The neurophysiological basis of excessive daytime sleepiness: suggestions of an altered state of consciousness

  • P. K. Hitchcott
  • D. Menicucci
  • S. Frumento
  • A. Zaccaro
  • A. GemignaniEmail author
Sleep Breathing Physiology and Disorders • Review
Part of the following topical collections:
  1. Excessive Daytime Sleepiness


Excessive daytime sleepiness (EDS) is characterized by difficulty staying awake during daytime, though additional features may be present. EDS is a significant problem for clinical and non-clinical populations, being associated with a range of negative outcomes that also represent a burden for society. Extreme EDS is associated with sleep disorders, most notably the central hypersomnias such as narcolepsy, Kleine-Levin syndrome, and idiopathic hypersomnia (IH). Although investigation of these conditions indicates that EDS results from diminished sleep quality, the underlying cause for this impairment remains uncertain. One possibility could be that previous research has been too narrow in scope with insufficient attention paid to non-sleep-related aspects. Here, we offer a broader perspective in which findings concerning the impact of EDS on cortical functioning are interpreted in relation to current understanding about the neural basis of consciousness. Alterations in the spatial distribution of cortical activity, in particular reduced connectivity of frontal cortex, suggest that EDS is associated with an altered state of consciousness.


Sleep Hypersomnia Excessive daytime sleepiness Altered state of consciousness 


Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical approval

This article does not contain any studies with human participants performed by any of the authors.


  1. 1.
    Dauvilliers Y, Bassetti CL (2017) Idiopathic hypersomnia. In: Kryger MH, Roth T, Dement WC (eds) Principles and practice of pediatric sleep medicine, 6th edn. Elsevier, Philadelphia, pp 883–891CrossRefGoogle Scholar
  2. 2.
    Ohayon MM, Dauvilliers Y, Reynolds CF (2012) Operational definitions and algorithms for excessive sleepiness in the general population: implications for DSM-5 nosology. Arch Gen Psychiatry 69:71–79. CrossRefPubMedPubMedCentralGoogle Scholar
  3. 3.
    Blachier M, Dauvilliers Y, Jaussent I, Helmer C, Ritchie K, Jouven X, Tzourio C, Amouyel P, Besset A, Ducimetiere P, Empana JP (2012) Excessive daytime sleepiness and vascular events: the three city study. Ann Neurol 71:661–667. CrossRefPubMedGoogle Scholar
  4. 4.
    Jaussent I, Bouyer J, Ancelin ML, Berr C, Foubert-Samier A, Ritchie K, Ohayon MM, Besset A, Dauvilliers Y (2012) Excessive sleepiness is predictive of cognitive decline in the elderly. Sleep 35:1201–1207. CrossRefPubMedPubMedCentralGoogle Scholar
  5. 5.
    Jaussent I, Empana JP, Ancelin ML, Besset A, Helmer C, Tzourio C, Ritchie K, Bouyer J, Davilliers Y (2013) Insomnia, daytime sleepiness and cardio-cerebrovascular diseases in the elderly: a 6-year prospective study. PLoS One 8:e56048. CrossRefPubMedPubMedCentralGoogle Scholar
  6. 6.
    Ohayon MM (2008) From wakefulness to excessive sleepiness: what we know and still need to know. Sleep Med Rev 12:129–141. CrossRefPubMedPubMedCentralGoogle Scholar
  7. 7.
    Ohayon MM (2012) Determining the level of sleepiness in the American population and its correlates. J Psychiatr Res 46:422–427. CrossRefPubMedGoogle Scholar
  8. 8.
    Strohl KP, Brown DB, Collop N, George C, Grunstein R, Han F, Kline L, Malhotra A, Pack A, Phillips B, Rodenstein D, Schwab R, Weaver T, Wilson K (2013) ATS ad hoc committee on sleep apnea, sleepiness, and driving risk in noncommercial drivers. An official American Thoracic Society clinical practice guideline: sleep apnea, sleepiness, and driving risk in noncommercial drivers. An update of a 1994 statement. Am J Respir Crit Care Med 187:1259–1266. CrossRefPubMedPubMedCentralGoogle Scholar
  9. 9.
    Partinen M (2011) Epidemiology of sleep disorders. In: Montagna P, Chokroverty S (eds) Handbook of clinical neurology, 98 (3rd series) Sleep Disorders, Part, vol 1. Elsevier, Philadelphia, pp 275–314Google Scholar
  10. 10.
    Shen J, Barbera J, Shapiro CM (2006) Distinguishing sleepiness and fatigue: focus on definition and measurement. Sleep Med Rev 10(1):63–76. CrossRefPubMedGoogle Scholar
  11. 11.
    Vgontzas AN, Chrousos GP (2002) Sleep, the hypothalamic-pituitary-adrenal axis, and cytokines: multiple interactions and disturbances in sleep disorders. Endocrinol Metab Clin N Am 31:15–36CrossRefGoogle Scholar
  12. 12.
    Carskadon MA, Dement WC, Mitler MM, Roth T, Westbrook PR, Keenan S (1986) Guidelines for the multiple sleep latency test (MSLT): a standard measure of sleepiness. Sleep 9:519–524CrossRefPubMedGoogle Scholar
  13. 13.
    Johns MW (1991) A new method for measuring daytime sleepiness: the Epworth sleepiness scale. Sleep 14:540–545CrossRefPubMedGoogle Scholar
  14. 14.
    Hoddes E, Zarcone V, Smythe H, Phillips R, Dement WC (1973) Quantification of sleepiness: a new approach. Psychophysiology 10:431–436CrossRefPubMedGoogle Scholar
  15. 15.
    Åkerstedt T, Gillberg M (1990) Subjective and objective sleepiness in the active individual. Int J Neurosci 52:29–37CrossRefPubMedGoogle Scholar
  16. 16.
    Bixler EO, Vgontzas AN, Lin HM, Calhoun SL, Vela-Bueno A, Kales A (2005) Excessive daytime sleepiness in a general population sample: the role of sleep apnea, age, obesity, diabetes, and depression. J Clin Endocrin Metab 90:4510–4515. CrossRefGoogle Scholar
  17. 17.
    Ohayon MM, Priest RG, Zulley J, Smirne S, Paiva T (2002) Prevalence of narcolepsy symptomatology and diagnosis in the European general population. Neurology 58:1826–1833CrossRefPubMedGoogle Scholar
  18. 18.
    Ford ES, Cunningham TJ, Giles WH, Croft JB (2015) Trends in insomnia and excessive daytime sleepiness among US adults from 2002 to 2012. Sleep Med 16:372–378. CrossRefPubMedPubMedCentralGoogle Scholar
  19. 19.
    Jaussent I, Morin CM, Ivers H, Dauvilliers Y (2017) Incidence, worsening and risk factors of daytime sleepiness in a population-based 5-year longitudinal study. Sci Rep 7:1372. CrossRefPubMedPubMedCentralGoogle Scholar
  20. 20.
    Pallesen S, Nordhus IH, Omvik S, Sivertsen B, Tell GS, Bjorvatn B (2007) Prevalence and risk factors of subjective sleepiness in the general adult population. Sleep 30:619–624CrossRefPubMedGoogle Scholar
  21. 21.
    Wu S, Wang R, Ma X, Zhao Y, Yan X, He J (2012) Excessive daytime sleepiness assessed by the Epworth sleepiness scale and its association with health related quality of life: a population-based study in China. BMC Public Health 12:849. CrossRefPubMedPubMedCentralGoogle Scholar
  22. 22.
    Fernandez-Mendoza J, Calhoun SL (2015) Excessive daytime sleepiness: age, sleep, mood, and metabolic modulation. In Watson RR (Ed.) Modulation of sleep by obesity, diabetes, age, and diet. Academic Press pp 193-202Google Scholar
  23. 23.
    American Academy of Sleep Medicine (2014) International classification of sleep disorders–third edition (ICSD-3). American Academy of Sleep Medicine, Darien, ILGoogle Scholar
  24. 24.
    Miglis MG, Guilleminault C (2014) Kleine-Levin syndrome: a review. Nat Sci Sleep 6:19–26. CrossRefPubMedPubMedCentralGoogle Scholar
  25. 25.
    Mignot E, Lin L, Finn L, Lopes C, Pluff K, Sundstrom ML, Young T (2006) Correlates of sleep-onset REM periods during the multiple sleep latency test in community adults. Brain 129:1609–1623CrossRefPubMedGoogle Scholar
  26. 26.
    Ohayon MM, Reynolds CF III, Dauvilliers Y (2013) Excessive sleep duration and quality of life. Ann Neurol 73:785–794. CrossRefPubMedPubMedCentralGoogle Scholar
  27. 27.
    Singh M, Drake CL, Roth T (2006) The prevalence of multiple sleep-onset REM periods in a population-based sample. Sleep 29:890–895CrossRefPubMedGoogle Scholar
  28. 28.
    Roth B (1981) Idiopathic hypersomnia: a study of 187 personally observed cases. Int J Neurol 15:108–118PubMedGoogle Scholar
  29. 29.
    Vernet C, Arnulf I (2009) Idiopathic hypersomnia with and without long sleep time: a controlled series of 75 patients. Sleep 32:753–759CrossRefPubMedPubMedCentralGoogle Scholar
  30. 30.
    Vernet C, Leu-Semenescu S, Buzare MA, Arnulf I (2010) Subjective symptoms in idiopathic hypersomnia: beyond excessive sleepiness. J Sleep Res 19:525–534. CrossRefPubMedGoogle Scholar
  31. 31.
    Vgontzas AN, Bixler EO, Kales A, Criley C, Vela-Bueno A (2000) Differences in nocturnal and daytime sleep between primary and psychiatric hypersomnia: diagnostic and treatment implications. Psychosom Med 62:220–226CrossRefPubMedGoogle Scholar
  32. 32.
    Pizza F, Ferri R, Poli F, Vandi S, Cosentino FI, Plazzi G (2013) Polysomnographic study of nocturnal sleep in idiopathic hypersomnia without long sleep time. J Sleep Res 22:185–196. CrossRefPubMedGoogle Scholar
  33. 33.
    Hara J, Beuckmann CT, Nambu T, Willie JT, Chemelli RM, Sinton CM, Sugiyama F, Yagami K, Goto K, Yanagisawa M, Sakurai T (2001) Genetic ablation of orexin neurons in mice results in narcolepsy, hypophagia, and obesity. Neuron 30:345–354CrossRefPubMedGoogle Scholar
  34. 34.
    Liblau RS, Vassalli A, Seifinejad A, Tafti M (2015) Hypocretin (orexin) biology and the pathophysiology of narcolepsy with cataplexy. Lancet Neurol 14:318–328. CrossRefPubMedGoogle Scholar
  35. 35.
    Dauvilliers Y, Baumann CR, Carlander B, Bischof M, Blatter T, Lecendreux M, Maly F, Besset A, Touchon J, Billiard M, Tafti M, Bassetti CL (2003) CSF hypocretin-1 levels in narcolepsy, Kleine-Levin syndrome, and other hypersomnias and neurological conditions. J Neurol Neurosurg Psychiatry 74:1667–1673CrossRefPubMedPubMedCentralGoogle Scholar
  36. 36.
    Kanbayashi T, Inoue Y, Chiba S, Aizawa R, Saito Y, Tsukamoto H, Fujii Y, Nishino S, Shimizu T (2002) CSF hypocretin-1 (orexin-A) concentrations in narcolepsy with and without cataplexy and idiopathic hypersomnia. J Sleep Res 11:91–93CrossRefPubMedGoogle Scholar
  37. 37.
    Mignot E, Lammers GJ, Ripley B, Okun M, Nevsimalova S, Overeem S, Vankova J, Black J, Harsh J, Bassetti C, Schrader H, Nishino S (2002) The role of cerebrospinal fluid hypocretin measurement in the diagnosis of narcolepsy and other hypersomnias. Arch Neurol 59:1553–1562CrossRefPubMedGoogle Scholar
  38. 38.
    Baumann CR, Bassetti CL (2005) Hypocretins (orexins) and sleep–wake disorders. Lancet Neurol 4:673–682. CrossRefPubMedGoogle Scholar
  39. 39.
    Kok SW, Overeem S, Visscher TL, Lammers GJ, Seidell JC, Pijl H, Meinders AE (2003) Hypocretin deficiency in narcoleptic humans is associated with abdominal obesity. Obes Res 11:1147–1154CrossRefPubMedGoogle Scholar
  40. 40.
    Nishino S, Sakurai E, Nevsimalova S, Yoshida Y, Watanabe T, Yanai K, Mignot E (2009) Decreased CSF histamine in narcolepsy with and without low CSF hypocretin-1 in comparison to healthy controls. Sleep 32:175–180CrossRefPubMedPubMedCentralGoogle Scholar
  41. 41.
    Brown RE, Basheer R, McKenna JT, Strecker RE, McCarley RW (2012) Control of sleep and wakefulness. Physiol Rev 92:1087–1187. CrossRefPubMedPubMedCentralGoogle Scholar
  42. 42.
    Cirelli C, Tononi G (2008) Is sleep essential? PLoS Biol 6:e216. CrossRefPubMedPubMedCentralGoogle Scholar
  43. 43.
    Montagna P, Gambetti P, Cortelli P, Lugaresi E (2003) Familial and sporadic fatal insomnia. Lancet Neurol 2:167–176CrossRefPubMedGoogle Scholar
  44. 44.
    Rechtschaffen A, Gilliland MA, Bergmann BM, Winter JB (1983) Physiological correlates of prolonged sleep deprivation in rats. Science 221:182–184CrossRefPubMedGoogle Scholar
  45. 45.
    Steriade M (2006) Grouping of brain rhythms in corticothalamic systems. Neuroscience 137:1087–1106CrossRefPubMedGoogle Scholar
  46. 46.
    Menicucci D, Piarulli A, Allegrini P, Laurino M, Mastorci F, Sebastiani L, Bedini R, Gemignani A (2013) Fragments of wake-like activity frame down-states of sleep slow oscillations in humans: new vistas for studying homeostatic processes during sleep. Int J Psychophysiol 89:151–157. CrossRefPubMedGoogle Scholar
  47. 47.
    Crunelli V, Hughes SW (2010) The slow (< 1 Hz) rhythm of non-REM sleep: a dialogue between three cardinal oscillators. Nat Neurosci 13:9–17. CrossRefPubMedGoogle Scholar
  48. 48.
    Siegel J (2004) Brain mechanisms that control sleep and waking. Naturwissenschaften 91:355–365CrossRefPubMedGoogle Scholar
  49. 49.
    Siegel JM (2005) Clues to the functions of mammalian sleep. Nature 437:1264–1271CrossRefPubMedGoogle Scholar
  50. 50.
    Siegel JM (2009) Sleep viewed as a state of adaptive inactivity. Nat Rev Neurosci 10:747–753. CrossRefPubMedPubMedCentralGoogle Scholar
  51. 51.
    Maquet P (1995) Sleep function(s) and cerebral metabolism. Behav Brain Res 69:75–83CrossRefPubMedGoogle Scholar
  52. 52.
    Maquet P (2000) Functional neuroimaging of normal human sleep by positron emission tomography. J Sleep Res 9:207–232CrossRefPubMedGoogle Scholar
  53. 53.
    Mackiewicz M, Shockley KR, Romer MA, Galante RJ, Zimmerman JE, Naidoo N, Baldwin DA, Jensen ST, Churchill GA, Pack AI (2008) Macromolecule biosynthesis - a key function of sleep. Physiol Genomics 31:441–457CrossRefGoogle Scholar
  54. 54.
    Reimund E (1994) The free radical flux theory of sleep. Med Hypotheses 43:231–233CrossRefPubMedGoogle Scholar
  55. 55.
    Xie L, Kang H, Xu Q, Chen MJ, Liao Y, Thiyagarajan M, O’Donnell J, Christensen DJ, Nicholson C, Illiff JJ, Takano T, Deane R, Nedergaard M (2013) Sleep drives metabolite clearance from the adult brain. Science 342:373–377. CrossRefPubMedGoogle Scholar
  56. 56.
    Ramm P, Smith CT (1990) Rates of cerebral protein synthesis are linked to slow wave sleep in the rat. Physiol Behav 48:749–753CrossRefPubMedGoogle Scholar
  57. 57.
    Eiland MM, Ramanathan L, Gulyani S, Gilliland M, Bergmann BM, Rechtschaffen A, Siegel JM (2002) Increases in amino-cupric-silver staining of the supraoptic nucleus after sleep deprivation. Brain Res 945:1–8CrossRefPubMedGoogle Scholar
  58. 58.
    Ramanathan L, Gulyani S, Nienhuis R, Siegel JM (2002) Sleep deprivation decreases superoxide dismutase activity in rat hippocampus and brainstem. Neuroreport 13:1387–1390CrossRefPubMedGoogle Scholar
  59. 59.
    Shain W, Forman DS, Madelian V, Turner JN (1987) Morphology of astroglial cells is controlled by beta-adrenergic receptors. J Cell Biol 105:2307–2314CrossRefPubMedGoogle Scholar
  60. 60.
    Blutstein T, Haydon PG (2013) The importance of astrocyte-derived purines in the modulation of sleep. Glia 61:129–139CrossRefPubMedGoogle Scholar
  61. 61.
    O’Donnell J, Ding F, Nedergaard M (2015) Distinct functional states of astrocytes during sleep and wakefulness: is norepinephrine the master regulator? Curr Sleep Med Rep 1:1–8CrossRefPubMedPubMedCentralGoogle Scholar
  62. 62.
    Dudai Y (2004) The neurobiology of consolidations, or, how stable is the engram? Ann Rev Psychol 55:51–86CrossRefGoogle Scholar
  63. 63.
    McGaugh JL (2000) Memory--a century of consolidation. Science 287:248–251CrossRefPubMedGoogle Scholar
  64. 64.
    Bosch M, Castro J, Saneyoshi T, Matsuno H, Sur M, Hayashi Y (2014) Structural and molecular remodeling of dendritic spine substructures during long-term potentiation. Neuron 82:444–459CrossRefPubMedPubMedCentralGoogle Scholar
  65. 65.
    Dudai Y, Karni A, Born J (2015) The consolidation and transformation of memory. Neuron 88:20–32CrossRefPubMedGoogle Scholar
  66. 66.
    Rasch B, Born J (2013) About sleep’s role in memory. Physiolol Rev 93:681–766CrossRefGoogle Scholar
  67. 67.
    O’Neill J, Pleydell-Bouverie B, Dupret D, Csicsvari J (2010) Play it again: reactivation of waking experience and memory. Trends Neurosci 33:220–229CrossRefPubMedGoogle Scholar
  68. 68.
    Tamminen J, Payne JD, Stickgold R, Wamsley EJ, Gaskell MG (2010) Sleep spindle activity is associated with the integration of new memories and existing knowledge. J Neurosci 30:14356–14360CrossRefPubMedPubMedCentralGoogle Scholar
  69. 69.
    Wagner U, Gais S, Haider H, Verleger R, Born J (2004) Sleep inspires insight. Nature 427:352–355CrossRefPubMedGoogle Scholar
  70. 70.
    Marshall L, Helgadóttir H, Mölle M, Born J (2006) Boosting slow oscillations during sleep potentiates memory. Nature 444:610–613CrossRefPubMedGoogle Scholar
  71. 71.
    Diekelmann S, Born J (2010) The memory function of sleep. Nat Rev Neurosci 11:114–126CrossRefPubMedGoogle Scholar
  72. 72.
    Sforza E, Gaudreau H, Petit D, Montplaisir J (2000) Homeostatic sleep regulation in patients with idiopathic hypersomnia. Clin Neurophysiol 111:277–282CrossRefPubMedGoogle Scholar
  73. 73.
    Reid LM, MacLullich AM (2006) Subjective memory complaints and cognitive impairment in older people. Dement Geriatr Cogn Disord 22:471–485CrossRefPubMedPubMedCentralGoogle Scholar
  74. 74.
    Wearden AJ, Appleby L (1996) Research on cognitive complaints and cognitive functioning in patients with chronic fatigue syndrome (CFS): what conclusions can we draw? J Psychosom Res 41:197–211CrossRefPubMedGoogle Scholar
  75. 75.
    Thomann J, Baumann CR, Landolt HP, Werth E (2014) Psychomotor vigilance task demonstrates impaired vigilance in disorders with excessive daytime sleepiness. J Clin Sleep Med 10:1019–1024PubMedPubMedCentralGoogle Scholar
  76. 76.
    Van Schie MK, Thijs RD, Fronczek R, Middelkoop HA, Lammers GJ, Van Dijk JG (2012) Sustained attention to response task (SART) shows impaired vigilance in a spectrum of disorders of excessive daytime sleepiness. J Sleep Res 21:390–395CrossRefPubMedGoogle Scholar
  77. 77.
    Naumann A, Bellebaum C, Daum I (2006) Cognitive deficits in narcolepsy. J Sleep Res 15:329–338CrossRefPubMedGoogle Scholar
  78. 78.
    Killgore WD (2010) Effects of sleep deprivation on cognition. In Progress in brain research (Vol. 185). Elsevier, pp. 105-129Google Scholar
  79. 79.
    Killgore WD, Schwab ZJ, Weiner MR (2012) Self-reported nocturnal sleep duration is associated with next-day resting state functional connectivity. Neuroreport 23:741–745CrossRefPubMedGoogle Scholar
  80. 80.
    Killgore WD, Schwab ZJ, Kipman M, DelDonno SR, Weber M (2012) Voxel-based morphometric gray matter correlates of daytime sleepiness. Neurosci Lett 518:10–13CrossRefPubMedGoogle Scholar
  81. 81.
    Goel N, Rao H, Durmer JS, Dinges DF (2009) Neurocognitive consequences of sleep deprivation. In seminars in neurology (Vol. 29, No. 04). Thieme Medical Publishers, pp. 320-339Google Scholar
  82. 82.
    Boucetta S, Montplaisir J, Zadra A, Lachapelle F, Soucy JP, Gravel P, Dang-Vu TT (2017) Altered regional cerebral blood flow in idiopathic hypersomnia. Sleep 40(10):zsx140CrossRefGoogle Scholar
  83. 83.
    Dang-Vu TT, Desseilles M, Laureys S, Degueldre C, Perrin F, Phillips C, Maquet P, Peigneux P (2005) Cerebral correlates of delta waves during non-REM sleep revisited. Neuroimage 28:14–21CrossRefPubMedGoogle Scholar
  84. 84.
    Laureys S (2005) The neural correlate of (un) awareness: lessons from the vegetative state. Trends Cogn Sci 9:556–559CrossRefPubMedGoogle Scholar
  85. 85.
    Fuller P, Sherman D, Pedersen NP, Saper CB, Lu J (2011) Reassessment of the structural basis of the ascending arousal system. J Comp Neurol 519:933–956CrossRefPubMedPubMedCentralGoogle Scholar
  86. 86.
    Saper CB, Lowell BB (2014) The hypothalamus. Curr Biol 24:R1111–R1116CrossRefPubMedGoogle Scholar
  87. 87.
    Panksepp J, Northoff G (2009) The trans-species core SELF: the emergence of active cultural and neuro-ecological agents through self-related processing within subcortical-cortical midline networks. Conscious Cogn 18:193–215CrossRefPubMedGoogle Scholar
  88. 88.
    Gemignani A, Menicucci D, Laurino M, Piarulli A, Mastorci F, Sebastiani L, Allegrini P (2015) Linking sleep slow oscillations with consciousness theories: new vistas on slow wave sleep unconsciousness. Arch Ital Biol 153:135–143PubMedGoogle Scholar
  89. 89.
    Massimini M, Ferrarelli F, Huber R, Esser SK, Singh H, Tononi G (2005) Breakdown of cortical effective connectivity during sleep. Science 309:2228–2232CrossRefPubMedGoogle Scholar
  90. 90.
    Gujar N, Yoo SS, Hu P, Walker MP (2010) The unrested resting brain: sleep deprivation alters activity within the default-mode network. J Cogn Neurosci 22:1637–1648CrossRefPubMedPubMedCentralGoogle Scholar
  91. 91.
    Sämann PG, Tully C, Spoormaker VI, Wetter TC, Holsboer F, Wehrle R, Czisch M (2010) Increased sleep pressure reduces resting state functional connectivity. MAGMA 23:375–389CrossRefPubMedGoogle Scholar
  92. 92.
    Verweij IM, Romeijn N, Smit DJ, Piantoni G, Van Someren EJ, van der Werf YD (2014) Sleep deprivation leads to a loss of functional connectivity in frontal brain regions. BMC Neurosci 15:88CrossRefPubMedPubMedCentralGoogle Scholar
  93. 93.
    Euston DR, Gruber AJ, McNaughton BL (2012) The role of medial prefrontal cortex in memory and decision making. Neuron 76:1057–1070CrossRefPubMedPubMedCentralGoogle Scholar
  94. 94.
    Etkin A, Egner T, Kalisch R (2011) Emotional processing in anterior cingulate and medial prefrontal cortex. Trends Cogn Sci 15:85–93CrossRefPubMedGoogle Scholar
  95. 95.
    Gusnard DA, Akbudak E, Shulman GL, Raichle ME (2001) Medial prefrontal cortex and self-referential mental activity: relation to a default mode of brain function. Proc Natl Acad Sci 98:4259–4264CrossRefPubMedGoogle Scholar
  96. 96.
    Muzur A, Pace-Schott EF, Hobson JA (2002) The prefrontal cortex in sleep. Trends Cogn Sci 6:475–481CrossRefPubMedGoogle Scholar
  97. 97.
    Hobson JA (2009) REM sleep and dreaming: towards a theory of protoconsciousness. Nat Rev Neurosci 10:803–813CrossRefPubMedGoogle Scholar
  98. 98.
    Nishida M, Pearsall J, Buckner RL, Walker MP (2008) REM sleep, prefrontal theta, and the consolidation of human emotional memory. Cereb Cortex 19:1158–1166CrossRefPubMedPubMedCentralGoogle Scholar
  99. 99.
    Fattinger S, Kurth S, Ringli M, Jenni OG, Huber R (2017) Theta waves in children’s waking electroencephalogram resemble local aspects of sleep during wakefulness. Sci Rep 7:11187CrossRefPubMedPubMedCentralGoogle Scholar
  100. 100.
    Strijkstra AM, Beersma DG, Drayer B, Halbesma N, Daan S (2003) Subjective sleepiness correlates negatively with global alpha (8–12 Hz) and positively with central frontal theta (4–8 Hz) frequencies in the human resting awake electroencephalogram. Neurosci Lett 340:17–20CrossRefPubMedGoogle Scholar
  101. 101.
    Vyazovskiy VV, Olcese U, Hanlon EC, Nir Y, Cirelli C, Tononi G (2011) Local sleep in awake rats. Nature 472:443–447CrossRefPubMedPubMedCentralGoogle Scholar
  102. 102.
    Bernardi G, Siclari F, Yu X, Zennig C, Bellesi M, Ricciardi E. ... & Tononi, G (2015) Neural and behavioral correlates of extended training during sleep deprivation in humans: evidence for local, task-specific effects. J Neurosci 35: 4487–4500Google Scholar
  103. 103.
    Dauvilliers Y, Evangelista E, De Verbizier D, Barateau L, Peigneux P (2017) [18F] fludeoxyglucose-positron emission tomography evidence for cerebral hypermetabolism in the awake state in narcolepsy and idiopathic hypersomnia. Frontiers Neurol 8:350CrossRefGoogle Scholar
  104. 104.
    Piarulli A, Zaccaro A, Laurino M, Menicucci D, De Vito A, Bruschini L, Berrettini S, Bergamasco M, Laureys S, Gemignani A (2018) Ultra-slow mechanical stimulation of olfactory epithelium modulates consciousness by slowing cerebral rhythms in humans. Sci Rep 8:6581CrossRefPubMedPubMedCentralGoogle Scholar
  105. 105.
    Zaccaro A, Piarulli A, Laurino M, Garbella E, Menicucci D, Neri B, Gemignani A (2018) How breath-control can change your life: a systematic review on psycho-physiological correlates of slow breathing. Front Hum Neurosci 12Google Scholar
  106. 106.
    Blanke O (2012) Multisensory brain mechanisms of bodily self-consciousness. Nat Rev Neurosci 13(8):556–571CrossRefGoogle Scholar
  107. 107.
    Tort AB, Brankačk J, Draguhn A (2018) Respiration-entrained brain rhythms are global but often overlooked. Trends Neurosci 41(4):186–197CrossRefPubMedGoogle Scholar

Copyright information

© Springer Nature Switzerland AG 2019

Authors and Affiliations

  1. 1.Department of Surgical, Medical and Molecular Pathology and Critical Care MedicineUniversity of PisaPisaItaly
  2. 2.National Research CouncilInstitute of Clinical PhysiologyPisaItaly
  3. 3.Azienda Ospedaliero-Universitaria PisanaPisaItaly

Personalised recommendations