In my research I study cognitive processing during sleep as well as how circadian rhythms brought about by the internal biological clock interact with higher cognitive functions including consciousness. For a short summary of these topics see below.
All publications are open access. If you nevertheless cannot find it or are just too lazy to search for it, just drop me a line and I will be happy to send you the PDF.
Blume, C., Schmidt, M.H., & Cajochen, C. (2020). Effects of the COVID-19 lockdown on human sleep and rest-activity rhythms. Current Biology. doi: https://doi.org/10.1016/j.cub.2020.06.021
Angerer M., Schabus M., Raml M., Pichler G., Kunz A.B., Scarpatetti M., Trinka E., & Blume C. (2020). Actigraphy in brain-injured patients – A valid measurement for assessing circadian rhythms? BMC Medicine. doi: https://doi.org/10.1101/839472
Blume, C., Garbazza, C., Spitschan, M. (2019). Effects of light on human circadian rhythms, sleep, and mood. Somnologie. https://doi.org/10.1007/s11818-019-00215-x
Blume, C., Angerer, M., Raml, M., del Giudice, R., Santhi, N., Pichler, G., Scarpatetti, M., Kunz, A. B., Trinka, E., & Schabus, M. (2019). Healthier Rhythm, Healthier Brain? Integrity of Circadian Melatonin and Temperature Rhythms Relates to the Clinical State of Brain-Injured Patients. European Journal of Neurology.
Blume, C., del Giudice, R., Wislowska, M., Heib, D. P. J., & Schabus, M. (2018). Standing Sentinel during Sleep: Continued Evaluation of Environmental Stimuli in the Absence of Consciousness. NeuroImage.
Blume, C., Lechinger, J., Santhi, N., Giudice, R. d., Gnjezda, M.-T., Pichler, G., Scarpatetti, M., Donis, J., Michitsch, G., & Schabus, M. (2017). Significance of circadian rhythms in severely brain-injured patients: A clue to consciousness? Neurology.
Blume, C., del Giudice, R., Lechinger, J., Wislowska, M., Heib, D. P. J., Hoedlmoser, K., & Schabus, M. (2016). Preferential processing of emotionally and self-relevant stimuli persists in unconscious N2 sleep. Brain and Language.
Cognitive Processing During Sleep
Are we really as passive during sleep as it feels for us? Do our brains “switch off”? Does our brain still differentiate potentially important from less important stimuli? If yes, how does it keep the sensitive balance between sleep protection and the processing of environmental stimuli? These are intriguing questions we try to shed light on with our research.
From our findings it seems that the brain is a lot less “passive” during sleep than previously thought and that environmental stimuli are processed, at least to some extent, in virtually all sleep stages including deep sleep.
Circadian rhythms, that is rhythms with a period length of about 24 hours, govern manifold bodily and psychological processes ranging from the level of genetic expression up to higher cognitive functions. Nevertheless it often seems that we just take it for granted that these rhythms are there and thus ignore the fact that things might go wrong. Or sometimes it just seems too complicated to include them for example in the clinical routine, wherefore we (unconsciously) ignore our circadian rhythmicity. My research is therefore dedicated to learn more about the importance of a properly functioning biological clock in higher cognitive functions and especially consciousness.
Our findings in patients, who suffer from disorders of consciousness (DOC) following severe brain injury indicate that the state of the patient improves with “more normal” circadian rhythmicity. Specifically, we were able to show that arousal, a necessary precondition for consciousness, is higher in these patients.
Besides this, I am interested in how artificial light exposure affects sleep in healthy participants. To this end, I study how light exposure affects cognitive processing during sleep. With my research I hope to contribute to a better understanding of how the light environment in the evening affects nocturnal sleep.
Full Publication List (H-Index 10)
Blume C., & Cajochen C. (2020, December 2). ‘SleepCycles’ package for R – A free software tool for the detection of sleep cycles from sleep staging. Open Science Framework (OSF). doi: https://doi.org/10.31219/osf.io/r2q8v
Angerer M., Schabus M., Pichler G., Angerer B., Scarpatetti M., & Blume C. (2020). From Dawn to Dusk – Mimicking Natural Daylight Exposure Improves Circadian Rhythm Entrainment in Patients with Severe Brain Injury. Open Science Framework (OSF). doi: https://doi.org/10.31219/osf.io/vk2d6
Blume C. & Schabus M. (2019). Commentary: Daylight Saving Time and Artificial Time Zones – A Battle Between Biological and Social Times. https://osf.io/6cxhs
Blume C.*, Cajochen C., & Spitschan M.* (2020). Effects of calibrated blue-yellow (–S+[L+M], +S–[L+M]) changes in light on the human circadian clock. Accepted as Registered Report (Stage 1).
Accepted | In Press
Spitschan, M., Schmidt, M.H., & Blume, C. (2020). Transparency and open science principles in reporting guidelines in sleep research and chronobiology journals. Wellcome Open Research. http://dx.doi.org/10.12688/wellcomeopenres.16111.1
Blume, C. & Schmidt, M.H. (2020). When the girdle of social timing relaxes: Effects of the COVID-19 lockdown on human sleep. TheScienceBreaker. https://doi.org/10.25250/thescbr.brk363
Blume, C., Schmidt, M.H., & Cajochen C. (2020). Effects of the COVID-19 lockdown on human sleep and rest-activity rhythms. Current Biology. https://doi.org/10.1016/j.cub.2020.06.021
Blume C. & Schabus M. (2020). “Perspective: Daylight Saving Time – An Advocacy for a Balanced View and Against Fanning Fear. Clocks & Sleep 2(1):19-25. doi: https://doi.org/10.3390/clockssleep2010003
Blume C., Hauser T., Gruber W.R., Heib D.P.J., Winkler T., & Schabus M. (2019). “How does Austria sleep?” Self-reported sleep habits and complaints in an online survey. Sleep and Breathing. doi: https://doi.org/10.31219/osf.io/bdy73
Blume C., Garbazza C., Spitschan M. (2019). Effects of light on human circadian rhythms, sleep, and mood. Somnologie. doi: https://doi.org/10.1007/s11818-019-00215-x
Blume C., Angerer M., Raml M., del Giudice R., Santhi N., Pichler G., Scarpatetti M., Kunz A. B., Trinka E., & Schabus M. (2019). Healthier Rhythm, Healthier Brain? Integrity of Circadian Melatonin and Temperature Rhythms Relates to the Clinical State of Brain-Injured Patients. European Journal of Neurology. doi: https://doi.org/10.1111/ene.13935
Wislowska M., Blume C., Angerer M., Wielek T., & Schabus M. (2018). Approaches to Sleep in Severely Brain Damaged Patients – Further comments and replies to Kotchoubey & Pavlov. Clinical Neurophysiology. doi:https://doi.org/10.1016/j.clinph.2018.08.029
Blume C., del Giudice R., Wislowska M., Heib D. P. J., & Schabus M. (2018). Standing Sentinel during Sleep: Continued Evaluation of Environmental Stimuli in the Absence of Consciousness. NeuroImage. doi: https://doi.org/10.1016/j.neuroimage.2018.05.056
Schabus M., Wislowska M., Angerer M., Blume C. (2018). Sleep and Circadian Rhythms in Severely Brain-Injured Patients – A Comment. Clinical Neurophysiology.
Wielek T., Lechinger J., Wislowska M., Blume C., Ott P., Wegenkittl S., del Giudice R., Heib D. P. J., Mayer H. A., Laureys S., Pichler G., & Schabus M. (2018). Sleep in patients with disorders of consciousness characterized by means of machine learning. PLOS ONE, 13(1), e0190458. doi: https://doi.org/10.1371/journal.pone.0190458
Blume C., Lechinger J., Santhi N., del Giudice R., Gnjezda M.-T., Pichler G., Scarpatetti M., Donis J., Michitsch G., & Schabus M. (2017). Significance of circadian rhythms in severely brain-injured patients: A clue to consciousness? Neurology. doi: https://doi.org/10.1212/wnl.0000000000003942
del Giudice R., Blume C., Wislowska M., Lechinger J., Heib D. P. J., Pichler G., Chinchilla M., Machado C., & Schabus M. (2016). Can self-relevant stimuli help assessing patients with disorders of consciousness? Consciousness and Cognition, 44, 51-60.
del Giudice R., Blume C., Wislowska M., Wielek T., Heib D.P.J., & Schabus M. (2016). The Voice of Anger: Oscillatory EEG Responses to Emotional Prosody. PLoS One, 11(7), e0159429.
Herbert C., Blume C., & Northoff G. (2016). Can we distinguish an “I” and “ME” during listening?—an event-related EEG study on the processing of first and second person personal and possessive pronouns. Self and Identity, 15(2), 120-138.
Blume C., Santhi N., & Schabus M. (2016). ‘nparACT’ package for R – A free software tool for the non-parametric analysis of actigraphy data. MethodsX. doi: https://doi.org/10.1016/j.mex.2016.05.006
Lechinger J., Wielek T., Blume C., Pichler G., Michitsch G., Donis J., Gruber W., & Schabus, M. (2016). Event-related EEG power modulations and phase connectivity indicate the focus of attention in an auditory own name paradigm. Journal of Neurology, 1-14. doi: https://doi.org/10.1007/s00415-016-8150-z
Blume C., del Giudice, R, Lechinger J., Wislowska M., Heib D. P. J., Hoedlmoser K., & Schabus, M. (2016). Preferential processing of emotionally and self-relevant stimuli persists in unconscious N2 sleep. Brain and Language. doi: https://doi.org/10.1016/j.bandl.2016.02.004
Blume C., Lechinger J., del Giudice R., Wislowska M., Heib D. P. J., & Schabus M. (2015). EEG oscillations reflect the complexity of social interactions in a non-verbal social cognition task using animated triangles. Neuropsychologia, 57, 330-340. doi: https://doi.org/10.1016/j.neuropsychologia.2015.06.009
Blume C.*, del Giudice R.*, Wislowska M.*, Lechinger J., & Schabus M. (2015). Across the consciousness continuum–from unresponsive wakefulness to sleep. Frontiers in Human Neuroscience, 9, 105. doi: https://doi.org/10.3389/fnhum.2015.00105
Blume C., & Herbert C. (2014). The HisMine-Paradigm: A new paradigm to investigate self-awareness employing pronouns. Social Neuroscience, 9(3), 289-299. doi: https://doi.org/10.1080/17470919.2014.886616
Software (R packages)
- The detection of sleep cycles in human sleep data (i.e. polysomnographically assessed sleep stages) enables fine-grained analyses of ultradian variations in sleep microstructure (e.g. sleep spindles, and arousals), or other amplitude- and frequency-specific electroencephalographic features during sleep. While many laboratories have software that is used internally, reproducibility requires the availability of open source software. Therefore, we here introduce the ‘SleepCycles’ package for R, an open-source software package that identifies sleep cycles and their respective (non-) rapid eye movement ([N]REM) periods from sleep staging data. Additionally, each (N)REM period is subdivided into parts of equal duration, which may be useful for further fine-grained analyses. The detection criteria are, with some adaptations, largely based on criteria originally proposed by Feinberg and Floyd (1979). The latest version of the package can be downloaded from the Comprehensive R Archives Network (CRAN).
- The package “nparACT” for R computes interdaily stability (IS), intradaily variability (IV) & the relative amplitude (RA) from actigraphy data as described in Blume et al. (2016) and van Someren et al. (1999). Additionally, it also computes L5 (i.e. the 5 hours with lowest average actigraphy amplitude) and M10 (the 10 hours with highest average amplitude) as well as the respective start times. The flex versions will also compute the L-value for a user-defined number of minutes. IS describes the strength of coupling of a rhythm to supposedly stable zeitgebers. It varies between 0 (Gaussian Noise) and 1 for perfect IS. IV describes the fragmentation of a rhythm, i.e. the frequency and extent of transitions between rest and activity. It is near 0 for a perfect sine wave, about 2 for Gaussian noise and may be even higher when a definite ultradian period of about 2 hrs is present. RA is the relative amplitude of a rhythm. Note that to obtain reliable results, actigraphy data should cover a reasonable number of days.