Electroencephalography (EEG), a technique for measuring the electrical activity of the brain, in real time, using electrodes placed on the scalp. The participant is placed in front of a screen on which visual stimulation is presented. Different studies use this type of instrumentation. For example, the subject’s reaction to orthographic neighbors, or the structure of a sentence, can be studied. The word evokes in the subject a cerebral reaction according to whether it is expected or not in its position inside the sentence for example. The production and perception of speech, reading, are all cognitive activities that can be studied through electroencephalography. Caption: EEG during a visual stimulation.