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The effect of 10 Hz transcranial alternating current stimulation (tACS) on corticomuscular coherence.

Wach C, Krause V, Moliadze V, Paulus W, Schnitzler A, Pollok B - Front Hum Neurosci (2013)

Bottom Line: However, the neurophysiological changes underlying these effects are not entirely understood yet.The data suggest that 10 Hz tACS significantly reduced low gamma band CMC during isometric contraction.Rather, the findings suggest cross-frequency interplay between alpha and low gamma band activity modulating functional interaction between motor cortex and muscle.

View Article: PubMed Central - PubMed

Affiliation: Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich-Heine-University Duesseldorf, Germany ; Department of Neurology, Medical Faculty, Duesseldorf University Hospital Duesseldorf, Germany.

ABSTRACT
Synchronous oscillatory activity at alpha (8-12 Hz), beta (13-30 Hz), and gamma (30-90 Hz) frequencies is assumed to play a key role for motor control. Corticomuscular coherence (CMC) represents an established measure of the pyramidal system's integrity. Transcranial alternating current stimulation (tACS) offers the possibility to modulate ongoing oscillatory activity. Behaviorally, 20 Hz tACS in healthy subjects has been shown to result in movement slowing. However, the neurophysiological changes underlying these effects are not entirely understood yet. The present study aimed at ascertaining the effects of tACS at 10 and 20 Hz in healthy subjects on CMC and local power of the primary sensorimotor cortex. Neuromagnetic activity was recorded during isometric contraction before and at two time points (2-10 min and 30-38 min) after tACS of the left primary motor cortex (M1), using a 306 channel whole head magnetoencephalography (MEG) system. Additionally, electromyography (EMG) of the right extensor digitorum communis (EDC) muscle was measured. TACS was applied at 10 and 20 Hz, respectively, for 10 min at 1 mA. Sham stimulation served as control condition. The data suggest that 10 Hz tACS significantly reduced low gamma band CMC during isometric contraction. This implies that tACS does not necessarily cause effects at stimulation frequency. Rather, the findings suggest cross-frequency interplay between alpha and low gamma band activity modulating functional interaction between motor cortex and muscle.

No MeSH data available.


Related in: MedlinePlus

Averaged sensor-plot for CMC within the low gamma band (30–45 Hz) prior to and post 10 Hz tACS. The insert indicates the sensor with the largest amplitude change following tACS.
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Figure 3: Averaged sensor-plot for CMC within the low gamma band (30–45 Hz) prior to and post 10 Hz tACS. The insert indicates the sensor with the largest amplitude change following tACS.

Mentions: Concerning relative changes of CMC amplitude there was no significant main effect or interaction in the beta band (p > 0.11). In the low gamma band (Figure 3 depicts the sensor-plot) a significant main effect of factor stimulation was revealed [F(2, 22) = 3.72, p = 0.041; Figure 4] suggesting that after 10 Hz tACS contralateral CMC amplitude was significantly reduced as compared to 20 Hz tACS and sham [10 Hz tACS vs. sham: t(35) = −3.09, p = 0.008; 10 Hz tACS vs. 20 Hz tACS: t(35) = −2.85, p = 0.021]. The main effect of factor stimulation is summarized in Figure 5. Neither a main effect of factor time [F(1, 11) = 0.72, p = 0.41] nor the stimulation x time interaction [F(2, 22) = 0.52, p = 0.60] was found to be significant.


The effect of 10 Hz transcranial alternating current stimulation (tACS) on corticomuscular coherence.

Wach C, Krause V, Moliadze V, Paulus W, Schnitzler A, Pollok B - Front Hum Neurosci (2013)

Averaged sensor-plot for CMC within the low gamma band (30–45 Hz) prior to and post 10 Hz tACS. The insert indicates the sensor with the largest amplitude change following tACS.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3756226&req=5

Figure 3: Averaged sensor-plot for CMC within the low gamma band (30–45 Hz) prior to and post 10 Hz tACS. The insert indicates the sensor with the largest amplitude change following tACS.
Mentions: Concerning relative changes of CMC amplitude there was no significant main effect or interaction in the beta band (p > 0.11). In the low gamma band (Figure 3 depicts the sensor-plot) a significant main effect of factor stimulation was revealed [F(2, 22) = 3.72, p = 0.041; Figure 4] suggesting that after 10 Hz tACS contralateral CMC amplitude was significantly reduced as compared to 20 Hz tACS and sham [10 Hz tACS vs. sham: t(35) = −3.09, p = 0.008; 10 Hz tACS vs. 20 Hz tACS: t(35) = −2.85, p = 0.021]. The main effect of factor stimulation is summarized in Figure 5. Neither a main effect of factor time [F(1, 11) = 0.72, p = 0.41] nor the stimulation x time interaction [F(2, 22) = 0.52, p = 0.60] was found to be significant.

Bottom Line: However, the neurophysiological changes underlying these effects are not entirely understood yet.The data suggest that 10 Hz tACS significantly reduced low gamma band CMC during isometric contraction.Rather, the findings suggest cross-frequency interplay between alpha and low gamma band activity modulating functional interaction between motor cortex and muscle.

View Article: PubMed Central - PubMed

Affiliation: Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich-Heine-University Duesseldorf, Germany ; Department of Neurology, Medical Faculty, Duesseldorf University Hospital Duesseldorf, Germany.

ABSTRACT
Synchronous oscillatory activity at alpha (8-12 Hz), beta (13-30 Hz), and gamma (30-90 Hz) frequencies is assumed to play a key role for motor control. Corticomuscular coherence (CMC) represents an established measure of the pyramidal system's integrity. Transcranial alternating current stimulation (tACS) offers the possibility to modulate ongoing oscillatory activity. Behaviorally, 20 Hz tACS in healthy subjects has been shown to result in movement slowing. However, the neurophysiological changes underlying these effects are not entirely understood yet. The present study aimed at ascertaining the effects of tACS at 10 and 20 Hz in healthy subjects on CMC and local power of the primary sensorimotor cortex. Neuromagnetic activity was recorded during isometric contraction before and at two time points (2-10 min and 30-38 min) after tACS of the left primary motor cortex (M1), using a 306 channel whole head magnetoencephalography (MEG) system. Additionally, electromyography (EMG) of the right extensor digitorum communis (EDC) muscle was measured. TACS was applied at 10 and 20 Hz, respectively, for 10 min at 1 mA. Sham stimulation served as control condition. The data suggest that 10 Hz tACS significantly reduced low gamma band CMC during isometric contraction. This implies that tACS does not necessarily cause effects at stimulation frequency. Rather, the findings suggest cross-frequency interplay between alpha and low gamma band activity modulating functional interaction between motor cortex and muscle.

No MeSH data available.


Related in: MedlinePlus