Prof. Dr. Christian Cajochen

Cajochen, C.

Head Centre for Chronobiology

Short-Biography:Prof. Christian Cajochen is heading the Centre for Chronobiology at the University of Basel. He received his PhD in natural sciences from the ETH in Zürich, Switzerland, followed by a 3-y postdoctoral stay at the Harvard Medical School in Boston, USA. His major research interests include investigative work on the influence of light on human cognition, circadian rhythms and sleep, circadian related disturbances in psychiatric disorders, and age-related changes in the circadian regulation of sleep and neurobehavioral performance. He has held a number of honours and has authored more than 150 original papers and reviews in his career.

Email: Christian.Cajochen@upkbs.ch

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Publications by Christian Cajochen

Chellappa, S. L.; Lasauskaite, R.; Cajochen, C.

In a Heartbeat: Light and Cardiovascular Physiology

Frontiers in Neurology, 8, pp. doi:10.3389/fneur.2017.00541, 2017.

(PDF & Links | BibTeX)

Münch, M.; Schmieder, M.; Bieler, K.; Goldbach, R.; Fuhrmann, T.; Zumstein, N.; Vonmoos, P.; Scartezzini, J.L.; Wirz-Justice, A.; ., C. Cajochen

Bright light delights: effects of daily light exposure on emotions, rest-activity cycles, sleep and melatonin secretion in severely demented patients

Current Alzheimer Research, 14, pp. doi:10.2174/1567205014666170523092858 , 2017.

Knaier, R.; Schäfer, J.; Rossmeissl, A.; Klenk, C.; Hanssen, H.; Höchsmann, C.; Cajochen, C.; Schmidt-Trucksäss, A

Prime time light exposures do not seem to improve maximal physical performance in male elite athletes, but enhance end-spurt performance

Frontiers in Psysiology, pp. doi:10.3389/fphys.2017.00264, 2017.

Eze, I.C.; Foraster, M.; Schaffner, E.; Vienneau, D.; Héritier, H.; Rudzik, F.; Thiesse, L.; Pieren, R.; Imboden, M.; Eckardstein, A. von; Schindler, C.; Brink, M.; Cajochen, C.; Wunderli, J.M.; Röösli, M.; Probst-Hensch, N.

Long-term exposure to transportation noise and air pollution in relation to incident diabetes in the SAPALDIA study

International Journal of Epidemiology, pp. doi:10.1093/ije/dyx020, 2017.

Héritier, H.; Vienneau, D.; Foraster, M.; Eze, I.C.; Schaffner, E.; Thiesse, L.; Rudzik, F.; Habermacher, M.; Köpfli, M.; Pieren, R.; Brink, M.; Cajochen, C.; Wunderli, J.M.; Probst-Hensch, N.; Röösli, M.; group, SNC study

Transportation noise exposure and cardiovascular mortality: a nationwide cohort study from Switzerland

European Journal of Epidemiology, pp. doi:10.1007/s10654-017-0234-2, 2017.

Brockmann, P. E.; Gozal, D.; Damiani, L. Villarroel F.; Nuñez, F.; Cajochen, C.

Geographic latitude and sleep duration: A population-based survey from the Tropic of Capricorn to the Antarctic Circle

Chronobiology International, pp. 1-9. doi:10.1080/07420528.2016.1277735, 2017.

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Birchler-Pedross, A.; Frey, S.; Götz, T.; Brunner, P.; Knoblauch, V.; Wirz-Justice, A.; Chellappa, S.L.; Cajochen, C.

Subjective mood in young unmedicated depressed women under high and low sleep pressure conditions

Biology, pp. doi:10.3390/biology5040052, 2016.

Cajochen, C.; Chellappa, S. L.

Commentary: Melanopsin regulates both sleep-promoting and arousal-promoting responses to light

Frontiers in Neural Circuits, pp. doi:10.3389/fncir.2016.00094, 2016.

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Wunderli, J. M.; Pieren, R.; Habermacher, M.; Vienneau, D.; Cajochen, C.; Probst-Hensch, N.; Röösli, M.; Brink, M.

Intermittency ratio: A metric reflecting short-term temporal variations of transportation noise exposure

Journal of Exposure Science and Environmental Epidemiology, 26, pp. 575-585, doi:10.1038/jes.2015.56, 2016.

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Baiardi, S.; Cirignotta, F.; Cicolin, A.; Garbazza, C.; D'Agostino, A.; Gambini, O.; Giordano, A.; Canevini, M.; Zambrelli, E.; Marconi, A. M.; Mondini, S.; Borgwardt, S.; Cajochen, C.; Rizzo, N.; Manconi, M.

Chronobiology, sleep-related risk factors and light therapy in perinatal depression: the "Life-ON" project

BMC Psychiatry, 16, pp. doi:10.1186/s12888-016-1086-0, 2016.

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Winzeler, K.; Voellmin, A.; Hug, E.; Kirmse, U.; Helmig, S.; Princip, M.; Cajochen, C.; Bader, K.; Wilhelm, F. H.

Adverse childhood experiences and autonomic regulation in response to acute stress: the role of the sympathetic and parasympathetic nervous systems

Anxiety, Stress, & Coping, pp. 1-10, doi:10.1080/10615806.2016.1238076, 2016.

Burkhalter, H.; DeGeest, S.; Wirz-Justice, A.; Cajochen, C.

Melatonin rhythms in renal transplant recipients with sleep-wake disturbances

Chronobiol Int., 21, pp. 1-11 [Epub ahead of print], 2016.

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vanderMeijden, W.P.; VanSomeren, J.L; BH, B.H Te Lindert; Bruijel, J.; Oosterhout, F. van; Coppens, J.E.; Kalsbeek, A.; Cajochen, C.; Bourgin, P.; VanSomeren, E.J.

Individual differences in sleep timing relate to melanopsin-based phototransduction in healthy adolescents and young adults

Sleep, 39 (6), pp. 1305-1310, 2016.

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Colombo, M.A.; Ramautar, J.R.; Wei, Y.; Gomez-Herrero, G.; Stoffers, D.; Wassing, R.; Benjamins, J.S.; Tagliazucchi, E.; Werf, Y.D. van der; Cajochen, C.; VanSomeren, E.J.

Wake high-density electroencephalographic spatiospectral signatures of insomnia

Sleep, 39 (5), pp. 1015-1027, 2016.

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Reichert, C.; Maire, M.; Schmidt, C.; Cajochen, C.

Sleep-wake regulation and its impact on working memory performance: the role of adenosine

Biology, 5 (1), pp. E11. doi:10.3390/biology5010011., 2016.

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Foraster, M.; Eze, I.C.; Vienneau, D.; Brink, M.; Cajochen, C.; Caviezel, S.; Héritier, H.; Schaffner, E.; Schindler, C.; Wanner, M; Wunderli, J.-M.; Röösli, M.; Probst-Hensch, N.

Long-term transportation noise annoyance is associated with subsequent lower levels of physical activity

Environment International, 91, pp. 341-349, 2016.

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Garbazza, C.; Bromundt, V.; Eckert, A.; Brunner, D.P.; Meier, F.; Hackethal, S.; Cajochen, C.

Non-24-Hour Sleep-Wake Disorder Revisited - A Case Study

Front Neurol. 2016 Feb 29;7:17 doi: 10.3389/fneur.2016.00017, 2016.

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Bernsmeier, C.; Weisskopf, D.M.; Pflueger, M.O.; Mosimann, J.; Campana, C. B.; Terracciano, L.; Beglinger, C.; Heim, M. H.; Cajochen, C.

Sleep Disruption and Daytime Sleepiness Correlating with Disease Severity and Insulin Resistance in Non-Alcoholic Fatty Liver Disease: A Comparison with Healthy Controls

PlosOne, DOI:10.1371/journal.pone.0143293, pp. 1-16, 2015.

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Schmidt, C.; Collette, F.; Reichert, C.F.; Maire, M.; Vandewalle, G.; Peigneux, P.; Cajochen, C.

Pushing the limits: chronotype and time of day modulate working memory-dependent cerebral activity

Frontiers in Neurology, 25 (6:199), pp. 1-9, 2015.

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Wunderli, J.M.; Pieren, R.; Habermacher, M.; Vienneau, D.; Cajochen, C.; Probst-Hensch, N.; Röösli, M.; Brink, M.

Intermittency ratio: A metric reflecting short-term temporal variations of transportation noise exposure

Journal of Exposure Science and Environmental Epidemiology, 9 September 2015; doi:10.1038/jes.2015.5, pp. 1-11, 2015.

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Knaier, R.; Meister, S.; Aeschbacher, T.; Gemperle, D.; Rossmeissl, A.; Cajochen, C.; Schmidt-Trucksäss, A.

Dose-response relationship between light exposure and cycling performance

Scand J Med Sci Sports, doi: 10.1111/sms.12535., 2015.

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Bassetti, C. L.; Ferini-Strambi, L.; Brown, S.; Adamantidis, A.; Benedetti, F.; Bruni, O.; Dolenc-Groselj, C. Cajochen and L.; Ferri, R.; Gais, S.; Huber, R.; Khatami, R.; Lammers, G. J.; Luppi, P. H.; Manconi, M.; Nissen, C.; Nobili, L.; Peigneux, P.; Pollmächer, T.; Randerath, W.; Riemann, D.; Santamaria, J.; Schindler, K.; Tafti, M.; Someren, E. Van; Wetter, T. C.

Neurology and psychiatry: waking up to opportunities of sleep. : State of the art and clinical/research priorities for the next decade

Eur J Neurol., doi: 10.1111/ene.12781., 2015.

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vanderMeijden, W. P.; teLindert, B. H. W.; Bijlenga, D.; Coppens, J. E.; Gomez-Herrero, G.; Bruijel, J.; Kooij, J. J. S.; Bourgin, C. Cajochen and P.; VanSomeren, E. J. W.

Post-illumination pupil response after blue light: Reliability of optimized melanopsin-based phototransduction assessment

Exp Eye Res., doi: 10.1016/j.exer.2015.07.010, 139, pp. 73-80, 2015.

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Maire, M.; Reichert, C.; Gabel, V.; Viola, A. U.; Phillips, C.; Krebs, J.; Scheffler, K.; Klarhöfer, M.; Strobel, W.; Cajochen, C.; Schmidt, C.

Fighting Sleep at Night: Brain Correlates and Vulnerability to Sleep Loss

Ann Neurol., doi: 10.1002/ana.24434., 78(2), pp. 235-247, 2015.

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Viola, A. U.; Gabel, V.; Chellappa, S. L.; Schmidt, C.; Hommes, V.; Tobaldini, E.; Montano, N.; Cajochen, C.

Dawn simulation light: a potential cardiac events protector

Sleep Med., doi: 10.1016/j.sleep.2014.12.016, 16(4), pp. 457-461, 2015.

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Buttgereit, F.; Smolen, J. S.; Coogan, A. N.; Cajochen, C.

Clocking in: chronobiology in rheumatoid arthritis

Nature Reviews Rheumatology, doi:10.1038/nrrheum.2015.31, 11, pp. 349–356, 2015.

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Gabel, V.; Maire, M.; Reichert, C. F.; Chellappa, S. L.; Schmidt, C.; Hommes, V.; Cajochen, C.; Viola, A. U.

Dawn simulation light impacts on different cognitive domains under sleep restriction

Behav Brain Res., doi: 10.1016/j.bbr.2014.12.043, 15, pp. 281: 258-266, 2015.

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vanderLely, S.; Frey, S.; Garbazza, C.; Wirz-Justice, A.; Jenni, O. G.; Steiner, R.; Wolf, S.; Cajochen, C.; Bromundt, V.; Schmidt, C.

Blue blocker glasses as a countermeasure for alerting effects of evening light-emitting diode screen exposure in male teenagers

J Adolesc Health, doi: 10.1016/j.jadohealth.2014.08.002, 56(1), pp. 113-119, 2015.

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Burkhalter, H.; Wirz-Justice, A.; Denhaerynck, K.; Fehr, T.; Steiger, J.; Venzin, R. M.; Cajochen, C.; Weaver, T. E.; DeGeest, S.

The effect of bright light therapy on sleep and circadian rhythms in renal transplant recipients: a pilot randomized, multicentre wait-list controlled trial.

Transpl Int., doi: 10.1111/tri.12443, 28(1), pp. 59-70, 2015.

(PDF & Links | BibTeX)

Cajochen, C.

Light: An underestimated environmental factor in sleep medicine

Sleep and Biological Rhythms, 13 (2), pp. 111, 2015.

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Reichert, C. F.; Maire, M.; Gabel, V.; Hofstetter, M.; Viola, A.U.; Kolodyazhniy, V.; Strobel, W.; Goetz, T.; V. Bachmann, ; Landolt, H.-P.; Cajochen, C.; Schmidt, C.

The Circadian Regulation of Sleep: Impact of a Functional ADA-Polymorphism and Ist Association to Working Memory

PLoS ONE, 9 (12), pp. 1-23, 2014.

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Cajochen, C.

Editorial: Tag-Wach & Nacht-Schlaf: Regulation, Störungen und Behandlung

Therapeutische Umschau, 71 (11), pp. 629, 2014.

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Tinguely, G.; Landolt, H-P.; Cajochen, C.

Schlafgewohnheiten, Schlafqualität und Schlafmittelkonsum der Schweizer Bevölkerung: Ergebnisse aus einer neuen Umfrage bei einer repräsentativen Stichprobe

Therapeutische Umschau, 71 (11), pp. 637-646, 2014.

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Cajochen, C.; Altanay-Ekici, S.; Münch, M.; Frey, S.; Knoblauch, V.; Wirz-Justice, A.

Reply to Cordi et al.

Current Biology, 24 (17), pp. R795, 2014.

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H, H. Burkhalter; Wirz-Justice, A.; Denhaerynck, K.; Fehr, T.; Steiger, J.; Venzin, R.M.; Cajochen, C.; Weaver, T.E.; DeGeest, S.

The effect of bright light therapy on sleep and circadian rhythms in renal transplant recipients: a pilot randomized, multicentre wait-list controlled trial

Transpl Int., doi: 10.1111/tri.12443. [Epub ahead of p, 2014.

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Najjar, R.P.; Wolf, L.; Taillard, J.; Schlangen, L.J.; Salam, A.; Cajochen, C.; Gronfier., C.

Chronic artificial blue-enriched white light is an effective countermeasure to delayed circadian phase and neurobehavioral decrements

PLoS One. 2014 Jul 29;9(7):e102827. doi: 10.1371/journal.pone.0102827. eCollection 2014., 9 (7), pp. 1-10, 2014.

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Chellappa, S.L.; Viola, A.U.; Schmidt, C.; Bachmann, V.; Gabel, V.; Maire, M.; Reichert, C.F.; Valomon, A.; Landolt, H.P.; Cajochen, C.

Light modulation of human sleep depends on a polymorphism in the clock gene Period3

Behavioural Brain Research, 271, pp. 23-29, 2014.

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Reichert, C. F.; Maire, M.; Gabel, V.; Viola, A.U.; Kolodyazhniy, V.; Strobel, W.; Götz, T.; Bachmann, V.; Landolt, H.P.; Cajochen, C.; Schmidt, C.

Insights into Behavioral Vulnerability to Differential Sleep Pressure and Circadian Phase from a Functional ADA Polymorphism

Journal of Biological Rhythms, 29 (2), pp. 119-130, 2014.

(Abstract | PDF & Links | BibTeX)

@article{586,
title = {Insights into Behavioral Vulnerability to Differential Sleep Pressure and Circadian Phase from a Functional ADA Polymorphism},
author = {C. F. Reichert and M. Maire and V. Gabel and A.U. Viola and V. Kolodyazhniy and W. Strobel and T. Götz and V. Bachmann and H.P. Landolt and C. Cajochen and C. Schmidt},
url = {http://www.chronobiology.ch/wp-content/uploads/2014/04/Reichert-2014-behavioral-vulnerability1.pdf},
year = {2014},
date = {2014-04-02},
journal = {Journal of Biological Rhythms},
volume = {29},
number = {2},
pages = {119-130},
abstract = {Sleep loss affects human behavior in a nonuniform manner, depending
on the cognitive domain and also the circadian phase. Besides, evidence
exists about stable interindividual variations in sleep loss–related performance
impairments. Despite this evidence, only a few studies have considered both
circadian phase and neurobehavioral domain when investigating trait-like
vulnerability to sleep manipulation. By applying a randomized, crossover
design with 2 sleep pressure conditions (40 h sleep deprivation vs. 40 h multiple
naps), we investigated the influence of a human adenosine deaminase
(ADA) polymorphism (rs73598374) on several behavioral measures throughout
nearly 2 circadian cycles. Confirming earlier studies, we observed that
under sleep deprivation the previously reported vulnerable G/A-allele carriers
felt overall sleepier than G/G-allele carriers. As expected, this difference
was no longer present when sleep pressure was reduced by the application of
multiple naps. Concomitantly, well-being was worse in the G/A genotype
under sleep loss when compared to the nap protocol, and n-back working
memory performance appeared to be specifically susceptible to sleep-wake
manipulation in this genotype. When considering psychomotor vigilance performance, however, a higher sensitivity to sleep-wake manipulation was detected in homozygous participants, but specifically at the end of the night
and only for optimal task performance. Although these data are based on a
small sample size and hence require replication (12 G/A- and 12 G/G-allele
carriers), they confirm the assumption that interindividual differences regarding
the effect of sleep manipulation highly depend on the cognitive task and
circadian phase, and thus emphasize the necessity of a multimethodological
approach. Moreover, they indicate that napping might be suitable to counteract endogenously heightened sleep pressure depending on the neurobehavioral
domain.},
keywords = {}
}

Valomon, A.; Holst, S.C.; Bachmann, V.; Viola, A.U.; Schmidt, C.; Zürcher, J.; Berger, W.; Cajochen, C.; Landolt, H.P.

Genetic polymorphisms of DAT1 and COMT differentially associate with actigraphy-derived sleep-wake cycles in young adults

Chronobiology International, 2014 Mar 13. [Epub ahead of print], 2014.

(PDF & Links | BibTeX)

Maire, M.; Reichert, C.F.; Gabel, V.; Viola, A.U.; Krebs, J.; Strobel, W.; Landolt, H.P.; Bachmann, V.; Cajochen, C.; Schmidt, C.

Time-on-task decrement in vigilance is modulated by inter-individual vulnerability to homeostatic sleep pressure manipulation

Frontiers in Behavioral Neuroscience, 8 (59), 2014, ISSN: 1662-5153.

(Abstract | PDF & Links | BibTeX)

@article{583,
title = {Time-on-task decrement in vigilance is modulated by inter-individual vulnerability to homeostatic sleep pressure manipulation},
author = {M. Maire and C.F. Reichert and V. Gabel and A.U. Viola and J. Krebs and W. Strobel and H.P. Landolt and V. Bachmann and C. Cajochen and C. Schmidt},
url = {http://www.chronobiology.ch/wp-content/uploads/2014/03/Timeontask_MAIREetal2014.pdf},
issn = {1662-5153},
year = {2014},
date = {2014-03-06},
journal = {Frontiers in Behavioral Neuroscience},
volume = {8},
number = {59},
abstract = {Under sleep loss, vigilance is reduced and attentional failures emerge progressively. It becomes difficult to maintain stable performance over time, leading to growing performance variability (i.e., state instability) in an individual and among subjects. Task duration plays a major role in the maintenance of stable vigilance levels, such that the longer the task, the more likely state instability will be observed. Vulnerability to sleep-loss-dependent performance decrements is highly individual and is also modulated by a polymorphism in the human clock gene PERIOD3 (PER3). By combining two different protocols, we manipulated sleep-wake history by once extending wakefulness for 40 h (high sleep pressure condition) and once by imposing a short sleep-wake cycle by alternating 160 min of wakefulness and 80 min naps (low sleep pressure condition) in a within-subject design. We observed that homozygous carriers of the long repeat allele of PER3 (PER35/5) experienced a greater time-on-task dependent performance decrement (i.e., a steeper increase in the number of lapses) in the Psychomotor Vigilance Task compared to the carriers of the short repeat allele (PER34/4). These genotype-dependent effects disappeared under low sleep pressure conditions, and neither motivation, nor perceived effort accounted for these differences. Our data thus suggest that greater sleep-loss related attentional vulnerability based on the PER3 polymorphism is mirrored by a greater state instability under extended wakefulness in the short compared to the long allele carriers. Our results undermine the importance of time-on-task related aspects when investigating inter-individual differences in sleep loss-induced behavioral vulnerability.},
keywords = {}
}

Winzeler, K.; Voellmin, A.; Schäfer, V.; A.H.Meyer, ; Cajochen, C.; Wilhelm, F.H.; Bader, K.

Daily stress, presleep arousal, and sleep in healthy young women: a daily life computerized sleep diary and actigraphy study

Sleep Medicine, 15 (3), pp. 359-366., 2014.

(PDF & Links | BibTeX)

Maire, M.; Reichert, C.F.; Gabel, V.; Viola, A.U.; Strobel, W.; Krebs, J.; Landolt, H.P.; Bachmann, V.; Cajochen, C.; Schmidt, C.

Sleep ability mediates individual differences in the vulnerability to sleep loss: Evidence from a PER3 polymorphism

Cortex, http://dx.doi.org/10.1016/j.cortex.2013., 2014.

(PDF & Links | BibTeX)

Burkhalter, H.; Wirz-Justice, A.; Cajochen, C.; Weaver, T.E.; Steiger, J.; Fehr, T.; Venzin, R. M.; DeGeest, S.

Daytime sleepiness in renal transplant recipients is associated with immunosuppressive non-adherence: a cross-sectional, multi-center study

Clin Transplant, doi: 10.1111/ctr.12279., 2013.

(PDF & Links | BibTeX)

Danilenko, K. V.; Verevkin, E.G.; Antyufeev, V.S.; Wirz-Justice, A.; Cajochen, C.

The hockey-stick method to estimate evening dim light melatonin onset

Chronobiology International, early online, pp. 1-7, 2013.

(Abstract | PDF & Links | BibTeX)

@article{579,
title = {The hockey-stick method to estimate evening dim light melatonin onset},
author = {K. V. Danilenko and E.G. Verevkin and V.S. Antyufeev and A. Wirz-Justice and C. Cajochen},
url = {http://www.chronobiology.ch/wp-content/uploads/2013/11/danilenko_atal_2013.pdf},
year = {2013},
date = {2013-11-19},
journal = {Chronobiology International},
volume = {early online},
pages = {1-7},
abstract = {The onset of melatonin secretion in the evening is the most reliable and most widely used index of circadian timing
in humans. Saliva (or plasma) is usually sampled every 0.5–1 hours under dim-light conditions in the evening
5–6 hours before usual bedtime to assess the dim-light melatonin onset (DLMO). For many years, attempts have been
made to find a reliable objective determination of melatonin onset time either by fixed or dynamic threshold
approaches. The here-developed hockey-stick algorithm, used as an interactive computer-based approach, fits
the evening melatonin profile by a piecewise linear-parabolic function represented as a straight line switching to the
branch of a parabola. The switch point is considered to reliably estimate melatonin rise time. We applied the hockeystick
method to 109 half-hourly melatonin profiles to assess the DLMOs and compared these estimates to visual
ratings from three experts in the field. The DLMOs of 103 profiles were considered to be clearly quantifiable.
The hockey-stick DLMO estimates were on average 4 minutes earlier than the experts’ estimates, with a range of 27
to þ13 minutes; in 47% of the cases the difference fell within 5 minutes, in 98% within 20 to þ13 minutes.
The raters’ and hockey-stick estimates showed poor accordance with DLMOs defined by threshold methods. Thus,
the hockey-stick algorithm is a reliable objective method to estimate melatonin rise time, which does not depend on
a threshold value and is free from errors arising from differences in subjective circadian phase estimates. The method
is available as a computerized program that can be easily used in research settings and clinical practice either for
salivary or plasma melatonin values.
Keywords: DLMO, hockey-stick algorithm, melatonin},
keywords = {}
}

Bromundt, V.; Frey, S.; Odermatt, J.; Cajochen, C.

Extraocular light via the ear canal does not acutely affect human circadian physiology, alertness and psychomotor vigilance performance

Chronobiology International, early online, pp. 1-6, 2013.

(Abstract | PDF & Links | BibTeX)

@article{580,
title = {Extraocular light via the ear canal does not acutely affect human circadian physiology, alertness and psychomotor vigilance performance},
author = {V. Bromundt and S. Frey and J. Odermatt and C. Cajochen},
url = {http://www.chronobiology.ch/wp-content/uploads/2013/11/bromundt_etal_2013.pdf},
year = {2013},
date = {2013-11-19},
journal = {Chronobiology International},
volume = {early online},
pages = {1-6},
abstract = {We aimed at testing potential effects of extraocular bright light via the ear canals on human evening melatonin levels,
sleepiness and psychomotor vigilance performance. Twenty healthy young men and women (10/10) kept a regular
sleep–wake cycle during the 2-week study. The volunteers reported to the laboratory on three evenings, 2 h 15 min
before usual bedtime, on average at 21:45 h. They were exposed to three different light conditions, each lasting for
12 min: extraocular bright light via the ear canal, ocular bright light as an active control condition and a control
condition (extraocular light therapy device with completely blacked out LEDs). The timing of exposure was on
average from 22:48 to 23:00 h. During the 2-h protocol, saliva samples were collected in 15-min intervals for melatonin
assays along with subjective sleepiness ratings, and the volunteers performed a 10-min visual psychomotor vigilance
task (PVT) prior to and after each light condition. The evening melatonin rise was significantly attenuated after the 12-
min ocular bright light exposure while no significant changes were observed after the extraocular bright light and
sham light condition. Subjective sleepiness decreased immediately over a short period only after ocular light
exposure. No significant differences were observed for mean reaction times and the number of lapses for the PVT
between the three light conditions. We conclude that extraocular transcranial light exposure in the late evening does
not suppress melatonin, reduce subjective sleepiness or improve performance, and therefore, does not acutely
influence the human circadian timing system.
Keywords: Bright light therapy, extraocular transcranial light therapy, melatonin, psychomotor vigilance
performance, sleepiness},
keywords = {}
}

Putilov, A.A.; Münch, M.Y.; Cajochen, C.

Principal component structuring of the Non-REM sleep EEG spectrum in older adults yields age-related changes in the sleep and wake drives

Current Aging Science, 6 epub ahead, pp. 1-13, 2013.

(Abstract | PDF & Links | BibTeX)

@article{578,
title = {Principal component structuring of the Non-REM sleep EEG spectrum in older adults yields age-related changes in the sleep and wake drives},
author = {A.A. Putilov and M.Y. Münch and C. Cajochen},
url = {http://www.chronobiology.ch/wp-content/uploads/2013/11/Putilov_2013.pdf},
year = {2013},
date = {2013-11-08},
journal = {Current Aging Science},
volume = {6 epub ahead},
pages = {1-13},
abstract = {Age-related disturbances of the sleep-wake cycle can reflect ontogenetic changes in regulatory mechanisms underlying
normal and pathological aging, but the exact nature of these changes remains unclear. The present report is the
first attempt to apply principal component analysis to the electroencephalographic (EEG) spectrum to examine of whether
the observed age-related changes in the objective sleep measures can be linked to the opponent sleep-promoting and
wake-promoting processes. The EEG indicators of these processes - scores on the 1st and 2nd principal components of the
EEG spectrum, respectively - were compared in 15 older (57-74 years) and 16 younger (20-31 years) healthy volunteers.
The scores were calculated for non-REM sleep episodes which occurred during ten 75-min naps scheduled every 150 min
throughout a 40-h constant routine protocol. Both, a decrease of the 1st principal component score and an increase of the
2nd principal component score were found to contribute to such most obvious age-related modification of the sleep EEG
spectrum as attenuation of EEG slow-wave activity in older people. Therefore, we concluded that the normal aging process
can reflect both a weakening of the sleep-promoting process and a strengthening of the wake-promoting process, respectively.
Such bidirectional changes in chronoregulatory processes may explain why sleep of older people is characterized
by the few profitable and a number of detrimental features (i.e., a better ability to cope with daytime sleepiness and
sleep loss vs. difficulty of falling asleep, decreased total nighttime sleep, “lightened” and fragmentized sleep, unwanted
early morning awakenings, etc.)},
keywords = {}
}

Burkhalter, H.; Wirz-Justice, A.; Cajochen, C.; Weaver, T.E.; Steiger, J.; Fehr, T.; Venzin, R. M.; Geest, S. De

Validation of a single item to assess daytime sleepiness for the Swiss Transplant Cohort Study

Progress in Transplantation, 23 (3), pp. 1-9, 2013.

(Abstract | PDF & Links | BibTeX)

@article{195,
title = {Validation of a single item to assess daytime sleepiness for the Swiss Transplant Cohort Study},
author = {H. Burkhalter and A. Wirz-Justice and C. Cajochen and T.E. Weaver and J. Steiger and T. Fehr and R. M. Venzin and S. De Geest},
url = {http://www.chronobiology.ch/wp-content/uploads/2013/11/Validation-of-a-single-item-to-assess-daytime-sleepiness-for-the-Swiss-Transplant-Cohort-Study2.pdf},
year = {2013},
date = {2013-11-05},
journal = {Progress in Transplantation},
volume = {23},
number = {3},
pages = {1-9},
abstract = {Context—Daytime sleepiness in kidney transplant recipients has emerged as a potential predictor of impaired adherence to the immunosuppressive medication regimen. Thus there is a need to assess daytime sleepiness in clinical practice and transplant registries. Objective—To evaluate the validity of a single-item measure of daytime sleepiness integrated in the Swiss Transplant Cohort Study (STCS), using the American Educational Research Association framework. Methods—Using a cross-sectional design, we enrolled a convenience sample of 926 home-dwelling kidney transplant recipients (median age, 59.69 years; 25%-75% quartile [Q25-Q75], 50.27-59.69), 63% men; median time since transplant 9.42 years (Q25-Q75, 4.93-15.85). Daytime sleepiness was assessed by using a single item from the STCS and the 8 items of the validated Epworth Sleepiness Scale. Receiver operating characteristic curve analysis was used to determine the cutoff for the STCS daytime sleepiness item against the Epworth Sleepiness Scale score. Results—Based on the receiver operating characteristic curve analysis, a score greater than 4 on the STCS daytime sleepiness item is recommended to detect daytime sleepiness. Content validity was high as all expert reviews were unanimous. Concurrent validity was moderate (Spearman ρ, 0.531; P< .001) and convergent validity with depression and poor sleep quality although low, was significant (ρ, 0.235; P<.001 and ρ, 0.318},
keywords = {}
}

Burkhalter, H.; Brunner, D.P.; Wirz-Justice, A.; Cajochen, C.; Weaver, T.E.; Steiger, J.; Fehr, T.; Venzin, R. M.; Geest, S. De

Self-reported sleep disturbances in renal transplant recipients

BMC Nephrology, 14 (220), pp. 1-12, 2013.

(Abstract | PDF & Links | BibTeX)

@article{196,
title = {Self-reported sleep disturbances in renal transplant recipients},
author = {H. Burkhalter and D.P. Brunner and A. Wirz-Justice and C. Cajochen and T.E. Weaver and J. Steiger and T. Fehr and R. M. Venzin and S. De Geest},
url = {http://www.chronobiology.ch/wp-content/uploads/2013/10/burkhalter_a_2013.pdf},
year = {2013},
date = {2013-10-31},
journal = {BMC Nephrology},
volume = {14},
number = {220},
pages = {1-12},
abstract = {Background: Poor sleep quality (SQ) and daytime sleepiness (DS) are common in renal transplant (RTx) recipients; however, related data are rare. This study describes the prevalence and frequency of self-reported sleep disturbances in RTx recipients. Methods: This cross-sectional study included 249 RTx recipients transplanted at three Swiss transplant centers. All had reported poor SQ and / or DS in a previous study. With the Survey of Sleep (SOS) self-report questionnaire, we screened for sleep and health habits, sleep history, main sleep problems and sleep-related disturbances. To determine a basis for preliminary sleep diagnoses according to the International Classification of Sleep Disorders (ICSD), 164 subjects were interviewed (48 in person, 116 via telephone and 85 refused). Descriptive statistics were used to analyze the data and to determine the frequencies and prevalences of specific sleep disorders. Results: The sample had a mean age of 59.1 ± 11.6 years (60.2% male); mean time since Tx was 11.1 ± 7.0 years. The most frequent sleep problem was difficulty staying asleep (49.4%), followed by problems falling asleep (32.1%). The most prevalent sleep disturbance was the need to urinate (62.9%), and 27% reported reduced daytime functionality. Interview data showed that most suffered from the first ICSD category: insomnias. Conclusion: Though often disregarded in RTx recipients, sleep is an essential factor of wellbeing. Our findings show high prevalences and incidences of insomnias, with negative impacts on daytime functionality. This indicates a need for further research on the clinical consequences of sleep disturbances and the benefits of insomnia treatment in RTx recipients. Keywords: Renal transplantation, Sleep disturbances, Sleep quality, Daytime sleepiness},
keywords = {}
}

Cajochen, C.; Altanay-Ekici, S.; Münch, M.; Frey, S.; Knoblauch, Vera; Wirz-Justice, A.

Evidence that the Lunar Cycle Inﬂuences Human Sleep

Current Biology, 23 (15), pp. 1-4, 2013.

(Abstract | PDF & Links | BibTeX)

@article{183,
title = {Evidence that the Lunar Cycle Inﬂuences Human Sleep},
author = {C. Cajochen and S. Altanay-Ekici and M. Münch and S. Frey and Vera Knoblauch and A. Wirz-Justice},
url = {http://www.chronobiology.ch/wp-content/uploads/publications/cajochen_2013-06.pdf
http://www.chronobiology.ch/wp-content/uploads/publications/cajochen_06-2013_SOM.pdf},
year = {2013},
date = {2013-07-25},
journal = {Current Biology},
volume = {23},
number = {15},
pages = {1-4},
abstract = {Endogenous rhythms of circalunar periodicity (∼29.5 days) and their underlying molecular and genetic basis have been demonstrated in a number of marine species [1 and 2]. In contrast, there is a great deal of folklore but no consistent association of moon cycles with human physiology and behavior [3]. Here we show that subjective and objective measures of sleep vary according to lunar phase and thus may reflect circalunar rhythmicity in humans. To exclude confounders such as increased light at night or the potential bias in perception regarding a lunar influence on sleep, we retrospectively analyzed sleep structure, electroencephalographic activity during non-rapid-eye-movement (NREM) sleep, and secretion of the hormones melatonin and cortisol found under stringently controlled laboratory conditions in a cross-sectional setting. At no point during and after the study were volunteers or investigators aware of the a posteriori analysis relative to lunar phase. We found that around full moon, electroencephalogram (EEG) delta activity during NREM sleep, an indicator of deep sleep, decreased by 30%, time to fall asleep increased by 5 min, and EEG-assessed total sleep duration was reduced by 20 min. These changes were associated with a decrease in subjective sleep quality and diminished endogenous melatonin levels. This is the first reliable evidence that a lunar rhythm can modulate sleep structure in humans when measured under the highly controlled conditions of a circadian laboratory study protocol without time cues. },
keywords = {}
}

Gabel, V.; Maire, M.; Chellappa, C.F. Reichert S.L.; Schmidt, C.; Hommes, V.; Viola, A.U.; Cajochen, C.

Effects of Artificial Dawn and Morning Blue Light on Daytime Cognitive Performance, Well-being, Cortisol and Melatonin Levels

Chronobiology International, 30, pp. 988-97, 2013.

(Abstract | PDF & Links | BibTeX)

@article{181,
title = {Effects of Artificial Dawn and Morning Blue Light on Daytime Cognitive Performance, Well-being, Cortisol and Melatonin Levels},
author = {V. Gabel and M. Maire and C.F. Reichert S.L. Chellappa and C. Schmidt and V. Hommes and A.U. Viola and C. Cajochen},
url = {http://www.chronobiology.ch/wp-content/uploads/publications/Gabel_2013.pdf},
year = {2013},
date = {2013-07-10},
journal = {Chronobiology International},
volume = {30},
pages = {988-97},
abstract = {Light exposure elicits numerous effects on human physiology and behavior, such as better cognitive performance and
mood. Here we investigated the role of morning light exposure as a countermeasure for impaired cognitive
performance and mood under sleep restriction (SR). Seventeen participants took part of a 48h laboratory protocol,
during which three different light settings (separated by 2 wks) were administered each morning after two 6-h sleep
restriction nights: a blue monochromatic LED (light-emitting diode) light condition (BL; 100 lux at 470 nm for 20 min)
starting 2 h after scheduled wake-up time, a dawn-simulating light (DsL) starting 30 min before and ending 20 min
after scheduled wake-up time (polychromatic light gradually increasing from 0 to 250 lux), and a dim light (DL)
condition for 2 h beginning upon scheduled wake time (58 lux). Cognitive tasks were performed every 2 h during
scheduled wakefulness, and questionnaires were administered hourly to assess subjective sleepiness, mood, and wellbeing. Salivary melatonin and cortisol were collected throughout scheduled wakefulness in regular intervals, and the
effects on melatonin were measured after only one light pulse. Following the first SR, analysis of the time course of
cognitive performance during scheduled wakefulness indicated a decrease following DL, whereas it remained stable
following BL and significantly improved after DsL. Cognitive performance levels during the second day after SR were
not significantly affected by the different light conditions. However, after both SR nights, mood and well-being were
significantly enhanced after exposure to morning DsL compared with DL and BL. Melatonin onset occurred earlier
after morning BL exposure, than after morning DsL and DL, whereas salivary cortisol levels were higher at wake-up
time after DsL compared with BL and DL. Our data indicate that exposure to an artificial morning dawn simulation
light improves subjective well-being, mood, and cognitive performance, as compared with DL and BL, with minimal
impact on circadian phase. Thus, DsL may provide an effective strategy for enhancing cognitive performance, wellbeing, and mood under mild sleep restriction.},
keywords = {}
}

Light exposure elicits numerous effects on human physiology and behavior, such as better cognitive performance and
mood. Here we investigated the role of morning light exposure as a countermeasure for impaired cognitive
performance and mood under sleep restriction (SR). Seventeen participants took part of a 48h laboratory protocol,
during which three different light settings (separated by 2 wks) were administered each morning after two 6-h sleep
restriction nights: a blue monochromatic LED (light-emitting diode) light condition (BL; 100 lux at 470 nm for 20 min)
starting 2 h after scheduled wake-up time, a dawn-simulating light (DsL) starting 30 min before and ending 20 min
after scheduled wake-up time (polychromatic light gradually increasing from 0 to 250 lux), and a dim light (DL)
condition for 2 h beginning upon scheduled wake time (58 lux). Cognitive tasks were performed every 2 h during
scheduled wakefulness, and questionnaires were administered hourly to assess subjective sleepiness, mood, and wellbeing. Salivary melatonin and cortisol were collected throughout scheduled wakefulness in regular intervals, and the
effects on melatonin were measured after only one light pulse. Following the first SR, analysis of the time course of
cognitive performance during scheduled wakefulness indicated a decrease following DL, whereas it remained stable
following BL and significantly improved after DsL. Cognitive performance levels during the second day after SR were
not significantly affected by the different light conditions. However, after both SR nights, mood and well-being were
significantly enhanced after exposure to morning DsL compared with DL and BL. Melatonin onset occurred earlier
after morning BL exposure, than after morning DsL and DL, whereas salivary cortisol levels were higher at wake-up
time after DsL compared with BL and DL. Our data indicate that exposure to an artificial morning dawn simulation
light improves subjective well-being, mood, and cognitive performance, as compared with DL and BL, with minimal
impact on circadian phase. Thus, DsL may provide an effective strategy for enhancing cognitive performance, wellbeing, and mood under mild sleep restriction.

Cajochen, C.

Chronobiologie: Licht- und Wachtherapie bei psychiatrischen Erkrankungen

PSYCH up2date, 7 (3), pp. 173-184, 2013.

(Abstract | PDF & Links | BibTeX)

Chellappa, S.L.; Steiner, R.; Oelhafen, P.; Lang, D.; Götz, T.; Krebs, J.; Cajochen, C.

Acute exposure to evening blue-enriched light impacts on human sleep

Journal of Sleep Research, 2013.

(Abstract | PDF & Links | BibTeX)

@article{177,
title = {Acute exposure to evening blue-enriched light impacts on human sleep},
author = {S.L. Chellappa and R. Steiner and P. Oelhafen and D. Lang and T. Götz and J. Krebs and C. Cajochen},
url = {http://www.chronobiology.ch/wp-content/uploads/publications/chellappa_evening_light_sleep.pdf},
year = {2013},
date = {2013-03-20},
journal = {Journal of Sleep Research},
abstract = {Light in the short wavelength range (blue light: 446–483 nm) elicits direct effects on human melatonin secretion, alertness and cognitive performance via non-image-forming photoreceptors. However, the impact of blue-enriched polychromatic light on human sleep architecture and sleep electroencephalographic activity remains fairly unknown. In this study we investigated sleep structure and sleep electroencephalographic characteristics of 30 healthy young participants (16 men, 14 women; age range 20–31 years) following 2 h of evening light exposure to polychromatic light at 6500 K, 2500 K and 3000 K. Sleep structure across the ﬁrst three non-rapid eye movement non-rapid eye movement – rapid eye movement sleep cycles did not differ signiﬁcantly with respect to the light
conditions. All-night non-rapid eye movement sleep electroencephalographic power density indicated that exposure to light at 6500 K resulted in a tendency for less frontal non-rapid eye movement electroencephalographic power density, compared to light at 2500 K and 3000 K. The dynamics of non-rapid eye movement electroencephalographic slow wave activity (2.0–4.0 Hz), a functional index of homeostatic sleep pressure, were such that slow wave activity was reduced signiﬁcantly during the ﬁrst sleep cycle after light at 6500 K compared to light at 2500 K and 3000 K, particularly in the frontal derivation. Our data suggest that exposure to blue-enriched polychromatic light at relatively low room light levels impacts upon homeostatic sleep regulation, as indexed by reduction in frontal slow wave activity during the ﬁrst nonrapid eye movement episode.},
keywords = {}
}

Chellappa, S.L.; Cajochen, C.

Ultradian and circadian modulation of dream recall: EEG correlates and age effects

International Journal of Psychophysiology, 89, pp. 165–170, 2013.

(Abstract | PDF & Links | BibTeX)

Bromundt, V.; Wirz-Justice, A.; Kyburz, S.; Opwis, K.; Dammann, G.; Cajochen, C.

Circadian sleep-wake cycles, well-being, and light therapy in Borderline Personality Disorder

Journal of Personality Disorders, 26. doi: 10.1521/pedi_2012_26_057, 2012.

(PDF & Links | BibTeX)

Kolodyazhniy, V.; Späti, J.; Frey, S.; Götz, T.; Wirz-Justice, A.; Kräuchi, K.; Cajochen, C.; Wilhelm, F.H.

An improved method for estimating human circadian phase derived from multichannel ambulatory monitoring and artificial neural networks

Chronobiology International Aug. 14. doi:10.3109/07420528.2012.700669, 2012.

(PDF & Links | BibTeX)

Schmidt, C.; Peigneux, P.; Cajochen, C.

Age-related changes in sleep and circadian rhythms: impact on cognitive performance and underlying neuroanatomical networks

Frontiers in Neurology 3:118. doi: 10.3389/fneur.2012.00118, 2012.

(PDF & Links | BibTeX)

Frey, S.; Birchler-Pedross, A.; Hofstetter, M.; Brunner, P.; Götz, T.; Münch, M.; Blatter, K.; Knoblauch, V.; Wirz-Justice, A.; Cajochen, C.

Challenging the sleep homeostat: Sleep in depression is not premature aging

Sleep Medicine 13: 933-945, 2012.

(PDF & Links | BibTeX)

Frey, S.; Birchler-Pedross, A.; Hofstetter, M.; Brunner, P.; Götz, T.; Münch, M.; Blatter, K.; Knoblauch, V.; Wirz-Justice, A.; Cajochen, C.

Young women with major depression live on higher homeostatic sleep pressure than healthy controls

Chronobiology International 29(3): 278-294, 2012.

(PDF & Links | BibTeX)

Dallmann, R.; Viola, A.U.; Tarokha, L.; Cajochen, C.; Brown, S.A.

The human circadian metabolome

PNAS January 31 doi: 10.1073/pnas.1114410109 (Epub ahead of print), 2012.

(PDF & Links | BibTeX)

Schmidt, C.; Peigneux, P.; Leclercq, Y.; Sterpenich, V.; Vandewalle, G.; Phillips, C.; Berthomier, P.; Berthomier, C.; Tinguely, G.; Gais, S.; Schabus, M.; Desseilles, M.; Dang-Vu, T.; Salmon, E.; Degueldre, C.; Balteau, E.; Luxen, A.; Cajochen, C.; Maquet, P.; Collette, F.

Circadian preference modulates the neural substrate of conflict processing across the day

PLoS ONE 7(1): e29658, 2012.

(PDF & Links | BibTeX)

Chellappa, S.L.; Münch, M.; Knoblauch, V.; Cajochen, C.

Age effects on spectral electroencephalogram activity prior to dream recall

J Sleep Res. Aug 18. doi: 10.1111/j.1365-2869.2011.00947.x (Epub ahead of print), 2011.

(PDF & Links | BibTeX)

Viola, A.U.; Chellappa, S.L.; Archer, S.N.; Pugin, F.; Götz, T.; Dijk, D.J.; Cajochen, C.

Interindividual differences in circadian rhythmicity and sleep homeostasis in older people: effect of a PER3 polymorphism

Neurobiology of Aging Dec 12 (Epub ahead of print), 2011.

(PDF & Links | BibTeX)

Chellappa, S.L.; Viola, A.U.; Schmidt, C.; Bachmann, V.; Gabel, V.; Maire, M.; Reichert, C.F.; Valomon, A.; Götz, T.; Landolt, H.P.; Cajochen, C.

Human melatonin and alerting response to blue-enriched light depend on a polymorphism in the clock gene PER3

J Clin Endocrinol Metab 97(3), 2011.

(PDF & Links | BibTeX)

Birchler-Pedross, A.; Frey, S.; Chellappa, S.L.; Götz, T.; Brunner, P.; Knoblauch, V.; Wirz-Justice, A.; Cajochen, C.

Higher frontal EEG synchronization in young women with major depression: A marker for increased homeostatic sleep pressure?

Sleep 34(12): 1699-1706, 2011.

(PDF & Links | BibTeX)

Chellappa, S.L.; Gordijn, M.C.M.; Cajochen, C.

Can light make us bright? Effects of light on cognition sleep

In: Kerkhof G. and Van Dongen H.P.A. (Eds), Progress in Brain Research 190: 119-133, 2011.

(PDF & Links | BibTeX)

Wirz-Justice, A.; Cajochen, C.

Zirkadiane Rhythmen und Depression: chronobiologische Behandlungsmöglichkeiten

Schweiz Med Forum 11(32-33): 536-541, 2011.

(PDF & Links | BibTeX)

Pagani, L.; Schmit, t K.; Meier, F.; Izakovic, J.; Roemer, K.; Viola, A.U.; Cajochen, C.; Wirz-Justice, A.; Brown, S.A.; Eckert, A.

Serum factors in older individuals change cellular clock properties

PNAS 108(17): 7218-7223, 2011.

(PDF & Links | BibTeX)

Chellappa, S.L.; Frey, S.; Knoblauch, V.; Cajochen, C.

Cortical activation patterns herald successful dream recall after NREM and REM sleep

Biol Psychology 87: 251-256, 2011.

(PDF & Links | BibTeX)

Bromundt, V.; Köster, M.; Georgiev-Kill, A.; Opwis, K.; Wirz-Justice, A.; Stoppe, G.; Cajochen, C.

Sleep-wake cycles and cognitive functioning in schizophrenia.

Br J Psychiatry, epub 10.1192/bjp.bp.110.078022, 2011.

(PDF & Links | BibTeX)

Cajochen, C.; Frey, S.; Anders, D.; Späti, J.; Bues, M.; Pross, A.; Mager, R.; Wirz-Justice, A.; Stefani, O.

Evening exposure to a light emitting diodes (LED)-backlit computer screen affects circadian physiology and cognitive performance

2011.

(PDF & Links | BibTeX)

Chellappa, S.L.; Steiner, R.; Blattner, P.; Oelhafen, P.; Götz, T.; Cajochen, C.

Non-Visual Effects of Light on Melatonin, Alertness and Cognitive Performance: Can Blue-Enriched Light Keep Us Alert?

PLoS ONE 6(1): e16429. doi:10.1371/journal.pone.0016429, 2011.

(PDF & Links | BibTeX)

Kolodyazhniy, V.; Späti, J.; Frey, S.; Götz, T.; Wirz-Justice, A.; Kräuchi, K.; Cajochen, C.; Wilhelm, F.H.

Estimation of human circadian phase via a multi-channel ambulatory monitoring system and a multiple regression model.

J Biol Rhythms 26: 55-67., 2011.

(PDF & Links | BibTeX)

Brown, S.A.; Pagani, L.; Cajochen, C.; Eckert, A.

Systemic and Cellular Reflections on ageing and the circadian oscillator - A Mini-Review.

Gerontology. Oct 28., 2010.

(PDF & Links | BibTeX)

Cajochen, C.; Chellappa, S.L.; Schmidt, C.

What keeps us awake?--the role of clocks and hourglasses, light, and melatonin.

Int Rev Neurobiol 93:57-90., 2010.

(PDF & Links | BibTeX)

Jung, C.M.; Khalsa, S.B.; Scheer, F.A.; Cajochen, C.; Lockley, S.W.; Czeisler, C.A.; Wright, K.P. Jr.

Acute effects of bright light exposure on cortisol levels.

J Biol Rhythms. 25(3):208-16., 2010.

(PDF & Links | BibTeX)

Pagani, L.; Semenova, E.A.; Moriggi, E.; Revell, V.L.; Hack, L.M.; Lockley, S.W.; Arendt, J.; Skene, D.J.; Meier, F.; Izakovic, J.; Wirz-Justice, A.; Cajochen, C.; Sergeeva, O.J.; Cheresiz, S.V.; Danilenko, K.V.; Eckert, A.; Brown, S.A.

The physiological period length of the human circadian clock in vivo is directly proportional to period in human fibroblasts.

PLoS One. 15;5(10):e13376., 2010.

(PDF & Links | BibTeX)

Wirz-Justice, A.; Schröder, C.M.; Gasio, P. Fontana; Cajochen, C.; Savaskan, E.

The circadian rest-activity cycle in Korsakoff psychosis.

Am J Geriatr Psychiatry 18(1): 33-41., 2010.

(PDF & Links | BibTeX)

Pagani, L.; Semenova, E.A.; Moriggi, E.; Revell, V.L.; Hack, L.M.; Lockley, S.W.; Arendt, J.; Skene, D.J.; Meier, F.; Izakovic, J.; Wirz-Justice, A.; Cajochen, C.; Sergeeva, O.J.; Cheresiz, S.V.; Danilenko, K.V.; Eckert, A.; Brown, S.A.

The physiological period length of the human circadian clock in vivo is directly proportional to period in human fibroblasts.

PLoS One. 15;5(10):e13376., 2010.

(PDF & Links | BibTeX)

Wirz-Justice, A.; Bromundt, V.; Cajochen, C.

Circadian disruption and psychiatric disorders: The importance of entrainment.

Sleep Med Clin, 4: 273-284., 2009.

(PDF & Links | BibTeX)

Birchler-Pedross, A.; Schröder, C.M.; Münch, M.; Knoblauch, V.; Blatter, K.; Schnitzler-Sack, C.; Wirz-Justice, A.; Cajochen, C.

Subjective well-being is modulated by circadian phase, sleep pressure, age, and gender.

Journal of Biological Rhythms, 24(3): 232-242., 2009.

(PDF & Links | BibTeX)

Chellappa, S.L.; Münch, M.; Blatter, K.; Knoblauch, V.; Cajochen, C.

Does the circadian modulation of dream recall modify with age?

Sleep, 32(9): 1201-1209., 2009.

(PDF & Links | BibTeX)

Chellappa, S.L.; Schröder, C.; Cajochen, C.

Chronobiology, excessive daytime sleepiness and depression: Is there a link?

Sleep Medicine, 10(5): 505-514., 2009.

(PDF & Links | BibTeX)

Frey, S.; Balu, S.; Greusing, S.; Rothen, N.; Cajochen, C.

Consequences of the timing of menarche on female adolescent sleep phase preference.

PLoS ONE, 4(4)., 2009.

(PDF & Links | BibTeX)

Jud, C.; Chappuis, S.; Revell, V.L.; Sletten, T.L.; Saaltink, D.-J.; Cajochen, C.; Skene, D.J.; Albrecht, U.

Age-dependent alterations in human PER2 levels after early morning blue light exposure.

Chronobiology International, 26(7): 1462-1469., 2009.

(PDF & Links | BibTeX)

Rosenberg, J.; Pusch, K.; Dietrich, R.; Cajochen, C.

The Tick-Tock of Language: Is Language Processing Sensitive to Circadian Rhythmicity and Elevated Sleep Pressure?

Chronobiology International, 26(5): 1-18., 2009.

(PDF & Links | BibTeX)

Schmidt, C.; Collette, F.; Leclercq, Y.; Sterpenich, V.; Vandewalle, G.; Berthomier, P.; Berthomier, C.; Phillips, C.; Tinguely, G.; Darsaud, A.; Gais, S.; Schabus, M.; Desseilles, M.; Dang-Vu, T.T.; Salmon, E.; Balteau, E.; Dequeldre, C.; Luxen, A.; Maquet, P.; Cajochen, C.; Peigneux, P.

Homeostatic sleep pressure and responses to sustained attention in the suprachiasmatic area.

Science, 324(5926):516-519., 2009.

(PDF & Links | BibTeX)

Späti, J.; Münch, M.; Blatter, K.; Knoblauch, V.; Jones, L.A.; Cajochen, C.

Impact of age, sleep pressure and circadian phase on time-of-day estimates.

Behav Brain Res, 201(1):48-52., 2009.

(PDF & Links | BibTeX)

Cajochen, C.; Biase, R. Di; Imai, M.

Interhemispheric EEG asymmetries during unilateral bright-light exposure

Am J Physiol Regulatory Integrative Comp Physiol, 294, pp. 1053-1060, 2008.

(PDF & Links | BibTeX)

Blatter, K.; Cajochen, C.

Circadian rhythms in cognitive performance: Methodological constraints, protocols, theoretical underpinnings.

Physiology & Behavior, 90: 196-208., 2007.

(PDF & Links | BibTeX)

Cajochen, C.

Alerting effects of light.

Sleep Med Rev, 11: 453-464., 2007.

(PDF & Links | BibTeX)

Münch, M.; Knoblauch, V.; Blatter, K.; Wirz-Justice, A.; Cajochen, C.

Is homeostatic sleep regulation under low sleep pressure modified by age?

Sleep, 30(6): 781-792., 2007.

(PDF & Links | BibTeX)

Schmidt, C.; Collette, F.; Cajochen, C.; Peigneux, P.

A time to think: circadian rhythms in human cognition.

Cogn Neuropsychol., 24(7):755-789., 2007.

(PDF & Links | BibTeX)

Cajochen, C.; Münch, M.; Knoblauch, V.; Blatter, K.; Wirz-Justice, A.

Age-related changes in the circadian and homeostatic regulation of human sleep.

Chronobiology International, 23: 461-474., 2006.

(PDF & Links | BibTeX)

Kräuchi, K.; Knoblauch, V.; Wirz-Justice, A.; Cajochen, C.

Challenging the sleep homeostat does not influence the thermoregulatory system in men: evidence from a nap vs. sleep-deprivation study.

American Journal of Physiology - Regulatory, Integrative and Comparative Physiology, 290: R1052-R1061., 2006.

(PDF & Links | BibTeX)

Blatter, K.; Graw, P.; Münch, M.; Knoblauch, V.; Wirz-Justice, A.; Cajochen, C.

Gender and age differences in psychomotor vigilance under differential sleep pressure conditions.

Behavioural Brain Research, 168: 312-317., 2006.

(PDF & Links | BibTeX)

Cajochen, C.; Jud, C.; Münch, M.; Kobialka, S.; Wirz-Justice, A.; Albrecht, U.

Evening exposure to blue light stimulates the expression of the clock gene PER2 in humans

European Journal of Neuroscience, 23: 1082-1086., 2006.

(PDF & Links | BibTeX)

Kräuchi, K.; Cajochen, C.; Pache, M.; Flammer, J.; Wirz-Justice, A.

Thermoregulatory effects of melatonin in relation to sleepiness.

Chronobiology International, 23: 475-484., 2006.

(PDF & Links | BibTeX)

Münch, M.; Kobialka, S.; Steiner, R.; Oelhafen, P.; Wirz-Justice, A.; Cajochen, C.

Wavelength-dependent effects of evening light exposure on sleep architecture and sleep EEG power density in men.

American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 290 : R1421-R1428., 2006.

(PDF & Links | BibTeX)

Savaskan, E.; Schnitzler, C.; Schröder, C.; Cajochen, C.; Müller-Spahn, F.; Wirz-Justice, A.

Treatment of behavioural, cognitive and circadian rest-activity cycle disturbances in Alzheimer's disease: haloperidol vs. quetiapine.

International Journal of Neuropsychopharmacology, 9: 507-516., 2006.

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Schmidt, C.; Peigneux, P.; Muto, V.; Schenkel, M.; Knoblauch, V.; Münch, M.; Quervain, D. J.-F. de; Wirz-Justice, A.; Cajochen, C.

Encoding difficulty promotes postlearning changes in sleep spindle activity during napping.

Journal of Neuroscience, 26(35): 8976-8982., 2006.

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Blatter, K.; Opwis, K.; Münch, M.; Wirz-Justice, A.; Cajochen, C.

Sleep loss-related decrements in planning performance in healthy elderly depend on task difficulty.

Journal of Sleep Research, 14: 409-417., 2005.

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Cajochen, C.

Schlafstörungen bei Schichtarbeit und Jetlag und die Rolle der inneren Uhr.

Praxis, 94: 1479-1483., 2005.

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Cajochen, C.

TAK-375 Takeda.

Current Opinion in Investigational Drugs, 6: 114-121., 2005.

Cajochen, C.; Münch, M.; Kobialka, S.; Kräuchi, K.; Steiner, R.; Oelhafen, P.; Orgül, S.; Wirz-Justice, A.

High sensitivity of human melatonin, alertness, thermoregulation and heart rate to short wavelength light.

Journal of Clinical Endocrinology and Metabolism, 90: 1311-1316., 2005.

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Knoblauch, V.; Münch, M.; Blatter, K.; Martens, W.L.J.; Schröder, C.; Schnitzler, C.; Wirz-Justice, A.; Cajochen, C.

Age-Related Changes in the Circadian Modulation of Sleep-Spindle Frequency During Nap Sleep.

Sleep, 28: 1093-1101, 2005.

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Kräuchi, K.; Cajochen, C.; Wirz-Justice, A.

Thermophysiologic aspects of the three-process-model of sleepiness regulation.

Clinics in Sports Medicine, 24: 287-300., 2005.

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Münch, M.; Cajochen, C.; Wirz-Justice, A.

Schlaf und zirkadiane Rhythmik im Alter.

Zeitschrift für Gerontologie und Geriatrie, 38 (Supplement 1) I/21â€“I/23., 2005.

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Münch, M.; Knoblauch, V.; Blatter, K.; Schröder, C.; Schnitzler, C.; Kräuchi, K.; Wirz-Justice, A.; Cajochen, C.

Age-related attenuation of the evening circadian arousal signal in humans.

Neurobiology of Aging, 26: 1307-1319, 2005.

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Cajochen, C.; Blatter, K.; Wallach, D.

Circadian and sleep-wake dependent impact on neurobehavioral function.

Psychologica Belgica, 44: 59-80., 2004.

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Cajochen, C.; Knoblauch, V.; Wirz-Justice, A.; Kräuchi, K.; Graw, P.; Wallach, D.

Circadian modulation of sequence learning under high and low sleep pressure conditions.

Behavioural Brain Research, 151: 167-176., 2004.

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Graw, P.; Kräuchi, K.; Knoblauch, V.; Renz, C.; Wirz-Justice, A.; Cajochen, C.

Circadian and wake-dependent modulation of fastest and slowest reaction times of the Psychomotor Vigilance Task (PVT).

Physiology & Behavior, 80: 695-701., 2004.

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Kräuchi, K.; Cajochen, C.; Wirz-Justice, A.

Waking up properly: is there a role of thermoregulation in sleep inertia?

Journal of Sleep Research, 13: 121-127., 2004.

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Münch, M.; Knoblauch, V.; Blatter, K.; Schröder, C.; Schnitzler, C.; Kräuchi, K.; Wirz-Justice, A.; Cajochen, C.

The frontal predominance in human EEG delta activity after sleep loss decreases with age.

European Journal of Neuroscience, 20: 1402-10., 2004.

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Wirz-Justice, A.; Kräuchi, K.; Cajochen, C.; Danilenko, K.V.; Renz, C.; Weber, J.

Evening melatonin and bright light administration induce additive phase shifts in dim light melatonin onset.

Journal of Pineal Research, 36: 192-194., 2004.

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Wyatt, J.K.; Cajochen, C.; Cecco, A. Ritz-De; Czeisler, C.A.; Dijk, D.J.

Low-dose repeated caffeine administration for circadian-phase-dependent performance degradation during extended wakefulness.

Sleep, 27: 374-381., 2004.

Cajochen, C.; Dijk, D.J.

Electroencephalographic activity during wakefulness, rapid eye movement, and non-rapid- eye movement sleep in humans: comparison of their circadian and homeostatic modulation.

Sleep and Biological Rhythms, 2: 85-95., 2003.

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Cajochen, C.; Jewett, M.E.; Dijk, D.J.

Human circadian melatonin rhythm phase delay during a fixed sleep-wake schedule interspersed with nights of sleep deprivation.

Journal of Pineal Research, 35: 149-157., 2003.

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Cajochen, C.; Kräuchi, K.; Wirz-Justice, A.

Role of melatonin in the regulation of human circadian rhythms and sleep.

Journal of Neuroendocrinology, 15: 432-437., 2003.

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Danilenko, K.V.; Cajochen, C.; Wirz-Justice, A.

Is sleep per se a zeitgeber in humans?

Journal of Biological Rhythms, 18: 170-178., 2003.

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Gasio, P. Fontana; Kräuchi, K.; Cajochen, C.; Someren, E.J.W. van; Amrhein, I.; Pache, M.; Savaskan, E.; Wirz-Justice, A.

Dawn-dusk simulation light therapy of disturbed circadian rest-activity cycles in demented elderly.

Experimental Gerontology, 38: 207-216., 2003.

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Khalsa, S.B.; Jewett, M.E.; Cajochen, C.; Czeisler, C.A.

A phase-response curve to single bright light pulses in human subjects.

Journal of Physiology, 549: 945-52., 2003.

Knoblauch, V.; Martens, W.J.L.; Wirz-Justice, A.; Cajochen, C.

Human sleep spindle characteristics after sleep deprivation.

Clinical Neurophysiology, 114: 2258-2267., 2003.

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Knoblauch, V.; Martens, W.J.L.; Wirz-Justice, A.; Kräuchi, K.; Cajochen, C.

Regional differences in the circadian modulation of human sleep spindle characteristics.

European Journal of Neuroscience, 18: 155-163., 2003.

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Knoblauch, V.; Kräuchi, K.; Renz, C.; Wirz-Justice, A.; Cajochen, C.

Homeostatic control of slow wave- and spindle frequency activity during human sleep: effect of differential sleep pressure and brain topography.

Cerebral Cortex, 12: 1092-1100., 2002.

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Kräuchi, K.; Cajochen, C.; Werth, E.; Wirz-Justice, A.

Alteration of internal circadian phase relationships after timed CHO-rich meals in humans.

Journal of Biological Rhythms, 17: 364-376., 2002.

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Cajochen, C.; Wyatt, J. K.; Czeisler, C.A.; Dijk, D.J.

Separation of circadian and wake-duration dependent modulation of EEG activation during wakefulness.

Neuroscience, 114: 1047-60., 2002.

Cajochen, C.; Knoblauch, V.; Kräuchi, K.; Renz, C.; Wirz-Justice, A.

Dynamics of frontal EEG activity, sleepiness and body temperature under high and low sleep pressure.

Neuroreport 12: 2277-2281., 2001.

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Graw, P.; Werth, E.; Kräuchi, K.; Gutzwiller, F.; Cajochen, C.; Wirz-Justice, A.

Early morning melatonin administration impairs psychomotor vigilance.

Behavioural Brain Research, 121: 167-172., 2001.

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Pache, M.; Kräuchi, K.; Cajochen, C.; Wirz-Justice, A.; Dubler, B.; Flammer, J.; Kaiser, H.J.

Cold feet and prolonged sleep-onset latency in vasospastic syndrome.

The Lancet, 358: 125-126., 2001.

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Wirz-Justice, A.; Haug, H.J.; Cajochen, C.

Disturbed circadian rest-activity cycles in schizophrenia patients: an effect of drugs?

Schizophr. Bull. 27: 497-502, 2001.

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Cajochen, C.; Brunner, D.P.; Kräuchi, K.; Graw, P.; Wirz-Justice, A

EEG and subjective sleepiness during extended wakefulness in Seasonal Affective Disorder: circadian and homeostatic influences.

Biological Psychiatry, 47: 610-617., 2000.

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Cajochen, C.; Zeitzer, J. M.; Czeisler, C.A.; Dijk, D.J.

Dose-response relationship for light intensity and ocular and electroencephalo-graphic correlates of human alertness.

Behavioural Brain Research 115: 75 - 83, 2000.

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Danilenko, K.V.; Wirz-Justice, A.; Kräuchi, K.; Cajochen, C.; Weber, J.M.; Fairhurst, S.; Terman, M.

Phase advance after one or three simulated dawns in humans.

Chronobiology International, 17: 659-668., 2000.

Kräuchi, K.; Cajochen, C.; Werth, E.; Wirz-Justice, A.

A functional link between distal vasodilation and sleep onset latency?

American Journal of Physiology, 278: R741-R748., 2000.

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Wirz-Justice, A.; Quinto, C.; Cajochen, C.; Werth, E.; Hock, C.

A rapid-cycling bipolar patient treated with long nights, bedrest, and light.

Biological Psychiatry, 45: 1075-1077., 1999.

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Kräuchi, K.; Cajochen, C.; Werth, E.; Wirz-Justice, A.

Warm feet promote the rapid onset of sleep.

Nature, 401: 36-37., 1999.

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Kräuchi, K.; Cajochen, C.; Wirz-Justice, A.

Circadian and homeostatic regulation of core body temperature and alertness in humans: what is the role of melatonin?

K.-I. Honma and S. Honma (Eds.), Circadian Clocks and Entrainment, Hokkaido University Press, Sapporo, 7: 131-146., 1998.

Cajochen, C.; Kräuchi, K.; Danilenko, K.V.; Wirz-Justice, A.

Evening administration of melatonin and bright light: interactions on the EEG during sleep and wakefulness.

Journal of Sleep Research, 7: 145-157., 1998.

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Kräuchi, K.; Cajochen, C.; Möri, D.; Graw, P.; Wirz-Justice, A.

Melatonin and S-20098 advance circadian phase and nocturnal regulation of core body temperature.

American Journal of Physiology, 272: R1178-R1188., 1997.

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Kräuchi, K.; Cajochen, C.; Wirz-Justice, A.

A relationship between heat loss and sleepiness: effects of postural change and melatonin administration.

Journal of Applied Physiology, 83: 134-139., 1997.

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Wirz-Justice, A.; Cajochen, C.; Nussbaum, P.

A schizophrenic patient with an arrhythmic circadian rest-activity cycle.

Psychiatry Research, 73: 83-90., 1997.

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Dijk, D.-J.; Cajochen, C.

Melatonin and the circadian regulation of sleep initiation, consolidation, structure and the sleep EEG.

Journal of Biological Rhythms, 12: 627-635., 1997.

Cajochen, C.; Kräuchi, K.; Möri, D.; Graw, P.; Wirz-Justice, A.

Melatonin and S-20098 phase advance REM sleep propensity and the wake-up threshold without modifying NREM-sleep homeostasis.

American Journal of Physiology, 272: R1189-R1196., 1997.

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Cajochen, C.; Kräuchi, K.; Wirz-Justice, A.

The acute soporific action of daytime melatonin administration: effects on waking EEG power density and alertness.

Journal of Biological Rhythms, 12: 636- 643., 1997.