Systems, apparatuses, and methods for memory recall and reactivation by targeted stimulation are provided. Systems, apparatuses, and methods are described for providing patterns of a reinforcing cue re-presentation during sleep. Systems, apparatuses, and methods are also described for determining patterns of a reinforcing cue for re-presentation during sleep. Systems, apparatuses, and methods are also described for determining reinforcing cues for re-presentation during sleep. Systems, apparatuses, and methods are also described for determining and predicting sleep intervals based only on sleep onset.