Oscillatory brain activity changes by anodal tDCS - An ECoG study on anesthetized beagles.

Measuring neuronal activity of transcranial direct current stimulation (tDCS) is essential for investigating tDCS in stimuli or after stimuli effects. The aim of this study was to investigate the oscillatory changes from anodal tDCS using electrocorticography (ECoG) on beagles. We applied 2 mA anodal tDCS and monitored the ECoG signals (32 channels, 512 Hz sampling rate) for 15 minutes in three anesthetized beagles. Then, we compared the power changes before, during, and after tDCS in six different bands (delta, theta, alpha, beta, low-gamma, and mid-gamma bands). The significantly increasing oscillatory changes from the mid-frequency bands (theta, alpha, and beta bands) to the high-frequency bands (low-gamma and mid-gamma bands) were observed. The results suggest that anodal tDCS may modulate high-frequency bands in the focal area of the cortex, which is relevant to electroencephalogram (EEG) studies.