Charles Darwin

"The love for all living creatures is the most noble attribute of man." Charles Darwin

Saturday, April 11, 2015

Dormez-vous ?






Albert Anker, 1895
IN A MAJOR sleep study almost 80% of respondents admitted to not getting the recommended amount of nightly rest. [1]






2015 U.S. National Sleep Foundation recommendations. [2]


Age 
Sleep Needs
Newborns (0–3 months)
14 to 17 hours
Infants (4–11 months)
12 to 15 hours
Toddlers (1–2 years)
11 to 14 hours
Preschoolers (3–5 years)
10 to 13 hours
School-age children (6–13 years)    
  9 to 11 hours
Teenagers (14–17 years)
  8 to 10 hours
Adults
  7 to 9 hours




SLEEP is broadly divided into 2 types:[7]

  • Rapid eye movement (REM)
  • Non-rapid eye movement (NREM)

EEG waveforms of brain activity during 
REM Sleep
REM [7]
  • Inhibition of nearly all voluntary muscles.
  • Stage during which most memorable dreams &/or nightmares occur.
  • Typically, a dream will last from 5 to 30 minutes. [8]



EEG waveforms of brain activity during Slow 
Wave Sleep (N3)
NREM [7]
  • Consists of three stages N1, N2, N3. 
  • During STAGE N1, we lose most conscious awareness of the external environment.
  • STAGE N2 is characterized by sleep spindles (bursts of electrical activity). This stage occupies 45–55% of total sleep in adults.


  • STAGE N3 is characterized by deep or slow-wave sleep; this is the stage during which parasomnias such as night terrors, bed-wetting, sleepwalking, and sleep-talking occur.
(NOTE: My understanding is N3 has now been merged with N4;  the hypnogram below still shows N4 as a separate stage.)

 
HYPNOGRAM showing sleep cycles from midnight to
6:30 am. There is more REM (red) before waking. [9]








WHY DO WE FALL ASLEEP AT NIGHT?


 OUR CIRCADIAN CLOCKS work in tandem with the neurotransmitter adenosine, which inhibits many of the bodily processes associated with wakefulness. Adenosine is created over the course of the day; high levels of adenosine lead to sleepiness. [6]

 Melatonin is considered a strongly circadian hormone, whose secretion increases at dim light and peaks during nocturnal sleep, diminishing with bright light to the eyes. [3]  

Rendering of human circadian (24-hour) biological clock



 THE EFFECTS OF SLEEP DEPRIVATION

[Source: Wikipedia Commons [10]]
HORMONES


  • Growth hormone & prolactin are critically sleep-dependent, and are suppressed in the absence of sleep.[11]
  • Cortisol, which is essential for metabolism is increased during REM sleep. [12]
  • Thyroid Stimulating Hormone increases during nocturnal sleep and decreases with prolonged periods of reduced sleep. [13][14] 

  • A 2002 study, [15] published in the American Journal of Respiratory and Critical Care Medicine found that sleep-disordered breathing is independently associated with glucose intolerance and insulin resistance.

  • In a 2011 study published in the journal, Diabetes Care, researchers found that people with diabetes who slept poorly had higher insulin resistance, and a harder time controlling the disease. [16]

  • A 2012 study, published in the journal, Sleep, suggested that teenagers could improve their insulin resistance and prevent the future onset of diabetes by increasing the amount of sleep they get. [17]




OBESITY

"When the body is forced to stay awake, it becomes very difficult for it to process blood sugar and leptin, a protein hormone that regulates appetite and metabolism. Over time, poor sleeping habits could lead to type 2 diabetes and weight gain, due to your body's decreased ability to process sugar and suppress food cravings." [1]


At this year’s The Endocrine Society's 97th Annual Meeting & Expo., researchers presented data from a study that found patients with more weekday sleep debt were more likely to be obese when compared to participants who had no weekday sleep debt. 
“After 12 months, for every 30 minutes of weekday sleep debt at baseline, the risk of obesity and insulin resistance was significantly increased by 17% and 39%, respectively.” [18][19]



THE BRAIN


  • After ~18 hours without sleep your level of impairment is equal to that of someone with a blood alcohol level (BAC) of 0.05%. [20]
  • By 24 hours of no sleep, you're operating at the same level as someone with a BAC of 0.10%.
  • A regular weekday routine sleep disruption in excess of 20 hours cannot be gained back by sleeping in on the weekend. [51]
  • Evolutionary advances in the size of the mammalian amygdala, (active during sleep and involved in memory processing), are associated with increases in NREM sleep durations. [21] 
  • Likewise, nighttime gene expression differs from daytime expression and specifically targets genes thought to be involved in memory consolidation and brain plasticity. [22]


Plasticity: Brain functions are not confined to certain fixed locations.



  • The sleeping brain has been shown to remove metabolic waste products at a faster rate than during an awake state. [23] It is theorized that sleep helps facilitate the synthesis of molecules that help repair and protect the brain from harmful elements like free radicals generated during waking hours. [24][25]

  • Studies have shown that sleep deprivation early in life can result in decreased brain mass and an abnormal amount of neuronal cell death. [26][27]

  • In a 2011 study [28][29] published in the journal, Current Biology, volunteers who napped before taking an evening memorization test performed ~10% better on an evening test than they had on the morning test. Conversely, the control group, who had stayed awake while the other group napped, performed  ~12% worse on the evening memorization test than they had on the morning test.

  • Building on this, a 2014 study [30][31] out of Saarland University in Germany found that a short sleep, lasting between 45 – 60 minutes produced a 5-fold improvement in memory recall.



THE IMMUNE SYSTEM

  • Researchers have found there exists a direct correlation between modest sleep deprivation - less than six hours - and reduced immune response. [1]
  •  In one 2007 study, the blood tests of sleep-deprived rats' indicated a 20% decrease in white blood cell count when compared to controls. [32]
  • A 2014 study found that depriving mice of sleep increased cancer growth and dampened the immune system's ability to control cancers. [33]

  • Rats kept awake indefinitely develop skin lesions, increased appetite, loss of body mass, hypothermia, and eventually, fatal sepsis. [34] 
(*I endeavor to keep my personal opinions out of these sorts of things,  but will say I'm glad my research days involved tissue culture ... poor mice & rats!)



THE HEART

  • Getting less than 6 hours of sleep a night means your heart (like the rest of your body) has to work overtime. [1]

  • The less sleep you get, the less time the brain has to regulate stress hormones, and over time, sleep deprivation could permanently hinder the brain's ability to regulate these hormones, leading to elevated blood pressure. [1]

 According to a 2013 study published in the European Journal of Preventative Cardiology: [35]

The addition of sufficient sleep to the four traditional healthy lifestyle factors: sufficient physical activity, a healthy diet, (moderate) alcohol consumption, and non-smoking, resulted in a 65% lower risk of composite cardiovascular disease (CVD) and an 83% lower risk of fatal CVD. If all participants adhered to all five healthy lifestyle factors, 36% of composite CVD and 57% of fatal CVD could theoretically be prevented or postponed.





SLEEP DISORDERS & SYNDROMES


 Sleep disorders include:[7][9]

  • FATAL FAMILIAL INSOMNIA  (FFI), is an extremely rare genetic disease with no known treatment or cure characterized by increasing insomnia. (FFI patients cannot pass STAGE 1 - see hypnogram above). Ultimately sufferers of the disease stop sleeping entirely, before dying of the disease. [46]


  • SLEEP PARALYSIS [1][47]  is a common phenomenon in which a person awakes from sleep but feels unable to move. Up to 40% of people report experiencing sleep paralysis at some point in their lives.
  • Researchers say that sleep paralysis happens when a person awakens during REM stage sleep. People in this stage of sleep are usually dreaming, but their muscles are nearly paralyzed. Some suggest this might be an evolutionary adaptation that keeps people from acting out their dreams. [47]


  • SUDDEN UNEXPECTED NOCTURNAL DEATH SYNDROME (SUNDS) is a genetic disease characterized by the body's inability to properly coordinate the electrical signals that cause the heart to beat. [48]
  • When the heart slows down for sleep, the electrical problems that cause SUNDS become more pronounced, overtake the body’s ability to regulate its own heart beat and send the heart into a deadly spasm.
  • Currently, there is no effective treatment for SUNDS, and no clear reason why it tends to affect Southeast Asians more frequently than other groups.
NIGHTMARES [36]

  • According to the American Academy of Sleep Medicine [40] (AASM), an estimated 10 - 50% of children between the ages of 5 and 12 years have nightmares severe enough to wake their parents.
  • The AASM reports an estimated 2 – 8% of the adult population as having severe nightmares. [40]

  • Studies have correlated a high prevalence of nightmares with high stress levels. [37]

  • Neurotransmitter imbalance is another suggested causative factor. The ‘Affective Network Dysfunction’ model suggests that a nightmare is a product of dysfunction of the circuitry normally involved in dreaming. [38][39]

  • A 2014 study [41] published in the journal, Sleep Medicine, found that blind people have four times more nightmares than those with vision. 
    • Nightmares tend to occur in the last third of the night when REM sleep is the strongest. [9]



    DREAMS

    • Dreams are successions of images, ideas, emotions, and sensations that occur involuntarily in the mind during certain stages of sleep (mainly the REM stage). The content and purpose of dreams are not yet clearly understood though various theories have been proposed. [7]

    • Some suggest that dreams are caused by the random firing of neurons in the cerebral cortex during the REM period. [42]
    • From an evolutionary standpoint, it has been suggested that dreams might simulate common threatening events in the animal's life and may be passed on in the form of genetic memories. [43][44]

    Some points from, 'How Sleep Works': [8]

    • All mammals dream.
    • Dreams tell a story. 
    • Dreams almost always involve you. 
    • Dreams incorporate things that have happened to you recently. 
    • They can also incorporate deep wishes and fears.
    • A noise in the environment is often worked in to a dream in some way, giving some credibility to the idea that dreams are simply the brain's response to random impulses.
    • You usually cannot control a dream. (*Lucid dreaming)
    • In sleep experiments where a person is woken up every time he/she enters REM sleep, the person becomes increasingly impatient and uncomfortable over time. 




    GENETICS

    What did Napoleon, Edison, Tesla and Franklin all have in common? They are believed to have needed no more than 5 hours of sleep a night to function normally. (Well, normally might be a bit of an understatement.)

    Researchers have discovered some evidence to support the idea that sleep duration may be regulated by genetics.

     From a 2009 study published in the journal, Science: [49]
    "We have identified a mutation in a transcriptional repressor (hDEC2-P385R) that is associated with a human short sleep phenotype."

    And more recently from Molecular Psychiatry (2011) via Science Daily: [50]
    An international team of researchers led by Ludwig-Maximilians-Universitaet Muenchen (LMU) chronobiologists Professor Till Roenneberg and Dr. Karla Allebrandt has identified the first genetic variant that has a significant effect on sleep duration and is found frequently in the general population. Researchers have shown that ABCC9, a known genetic factor in heart disease and diabetes, also influences the duration of sleep in humans. 
    THE NIGHT OWLS

    And then there’s this category, the one to which I belong: The Night Owls; the group whose brains seem to function at their optimum whilst the so-called, Morning Larks are refueling.

    The good news, as reported in Medical Daily’s Up All Night: 7 Little-Known Facts About Night Owls [52] is that there are benefits to be reaped from being a Night Owl, provided we get our daily 7 to 9 hours of sleep. Visit the above link for details, but here are a few from the list: (both good & bad)

    1. Night owls are more creative.
    2. Night owls score higher on general intelligence tests.
    5. Night owls are more likely to be psychopaths.
    6. Night owls have greater physical strength in the evening.




    AND LASTLY, for what it’s worth (as I’m pretty sure we are all well aware of what it is we should be doing), the following are a few commonly suggested ways to improve the quality of your sleep:

    • EXERCISE
    • HEALTHY DIET
    • KEEP CAFFEINE CONSUMPTION TO A MINIMUM
    • ADHERE TO A SLEEP ROUTINE
    • TURN OFF T.V., COMPUTER, ETC. (Remember, light messes with your melatonin.)

    FYI: There's a new product called Sprayable Sleep, [4] that claims its trans-dermal application (2 spritzes) of melatonin will have you sleeping within an hour of delivery. [5]















    ***
    FIN







    UPDATES / RELATED

    Take A Nap To Counteract Impulsive Behavior, Ease Frustration / Medical Daily / June 30, 2015
    Disrupted Deep Sleep Linked To Alzheimer's With Buildup Of Amyloid Plaques, Memory Loss / Medical Daily / June 1, 2015
     How Sleep Deprivation Works / How Stuff Works






    REFERENCES

    [1] http://health.howstuffworks.com/mental-health/sleep/basics/5-effects-of-sleep-deprivation.htm#page=1
    The Editors of Publications International, Ltd., and Victoria Plummer. "5 Effects of Sleep Deprivation" 30 August 2010. HowStuffWorks.com. <http://health.howstuffworks.com/mental-health/sleep/basics/5-effects-of-sleep-deprivation.htm> 08 April 2015.
    [2] Hirshkowitz, Max ; Whiton, Kaitlyn et al. (14 January 2015). "National Sleep Foundation’s sleep time duration recommendations: methodology and results summary". Sleep Health: Journal of the National Sleep Foundation (Elsevier Inc). doi:10.1016/j.sleh.2014.12.010.
    [3] Lewy, A.; Wehr, T.; Goodwin, F.; Newsome, D.; Markey, S. (12 December 1980). "Light suppresses melatonin secretion in humans". Science 210 (4475): 1267–1269.doi:10.1126/science.7434030.
    [4] https://www.indiegogo.com/projects/sprayable-sleep-sleep-you-spray-on-your-skin
    [5] http://www.medicaldaily.com/magic-bullet-sleep-sprayable-sleep-uses-melatonin-help-you-knock-out-transdermal-319578
    [6] Molecules that build up and make you sleep. thebrain.mcgill.ca
    [7] http://en.wikipedia.org/wiki/Neuroscience_of_sleep
    [8] http://science.howstuffworks.com/life/inside-the-mind/human-brain/sleep4.htm
    Brain, Marshall. "How Sleep Works" 01 April 2000. HowStuffWorks.com. <http://science.howstuffworks.com/life/inside-the-mind/human-brain/sleep.htm> 05 April 2015.
    [9] http://en.wikipedia.org/wiki/Sleep
    [10] Reference list is found on image page in Commons: Commons:File:Effects of sleep deprivation.svg#References
    [11] Van Cauter, E. (1 June 1992). "A quantitative estimation of growth hormone secretion in normal man: reproducibility and relation to sleep and time of day". Journal of Clinical Endocrinology & Metabolism 74 (6): 1441–1450. doi:10.1210/jc.74.6.1441.
    [12] Kern, W.; Dodt, C.; Born, J.; Fehm, H. L. (1 January 1996). "Changes in Cortisol and Growth Hormone Secretion During Nocturnal Sleep in the Course of Aging". The Journals of Gerontology Series A: Biological Sciences and Medical Sciences51A (1): M3–M9. doi:10.1093/gerona/51A.1.M3.
    [13] Knutson, Kristen L.; Spiegel, Karine; Penev, Plamen; Van Cauter, Eve. "The metabolic consequences of sleep deprivation".Sleep Medicine Reviews 11 (3): 163–178.doi:10.1016/j.smrv.2007.01.002. PMC 1991337.PMID 17442599.
    [14] Spiegel, Karine; Leproult, Rachel; Van Cauter, Eve (1 October 1999). "Impact of sleep debt on metabolic and endocrine function".The Lancet 354 (9188): 1435–1439. doi:10.1016/S0140-6736(99)01376-8. PMID 10543671.
    [15] http://www.atsjournals.org/doi/full/10.1164/ajrccm.165.5.2104087#.VSHdEGjF_UU
    [16] http://www.sciencedaily.com/releases/2011/05/110502151427.htm
    University of Chicago Medical Center. "Insomnia linked to high insulin resistance in diabetics." ScienceDaily. ScienceDaily, 3 May 2011. <www.sciencedaily.com/releases/2011/05/110502151427.htm>.
    [17] http://www.sciencedaily.com/releases/2012/09/120929140234.htm
    American Academy of Sleep Medicine. "Lack of sleep leads to insulin resistance in teens." ScienceDaily. ScienceDaily, 29 September 2012. <www.sciencedaily.com/releases/2012/09/120929140234.htm>
    [18] http://www.medicaldaily.com/got-sleep-problems-losing-30-minutes-sleep-each-day-could-mess-metabolic-function-324852
    [19] Taheri S, et al. Losing 30 minutes of sleep per day may promote weight gain and adversely affect blood sugar control. At ENDO 2015, The Endocrine Society's 97th Annual Meeting & Expo. 2015.
    [20] http://health.howstuffworks.com/mental-health/sleep/basics/can-you-die-if-you-dont-sleep.htm
    Turner, Bambi. "Can you die if you don’t sleep?" 12 March 2015. HowStuffWorks.com. <http://health.howstuffworks.com/mental-health/sleep/basics/can-you-die-if-you-dont-sleep.htm> 05 April 2015
    [21] Capellini I, McNamara P, Preston BT, Nunn CL, Barton RA (2009). Sporns, Olaf, ed. "Does sleep play a role in memory consolidation? A comparative test". PLoS ONE 4 (2): 4609. Bibcode:2009PLoSO...4.4609C. doi:10.1371/journal.pone.0004609. PMC 2643482.PMID 19240803.
    [22] Cirelli C, Gutierrez CM, Tononi G (2004). "Extensive and divergent effects of sleep and wakefulness on brain gene expression". Neuron 41 (1): 35–43. doi:10.1016/S0896-6273(03)00814-6. PMID 14715133.
    [23] "Brain may flush out toxins during sleep". National Institutes of Health.
    [24] Siegel JM (2005). "Clues to the functions of mammalian sleep". Nature 437 (7063): 1264–1271. Bibcode:2005Natur.437.1264S.doi:10.1038/nature04285. PMID 16251951.
    [25] Reimund E (October 1994). "The free radical flux theory of sleep". Medical Hypotheses 45 (4): 231–3. doi:10.1016/0306-9877(94)90071-X.PMID 7838006.
    [26] Mirmiran M, Scholtens J, van de Poll NE, Uylings HB, van der Gugten J, Boer GJ (April 1983). "Effects of experimental suppression of active (REM) sleep during early development upon adult brain and behavior in the rat". Brain Research 283 (2-3): 277–86. doi:10.1016/0165-3806(83)90184-0. PMID 6850353.
    [27] Morrissey MJ, Duntley SP, Anch AM, Nonneman R (2004). "Active sleep and its role in the prevention of apoptosis in the developing brain".Medical Hypotheses 62 (6): 876–9. doi:10.1016/j.mehy.2004.01.014. PMID 15142640.
    [28] http://www.livescience.com/13125-sleep-naps-boost-memory.html
    [29] http://www.sciencedirect.com/science/article/pii/S096098221100042X
    [30] http://www.medicaldaily.com/power-nap-school-and-office-may-help-you-retain-learned-memory-better-326558
    [31] Studte S, Bridger E, and Mecklinger A. Nap sleep preserves associative but not item memory performance. Neurobiology of Learning and Memory, 2015.
    [32] Zager A, Andersen ML, Ruiz FS, Antunes IB, Tufik S (2007). "Effects of acute and chronic sleep loss on immune modulation of rats". American Journal of Physiology. Regulatory, Integrative and Comparative Physiology 293 (1): R504–9. doi:10.1152/ajpregu.00105.2007.PMID 17409265.
    [33] Reimund E (October 1994). "The free radical flux theory of sleep". Medical Hypotheses 45 (4): 231–3. doi:10.1016/0306-9877(94)90071-X.PMID 7838006.
    [34] Guidelines for the Care and Use of Mammals in Neuroscience and Behavioral Research. Institute for Laboratory Animal Research (ILAR), National Research Council. The National Academies Press. 2003. p. 121. ISBN 978-0-309-08903-6. Sleep deprivation of over 7 days with thedisk-over-water system results in the development of ulcerative skin lesions, hyperphagia, loss of body mass, hypothermia, and eventually septicemia and death in rats (Everson, 1995; Rechtschaffen et al., 1983).
    [35] http://www.dailymail.co.uk/health/article-2353692/Lack-sleep-increases-risk-heart-disease-SMOKING.html
    [36] http://www.medicaldaily.com/bad-dream-more-just-dream-science-nightmares-327586
    [37] Sadeh, Avi; Keinan, Giora; Daon, Keren (1 January 2004). "Effects of Stress on Sleep: The Moderating Role of Coping Style.".Health Psychology 23 (5): 542–545. doi:10.1037/0278-6133.23.5.542.
    [38] Pagel, J.F. "Drugs, Dreams, and Nightmares". Sleep Medicine Clinics 5 (2): 277–287. doi:10.1016/j.jsmc.2010.01.007.
    [39] Levin, Ross; Nielsen, Tore (1 April 2009). "Nightmares, Bad Dreams, and Emotion Dysregulation: A Review and New Neurocognitive Model of Dreaming". Current Directions in Psychological Science 18 (2): 84–88. doi:10.1111/j.1467-
    [40] http://www.aasmnet.org/resources/factsheets/nightmareparasom.pdf
    [41] http://www.medicaldaily.com/blind-peoples-nightmares-product-intense-negative-emotion-while-awake-306533
    [42] Cirelli C, Gutierrez CM, Tononi G (2004). "Extensive and divergent effects of sleep and wakefulness on brain gene expression". Neuron 41 (1): 35–43. doi:10.1016/S0896-6273(03)00814-6. PMID 14715133.
    [43] Revonsuo, A (December 2000). "The reinterpretation of dreams: an evolutionary hypothesis of the function of dreaming.". The Behavioral and brain sciences 23 (6): 877–901; discussion 904–1121. doi:10.1017/s0140525x00004015. PMID 11515147.
    [44] Montangero, Jacques (2000). "A more general evolutionary hypothesis about dream function". Behavioral and Brain Sciences23 (6): 972–973. doi:10.1017/s0140525x00664026.
    [45] Hobson JA, McCarley RW (1977). "The brain as a dream state generator: An activation-synthesis hypothesis of the dream process". American Journal of Psychiatry 134 (12): 1335–1348. PMID 21570.
    [46] Schenkein J, Montagna P (2006). "Self management of fatal familial insomnia. Part 1: what is FFI?". MedGenMed 8 (3): 65.PMC 1781306. PMID 17406188.
    [47] http://www.livescience.com/49457-sleep-paralysis-hallucinations.html
    [48] http://www.livescience.com/8215-die-nightmares.html
    [49] He Y, Jones CR, Fujiki N, et al. The Transcriptional Repressor DEC2 Regulates Sleep Length in Mammals.Science (New York, NY). 2009;325(5942):866-870. doi:10.1126/science.1174443.
    [50] Ludwig-Maximilians-Universitaet Muenchen (LMU). "The ABCC9 of sleep: A genetic factor regulates how long we sleep." ScienceDaily. ScienceDaily, 25 November 2011. <www.sciencedaily.com/releases/2011/11/111124150237.htm>.
    [51] http://www.medicaldaily.com/pulse/sleep-deprivation-changes-our-genes-which-hurts-our-overall-health-323338
    [52] Up All Night: 7 Little-Known Facts About Night Owls / Feb 25, 2015 / By Lizette Borreli




    IMAGE CREDITS


    "Auf dem Ofen 1895" by Albert Anker - Unknown. Licensed under Public Domain via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Auf_dem_Ofen_1895.jpg#/media/File:Auf_dem_Ofen_1895.jpg
    "SWS". Licensed under Public Domain via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:SWS.jpg#/media/File:SWS.jpg

    "Sleep EEG REM" by MrSandman at English Wikipedia - Transferred from en.wikipedia to Commons.. Licensed under Public Domain via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Sleep_EEG_REM.png#/media/File:Sleep_EEG_REM.png

    "Sleep Hypnogram" by I, RazerM. Licensed under CC BY-SA 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Sleep_Hypnogram.svg#/media/File:Sleep_Hypnogram.svg

    "Biological clock human" by NoNameGYassineMrabetTalk✉ fixed by Addicted04 - The work was done with Inkscape by YassineMrabet. Informations were provided from "The Body Clock Guide to Better Health" by Michael Smolensky and Lynne Lamberg; Henry Holt and Company, Publishers (2000). Landscape was sampled from Open Clip Art Library (Ryan, Public domain). Vitruvian Man and the clock were sampled from Image:P human body.svg (GNU licence) and Image:Nuvola apps clock.png, respectively.. Licensed under CC BY-SA 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Biological_clock_human.svg#/media/File:Biological_clock_human.svg

    "Effects of sleep deprivation" by Mikael Häggström.When using this image in external works, it may be cited as follows:Häggström, Mikael. "Medical gallery of Mikael Häggström 2014". Wikiversity Journal of Medicine 1 (2). DOI:10.15347/wjm/2014.008. ISSN 20018762. - All used images are in public domain.. Licensed under CC0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Effects_of_sleep_deprivation.svg#/media/File:Effects_of_sleep_deprivation.svg

    "Brain 2". Licensed under Public Domain via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Brain_2.jpg#/media/File:Brain_2.jpg


    Posted by at
    Labels: , , , , ,

    No comments:

    Post a Comment

    Subscribe to: Post Comments (Atom)