Frequency-dependent effects of oscillatory-tDCS on EEG oscillations: A study with better oscillation detection method (BOSC)

Aurora D'Atri, E. De Simoni, M. Gorgoni, M. Ferrara, F. Ferlazzo, P. M. Rossini, L. De Gennaro

Research output: Contribution to journalArticlepeer-review


Oscillating transcranial direct current stimulation (osc-tDCS) modulates the spontaneous brain activity in a frequency-specific manner. Most studies evaluated cortical effects of osc-tDCS through measures spectral analysis, without differentiating components associated with rhythmic and non-rhythmic activity. Since osc-tDCS mainly affects brain oscillatory activity, our aim was to investigate on the specific changes of EEG oscillations following a frontal osc-tDCS at 0.8 and at 5 Hz. 20 healthy subjects (26.8 ± 2.5 years) participated in one of two experiments (Exp.1= 0.8-Hz tDCS, n= 10; Exp.2= 5-Hz tDCS, n= 10), consisting of 3 within-subject sessions: two active conditions with different stimulation polarity (anodal osc-tDCS, cathodal osc-tDCS), and a control condition (sham). EEG oscillatory components (28 cortical derivations) at the stimulation frequency were measured by the Better OSCillation detection method (BOSC). Variations between before and after the osc-tDCS were compared between conditions as a function of polarity (anodal vs. cathodal vs. sham) and frequency (0.8 vs. 5 Hz) of stimulation. The main finding is a significant local increase of 0.81-Hz slow oscillations (F1,18=19.97; p=0.0004) and 5.3-Hz theta oscillations (F1,18=26.93; p= 0.0001) after 5 Hz compared to 0.8-Hz tDCS. Our study shows larger frequency-specific and cross-frequency effects of 5-Hz compared to 0.8-Hz stimulation, not revealed by conventional FFT analyses. This finding is consistent with a more effective induction of EEG synchronization during wakefulness by means of a stimulation in the theta range, and it suggests to combine measurement of EEG power and EEG oscillations in future studies involving transcranial stimulations.

Original languageEnglish
JournalArchives Italiennes de Biologie
Issue number2-3
Publication statusPublished - 2015


  • Better OSCillation method (BOSC)
  • EEG oscillations
  • EEG synchronization
  • Frontal cortex
  • Resting EEG
  • Transcranial direct current stimulation (tDCS)

ASJC Scopus subject areas

  • Medicine(all)
  • Cell Biology
  • Physiology


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