Fig. 1.

Scheme of the experimental paradigm and the three types of acoustic stimulation. (A) CR stimulation pattern: for acoustic CR neuromodulation, we employ the tonotopic organization of the primary auditory cortex (left panel, brain adapted from (Chittka and Brockmann, 2005) with kind permission of the authors) and deliver brief sinusoidal tones of different frequencies (pitch) f₁, …, f₄ equidistantly in time at a cycle repetition rate of 1.5 Hz (Tass et al., 2012a). Three CR cycles, each comprising a randomized sequence of four tones (right panel), were followed by two silent cycles without stimuli (“pause”). The 3 cycles stim ON-2 cycles stim OFF pattern was repeated periodically (Tass and Majtanik, 2006, Tass, 2003a, Tass, 2003b, Lysyansky et al., 2011). Right panel from (Tass et al., 2012a) with kind permission by the authors. Copyright by Forschungszentrum Jülich GmbH. (B) Experimental session: during the first 10 min of silence, the baseline EEG was recorded and the baseline VAS-L and VAS-A scores were obtained. Thereafter one of the three stimulation paradigms, i.e. acoustic CR neuromodulation, noisy CR-like stimulation or LFR stimulation, was performed for 16 min. VAS-L and VAS-A were obtained during stimulation at the end of this stimulation period. During the next period of silence EEG recording was obtained for 2 min followed by the VAS-L and VAS-A evaluation (2 min) and another 2 min of rest EEG recording. After each session participants received a pause during which tinnitus returned to the normal level. Thereafter the next session was started. (C) Stimulus tones and repetition rates of acoustic CR neuromodulation, noisy CR-like stimulation and low frequency range stimulation (explanation see text). Panel partly redrawn from (Tass et al., 2012a) with kind permission by the authors.

Copyright by Forschungszentrum Jülich GmbH.