Sleep, Learning and Memory

Sleep function remains elusive despite our rapidly increasing comprehension of the processes generating and maintaining the different sleep stages. Several lines of evidence support the hypothesis that sleep is involved in the off-line reprocessing of recently-acquired memories. In this review, we summarize the main results obtained in the field of sleep and memory consolidation in both animals and humans, and try to connect sleep stages with the different memory systems. To this end, we have collated data obtained using several methodological approaches, including electrophysiological recordings of neuronal ensembles, post-training modifications of sleep architecture, sleep deprivation and functional neuroimaging studies. Broadly speaking, all the various studies emphasize the fact that the four long-term memory systems (procedural memory, perceptual representation system, semantic and episodic memory, according to Tulving's SPI model; Tulving, 1995) benefit either from non-rapid eye movement (NREM) (not just SWS) or rapid eye movement (REM) sleep, or from both sleep stages. Tulving's classification of memory systems appears more pertinent than the declarative/non-declarative dichotomy when it comes to understanding the role of sleep in memory. Indeed, this model allows us to resolve several contradictions, notably the fact that episodic and semantic memory (the two memory systems encompassed in declarative memory) appear to rely on different sleep stages. Likewise, this model provides an explanation for why the acquisition of various types of skills (perceptual-motor, sensory-perceptual and cognitive skills) and priming effects, subserved by different brain structures but all designated by the generic term of implicit or non-declarative memory, may not benefit from the same sleep stages.

Memory consolidation is greatly influenced by an adequate quantity and quality of sleep. There are a number of studies that have looked at the effects of night time time sleep as well as afternoon naps on learning especially memory, but there is a paucity of studies looking at this relationship in the context of Quranic memorisation. In this project paper, we set out to determine three things: 1) Adequacy of sleeping time allocated by tahfiz schools; 2) The practice of afternoon napping(qaylulah) in Khalifah Model School Secondary (KMSS); and 3) The effect of qaylulah on recall of Quran memorised in the morning of 20 students in that school. Of the thirteen tahfiz schools surveyed, none provided adequate sleeping time for their students as measured against the recommendations of the National Sleep Foundation, with tahfiz combined with academic schools doing worse. KMSS uses the practice of qaylulah to supplement night time sleep and can be a model for schools that want to ensure their students get adequate sleep. For the test of recall, using ANCOVA analysis with pre-intervention scores as a covariate, we found a significant and large effect (p=0.051, partial Eta Squared= 0.231) of qaylulah on recall of Quran memorised in the morning whereby students who slept for 45 minutes during qaylulah did much better than those who used the equivalent time watching a documentary. Tahfiz schools should ensure their students get adequate night time sleep which can be supplemented with qaylulah as it will help the students memorise better.

The following document offers a new perspective on Freud's botanical monograph dream based on the following assumptions:
1. The dream is an example of partial REM content since it probably related to only the last part of Freud's last REM dream of the night, but mostly because REM content recall was produced by conscious faculties that can unearth only explicit memories, which represent a small portion of any REM period's actual content.
2. The dream nevertheless can be seen as exemplifying parallel distributed processing, in that the dream can be examined by assuming that dream content unfolds in parallel on several thematic planes at the same time.
3. The dream can be analyzed with NO recourse to fanciful thinking. This is done by showing that the various subjects of the dream are accompanied by related past experiences that offer examples of lessons learned that bear directly on the dreamer's current life circumstances.
4. The object of the REM presentation in the motivational sphere is to build emotional support for actions to be carried out during the dreamer's subsequent waking interval. It is assumed that this emotional support acts much like post-hypnotic suggestions in guiding the dreamer during the next waking interval.

George Mason University (GMU) can't inspire students toward greater academic achievement if they don’t get enough sleep. Nap Rooms are the answer. But how will the benefits be tracked and demonstrated over time? An interdisciplinary approach is required.

As part of a Development Team working on Micro Project innovations for the built environment on GMU’s Fairfax Campus, a group students in Prof. Smirniotopoulos' Real Estate Development course (FNAN-454-001) are developing a Nap Room Prototype to be installed in as many as three (3) locations on the Fairfax Campus. The Nap Room Prototypes are intended to test the viability and potential benefits of giving sleep-deprived GMU students, approximately 70% of whom do not occupy student housing on campus (and, consequently, are relegated to napping in their cars, study areas, and during class), the opportunity to take 20-40 minute naps between classes, to help them make it through what are often twelve and fifteen-hour days.

In order to fully test this concept, a longitudinal test of performance improvements among Nap Room users needs to be developed and administered.

"Objectives: Explore the psychometric properties of a sleep quality index to be used with the elderly population.
Methods: 99 elderly (mean age, M=78.65; SD= 6.92; range=60-95) under social responses in institutions from Coimbra Council were assessed through a sleep questionnaire, composed of a sleep quality index and questions assessing sleep correlates. The sleep index is composed by seven items assessing sleep latency, difficulty in falling asleep, number of night awakenings, waking up spontaneously too early, subjective perception that waking up too early constitutes a problem for the person and two items that evaluate general subjective sleep quality and sleep depth.
Results: KMO = .830; Bartlett’s Test of Sphericity ≤.001. A principal components analysis and the scree plot inspection revealed a one-factor solution, explaining 48.8% of the total variance. Very good internal consistency (Cronbach alpha coefficient; α=.812).
Conclusion: This sleep quality index presents good psychometric properties. Since, in terms of assessment, it is important not to overload the elderly population, this very short instrument constitutes a good option to assess sleep quality.  "

This paper explores the content of the somniloquies of Dion McGregor, the most extensive sleep talker ever recorded, and compares these with dream content from normative male dreams on the Hall and van de Castle Content Scales (1966) and Hobson (et al., 1987) Bizarreness Scales. On the Hall and van de Castle Scales, the somniloquies contained significantly more female characters relative to males than for the norms, more familiar characters and friends, but fewer family members. The dreamer-as-character was much likelier to be either a befriender or an aggressor than in the normative dreams but much less likely to engage in physical aggression specifically.  There was less aggression, friendliness, or sex per character in McGregor’s narratives, as well as less of all three of these types of interaction total than for the norms, but much more self negativity.  There was a lower percentage of negative emotions, good fortune, and success, but the somniloquies were similar to the norms in their levels of misfortune and failure.    On the Hobson Bizarreness Scales, the McGregor somniloquies were not differentiated from dreams on 3 of 6 scales—having similar levels of discontinuity of plot, characters, object, or actions but had slightly fewer incongruities of plot, and many fewer instances of incongruity or  uncertainly of thought. These findings are discussed in terms of presumed brain activation differences—more frontal activation--and also in terms of McGregor’s (1964) personal idiosyncrasies.

"We assessed 99 institutionalized elderly to analyze the influence of subjective sleep aspects on several measures of cognitive functioning.
Sleep problems were common, including trouble in falling asleep, sleep fragmentation, short sleep duration, global poor sleep quality, napping, and daytime sleepiness. Many elderly did physical exercise, and had sleep routines.
Poorer subjective sleep quality was associated with the results of the clock drawing task from MoCA and FAB abstraction task after controlling the educational level"

The following document offers the second part of a minimally updated version of a theory of sleep-related memory processing that was essentially developed in the 1970s. Its possible pertinence to current research derives from the following circumstances.
1. This paper and the first paper on sleep cycling (found on this website) offer substantial evidence that a comprehensive selection of sleep cycling data can interpreted in terms of sleep being a continuous memory-related process that has REM sleep as its focus. In other words, it is claimed that NREM sleep is ever a preparation for REM sleep.
2. REM sleep is seen as being fundamentally different from NREM sleep in that during REM sleep memories literally experienced, whereas during NREM sleep they are not. One important function of having memories experienced is to activate related memories so that they may become integrated with new memories. Also stressed is the notion of reality testing, in that the new memories are being experienced in the real world of the mammal's memory.
3. This view stresses the integration of new memories with their related counterparts to create memory complexes, called behavioral integrations, that will help mammals deal with the complexities of their lives when subsequently evoked by life circumstances.

The following document offers the first part of a minimally updated version of a theory of sleep-related memory processing that was essentially developed in the 1970s. Its possible pertinence to current research derives from the following circumstances.
1. This paper and the other on sleep cycling (found on this website) offer substantial evidence that a comprehensive selection of sleep cycling data can interpreted in terms of sleep being a continuous memory-related process that has REM sleep as its focus. In other words, it is claimed that NREM sleep is ever a preparation for REM sleep.
2. REM sleep is seen as being fundamentally different from NREM sleep in that during REM sleep memories literally experienced, whereas during NREM sleep they are not. One important function of having memories experienced is to activate related memories so that they may become integrated with new memories. Also stressed is the notion of reality testing, in that the new memories are being experienced in the real world of the mammal's memory.
3. This view stresses the integration of new memories with their related counterparts to create memory complexes, called behavioral integrations, that will help mammals deal with the complexities of their lives when subsequently evoked by life circumstances.

Here our goal was to determine the magnitude of sleep-related motor skill enhancement. Performance on the finger tapping task (FTT) was evaluated after a 90 min daytime nap (n=15) or after quiet wakefulness (n=15). By introducing a slight modification in the formula used to calculate the offline gains we were able to refine the estimated magnitude of sleep׳s effect on motor skills. The raw value of improvement after a nap decreased after this correction (from ~15% to ~5%), but remained significantly higher than the control. These results suggest that sleep does indeed play a role in motor skill consolidation.

"Objectives: To describe subjective sleep quality and explore the associations between several correlates and sleep quality in an institutionalised elderly sample.
Methods: We evaluated 99 institutionalised elderly from Coimbra Council, (mean age, M = 78.65; SD = 6.92; range = 60-95) that filled in voluntarily a test battery (or whose relatives/caregivers bestowed consent), including socio-demographic questions, initial sleep assessment, a subjective sleep quality index (SSQI), depressive (Geriatric Depression Scale) and anxious (Geriatric Anxiety Inventory) symptomatology, and satisfaction with life (Satisfaction with Life Scale).
Results: Forty-nine percent of the elderly reported poor sleep.
Older age was associated with early awakenings and decreased sleep depth, both in men and women. In men, age was associated with early awakenings, decreased sleep depth, diminished sleep satisfaction, and more daytime naps. In women, older age was not associated to any variable.
Poor subjective sleep quality was associated with less education, no sleep satisfaction, more daytime sleepiness, pain during night, presence of medical problems that affect sleep, and depressive symptoms, both in men and women. In men, subjective sleep quality was associated with diminished sleep satisfaction, more daytime sleepiness, pain, and noise during night; older women had less sleep satisfaction, more daytime sleepiness, medical problems that affect sleep and more depressive symptoms.
Conclusions: Decrease in sleep quality is moderately common in old institutionalised persons, and poor sleep is associated with less education, no sleep satisfaction, more daytime sleepiness, pain during the night, presence of medical problems that affect sleep and higher depressive symptoms.
Studies are required to establish whether improvements in these outcomes will ameliorate sleep in institutionalised elderly."

My documents posted on this website are mostly devoted to the sleep research I conducted in the 1970s. Thanks to intervening advances, many sleep researchers have ceased taking issue with the position I took nearly 50 years ago that adaptive learning permeates a significant portion of human sleep. I recommend a perusal of my research, despite its advanced age, because many of the predictions made back then have been verified experimentally, creating the possibility that other major predictions will prove accurate, as well, thereby providing a basis for taking sleep research in new directions. Some of these predictions are summarized in this note.

The following document offers an introduction to a minimally updated version of a theory of sleep-related memory processing that was essentially developed in the 1970s. Its possible pertinence to current research derives from the following circumstances.
1. This paper and the two on sleep cycling (found on this website) offer substantial evidence that a comprehensive selection of sleep cycling data can interpreted in terms of sleep being a continuous memory-related process that has REM sleep as its focus. In other words, it is claimed that NREM sleep is ever a preparation for REM sleep.
2. REM sleep is seen as being fundamentally different from NREM sleep in that during REM sleep memories literally experienced, whereas during NREM sleep they are not. One important function of having memories experienced is to activate related memories so that they may become integrated with new memories. Also stressed is the notion of reality testing, in that the new memories are being experienced in the real world of the mammal's memory.
3. This view stresses the integration of new memories with their related counterparts to create memory complexes, called behavioral integrations, that will help mammals deal with the complexities of their lives when subsequently evoked by life circumstances.
4. This paper then applies this general viewpoint to provide a possible explanation for the psychoanalytic finding that childhood memories actively participate in adult human behavior.