What is Magnetoencephalography?
Magnetoencephalography (MEG) is a neuroimaging technique that records the magnetic fields produced by electrical currents in the brain. It combines the millisecond temporal resolution of EEG with better spatial localization.
How it works
MEG uses superconducting quantum interference devices (SQUIDs) to detect the extremely weak magnetic fields generated by neural activity. Unlike EEG, magnetic fields are not distorted by the skull and scalp, allowing more accurate localization of the source. MEG is particularly useful for mapping the precise timing and location of sensory processing, language function, and epileptic activity. The main limitation is cost: MEG systems require expensive magnetically shielded rooms and cryogenic cooling.
Applied example
Before brain surgery to remove an epileptic focus, MEG maps the patient’s language areas with millisecond precision, allowing the surgeon to identify and avoid critical speech regions that would cause devastating disability if damaged.
Why it matters
MEG provides a unique combination of temporal and spatial precision for studying brain function, filling the gap between EEG’s timing advantage and fMRI’s spatial advantage.
