Fig. 5.

Source localisation of the evoked response: A) Averaged time courses of OPM data (black) recorded at the 13 different sensor locations across the head-cast, and SQUID data (red) corresponding to the 271 SQUID channels. Note the electrical stimulus artefact at t=0 and the evoked response peak at t=20 ms. B) Left and right panels show the scalp spatial topography (for the SQUIDs and OPMs, respectively) of the measured (bottom) and modelled (top) fields. The centre plot shows correlation between the modelled and measured fields for the OPMs (black) and SQUIDs (red). C) Two views of the N20 evoked response location. Note that the motor strip is shown in green and the sensory strip in blue. The peak localises to right primary sensory (S1) region as expected. The black marker shows localisation using the OPM system and the red marker shows equivalent localisation using the SQUID system. D) Reconstructed dipole time courses using the OPM (black) and SQUID (red) data.