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Memory
Published in Allan Hobson, Psychodynamic Neurology, 2014
I hope to address and solve a problem that besets modern sleep science especially in its efforts to explore sleep’s function. It is assumed by many scientists that sleep consolidates memory, and with that hypothesis I agree. I also find the evidence for this hypothesis to be compelling. But that evidence also suggests that the memory consolidation effect of sleep is surprisingly weak. The consolidation of memory effect is, in fact, so small as to suggest that it cannot be either the major function of sleep or the only memory function of sleep. Later in this chapter, I will argue that the memory consolidation function is small because it takes second place to the rehearsal of genetic memory and that genetic memory is the reliable and robust template upon which experiential memory is inscribed. In other words experience does have an effect, but the brain is conservative in incorporating daily experience into its genetically programmed plan of action which has been proven effective over millennia and not just overnight and not even over a single lifetime.
Sleep Disorders
Published in Divya Vohora, The Third Histamine Receptor, 2008
Jonathan E. Shelton, Timothy W. Lovenberg, Christine Dugovic
Additional theories highlight the importance of REM sleep. One theory supports the link between REM sleep and behavior. REM-centric sleep deprivation during the early years of development can result in behavioral maladjustments, lasting sleep fragmentation, and alteration in neuron survival [14, 15]. In addition, several studies have emphasized the relationship between REM sleep and spatial and procedural memory consolidation, whereas slow wave sleep (stages 3 and 4) of NREM sleep is important in tasks involving declarative memory [16,17]. Another study has reported improved performance on perceptual or motor task following sleep [18]. However, the underlying mechanisms demonstrating a direct connection between sleep and memory are still under investigation. The results of these investigations will help to clarify how the various stages of sleep shape brain plasticity.
Sleep Promoting Improvement of Declarative Memory
Published in Bahman Zohuri, Patrick J. McDaniel, Electrical Brain Stimulation for the Treatment of Neurological Disorders, 2019
Bahman Zohuri, Patrick J. McDaniel
In summary, the investigation of electrophysiological brain activity in humans revealed increased spindle density during early non-REM sleep and in EEG coherence during the depolarizing up state of slow oscillations after declarative learning. Because these changes followed declarative learning, a causative role of these phenomena for sleep-dependent memory consolidation remains to be established. Nevertheless, such findings agree well with recent concepts assuming that the consolidation of newly acquired declarative memories and their integration for long-term storage relies on an iterative reprocessing of these memories in hippocampal-neocortical circuitry.55,56,75 Central to this view is the grouping effect of slow oscillations originating in the neocortex. The long-range synchrony in cortical activity associated with the upstate of slow oscillations drives thalamocortical spindle activity, which through the strong and simultaneous calcium influx into cortical pyramidal cells predisposes these cells toward the induction of plastic synaptic changes that underlie long-term memory formation. Concurrently, the strong synchronous cortical excitation associated with the slow oscillation upstate might facilitate the occurrence of hippocampal sharp wave-ripple activity, a pattern thought to reflect reactivation of memories at the hippocampal level and their propagation to neocortical networks.76 Slow oscillations driving coincident inputs from thalamic spindle and hippocampal sharp wave-ripple activity to cortical populations might in this way set the stage for plastic processes specifically in neocortical representations of newly encoded memories. Interestingly, miniature EPSP has been considered as one mechanism initiating the depolarizing up state of slow oscillations. These miniature potentials summate during the downstate and thereby contribute to the depolarization of cortical pyramidal cells above the threshold.65 There is some evidence suggesting that the probability of such miniature EPSPs during the silent down phase is selectively enhanced at synapses previously activated during associative learning.66–68 If so, this would mean that slow oscillation-driven reprocessing during sleep originates preferentially in those neocortical neuron populations previously engaged in encoding during the wake phase.
EEG coherence and power spectra during REM sleep related to melatonin intake in mild-to-moderate Alzheimer’s disease: a pilot study
Published in International Journal of Neuroscience, 2023
Manuel Alejandro Cruz-Aguilar, Ignacio Ramírez-Salado, Marisela Hernández-González, Miguel Angel Guevara, Ana Paula Rivera-García
There is a growing body of research on humans and animals that provides evidence for a prominent role of REM sleep in memory consolidation [17, 43]. Thus, it is important to test pharmacological alternatives that may improve the clinical conditions of REM sleep in AD patients. For this reason, the aim of the present study was to determine the effect of melatonin on EEG activity and the degree of EEG synchronization between different cortical areas during REM sleep in AD patients who received melatonin. Considering that melatonin reduces brain electrical activity by modulating GABAA receptors [31–35], that GABArgic activity is required for REM sleep generation [23–27], and that melatonin intake in AD patients reduces REM sleep latency [37], we hypothesized that the facilitator effect of melatonin on REM sleep onset will be associated with a lower percentage of fast frequencies (in β and γ) and a decrease in the degree of EEG synchronization (coherence) between cortices in these same fast frequencies. To test these hypotheses, we evaluated the effects of melatonin on REM sleep latency, EEG spectral power, and EEG coherences during the first nocturnal episode of REM sleep in a group of mild-to-moderate AD patients previously treated with melatonin [41, 42].
Hierarchical measurement structure in the Women’s Health Questionnaire: a confirmatory factor analysis
Published in Climacteric, 2019
B. J. Shen, Q. Fan, J. S. Huang, M. H. R. Ho, W. J. Mack, H. N. Hodis
Although Sleep Problems and Memory/Concentration primarily represented mental health functioning, they were also associated with physical health, albeit to a lesser extent. Ample research has shown that sleep disturbances and memory difficulties are indicative of psychological distress, especially in depression or anxiety27, and they are commonly included in mental health measures28,29. Although our findings did support this observation, sleep and memory deficits also appeared to indicate physical health concerns among older women. It is conceivable that, although sleep and memory difficulties are not defining symptoms of common physical diseases, they are often associated with chronic physical ailments, such as heart disease, pulmonary illness, and diabetes30–32. In sum, while sleep and memory difficulties in older women primarily reflect mental health issues, they may also signify physical difficulties secondarily.
An evening milk drink can affect word recall in Indonesian children with decreased sleep efficiency: A randomized controlled trial
Published in Nutritional Neuroscience, 2018
Rini Sekartini, Dian Novita Chandra, Tiana Arsianti, Saptawati Bardosono, Tjhin Wiguna, Anne Schaafsma
The importance of sleep to memory (verbal task) consolidation has been examined and confirmed in several narrative reviews.31–33 In children aged 9–12 years, the effect on memory was shown by comparing memory retrieval following a period of sleep to memory retrieval following a similar duration of wakefulness.34 Furthermore, seven consecutive nights of restricting time in bed to 6.5 hours increased academic problems in children ages 6–12 years.35 Even one night of sleep deprivation in 12–15 year olds revealed significant decrements on a word memory task.36 However, a meta-analysis of studies in healthy school-aged children (5–12 years) failed to confirm the association between sleep and sustained memory, although shorter sleep was associated with worse cognitive functioning and more behavioral problems.37