TY - JOUR
T1 - Inhibition of motor cortex excitability with 15Hz transcranial alternating current stimulation (tACS)
AU - Zaghi, Soroush
AU - de Freitas Rezende, Larissa
AU - de Oliveira, Laís Machado
AU - El-Nazer, Rasheda
AU - Menning, Sanne
AU - Tadini, Laura
AU - Fregni, Felipe
N1 - Funding Information:
This publication was made possible with partial funding by grant number R21DK081773 from the National Institutes of Health and American Heart Association . Limited research funding support was also sponsored by Fisher Wallace Laboratories, LLC .
PY - 2010/8
Y1 - 2010/8
N2 - There remains a lack of solid evidence showing whether transcranial stimulation with weak alternating current (transcranial alternating current stimulation, tACS) can in fact induce significant neurophysiological effects. Previously, a study in which tACS was applied for 2 and 5min with current density=0.16-0.25A/m2 was unable to show robust effects on cortical excitability. Here we applied tACS at a significantly higher current density (0.80A/m2) for a considerably longer duration (20min) and were indeed able to demonstrate measurable changes to cortical excitability. Our results show that active 15Hz tACS of the motor cortex (electrodes placed at C3 and C4) significantly diminished the amplitude of motor evoked potentials and decreased intracortical facilitation (ICF) as compared to baseline and sham stimulation. In addition, we show that our method of sham tACS is a reliable control condition. These results support the notion that AC stimulation with weak currents can induce significant changes in brain excitability; in this case, 15Hz tACS led to a pattern of inhibition of cortical excitability. We propose that tACS may have a dampening effect on cortical networks and perhaps interfere with the temporal and spatial summation of weak subthreshold electric potentials.
AB - There remains a lack of solid evidence showing whether transcranial stimulation with weak alternating current (transcranial alternating current stimulation, tACS) can in fact induce significant neurophysiological effects. Previously, a study in which tACS was applied for 2 and 5min with current density=0.16-0.25A/m2 was unable to show robust effects on cortical excitability. Here we applied tACS at a significantly higher current density (0.80A/m2) for a considerably longer duration (20min) and were indeed able to demonstrate measurable changes to cortical excitability. Our results show that active 15Hz tACS of the motor cortex (electrodes placed at C3 and C4) significantly diminished the amplitude of motor evoked potentials and decreased intracortical facilitation (ICF) as compared to baseline and sham stimulation. In addition, we show that our method of sham tACS is a reliable control condition. These results support the notion that AC stimulation with weak currents can induce significant changes in brain excitability; in this case, 15Hz tACS led to a pattern of inhibition of cortical excitability. We propose that tACS may have a dampening effect on cortical networks and perhaps interfere with the temporal and spatial summation of weak subthreshold electric potentials.
KW - Cortical excitability
KW - Neuromodulation
KW - Non-invasive brain stimulation
KW - Safety
KW - Transcranial alternating current stimulation
KW - Transcranial electrical stimulation
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U2 - 10.1016/j.neulet.2010.05.060
DO - 10.1016/j.neulet.2010.05.060
M3 - Article
C2 - 20553804
AN - SCOPUS:77954145650
SN - 0304-3940
VL - 479
SP - 211
EP - 214
JO - Neuroscience letters
JF - Neuroscience letters
IS - 3
ER -