Network architecture. Neural units are represented by circles. (a) The executive control network consists of one Central Unit and some Memory Units which represent different positions of a dot or different directions of an arrow. The Central Unit oscillates at theta rhythm while the Memory Units oscillate at alpha rhythm. The Central Unit tries to synchronize the Memory Units (red arrows) but the Memory Units de-synchronize each other (blue arrows). Memory Units receive sensory inputs (green arrows). Motion-related Memory Units can give a go / no-go signal to the Central Unit (pink arrows). (b) One position-related Memory Unit and one motion-related Memory Unit converge to a co-incidence detection unit which generates the output by activating the corresponding position-related Memory Unit.