scholarly journals Interactive effects of stress reactivity and rapid eye movement sleep theta activity on emotional memory formation

Hippocampus ◽  
2019 ◽  
Vol 30 (8) ◽  
pp. 829-841 ◽  
Author(s):  
Sara Y. Kim ◽  
Sarah M. Kark ◽  
Ryan T. Daley ◽  
Sara E. Alger ◽  
Daniella Rebouças ◽  
...  
Author(s):  
Vaishnav Krishnan ◽  
Bernard S. Chang ◽  
Donald L. Schomer

The normal adult electroencephalogram (EEG) is not a singular entity, and recognizing and appreciating the various expressions of a normal EEG is vital for any electroencephalographer. During wakefulness, the posterior dominant rhythm (PDR) must display a frequency within the alpha band, although an absent PDR is not abnormal. A symmetrically slowed PDR, excessive theta activity, or any delta activity during wakefulness is abnormal and a biomarker of encephalopathy. Low-voltage EEGs have been associated with a variety of neuropathological states but are themselves not abnormal. During non-rapid eye movement sleep, a normal EEG will display progressively greater degrees of background slowing and amplitude enhancement, which may or may not be associated with specific sleep-related transients. In contrast, the EEG during rapid eye movement sleep more closely resembles a waking EEG (“desynchronized”) in amplitude and background frequencies. Across both wakefulness and sleep, significant asymmetries in background frequencies and amplitude are abnormal.


Author(s):  
Mayumi Machida ◽  
Brook L.W. Sweeten ◽  
Austin M. Adkins ◽  
Laurie L. Wellman ◽  
Larry D. Sanford

2004 ◽  
Vol 286 (3) ◽  
pp. R528-R538 ◽  
Author(s):  
Oskar G. Jenni ◽  
Alexander A. Borbély ◽  
Peter Achermann

The development of nocturnal sleep and the sleep electroencephalogram (EEG) was investigated in a longitudinal study during infancy. All-night polysomnographic recordings were obtained at home at 2 wk and at 2, 4, 6, and 9 mo after birth (analysis of 7 infants). Total sleep time and the percentage of quiet sleep or non-rapid eye movement sleep (QS/NREMS) increased with age, whereas the percentage of active sleep or rapid eye movement sleep (AS/REMS) decreased. Spectral power of the sleep EEG was higher in QS/NREMS than in AS/REMS over a large part of the 0.75- to 25-Hz frequency range. In both QS/NREMS and AS/REMS, EEG power increased with age in the frequency range <10 Hz and >17 Hz. The largest rise occurred between 2 and 6 mo. A salient feature of the QS/NREMS spectrum was the emergence of a peak in the sigma band (12-14 Hz) at 2 mo that corresponded to the appearance of sleep spindles. Between 2 and 9 mo, low-frequency delta activity (0.75-1.75 Hz) showed an alternating pattern with a high level occurring in every other QS/NREMS episode. At 6 mo, sigma activity showed a similar pattern. In contrast, theta activity (6.5-9 Hz) exhibited a monotonic decline over consecutive QS/NREMS episodes, a trend that at 9 mo could be closely approximated by an exponential function. The results suggest that 1) EEG markers of sleep homeostasis appear in the first postnatal months, and 2) sleep homeostasis goes through a period of maturation. Theta activity and not delta activity seems to reflect the dissipation of sleep propensity during infancy.


SLEEP ◽  
2019 ◽  
Vol 42 (Supplement_1) ◽  
pp. A12-A12
Author(s):  
Mayumi Machida ◽  
Laurie L Wellman ◽  
Brook L Williams ◽  
Gyorgy Lonart ◽  
Larry D Sanford

2019 ◽  
Author(s):  
Sarah K. Schäfer ◽  
Benedikt E. Wirth ◽  
Marlene Staginnus ◽  
Nicolas Becker ◽  
Tanja Michael ◽  
...  

SummaryNumerous studies have shown that sleep enhances the consolidation of episodic memory. However, it remains unclear whether this consolidation benefit is moderated by the emotional valence of the learned material. To clarify whether sleep selectively enhances the consolidation of emotional material, we conducted a meta-analysis including N = 1,059 observations. Overall, our results do not support this hypothesis. When only studies with a sleep-group wake-group comparison were included in the analysis (k = 22), the retention advantage for emotional over neutral material was not significantly different between sleep and wake groups. When studies initially lacking a wake-control group were included in the analysis after statistical estimation of wake-group parameters, the retention advantage for emotional material was significantly larger in wake-groups than in sleep-groups (k = 34). Interestingly, however, an additional analysis of k = 8 studies investigating the selective effects of rapid-eye-movement sleep and slow-wave sleep on emotional memory consolidation provided evidence for a selective enhancement of emotional over neutral memory consolidation after rapid-eye-movement sleep compared to slow-wave sleep. These results suggest that sleep does not generally enhance emotional memory consolidation over neutral memory consolidation. However, specific sleep stages might preferentially enhance consolidation of emotional and neutral material, respectively.


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