Incorporation of presleep stimuli into dream contents: evidence for a consolidation effect on declarative knowledge during REM sleep?

Abstract

Summary Presleep stimuli to be retained for further recall is often incorporated into dream contents. To establish whether processing for insertion into dream contents may improve consolidation, we compared the retention rate at delayed recall of contents resulting from incorporation of presleep sentence‐stimuli with those of other contents of the same dream experiences. We hypothesized that association with a cognitive task of recall facilitates access to recently acquired items of declarative knowledge such as presleep stimuli, and triggers the deep elaboration of their semantic features, which involves rehearsal. Twelve subjects were given a task of delayed recall for three nonsense sentences delivered once a time before each of the sleep (re‐)onsets over an experimental night. After each awakening in rapid eye movement sleep, subjects were asked to report dream experience and recall the sentence to be retained. In the morning, after spontaneous awakening, subjects were unexpectedly requested to again report their dream experiences and to recall the stimuli. Two pairs of judges independently identified possible incorporations of the stimuli, and parsed dream reports into propositional content units. The proportion of night reports with at least one incorporation of the stimulus delivered (i.e. valid incorporations) was higher than that of reports with contents similar to a stimulus(‐i) not yet delivered (forward pseudo‐incorporations) or delivered prior to an earlier sleep period (backward pseudo‐incorporations). The proportion of content units common to night and morning reports (considered to be better consolidated) was significantly higher for incorporated contents than for other contents, including pseudo‐incorporated contents. Instead, the retention at morning recall of words of sentence‐stimuli corresponding to incorporated contents was not significantly higher than that of other words. The better retention of incorporated contents provides a partial confirmation (that is, limited to the output of the processing) that a generation effect, which benefits retention of actively processed information, is operative during sleep as well as in waking.

Cognitive and emotional processes during dreaming: A neuroimaging view

“…More recent models involve that dreams echo dynamic functions like reactivation and further consolidation of novel and individually-relevant features encountered during previous waking experience (e.g. Cipolli, Fagioli, Mazzetti, & Tuozzi, 2004;Schwartz, 2010;Wamsley & Antrobus, 2009;Wamsley, Perry, Djonlagic, Reaven, & Stickgold, 2010). Such models of dreaming might be consistent with accumulating evidence showing the potential benefit of reprocessing freshly encoded information for long-term storage (Diekelmann & Born, 2010;.…”

“…While a large body of data support the involvement of sleep in memory (for review, see Dang-Vu, Desseilles, Peigneux, & Maquet, 2006), the relationship between processes related to memory consolidation and those underlying dream experience is still poorly understood (e.g. Cipolli et al, 2004;Frank & Benington, 2006;Schwartz, 2003;e.g. Wamsley & Antrobus, 2009;Wamsley, Perry, et al, 2010;Wamsley, Tucker, Payne, Benavides, & Stickgold, 2010).…”

Do Dolphins Rehearse Show-Stimuli When at Rest? Delayed Matching of Auditory Memory

“…Actually, memories of salient events can lead to rehearsal in the form of dreams during sleep both in humans and animals (Cipolli et al, 2004). Animals that have undergone a lesion of their locus coeruleus present motor expressions of their dreams, e.g., hunting in sleeping cats (Jouvet, 1979).…”

DreamThrower: Creating, Throwing and Catching Dreams for Collaborative Dream Sharing

“…Sound stimuli while sleeping has been studied extensively: verbal sentences during REM sleep can assist in accessing declarative knowledge during sleep and help consolidate knowledge but these verbal cue will not be inserted into dream content [10]; the insertion of verbal content when sleeping also showed that external verbal stimuli are perceived as belonging to the events of the dream [3]; the insertion of verbal stimuli prior to falling asleep was also studied and shown to effect dream content as well as recall after waking [9]; and finally another study revealed that sound stimuli while sleeping cannot be used as an alert [5]. Smell stimuli has also been studied although it has been shown that olfactory senses are very limited while sleeping, and therefore has little effect on dream content [2,8].…”

“…This will provide focus to our evaluation in understanding the effects of environmental sound stimulus. Further study can be done to include other sounds such as music and verbal speech, as it has been recognized that speech sounds do influence dreams [9,10]. Once the system detects that REM sleep has ended, the prototype plays a speech recording, "wake-up" very loudly, so that the user can awaken and report their dream experiences, which was done so that the prototype can be evaluated.…”