Continuous data were recorded with a hard-wired high-pass filter of 0.1 Hz and a sampling rate of 678.17 Hz. MEG data were analyzed with the fieldtrip toolbox51 (www.ru.nl/fcdonders/fieldtrip), run in a Matlab environment (www.mathworks.com). All data sets were down-sampled to 600 Hz and cut into epochs of 2 s. Epochs containing eye movements, eye blinks or muscle artifacts were detected and excluded from further analysis based on visual inspection. Next, an independent component analysis (ICA) was calculated for each individual data set to identify and reject the components that reflect the heart beat (‘fastica' algorithm, implemented in EEGLAB52). After artifact correction, 90 trials (180 s in total) were randomly selected from the remaining trials and used for subsequent analyses. Prior to power spectra calculations, the MEG data from each participant were realigned to a standard sensor position with respect to the participant's head53.
