Magnetoencephalography (MEG)

The brain's neuronal activity is associated with magnetic fields that pass essentially unimpeded through the skull, resulting in an undistorted signature of neural activity that can be recorded at the scalp level. Magnetoencephalography (MEG) measures tiny fluctuations in these magnetic fields using an array of extremely sensitive Superconducting QUantum Interference Devices (SQUIDs). This magnetic signal is especially useful for spatial localisation of the underlying brain activity, as well as detecting high-frequency oscillations.

OHBA houses a state-of-the-art TRIUX™ NEO system from Finnish manufacturer MEGIN (MEGIN is a Croton Healthcare Company). The system features resource friendly Helium re-liquefaction minimising weekly maintenance time. Latest real-time electronics and low-temperature materials guarantee excellent dynamic range, signal-to-noise ratio and stability of operation, facilitating scans even in the presence of sources of artefacts. A superior geometric form factor allows to record signals from all brain areas with equal quality of data.

At its core, the TRIUX™ NEO consists of 306 SQUID measurement channels, which simultaneously measure the magnetic field and magnetic field gradients (spatial variation) around the head at up to 8 kHz. Equipment and software for co-registering the MEG data to individual structural and functional MR scans are available in the MEG laboratory. As well as the 306-channel system itself, dedicated systems can deliver high-quality visual and auditory stimuli. Fibre-optic button boxes are also used for monitoring the behavioural responses of volunteers. An integrated 128-channel Electroencephalography (EEG) system can measure scalp-potentials during the MEG experiment, where the EEG signals are recorded in the same dataset as the MEG channels. The MEG system is also equipped with a fully integrated high-precision eye-tracking system.

If you are interested in using the MEG facilities, please contact anna.camera@psych.ox.ac.uk