Summary: Early risers have significantly weaker sleep spindle activity than those who prefer to stay up late at night, a new study reveals.
Source: University of Helsinki.
A new Finnish study shows that individual circadian preference is associated with brain activity patterns during the night.
Sleep spindles are bursts of oscillatory brain activity visible on an EEG that occur mainly during stage 2 sleep. Sleep spindles are linked for example to sleep maintenance and strengthening of the memory traces during sleep.
The study explored the association between individual circadian preference and sleep spindle activity among 170 17-year-old participants, who underwent a sleep EEG monitoring at their home environment.
“We observed a significantly weaker spindle activity among the morning preference group compared to other groups. The spindle activity also decreased more towards the morning hours,” explains the principal investigator, Professor Anu-Katriina Pesonen. “This might be a potential facilitator underlying earlier circadian rhythm.”
The study published in Scientific Reports shows for the first time a link between circadian preference and sleep maintaining sleep microstructures, indicated by sleep spindle activity.
The research was conducted in Sleep & Mind -research group at the University of Helsinki, Faculty of Medicine.
Source: Anu-Katriina Pesonen – University of Helsinki
Publisher: Organized by NeuroscienceNews.com.
Image Source: NeuroscienceNews.com image is in the public domain.
Original Research: Full open access research for “Circadian preference towards morningness is associated with lower slow sleep spindle amplitude and intensity in adolescents” by Ilona Merikanto, Liisa Kuula, Tommi Makkonen, Róbert Bódizs, Risto Halonen, Kati Heinonen, Jari Lahti, Katri Räikkönen & Anu-Katriina Pesonen in Scientific Reports. Published online November 3 2017 doi:10.1038/s41598-017-13846-7
Circadian preference towards morningness is associated with lower slow sleep spindle amplitude and intensity in adolescents
Individual circadian preference types and sleep EEG patterns related to spindle characteristics, have both been associated with similar cognitive and mental health phenotypes. However, no previous study has examined whether sleep spindles would differ by circadian preference. Here, we explore if spindle amplitude, density, duration or intensity differ by circadian preference and whether these associations are moderated by spindle location, frequency, and time distribution across the night. The participants (N = 170, 59% girls; mean age = 16.9, SD = 0.1 years) filled in the shortened 6-item Horne-Östberg Morningness-Eveningness Questionnaire. We performed an overnight sleep EEG at the homes of the participants. In linear mixed model analyses, we found statistically significant lower spindle amplitude and intensity in the morning as compared to intermediate (P < 0.001) and evening preference groups (P < 0.01; P > 0.06 for spindle duration and density). Spindle frequency moderated the associations (P < 0.003 for slow (<13 Hz); P > 0.2 for fast (>13 Hz)). Growth curve analyses revealed a distinct time distribution of spindles across the night by the circadian preference: both spindle amplitude and intensity decreased more towards morning in the morning preference group than in other groups. Our results indicate that circadian preference is not only affecting the sleep timing, but also associates with sleep microstructure regarding sleep spindle phenotypes.
“Circadian preference towards morningness is associated with lower slow sleep spindle amplitude and intensity in adolescents” by Ilona Merikanto, Liisa Kuula, Tommi Makkonen, Róbert Bódizs, Risto Halonen, Kati Heinonen, Jari Lahti, Katri Räikkönen & Anu-Katriina Pesonen in Scientific Reports. Published online November 3 2017 doi:10.1038/s41598-017-13846-7