Neural NoiseMagnetoencephalography (MEG) measures the weak magnetic fields generated by electrical currents in neuronal assemblies, providing a non-invasive window into brain activity with millisecond temporal resolution. Because magnetic fields pass through the skull and scalp with minimal distortion — unlike the volume-conducted electrical signals measured by eeg — MEG offers superior source localization and is particularly sensitive to tangentially oriented currents in cortical sulci.
MEG systems traditionally rely on arrays of superconducting quantum interference devices (SQUIDs) cooled to near absolute zero, requiring fixed helmet-shaped dewars that constrain head movement. More recent optically pumped magnetometer (OPM) technology enables wearable, room-temperature MEG sensors that can be placed directly on the scalp, dramatically improving spatial sampling and enabling recordings during natural movement. These advances are expanding MEG’s applicability beyond traditional cognitive neuroscience into clinical and neurotechnology contexts.
In clinical practice, MEG is used for presurgical mapping of eloquent cortex and seizure-detection focus localization in epilepsy patients. For neurotechnology research, MEG provides high-fidelity measurements of oscillatory dynamics, sensorimotor rhythms, and cortical connectivity that inform bci-and-neural-decoding design and validate stimulation-and-neuromodulation effects. MEG-based neurofeedback and real-time source imaging are emerging applications that leverage MEG’s temporal precision for closed-loop brain-state regulation.