TY  - JOUR
AU  - Cukić, Milena
AU  - Oommen, J.
AU  - Mutavdžić, D.
AU  - Jorgovanović, N.
AU  - Ljubisavljević, M.
PY  - 2013
UR  - http://intor.torlakinstitut.com/handle/123456789/392
AB  - The aim of this study was to examine whether single-pulse transcranial magnetic stimulation (spTMS) affects the pattern of corticospinal activity once voluntary drive has been restored after spTMS-induced EMG silence. We used fractal dimension (FD) to explore the 'complexity' of the electromyography (EMG) signal, and median frequency of the spectra (MDF) to examine changes in EMG spectral characteristics. FD and MDF of the raw EMG epochs immediately before were compared with those obtained from epochs after the EMG silence. Changes in FD and MDF after spTMS were examined with three levels of muscle contraction corresponding to weak (20-40 %), moderate (40-60 %) and strong (60-80 % of maximal voluntary contraction) and three intensities of stimulation set at 10, 20 and 30 % above the resting motor threshold. FD was calculated using the Higuchi fractal dimension algorithm. Finally, to discern the origin of FD changes between the CNS and muscle, we compared the effects of spTMS with the effects of peripheral nerve stimulation (PNS) on FD and MDF. The results show that spTMS induced significant decrease in both FD and MDF of EMG signal after stimulation. PNS did not have any significant effects on FD nor MDF. Changes in TMS intensity did not have any significant effect on FD or MDF after stimulation nor had the strength of muscle contraction. However, increase in contraction strength decreased FD before stimulation but only between weak and moderate contraction. The results suggest that the effects of spTMS on corticospinal activity, underlying voluntary motor output, outlast the TMS stimulus. It appears that the complexity of the EMG signal is reduced after spTMS, suggesting that TMS alters the dynamics of the ongoing corticospinal activity most likely temporarily synchronizing the neural network activity. Further studies are needed to confirm whether observed changes after TMS occur at the cortical level.
PB  - Springer, New York
T2  - Experimental Brain Research
T1  - The effect of single-pulse transcranial magnetic stimulation and peripheral nerve stimulation on complexity of EMG signal: fractal analysis
EP  - 104
IS  - 1
SP  - 97
VL  - 228
DO  - 10.1007/s00221-013-3541-1
ER  - 

@article{
author = "Cukić, Milena and Oommen, J. and Mutavdžić, D. and Jorgovanović, N. and Ljubisavljević, M.",
year = "2013",
abstract = "The aim of this study was to examine whether single-pulse transcranial magnetic stimulation (spTMS) affects the pattern of corticospinal activity once voluntary drive has been restored after spTMS-induced EMG silence. We used fractal dimension (FD) to explore the 'complexity' of the electromyography (EMG) signal, and median frequency of the spectra (MDF) to examine changes in EMG spectral characteristics. FD and MDF of the raw EMG epochs immediately before were compared with those obtained from epochs after the EMG silence. Changes in FD and MDF after spTMS were examined with three levels of muscle contraction corresponding to weak (20-40 %), moderate (40-60 %) and strong (60-80 % of maximal voluntary contraction) and three intensities of stimulation set at 10, 20 and 30 % above the resting motor threshold. FD was calculated using the Higuchi fractal dimension algorithm. Finally, to discern the origin of FD changes between the CNS and muscle, we compared the effects of spTMS with the effects of peripheral nerve stimulation (PNS) on FD and MDF. The results show that spTMS induced significant decrease in both FD and MDF of EMG signal after stimulation. PNS did not have any significant effects on FD nor MDF. Changes in TMS intensity did not have any significant effect on FD or MDF after stimulation nor had the strength of muscle contraction. However, increase in contraction strength decreased FD before stimulation but only between weak and moderate contraction. The results suggest that the effects of spTMS on corticospinal activity, underlying voluntary motor output, outlast the TMS stimulus. It appears that the complexity of the EMG signal is reduced after spTMS, suggesting that TMS alters the dynamics of the ongoing corticospinal activity most likely temporarily synchronizing the neural network activity. Further studies are needed to confirm whether observed changes after TMS occur at the cortical level.",
publisher = "Springer, New York",
journal = "Experimental Brain Research",
title = "The effect of single-pulse transcranial magnetic stimulation and peripheral nerve stimulation on complexity of EMG signal: fractal analysis",
pages = "104-97",
number = "1",
volume = "228",
doi = "10.1007/s00221-013-3541-1"
}

Cukić, M., Oommen, J., Mutavdžić, D., Jorgovanović, N.,& Ljubisavljević, M.. (2013). The effect of single-pulse transcranial magnetic stimulation and peripheral nerve stimulation on complexity of EMG signal: fractal analysis. in Experimental Brain Research
Springer, New York., 228(1), 97-104.
https://doi.org/10.1007/s00221-013-3541-1

Cukić M, Oommen J, Mutavdžić D, Jorgovanović N, Ljubisavljević M. The effect of single-pulse transcranial magnetic stimulation and peripheral nerve stimulation on complexity of EMG signal: fractal analysis. in Experimental Brain Research. 2013;228(1):97-104.
doi:10.1007/s00221-013-3541-1 .

Cukić, Milena, Oommen, J., Mutavdžić, D., Jorgovanović, N., Ljubisavljević, M., "The effect of single-pulse transcranial magnetic stimulation and peripheral nerve stimulation on complexity of EMG signal: fractal analysis" in Experimental Brain Research, 228, no. 1 (2013):97-104,
https://doi.org/10.1007/s00221-013-3541-1 . .