Electroencephalographic cartography of conscious states.

We analyzed monopolar recordings obtained from a brain area implicated in the implementation of conscious intention--the Supplementary Motor Area. Other monopolar recordings were taken at F3, F4, C3, C4, P3, P4, O1, O2, F7, F8, T3, T4, T5, T6, and Cz using the standard international (10/20) pattern with linked ears as reference. Using on line fast-fourier transforms of brainwave signals and computer displays with one-second updates of 1Hz wide brainwave bands of 5, 7, 10, 12, 14, 16, 20 and 28 Hz, specific brainwave signatures were identified for attentional, cognitive, imaginal, and somatosensory states. This first, and thus limited, cartography of consciousness is discussed in light of the cognitive descriptions clinically ascribed to the commonly used brainwave frequency bands designated as Delta, Theta, Alpha, and Beta.