Magnetoencephalography (MEG)
A non-invasive functional neuroimaging technique mapping brain activity by measuring weak magnetic fields produced by neuronal electric currents using SQUID sensors.
Governing formula
Magnetic Field B ~ 10–100 fT (10⁻¹⁵ Tesla)
SI unit
fT (Femtoteslas = 10⁻¹⁵ T)
In depth
Detects magnetic fields (~10–100 femtoteslas) generated by synchronized dendritic ionic currents in cortical pyramidal neurons using liquid-helium-cooled SQUID sensors inside magnetically shielded rooms.
Examples in the real world
Mapping millisecond-resolution auditory and visual sensory processing in the human cerebral cortex.