Electroencephalography

Electroencephalography, abbreviated EEG, is a method used to record an electrogram of the spontaneous electrical activity of the brain, whose biosignals represent the postsynaptic potentials of pyramidal neurons in the neocortex and allocortex. It is typically non-invasive, with electrodes placed along the scalp using the International 10-20 system or variations of it, though a surgically placed intracranial variant is called electrocorticography. EEG is widely used both as a clinical diagnostic tool, particularly in epilepsy, and as a research tool in neuroscience, and clinical interpretation of its recordings is performed chiefly by visual inspection of the tracing, sometimes supplemented by quantitative analysis in specific settings.