Whole-hand water flow stimulation increases motor cortical excitability: a study of transcranial magnetic stimulation and movement-related cortical potentials

Abstract

Maruyama A. Whole-hand water flow stimulation increases motor cortical excitability: a study of transcranial magnetic stimulation and movement-related cortical potentials. J Neurophysiol 113: 822-833, 2015. First published November 5, 2014 doi:10.1152/jn.00161.2014.-Previous studies examining the influence of afferent stimulation on corticospinal excitability have demonstrated that the intensity of afferent stimulation and the nature of the afferents targeted (cutaneous/proprioceptive) determine the effects. In this study, we assessed the effects of whole-hand water immersion (WI) and water flow stimulation (WF) on corticospinal excitability and intracortical circuits by measuring motor evoked potential (MEP) recruitment curves and conditioned MEP amplitudes. We further investigated whether whole-hand WF modulated movement-related cortical activity. Ten healthy subjects participated in three experiments, comprising the immersion of participants' right hands with (whole-hand WF) or without (whole-hand WI) water flow, and no immersion (control). We evaluated MEP recruitment curves produced by a single transcranial magnetic stimulation (TMS) pulse at increasing stimulus intensities, short-interval intracortical inhibition (SICI), and intracortical facilitation (ICF) using the paired TMS technique before and after 15 min of intervention. Movement-related cortical potentials (MRCPs) were evaluated to examine primary motor cortex, supplementary motor area, and somatosensory cortex excitability upon movement before and after whole-hand WF. After wholehand WF, the slope of the MEP recruitment curve significantly increased, whereas SICI decreased and ICF increased in the contralateral motor cortex. The amplitude of the Bereitschaftspotential, negative slope, and motor potential of MRCPs significantly increased after whole-hand WF. We demonstrated that whole-hand WF increased corticospinal excitability, decreased SICI, and increased ICF, although whole-hand WI did not change corticospinal excitability and intracortical circuits. Whole-hand WF modulated movement-related cortical activity, increasing motor cortex activation for the planning and execution of voluntary movements.whole-hand water flow stimulation; primary motor cortex; corticospinal excitability; intracortical circuit; movement-related cortical potentials

Quantification of Movement-Related EEG Correlates Associated with Motor Training: A Study on Movement-Related Cortical Potentials and Sensorimotor Rhythms

“…The increase in negativity could be due to an increase in cortical excitability, which has been shown after hand motor skill training where improvements in performance were observed (Pascual-Leone et al, 1995 ). This hypothesis is supported by previous studies that have shown that increases in MRCP amplitude reflect increased cortical excitability (Birbaumer et al, 1990 ; Sato et al, 2015 ). It should be noted, however, that it also has been shown that the MRCP amplitude is inversely correlated with the amplitude of the TMS-elicited motor evoked potential (Lu et al, 2009 ).…”

“…A number of studies have reported the effect of induction of plasticity, motor training or skill acquisition on the amplitude of the MRCP segments with conflicting results. Increased amplitudes have both been associated with increased and decreased cortical excitability (Birbaumer et al, 1990 ; Rossi et al, 2000 ; Holler et al, 2006 ; Lu et al, 2009 , 2011 ; de Tommaso et al, 2012 ; Thacker et al, 2014 ; Sato et al, 2015 ), which is also associated with motor skill acquisition (Pascual-Leone et al, 1995 ). In studies investigating motor skill training specifically, the MRCP amplitude has been reported to increase and decrease as well (Taylor, 1978 ; Lang et al, 1983 , 1986 ; Niemann et al, 1991 ; Staines et al, 2002 ; Chiang et al, 2004 ; Smith and Staines, 2006 , 2010 , 2012 ; Wright et al, 2012a ).…”

Movement-related potentials in Parkinson’s disease

“…A great potential for further research of MRPs in PD and also in healthy controls lies in combining different methodologies -EEG and imaging (Nguyen et al , 2014, Plichta et al , 2013, transcranial magnetic stimulation (TMS) (de Tommaso et al , 2012, Sato et al , 2015, or MEG -since every technique has strengths and drawbacks. Furthermore, most of the studies completed to date have used a limited number of electrodes restricted to the central and frontocentral motor regions of the scalp to record MRPs.…”

Nonpainful wide-area compression inhibits experimental pain

“… 20 , 43 , 54 Increase in M1 excitability was also reported in response to large-area non-noxious somatosensory stimuli. This was demonstrated by reduced motor activity threshold, increased amplitude of motor-evoked potentials, and increased intracortical facilitation in response to whole-hand or whole-body water flow stimulation 60 , 61 and in response to whole-hand mesh-flow electrical stimulation. 23 , 24 Thus, the theoretical increase in M1 excitability in large-body compression can be attributed to CIA in our study.…”