Citations and Stuff

Citations and Reviews!

This article I found discusses the changes in REM sleep after performing memory tasks. Participants of different IQ levels were placed into groups according to their IQ. These groups were asked to complete cognitive procedural/implicit task acquisition  Researchers found that while the duration of REM sleep did not change, the density and number of REMs changed. 

Smith, C. T., Nixon, M. R., & Nader, R. S. (2004). Posttraining increases in REM sleep intensity implicate REM sleep in memory processing and provide a biological marker of learning potential. Learning & memory (Cold Spring Harbor, N.Y.), 11(6), 714–719. https://doi.org/10.1101/lm.74904 

This experiment I found explores how slow-wave sleep (deep sleep) and REM sleep awakenings affect sleep-dependent motor and declarative memory consolidation. They did this by having participants participate in sleep studies where they would be woken up during either deep sleep or REM sleep stages. This led to a significant reduction in the amount of time spent in those respective stages. Participants would then perform certain memory tasks to see how much these sleep stages affect their memory consolidation. Researchers found that these stages did not significantly affect their memory consolidation.

Genzel, L., Dresler, M., Wehrle, R., Grözinger, M., & Steiger, A. (2009). Slow wave sleep and REM sleep awakenings do not affect sleep dependent memory consolidation. Sleep, 32(3), 302–310. https://doi.org/10.1093/sleep/32.3.302 

In this experiment, researchers studied the effect of REM sleep on facial recognition. participants spent one night in a sleep lab where they interacted in a virtual reality simulation with generated characters. Half the group were then deprived of REM sleep, and the other group received a normal amount of REM sleep. The density of REM was recorded as well as fast and slow spindles in both groups. Results showed that the REM deprived group performed worse. Interestingly, REM density did not appear to influence this, but rather the fast and slow spindles. 

Solomonova, E., Stenstrom, P., Schon, E., Duquette, A., Dubé, S., O'Reilly, C., & Nielsen, T. (2017). Sleep-dependent consolidation of face recognition and its relationship to REM sleep duration, REM density and Stage 2 sleep spindles. Journal of sleep research, 26(3), 318–321. https://doi.org/10.1111/jsr.12520 

This study found an interesting link between REM sleep and consolidation of skill memory. Researchers gaved half the participants doses of REM suppressors and had them perform memory tasks the following morning. contrary to their expectations, these participants had improved scores rather than lower scores. They determined that REM sleep is not required for skill-memory consolidation.

 Rasch, B., Pommer, J., Diekelmann, S., & Born, J. (2009). Pharmacological REM sleep suppression paradoxically improves rather than impairs skill memory. Nature neuroscience, 12(4), 396–397. https://doi.org/10.1038/nn.2206 

This experiment looks at the effect of antidepressant drugs on REM sleep and subsequent memory performance. Participants first had their baseline sleep and performance on neuropsychological tasks recorded. Then they recieved different antidepressant drugs in their respective groups. after their night of sleep, it was found that while these drugs suppress REM sleep, it had no affect on their memory consolidation task the following morning. 

Göder, R., Seeck-Hirschner, M., Stingele, K., Huchzermeier, C., Kropp, C., Palaschewski, M., Aldenhoff, J., & Koch, J. (2011). Sleep and cognition at baseline and the effects of REM sleep diminution after 1 week of antidepressive treatment in patients with depression. Journal of sleep research, 20(4), 544–551. https://doi.org/10.1111/j.1365-2869.2011.00914.x

This study looks at the effects of alcohol on the sleep stages. participants recieved varying doses of alcohol and then had their sleep monitored. They found that people recieving a lower dose of alcohol had subtle changes in their sleep patterns, whereas those who had higher doses had significant reduction in their REM sleep cycles. Interestingly it also caused a higher amount of slow-wave sleep across all doses.

Ebrahim, I.O., Shapiro, C.M., Williams, A.J. and Fenwick, P.B. (2013), Alcohol and Sleep I: Effects on Normal Sleep. Alcohol Clin Exp Res, 37: 539`-549. https://doi.org/10.1111/acer.12006 

This article looks at the effect of alcohol on sleep patterns across several nights. the study found that for the first night, the amount of REM sleep was decreasing, but across the next two nights, they saw elevated levels of REM sleep. On the fourth night of the study, researchers found that REM sleep levels had returned to a homeostatic normal level.

YULES RB, LIPPMAN ME, FREEDMAN DX. Alcohol Administration Prior to Sleep: The Effect on EEG Sleep Stages. Arch Gen Psychiatry. 1967;16(1):94–97. doi:10.1001/archpsyc.1967.01730190096012 

This article looks at how heavy drinking affects our sleep, and in particular, problems associated with sleep. For example, insomnia, snoring, deoxygenation, and other breathing-related issues while sleeping. This study found that while it may not directly cause some of these issues, it often aggravates or brings out these issues. It is often associated with circadian rhythm abnormalities. 

Sean He, Brant P Hasler, Subhajit Chakravorty, Alcohol and sleep-related problems, Current Opinion in Psychology, Volume 30, 2019, Pages 117-122, ISSN 2352-250X, https://doi.org/10.1016/j.copsyc.2019.03.007.

This article discusses how REM and NREM sleep are associated with memory consolidation, and in particular the underlying mechanisms and the extent of the effect of REM sleep. Using optogenetic inhibition they were able to inhibit certain waves of REM and leave the others intact. With this inhibition, they expressed reduced spatial awareness and fear-conditioned memory recall but did not express any cognitive impairment. 

Boyce, R., Williams, S., & Adamantidis, A. (2017). REM sleep and memory. Current Opinion in Neurobiology, 44, 167-177. https://doi.org/10.1016/j.conb.2017.05.001 

This study looks at the effects of stress on sleep patterns and the amount of time spent in each cycle of sleep in rats. Researchers first recorded the rat's baseline amount of REM sleep, then put them under intense stress and measured their sleep response. For the first night, they saw a dramatic decrease in all sleep cycles. the second night was only a further decrease in REM sleep. By the end of the study, sleep had rebounded to a near-normal level.

 G. Jean Kant, Ross H. Pastel, Richard A. Bauman, Glenn R. Meininger, Kevin R. Maughan, Thomas N. Robinson, Wanda L. Wright, Parrick S. Covington, Effects of chronic stress on sleep in rats, Physiology & Behavior, Volume 57, Issue 2, 1995, Pages 359-365, ISSN 0031-9384, https://doi.org/10.1016/0031-9384(94)00241-V.

Second Set:

This study aims to look at the theory of memory formation and the physiological support of that theory. In particular, it looks at the changes in cholinergic tone within the hippocampus in the different stages of the sleep-wake cycle. They found that high levels of acetylcholine that are present during active waking, might set appropriate dynamics for encoding new information in the hippocampus. This would partially suppress excitatory feedback to prevent interference from previously stored information. Additionally, lower levels of acetylcholine during quiet waking and slow-wave sleep might release this suppression allowing stronger activity within the hippocampus thus facilitating consolidation of separate memory traces. They conclude that consolidation doesn't necessarily form now links in the neocortex but could be strengthening of representations within the hippocampus.

Hasselmo, ME. “Neuromodulation: acetylcholine and memory consolidation.” Trends in cognitive sciences vol. 3,9 (1999): 351-359. doi:10.1016/s1364-6613(99)01365-0 

This study investigates the proposition that the cAMP/cAMP-dependent PKA signalling pathway participates in both late phase of LTP in the hippocampus as well as the protein synthesis-dependent phase of memory formation. This was studied through the use of several agents related to cAMP/PKA pathways in different areas of the brain. These agents either increased or decreased PKA activity. Together the findings indicate that the late of phase memory consolidaiton of an inhibitory avoidance is modulated cAMP/PKA signaling pathways in the hippocampus.

Bernabeu, R et al. “Involvement of hippocampal cAMP/cAMP-dependent protein kinase signaling pathways in a late memory consolidation phase of aversively motivated learning in rats.” Proceedings of the National Academy of Sciences of the United States of America vol. 94,13 (1997): 7041-6. doi:10.1073/pnas.94.13.7041 

This study made use of paradoxical sleep deprivation (PSD) to study memory. After 12 hours of PSD subjects were either trained immediately or after a 12-hour interval. The group that received training immediately after PSD presented with impaired learning on the second day of training compared to the delayed group as well as the control. This experiment was also completed similarly but with only 4 hours of PSD. Only rats with PSD during the period beginning 4 hours after the end of training showed a deficit. In a third experiment, rats were trained in a Morris Water Maze, but results showed that neither group was impaired. Reseachers concluded that there may be a PS window for place, but not cue, learning in the Morris water maze.

Smith, C, and G M Rose. “Evidence for a paradoxical sleep window for place learning in the Morris water maze.” Physiology & behavior vol. 59,1 (1996): 93-7. doi:10.1016/0031-9384(95)02054-3 

This experiment investigates the hypothesis that disruption of REM sleep will cause impairment of long-term memory. They deprived mince if REM sleep for 3, 5, or 7 continuous days, after receiving a training. A retention test administered after the deprivation showed a temporary retrograde amnesia when tested 30mins or three hours after the end of the REM deprivation. This study suggests that disruption of REM sleep impairs the formation of long-term memory.

Fishbein, W. “Disruptive effects of rapid eye movement sleep deprivation on long-term memory.” Physiology & behavior vol. 6,4 (1971): 279-82. doi:10.1016/0031-9384(71)90155-7 

This study monitored variations in acetylcholine released by the cerebral cortex and dorsal hippocampus in cats during sleep-waking cycle in freely moving cats. They found that ACh increased by around 100% during quiet waking, and by 175% in active waking. During REM sleep, Ach reached levels in the cortex approximately the same as during quiet waking. Levels in the hippocampus rose to about 4 times the the levels reached during slow wave sleep and twice that of quiet waking. These results recieved indicate that the increase in ACh release in the cortext matches the desynchronized EEG of wakefulness and REM sleep. The increase of ACh during REM in the hippocampus seems to be related to the sustained theta activity in the area.

Marrosu, F et al. “Microdialysis measurement of cortical and hippocampal acetylcholine release during sleep-wake cycle in freely moving cats.” Brain research vol. 671,2 (1995): 329-32. doi:10.1016/0006-8993(94)01399-3 

In this study researchers looked at the effects of disterbances to the paradoxical sleep window (PSW). This was completed through two different experiments. Experiment 1 used a biochemical protein synthesis inhibito ansomycin (ANI) which was administered after a training session timed to match with the PSW. control groups were given saline or ANI three hours before or after the beginning of the PSW. Three hours after the injection they were retested. immediately after the animals were sacrificed to see levels of ACh and AChE. they found that all ANI groups had significantly less ACh and AChE activity.  In experiment 2 an ACh agonist was injected into the rats during the same times as before. After retesting they found that only the groups recieving the agonist had learning deficits were the groups that coincided with the PSW. These results suggest that ACh plays and important role in memory processing during the PSW.

Smith, C et al. “Some biochemical and behavioural aspects of the paradoxical sleep window.” Canadian journal of psychology vol. 45,2 (1991): 115-24. doi:10.1037/h0084279