Phase of the theta wave in relation to different limb movements in awake rats.

A significant relationship was observed between the moment of self-initiated pressing or releasing of a lever and the phase of the hippocampal theta wave recorded concurrently in rats. In addition, the phase of the theta wave at which lever pressing was most likely to occur was opposite to that at which lever releasing was most likely to occur. These findings imply that, in rats, sensorimotor integration occurs not continuously, but intermittently and rhythmically, in phasic relation to hippocampal theta activity.