Brain activity was measured using the Elekta NeuroMag 306-channel MEG system at the Oxford Centre for Human Brain Activity (OHBA). Head position inside the scanner was monitored by means of a magnetic Polhemus FastTrack 3D system. Data were acquired with a sampling frequency of 1000 Hz and using a band-pass filter between 0.03 and 300 Hz. Electrocardiography (ECG), electrooculography (EOG) and bilateral electromyography (EMG) were acquired concurrently. EMG electrodes were placed over flexor digitorum superficialis (forearm) in a bipolar configuration, with a reference electrode on the lateral epicondyles of each arm (similar to Proudfoot et al., 2018 (link); van Ede and Maris, 2013 (link)).
Participants were presented with visual stimuli on a 58 × 46 cm screen which was 120 cm away and which had a spatial resolution of 1280 × 1024 pixels. The task was programmed and implemented using Presentation (Neurobehavioral Systems, Inc., Berkeley, CA, www.neurobs.com). For the duration of the session, participants were seated upright in the MEG scanner with their arms resting on their laps, while holding the grippers on their resting hands. Participants’ responses on each trial were recorded using a bimanual fibre-optic gripping device that measured gripping strength and which was compatible with the MEG scanner (Grip Force, Force Fibre Optic Response Pad, Current Designs, USA).
Participants were presented with visual stimuli on a 58 × 46 cm screen which was 120 cm away and which had a spatial resolution of 1280 × 1024 pixels. The task was programmed and implemented using Presentation (Neurobehavioral Systems, Inc., Berkeley, CA, www.neurobs.com). For the duration of the session, participants were seated upright in the MEG scanner with their arms resting on their laps, while holding the grippers on their resting hands. Participants’ responses on each trial were recorded using a bimanual fibre-optic gripping device that measured gripping strength and which was compatible with the MEG scanner (Grip Force, Force Fibre Optic Response Pad, Current Designs, USA).