scholarly journals Neural Mechanisms of Learning are Critically Dependent on Sleep

2021 ◽  
Author(s):  
Anna á V. Guttesen ◽  
M. Gareth Gaskell ◽  
Emily V. Madden ◽  
Gabrielle Appleby ◽  
Zachariah Reuben Cross ◽  
...  
Keyword(s):  
Sleep Deprivation ◽  
Memory Consolidation ◽  
Qualitative Change ◽  
Learning Mechanisms ◽  
Active Systems ◽  
Memory Processing ◽  
Effective Learning ◽  
Episodic Encoding ◽  
Within Subjects ◽  
Neural Signature

Sleep supports memory consolidation as well as next-day learning. The Active Systems account of offline consolidation suggests that sleep-associated memory processing paves the way for new learning, but empirical evidence in support of this idea is scarce. Using a within-subjects, crossover design, we assessed behavioural and electrophysiological indices of episodic encoding after a night of sleep or total sleep deprivation in healthy adult humans (aged 18-25 years), and investigated whether the behavioural measures were predicted by the overnight consolidation of episodic associations formed the previous day. Sleep supported memory consolidation and next-day learning, as compared to sleep deprivation. However, the magnitude of this sleep-associated consolidation benefit did not significantly predict the ability to form novel memories after sleep. Interestingly, sleep deprivation prompted a qualitative change in the neural signature of encoding: whereas 12-20 Hz beta desynchronization - an established EEG marker of successful encoding - was observed after sleep, sleep deprivation disrupted beta desynchrony during successful learning. Taken together, our findings suggest that effective learning mechanisms are critically dependent on sleep, but not necessarily sleep-associated consolidation.

scholarly journals Sounding It Out: Auditory Stimulation and Overnight Memory Processing

2021 ◽  
Author(s):  
Marcus O. Harrington ◽  
Scott A. Cairney
Keyword(s):  
Rem Sleep ◽  
Memory Consolidation ◽  
Slow Wave Sleep ◽  
Auditory Stimulation ◽  
Theta Oscillations ◽  
Neural Oscillations ◽  
Healthy Children ◽  
Factors Affecting ◽  
Memory Processing ◽  
Eeg Recordings

Abstract Purpose of Review Auditory stimulation is a technique that can enhance neural oscillations linked to overnight memory consolidation. In this review, we evaluate the impacts of auditory stimulation on the neural oscillations of sleep and associated memory processes in a variety of populations. Recent Findings Cortical EEG recordings of slow-wave sleep (SWS) are characterised by two cardinal oscillations: slow oscillations (SOs) and sleep spindles. Auditory stimulation delivered in SWS enhances SOs and phase-coupled spindle activity in healthy children and adults, children with ADHD, adults with mild cognitive impairment and patients with major depression. Under certain conditions, auditory stimulation bolsters the benefits of SWS for memory consolidation, although further work is required to fully understand the factors affecting stimulation-related memory gains. Recent work has turned to rapid eye movement (REM) sleep, demonstrating that auditory stimulation can be used to manipulate REM sleep theta oscillations. Summary Auditory stimulation enhances oscillations linked to overnight memory processing and shows promise as a technique for enhancing the memory benefits of sleep.

Verbal memory deficits associated with fornix atrophy in carbon monoxide poisoning

2001 ◽  
Vol 7 (5) ◽  
pp. 640-646 ◽  
Author(s):  
SHELLI R. KESLER ◽  
RAMONA O. HOPKINS ◽  
LINDELL K. WEAVER ◽  
DUANE D. BLATTER ◽  
HOLLY EDGE-BOOTH ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Verbal Memory ◽  
Visual Memory ◽  
Carbon Monoxide Poisoning ◽  
Neuropsychological Testing ◽  
Mr Images ◽  
Cross Sectional ◽  
Memory Processing ◽  
Within Subjects ◽  
And Gender

Magnetic resonance (MR) images and neuropsychological testing data of 69 carbon monoxide (CO) poisoned patients were prospectively obtained within 1 day of CO poisoning, two weeks and six months. CO patients' Day 1 cross-sectional fornix surface area measurements, corrected for head size by using a fornix-to-brain ratio (FBR), were compared to normal age and gender-matched controls. Additionally, a within-subjects analysis was performed comparing the mean areas between CO patients' Day 1, 2 weeks and 6-month FBR. The FBR was correlated with patients' neuropsychological data. There were no significant differences between CO patients' Day 1 fornix measurements compared to normal control subjects. However, significant atrophic changes in the fornix of CO poisoned patients occurred at two weeks with no progressive atrophy at 6 months. By 6 months, CO patients showed significant decline on tests of verbal memory (when practice effects were taken into account), whereas visual memory, processing speed and attention/concentration did not decline. This study indicates that CO results in brain damage and cognitive impairments in the absence of lesions and other neuroanatomic markers. (JINS, 2001, 7, 640–646.)

scholarly journals Localizing spontaneous memory reprocessing during human sleep

2021 ◽  
Author(s):  
Lea Himmer ◽  
Zoé Bürger ◽  
Leonie Fresz ◽  
Janina Maschke ◽  
Lore Wagner ◽  
...  
Keyword(s):  
Machine Learning ◽  
Memory Consolidation ◽  
High Frequency ◽  
Gamma Oscillations ◽  
Gamma Activity ◽  
Related Activity ◽  
Memory Processing ◽  
Slow Oscillations ◽  
Parallel Memory ◽  
Human Sleep

Reactivation of newly acquired memories during sleep across hippocampal and neocortical systems is proposed to underlie systems memory consolidation. Here, we investigate spontaneous memory reprocessing during sleep by applying machine learning to source space-transformed magnetoencephalographic data in a two-step exploratory and confirmatory study design. We decode memory-related activity from slow oscillations in hippocampus, frontal cortex and precuneus, indicating parallel memory processing during sleep. Moreover, we show complementary roles of hippocampus and neocortex: while gamma activity indicated memory reprocessing in hippocampus, delta and theta frequencies allowed decoding of memory in neocortex. Neocortex and hippocampus were linked through coherent activity and modulation of high-frequency gamma oscillations by theta, a dynamic similar to memory processing during wakefulness. Overall, we noninvasively demonstrate localized, coordinated memory reprocessing in human sleep.

Cooperation between the Hippocampus and the Striatum during Episodic Encoding

2011 ◽  
Vol 23 (7) ◽  
pp. 1597-1608 ◽  
Author(s):  
Talya Sadeh ◽  
Daphna Shohamy ◽  
Dana Rubi Levy ◽  
Niv Reggev ◽  
Anat Maril
Keyword(s):  
Episodic Memory ◽  
Learning And Memory ◽  
Cooperative Interaction ◽  
Memory Encoding ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
System A ◽  
Episodic Encoding ◽  
Within Subjects

The hippocampus and the striatum are thought to play distinct roles in learning and memory, each supporting an independent memory system. A fundamental question is whether, and how, these systems interact to jointly contribute to learning and memory. In particular, it remains unknown whether the striatum contributes selectively to implicit, habitual learning, or whether the striatum may also contribute to long-term episodic memory. Here, we show with functional magnetic resonance imaging (fMRI) that the hippocampus and the striatum interact cooperatively to support episodic memory formation. Participants were scanned during a memory encoding paradigm and, subsequently, were tested for memory of encoded items. fMRI data revealed that successful memory was associated with greater activity in both the hippocampus and the striatum (putamen) during encoding. Furthermore, activity in the hippocampus and the striatum was correlated within subjects for items that were later remembered, but not for items that were forgotten. Finally, across subjects, the strength of the correlation between the hippocampus and the striatum predicted memory success. These findings provide novel evidence for contributions of both the striatum and the hippocampus to successful episodic encoding and for a cooperative interaction between them.

scholarly journals Sleep deprivation‐induced impairment of memory consolidation is not mediated by glucocorticoid stress hormones

2019 ◽  
Vol 29 (5) ◽  
Author(s):  
Frank Raven ◽  
Pim R. A. Heckman ◽  
Robbert Havekes ◽  
Peter Meerlo
Keyword(s):  
Sleep Deprivation ◽  
Memory Consolidation ◽  
Stress Hormones

scholarly journals Does Sleep Promote False Memories?

2011 ◽  
Vol 23 (1) ◽  
pp. 26-40 ◽  
Author(s):  
Annabelle Darsaud ◽  
Hedwige Dehon ◽  
Olaf Lahl ◽  
Virginie Sterpenich ◽  
Mélanie Boly ◽  
...  
Keyword(s):  
Sleep Deprivation ◽  
Memory Consolidation ◽  
Declarative Memory ◽  
False Memories ◽  
Retrosplenial Cortex ◽  
New Words ◽  
Brain Responses ◽  
Fmri Session ◽  
Significant Difference ◽  
Lack Of Sleep

Memory is constructive in nature so that it may sometimes lead to the retrieval of distorted or illusory information. Sleep facilitates accurate declarative memory consolidation but might also promote such memory distortions. We examined the influence of sleep and lack of sleep on the cerebral correlates of accurate and false recollections using fMRI. After encoding lists of semantically related word associates, half of the participants were allowed to sleep, whereas the others were totally sleep deprived on the first postencoding night. During a subsequent retest fMRI session taking place 3 days later, participants made recognition memory judgments about the previously studied associates, critical theme words (which had not been previously presented during encoding), and new words unrelated to the studied items. Sleep, relative to sleep deprivation, enhanced accurate and false recollections. No significant difference was observed in brain responses to false or illusory recollection between sleep and sleep deprivation conditions. However, after sleep but not after sleep deprivation (exclusive masking), accurate and illusory recollections were both associated with responses in the hippocampus and retrosplenial cortex. The data suggest that sleep does not selectively enhance illusory memories but rather tends to promote systems-level consolidation in hippocampo-neocortical circuits of memories subsequently associated with both accurate and illusory recollections. We further observed that during encoding, hippocampal responses were selectively larger for items subsequently accurately retrieved than for material leading to illusory memories. The data indicate that the early organization of memory during encoding is a major factor influencing subsequent production of accurate or false memories.

Learning crisis unit through post-crisis: characteristics and mechanisms

2015 ◽  
Vol 22 (4) ◽  
pp. 198-214 ◽  
Author(s):  
Hela Chebbi ◽  
Aline Pereira Pündrich
Keyword(s):  
Design Methodology ◽  
Single Case ◽  
Learning Cycle ◽  
Learning Mechanisms ◽  
Content Type ◽  
Effective Learning ◽  
Oil Company ◽  
Practical Implications ◽  
Mixed Framework

Purpose – This paper aims to identify the characteristics that a crisis unit should have to achieve effective learning after crisis. Literature has identified many relations between learning organizations and crisis; yet, there is a dearth of research on specific studies about crisis units and their post-crisis learning features. Thus, this paper aims to fill such a gap by giving some practical answers to this question: How can the crisis unit reduce defensiveness phase and extend openness and forgetfulness while learning after the crisis? Design/methodology/approach – This research mobilizes a framework composed by three theoretical grids: the post-crisis learning cycle (Kovoor-Misra and Nathan, 2000); the characteristics of a learning organization (Senge, 1990); and the mechanisms of crisis learning (Mitki and Herstein, 2011). A qualitative investigation is conducted to study a crisis within an oil company (PON). Findings – This paper shows that the duration of the learning cycle depends not only on the organization context but also on the characteristics of the crisis unit. Along with the cognitive, structural and procedural mechanisms, which contributed differently in each phase, the mixed framework allowed operationalizing Senge’s dimensions. Research limitations/implications – The elaboration of a single case study could be considered as a limitation, although it allows a deeper analysis of events within the organization. Practical implications – This paper pinpoints the characteristics that organizations should have as well as the learning mechanisms they should use during each phase of the post-crisis learning cycle. Originality/value – This paper analyzes crisis units as learning structures, which has not been seen yet in known literature.

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