Neurons communicate with each other via electrochemical events.
Electrical changes caused by the activity of the neurons can be recorded at the scalp using electrodes. The EEG has been used to examine brain activity in infants, children and adults for over 30 years. It is a safe, non-invasive method. In our laboratory, a net of 65 electrodes is placed on the scalp. Each electrode is made of tin and makes contact with the scalp via a sponge soaked in a solution of water and salt.