_US
dc.subject.mesh	Adult	en_US
dc.subject.mesh	Middle Aged	en_US
dc.subject.mesh	Female	en_US
dc.subject.mesh	Male	en_US
dc.subject.mesh	Transcranial Magnetic Stimulation	en_US
dc.subject.mesh	Functional Laterality	en_US
dc.subject.mesh	Young Adult	en_US
dc.title	Cathodal transcranial direct current stimulation suppresses ipsilateral projections to presumed propriospinal neurons of the proximal upper limb	en_US
dc.type	Journal Article
utslib.citation.volume	5	en_US
utslib.citation.volume	105	en_US
utslib.for	110317 Physiotherapy	en_US
utslib.for	11 Medical and Health Sciences	en_US
utslib.for	17 Psychology and Cognitive Sciences	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Graduate School of Health
pubs.organisational-group	/University of Technology Sydney/Strength - CHT - Health Technologies
utslib.copyright.status	closed_access
pubs.issue	5	en_US
pubs.publication-status	Published	en_US
pubs.volume	105	en_US

Abstract:

This study investigated whether cathodal transcranial direct current stimulation (c-tDCS) of left primary motor cortex (M1) modulates excitability of ipsilateral propriospinal premotoneurons (PNs) in healthy humans. Transcranial magnetic stimulation (TMS) of the right motor cortex was used to obtain motor evoked potentials (MEPs) from the left biceps brachii (BB) while participants maintained contraction of the left BB. To examine presumed PN excitability, left BB MEPs were compared with those conditioned by median nerve stimulation (MNS) at the left elbow. Interstimulus intervals between TMS and MNS were set to produce summation at the C3-C4 level of the spinal cord. MNS facilitated BB MEPs elicited at TMS intensities near active motor threshold but inhibited BB MEPs at slightly higher intensities, indicative of putative PN modulation. c-tDCS suppressed the facilitatory and inhibitory effects of MNS. Sham tDCS did not alter either component. There was no effect of c-tDCS and sham tDCS on nonconditioned left BB MEPs or on the ipsilateral silent period of left BB. Right first dorsal interosseous MEPs were suppressed by c-tDCS. These results indicate that M1 c-tDCS can be used to modulate excitability of ipsilateral projections to presumed PNs controlling the proximal arm muscle BB. This technique may hold promise for promoting motor recovery of proximal upper limb function after stroke. © 2011 the American Physiological Society.

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http://hdl.handle.net/10453/110368