Curry7.4 neuroscan

The data were prepared as follows. Average event-related potentials (ERPs) were extracted from epochs of −500 to 6,000 ms relative to the stimulus onset, then baseline-corrected using the 500 ms interval before stimulus onset. Each epoch was extracted at one of the trigger events where a single image stimulus provoked phase-locked averaging (Figure 1B). As we were interested in visual stimulation and the difference between monomodal and bimodal stimulation, we investigated a narrow gamma band range from 33 to 38 Hz.
Coherence was calculated in CURRY 7.4 Neuroscan in three different time windows: 100, 1,000, and 6,000 ms. The 100 ms time window was used in the main analysis and the others in Table 6. The parameters that needed to be specified were the minimal distance between electrodes (50 mm), minimum lag (1 ms), and the maximum lag (2.5 ms). In all cases, we chose the standard value in CURRY 7.4 Neuroscan. Before analyzing the data, epochs were visually inspected for muscle artifacts, eye movements, ECG artifacts, and other detectable artifacts, which were then rejected using covariance methods. Data were also rejected if eye movement artifacts or electrode drifts were visible in the data plots.

A soft elastic cap with 64 surface electrodes (Ag/AgCl) was used (Quick-Cap, Compumedics), with the electrodes placed according to the international 10–20 system and connected to a bioamplifier (SynAmps, Compumedics). Neuroscan (Curry7.4 NeuroScan, Compumedics) was used to record signals and for data processing. The ground electrode was incorporated into the cap by the manufacturer over the midline frontal region and the reference placed between the Cz and Pz electrodes. In the data analysis the signals were re-referenced to bimastoid electrodes (M1, M2). We chose to reference the signal to the mastoid electrodes out of concern of clinical relevance. Mastoid referencing can yield reasonable results even in the case of few electrodes.
Electrode impedance was kept below 5 kΩ. Horizontal and vertical electro-oculographic data were registered with two bipolar channels. Two Electrocardiogram (ECG) electrodes were placed in the heart axis and two electrodes in a submental position to record EMG artifacts. EEG measurements were sampled at 2 kHz with an analog, anti-aliasing RC low-pass filter at 800 Hz. The EEG data were digitally high-pass and low-pass filtered offline with a Hann function filter at 0.5 Hz and 250 Hz and a tapering window at 10%. No notch filters were applied.

As explained in Horwitz et al. (2017a) (link), we used a soft elastic cap with 64 surface Ag/AgCl electrodes (Quick-Cap, Compumedics), placed the electrodes according to the international 10–20 system, and connected the cap to a bioamplifier (SynAmps, Compumedics). We used Neuroscan (Curry7.4 NeuroScan, Compumedics) for signals recording and data processing. The ground electrode is incorporated over the midline frontal region of the cap and the reference was placed between the Cz and Pz-electrodes by the manufacturer. In the data analysis, the signals were re-referenced to bimastoid electrodes (M1, M2).
We kept electrode impedance below 5 kΩ. Furthermore, we registered horizontal and vertical electro-oculographic (EOG) data with two bipolar channels. Moreover, we placed two EKG-electrodes in the heart axis on the chest and two electrodes in submental positions to record EMG-artifacts. We sampled the EEG measurements at 2 kHz with an analog, antialiasing RC low-pass filter at 800 Hz and digitally high-pass and low-pass bandpass filtered the EEG-data offline with a Hann function filter at 0.5 and 250 Hz with a tapering window at 10%. We did not apply any notch filters.