Human Chronobiology Lab - Prof. Dr. Till Roenneberg and colleagues:
1. Roenneberg, T. Von Türhöhen, Vögeln und starren Gesellschaftssystemen. Schlaf 1–6 (2013).
2. Roenneberg, T. The human sleep project. Nature 498, 427–428 (2013).
3. Roenneberg, T. & Allebrandt, K. V. Genetic approaches to understanding circadian entrainment. Shaw Book 1–9 (2013).
4. Genzel, L. et al. Sleep timing is more important than sleep length or quality for medical school performance. Chronobiol Int 00, 1–6 (2013).
5. Blautzik, J. et al. Classifying fMRI-derived resting-state connectivity patterns according to their daily rhythmicity. NeuroImage 71, 298–306 (2013).
6. Juda, M., Vetter, C. & Roenneberg, T. Chronotype Modulates Sleep Duration, Sleep Quality, and Social Jet Lag in Shift-Workers. J. Biol. Rhythms 28, 141–151 (2013).
7. Juda, M., Vetter, C. & Roenneberg, T. The Munich ChronoType Questionnaire for Shift-Workers (MCTQShift). J. Biol. Rhythms 28, 130–140 (2013).
8. Allebrandt, K. V. et al. A K(ATP) channel gene effect on sleep duration: from genome-wide association studies to function in Drosophila. Mol Psychiatry 18, 122–132 (2013).
9. Roenneberg, T., Kantermann, T., Juda, M., Vetter, C. & Allebrandt, K. V. in Handbook of Experimental Pharmacology 217, 311–331 (Springer Berlin Heidelberg, 2013).
10. Foster, R. G. et al. in Progress in Molecular Biology and Translational Science 119, 325–346 (Elsevier, 2013).
Placebo Research Lab, PD Dr. Karin Meissner and colleagues
1. Zimmermann-Viehoff F, Meissner K, Koch J, Weber CS, Richter S & Deter HC (2013): Autonomic effects of suggestive placebo interventions to increase or decrease blood pressure: a randomized controlled trial in healthy subjects. Journal of Psychosomatic Researc. IF 2.839
2. Linde K, Friedrichs C, Alscher A, Blank W, Schneider A, Fässler M, Meissner K (2013): Use of placebos and non-specific and complementary treatments by German physicians – rationale and development of a questionnaire. Forschende Komplementärmedizin 20:361–367. IF 1.053
3. Beissner F, Meissner K, Bär KJ, & Napadow V (2013). The Autonomic Brain: An Activation Likelihood Estimation Meta-Analysis for Central Processing of Autonomic Function. The Journal of Neuroscience, 33(25), 10503-10511. IF 6.747
4. Meissner, K., Fässler, M., Rücker, G., Kleijnen, J., Hróbjartsson, A., Schneider, A., Antes, G., Linde, K. (2013). Differential Effectiveness of Placebo Treatments - A Systematic Review of Migraine Prophylaxis. JAMA Internal Medicine 173(21):1941-1951. IF 13,246
Cognitive Neurosciences Lab, Prof. Dr. Ernst Pöppel and colleagues
1. Mihai Avram, Evgeny Gutyrchik, Yan Bao, Ernst Pöppel, Maximilian Reiser, Janusch Blautzik: Neurofunctional correlates of aesthetic and moral judgments: Equal but not the same. “Neuroscience Letters” 534 (2013)
2.Verena Graupmann, Isabella Peres, Tonia Michaely, Thomas Meindl, Dieter Frey, Maximilian Reiser, Ernst Pöppel, Kai Fehse, Evgeny Gutyrchik: Culture and its neurofunctional correlates when death is in mind. “Neuroscience Letters” 548 (2013) 239-243
3.Aline Lutz, Armin Nassehi, Yan Bao, Ernst Pöppel, Anikó Sztrókay, Maximilian Reiser, Kai Fehse, Evgeny Gutyrchik: Neurocognitive processing of body representations in artistic and photographic images. “NeuroImage”
66 (2013) 288-292
4.Mona Park, Kristina Hennig-Fast, Yan Bao, Petra Carl, Ernst Pöppel, Lorenz Welker, Maximilian Reiser, Thomas Meindl, Evgeny Gutyrchik: Personality traits modulate neural responses to emotions expressed in music: An fMRI study. „Brain Research“ 1523 (2013) 68-76
5.Ernst Pöppel, Mihai Avram, Yan Bao, Verena Graupmann, Evgeny Gutyrchik, Aline Lutz, Mona Park, Maximilian Reiser, Edmund Russell, Sarita Silveira, Lukasz Smigielski, Caroline Szymanski, Yuliya Zaytseva: Sensory processing of art as a unique window into cognitive mechanisms: Evidence from behavioral experiments and fMRI studies. “Procedia – Social and Behavioral Sciences” 86 (2013) 10-17
Chronotype and sleep duration: The influence of season of assessment
Karla V. Allebrandt, Maris Teder-Laving, Thomas Kantermann, Annette Peters, Harry Campbell, Igor Rudan, James F. Wilson, Andres Metspalu, and Till Roenneberg
Little is known about human entrainment under natural conditions, partly due to the complexity of human behavior, torn between biological and social time and influenced by zeitgebers (light–dark cycles) that are progressively ‘‘polluted’’ (and thereby weakened) by artificial light. In addition, data about seasonal variations in sleep parameters are scarce. We, therefore, investigated seasonal variation in cross-sectional assessments of sleep/wake times of 9765 subjects from four European populations (EGCUT Estonian Genome Centre, University of Tartu in Estonia; KORA Cooperative Health Research in the Region of Augsburg in Germany; KORCULA The Korcula study in Croatia; and ORCADES The Orkney Complex Disease Study in Scotland). We identified time-of-year dependencies for the distribution of chronotype (phase of entrainment assessed as the mid-sleep time point on free days adjusted for sleep deficit of workdays) in cohorts from Estonia (EGCUT) and Germany (KORA).
Our results indicate that season (defined as daylight saving time – DST and standard zonetime periods – SZT) specifications of photoperiod influence the distribution of chronotype (adjusted for age and sex). Second, in the largest investigated sample, from Estonia (EGCUT; N 5878), we could detect that seasonal variation in weekly average sleep duration was dependent on individual chronotype.
Later chronotypes in this cohort showed significant variation in their average sleep duration across the year, especially during DST (1 h advance in social time from the end of March to end of October), while earlier chronotypes did not. Later chronotypes not only slept less during the DST period but the average chronotype of the population assessed during this period was earlier than during the SZT (local time for a respective time zone) period.
More in detail, hierarchical multiple regression analyses showed that, beyond season of assessment (DST or SZT), social jetlag (SJl; the discrepancy between the mid sleep on free and work days – which varied with age and sex) contributed to a greater extent to the variation in sleep duration than chronotype (after taking into account factors that are known to influence sleep duration, i.e. age, sex and body mass index).
Variation in chronotype was also dependent on age, sex, season of assessment and SJl (which is highly correlated with chronotype – SJl was larger among later chronotypes).
In summary, subjective assessments of sleep/wake times are very reliable to assess internal time and sleep duration (e.g. reproducing sleep duration and timing tendencies related to age and sex across the investigated populations), but season of assessment should be regarded as a potential confounder. We identified in this study photoperiod (seasonal adaptation) and SJl as two main factors influencing seasonal variation in chronotype and sleep duration. In conclusion, season of assessment, sex and age have an effect on epidemiological variation in sleep duration, chronotype and SJl, and should be included in studies investigating associations between these phenotypes and health parameters, and on the development of optimal prevention strategies.
Keywords: Chronotype, DST, photoperiod, seasonality, sleep duration, social jetlag
Social jetlag negatively correlates with academic performance in undergraduates
Re´ka A´ gnes Haraszti, Krisztina Ella1, Norbert Gyo¨ngyo¨, Till Roenneberg, and Krisztina Ka´ldi
Discrepancies between sleep timing on workdays and weekends, also known as social jetlag (SJL), affect the majority of the population and have been found to be associated with increased health risk and health-impairing behaviors. In this study, we explored the relationship between SJL and academic performance in a sample of undergraduates of the Semmelweis University. We assessed SJL and other sleep-related parameters with the Munich ChronoType Questionnaire (MCTQ) (n¼753). Academic performance was measured by the average grade based on weekly test results as well as scores acquired on the final test (n¼247). The average mid-sleep point on free days in the Hungarian sample fits well the regression line plotted for longitudes within the Central European Time Zone and chronotypes, confirming that sunlight has a major impact on chronotype. Multivariate analysis showed negative effect of SJL on the weekly average grade (p¼0.028, n¼247) during the lecture term with its highly regular teaching schedules, while this association disappeared in the exam period (p¼0.871, n¼247) when students had no scheduled obligations (lower SJL). We also analyzed the relationship between the time of the weekly tests and academic performance and found that students with later sleep times on free days achieved worse in the morning (p¼0.017, n¼129), while the inverse tendency was observed for the afternoon test-takers (p¼0.10, n¼118).
We did not find significant association between academic performance and sleep duration or sleep debt on work days. Our data suggest that circadian misalignment can have a significant negative effect on academic performance. One possible reason for this misalignment is socially enforced sleep times.
Keywords: Chronotype, circadian rhythm, class schedule, Munich ChronoType Questionnaire, sleep timing
Comment by Prof. Dr. Till Roenneberg in NATURE
27 June 2013; Vol. 498, No. 7455, page 427
The human sleep project
To establish the true role of sleep, researchers must gather real-world data from thousands, eeven millions, of people, says Till Roenneberg
Sleep is essential for health, performance and wellbeing. Yet in many countries, people sleep 1-2 hours shorter than their ancestors did 50–100 years ago. Sleep pathologies are approaching epidemic levels, affecting an estimated 70 million people in the United States alone, and in some countries, direct and indirect costs of sleep-related problems may approach 1% of gross domestic product. Researchers have made great advances in understanding sleep, but we still do not have answers to the most basic questions. We need to start investigating sleep in the real world and for this, we need a multidisciplinary ‘human sleep project’.
Chronotype Modulates Sleep Duration, Sleep Quality, and Social Jet Lag in Shift-Workers
Juda, Myriam, Vetter, Céline, & Roenneberg, Till: J Biol Rhythms April 2013 vol. 28 no. 2 141-151
This study explores chronotype-dependent tolerance to the demands of working morning, evening, and night shifts in terms of social jet lag, sleep duration, and sleep disturbance. A total of 238 shift-workers were chronotyped with the Munich ChronoType Questionnaire for shift-workers (MCTQShift), which collects information about shift-dependent sleep duration and sleep timing. Additionally, 94 shift-workers also completed those items of the Sleep Questionnaire from the Standard Shift-Work Index (SSI) that assess sleep disturbances. Although all participants worked morning, evening, and night shifts, subsamples differed in rotation direction and speed. Sleep duration, social jet lag, and sleep disturbance were all significantly modulated by the interaction of chronotype and shift (mixed-model ANOVAs). Earlier chronotypes showed shortened sleep duration during night shifts, high social jet lag, as well as higher levels of sleep disturbance. A similar pattern was observed for later chronotypes during early shifts. Age itself only influenced sleep duration and quality per se, without showing interactions with shifts. We found that workers slept longer in fast, rotating shift schedules. Since chronotype changes with age, investigations on sleep behavior and circadian misalignment in shift-workers have to consider chronotype to fully understand interindividual and intraindividual variability, especially in view of the current demographic changes. Given the impact of sleep on health, our results stress the importance of chronotype both in understanding the effects of shift-work on sleep and in devising solutions to reduce shift-work–related health problems.
Classifying fMRI-derived resting-state connectivity patterns according to their daily rhythmicity.
Blautzik J, Vetter C, Peres I, Gutyrchik E, Keeser D, Berman A, Kirsch V, Mueller S, Pöppel E, Reiser M, Roenneberg T, Meindl T.
Neuroimage. 2013 May 1;71:298-306
The vast majority of biological functions express rhythmic fluctuations across the 24-hour day. We investigated the degree of daily modulation across fMRI (functional Magnetic Resonance Imaging) derived resting-state data in 15 subjects by evaluating the time courses of 20 connectivity patterns over 8h (4 sessions). For each subject, we determined the chronotype, which describes the relationship between the individual circadian rhythm and the local time. We could therefore analyze the daily time course of the connectivity patterns controlling for internal time. Furthermore, as the participants' scan times were staggered as a function of their chronotype, we prevented sleep deprivation and kept time awake constant across subjects. Individual functional connectivity within each connectivity pattern was defined at each session as connectivity strength measured by a mean z-value and, in addition, as the spatial extent expressed by the number of activated voxels. Highly rhythmic connectivity patterns included two sub-systems of the Default-Mode Network (DMN) and a network extending over sensori-motor regions. The network characterized as the most stable across the day is mainly associated with processing of executive control. We conclude that the degree of daily modulation largely varies across fMRI derived resting-state connectivity patterns, ranging from highly rhythmic to stable. This finding should be considered when interpreting results from fMRI studies.
Circadian regulation of olfaction and an evolutionarily conserved, nontranscriptional marker in Caenorhabditis elegans.
Olmedo M, O'Neill JS, Edgar RS, Valekunja UK, Reddy AB, Merrow M.
Circadian clocks provide a temporal structure to processes from gene expression to behavior in organisms from all phyla. Most clocks are synchronized to the environment by alternations of light and dark. However, many organisms experience only muted daily environmental cycles due to their lightless spatial niches (e.g., caves or soil). This has led to speculation that they may dispense with the daily clock. However, recent reports contradict this notion, showing various behavioral and molecular rhythms in Caenorhabditis elegans and in blind cave fish. Based on the ecology of nematodes, we applied low-amplitude temperature cycles to synchronize populations of animals through development. This entrainment regime reveals rhythms on multiple levels: in olfactory cued behavior, in RNA and protein abundance, and in the oxidation state of a broadly conserved peroxiredoxin protein. Our work links the nematode clock with that of other clock model systems; it also emphasizes the importance of daily rhythms in sensory functions that are likely to impact on organism fitness and population structure.
Peroxiredoxins are conserved markers of circadian rhythms
by R. Edgar*, E. Green*, Y. Zhao*, G. van Ooijen*, Maria Olmedo*, X. Qin, Y. Xu, M. Pan, U. Valekunja, K. Feeney, E. Maywood, M. Hastings, N. Baliga, Martha Merrow, A. Millar, C. Johnson, C. Kyriacou, J. O'Neill, A. Reddy in Nature, 2012 May 16;485(7399):459-64. doi: 10.1038/nature11088. (Names with asterisks * are shared first authors.) http://www.nature.com/nature/journal/vaop/ncurrent/full/nature11088.html
In this work, a worldwide collaboration shows that the oxidation state of PRX oscillates with a 24h rhythm in prokaryotes, archaea, fungi, plants and animals. This oscillation furthermore continues in mutants that were previously thought to lack a functioning clock, thus revealing elements of a primordial clock system. Maria Olmedo of the IMP is a co-first author!
Social jetlag and obesity
by Till Roenneberg, Karla Allebrandt, Martha Merrow & Celine Vetter in Current Biology: 22, 939-943, doi:10.1016/j.cub.2012.03.038 (2012). http://www.cell.com/current-biology/retrieve/pii/S0960982212003259
This paper uses epidemiological methods to show that it is not short sleep per se that leads to overweight but rather short sleep due to the use of an alarm clock. This results in differences in sleep timing as well as duration during the workweek and the weekend, which we propose leads to metabolic disturbances.