A sample of the recorded signals of phase I recording. The vertical arrows with V-shaped and diamond-shaped heads indicate the time instances of on- and off-switching the EMF source, respectively. Start- and end times of bursts are marked by dashed and dash-dotted lines, respectively. Three events, the endpoints of the first and the third stimulation period as well as the onset of the second stimulation period are discarded as they occur during bursts. Also, the endpoint of the second stimulation period is discarded because the EMF source is switched on again before a burst occurs. Two stimulation-start-to-burst intervals (SSBI) and two interburst intervals (IBI) are indicated in the figure. The EEG signal is contaminated by ECG artifact, however, the bursts can easily be detected by visual analysis. The ECG artifact was not present during the periods of continuous 10 minute exposure of phase II.