The Journal of neuroscience : the official journal of the Society for Neuroscience
February 24, 2021
Annalotta Scheinin, Oskari Kantonen, Michael Alkire et al.
92 citations
Consciousness often persists even when unresponsiveness occurs. In two experiments involving 76 healthy males, brain activity was measured during varying states of consciousness induced by propofol and dexmedetomidine (n = 39) and during sleep-deprived wakefulness and non-REM sleep (n = 37). Most participants reported internally generated experiences while unresponsive. Key brain regions, including the thalamus and cingulate cortices, were found critical for consciousness, showing consistent activity patterns regardless of anesthetic type or sleep state, highlighting a core network essential for conscious awareness.
Translational Psychiatry
February 27, 2024
Hanna M. Ollila, Nasa Sinnott-Armstrong, Katri Kantojärvi et al.
18 citations
Nightmares are vivid, negative dreams that awaken the dreamer. While occasional nightmares are common, frequent ones often indicate underlying emotional regulation problems. A genome-wide association study of 45,255 individuals found no single genetic variants linked to nightmare frequency, but estimated heritability at 5%. Genetic correlation analysis revealed strong correlations between nightmares and anxiety, depressive disorders, posttraumatic stress disorder, and the personality trait neuroticism. Mendelian randomization suggested that insomnia may causally increase the likelihood of frequent nightmares. These findings indicate that nightmares share genetic factors with psychiatric conditions and that insomnia may heighten susceptibility to nightmares, highlighting the need for systematic nightmare assessment in clinical settings.
bioRxiv (Cold Spring Harbor Laboratory)
November 9, 2019
Hanna M. Ollila, Nasa Sinnott-Armstrong, Katri Kantojärvi et al.
5 citations
preprint
Nightmares are vivid, disturbing dreams that wake the dreamer. Twin studies show nightmare frequency is 36–51% heritable. A genome-wide association study of 28,596 individuals from Finland and the United States identified genetic variants near MYOF and PTPRJ (a gene previously linked to sleep duration) that predispose to nightmares. Strong genetic correlations were found between nightmare frequency and neuroticism, post-traumatic stress disorder, major depressive disorder, daytime sleepiness, and insomnia. Mendelian randomization indicated that feelings of being fed-up, nervous, and miserable cause nightmares, with no evidence that nightmares cause psychological problems. The findings suggest nightmares arise from unique genetic risk factors and are substantially caused by underlying psychological and sleep problems.
Consciousness and Cognition
November 1, 2021
Linda Radek, Lauri Koskinen, Nils Sandman et al.
Subjective experiences, most often dreaming or incorporating elements of the setting, are common during sedation with anesthetics that act through different molecular mechanisms. In healthy male participants given equisedative doses of dexmedetomidine, propofol, sevoflurane, or S-ketamine for one hour, 46.9% of those who were arousable reported experiences. Dexmedetomidine was associated with the most frequent reports, while S-ketamine produced the most multimodal experiences. Whether participants were responsive at the end of administration did not affect the prevalence or content of the experiences. The differences between drugs were small in this sample.
Journal of Sleep Research
April 1, 2018
Pilleriin Sikka, Antti Revonsuo, Nils Sandman et al.
Dreams collected at home upon morning awakening are more emotional and more negative than those collected in the lab after early REM sleep awakenings, but not more emotional than those after late REM awakenings. Home dreams also contain a higher density of emotions than lab dreams from either early or late REM sleep. The differences in overall emotionality may be due to the time of night, while the causes of differences in emotion density and negativity—whether from the sleep environment, reporting procedures, or time spent in a sleep stage—remain unclear.