Brainamp mr plus eeg amplifiers

All experiments were conducted at the Birmingham University Imaging Centre (BUIC) using a 3T Philips Achieva MRI scanner. An eight-channel phased-array head coil was used to acquire a T1-weighted anatomical image (1 mm isotropic voxels) and wholebrain T2*-weighted, functional EPI data (180 volumes, 32 slices, 3x3x4 mm voxels, TR=2000 ms, TE=35 ms, SENSE factor=2, flip angle=80°). Subject's cardiac and respiratory cycles were continuously recorded throughout using the scanner's inbuilt pulse oximeter and respiratory belt. EEG data were simultaneously recorded from 62 scalp Ag/AgCl ring-type electrodes distributed according to the 10-20 system (EasyCap, Germany) with two additional channels used for recording the electrocardiogram and electrooculogram. The impedance at all recording electrodes was maintained below 20 kΩ. BrainAmp MR-plus EEG amplifiers (Brain Products, Munich) were used for recording data at 5 kHz with 0.016-250 Hz hardware filters. Subjects were positioned such that electrodes Fp1 and Fp2 were at the magnet isocentre in the foot/head direction so as to minimise the gradient artefact (Mullinger et al., 2011) . The EEG acquisition clock was synchronised with the MR scanner clock, with the TR equal to a multiple of the EEG sampling period, to ensure consistent sampling of the artefact waveforms (Mullinger et al., 2008) .