Introduction to EEG

Electroencephalography (EEG) is an electrophysiological monitoring method to record the electrical activity of one’s brain. There are around 100 billion neurons in human brain. The synapses of the neuron emit subtle electric field (so-called ionic current) when they triggered. In other words, transmitting information from one neuron to the other. We cannot measure such tiny potentials with any equipment currently exists. But a group of neurons provides measurable electrical field. So we are measuring an electrical activity in some area of the scalp. Generally, one or more electrodes should be placed on the scalp. Those electrodes can be wet or dry.



  • Non-invasive monitoring method
  • Inexpensive compared to other methods
  • Provides portability
  • EEG has high temporal resolution


  • Poorly measures neural activity
  • High caliberation time
  • Low spatial resolution
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