Table 1. Overview of Stimulation Techniques.

Pre-sleep priming presents a stimulus before sleep, e.g., a video or music to influence dream content in subsequent sleep. Dream incubation involves pre-sleep rehearsal of content, such as visualization of a rescripted nightmare, repeating an intention to become lucid (lucid dream incubation), or focusing on a personal problem to incubate a creative solution. Dream direction applies a sensory stimulus during sleep and relies on implicit associations to sensation to direct dreams: a pleasant scent to ameliorate dream emotion, muscle stimulation to augment dream movement, speech to direct dream narrative. Of note, pre-sleep priming, dream incubation, and dream direction may affect dream content in relatively metaphorical or idiosyncratic, but nonetheless functional ways. Rhythmic entrainment acts on physiological rhythms during sleep, from fast rhythms like neural oscillations to slower rhythms like respiration or circadian changes in temperature; while entrainment does not necessarily influence dream content, it may improve sleep functions. Finally, in targeted reactivation, a stimulus is paired with specific content during wake, and when the stimulus is re-presented during sleep its associated content is reactivated. Targeted reactivation can enhance consolidation of specific memory traces (targeted memory reactivation), trigger imagery that was rehearsed prior to sleep (targeted dream reactivation), or induce lucidity (targeted lucidity reactivation).

	Wake		Sleep
	Stimulus	Content	Stimulus	Content
Pre-Sleep Priming	✔	X	X	✔
Dream Incubation	X	✔	X	✔
Dream Direction	X	X	✔	✔
Rhythmic Entrainment	X	X	✔	X
Targeted Reactivation	✔	✔	✔	✔