The non-invasive study was made possible by EEG. The study of human cognitive neuroscience using non-invasive brain stimulation is now widely spread because this lead to the the advancement of perception and cognition understanding. And this non-invasive brain simulation study was made possible by EEG in 1929. And EEG means Electroencephalography which is an electrophysiological method used to monitor and record electrical activities in the brain.