Summary: Using EEG to study twin teenagers, researchers tease apart the influence of genetic and environmental factors on brain activity during sleep.
Some patterns of electrical activity generated by the brain during sleep are inherited, according to a study of teenage twins published in Journal of Neuroscience.
Pinpointing the relative contributions of biology and experience to sleep neurophysiology could inform therapies for numerous psychiatric disorders in which alterations in brain activity during sleep can be detected.
Leila Tarokh and colleagues used electroencephalography to measure the brain activity of 11- to 14-year-old pairs of identical and fraternal twins during two consecutive nights of sleep at home.
This study design allowed the researchers to tease apart the influence of genetic and environmental factors on brain activity during sleep.
They found both types of factors shape two patterns of activity — slow waves and spindles — that are crucial for core functions of sleep, including memory consolidation.
The influence of genes and environment on this activity depended on the brain region in question, with frontal regions being under strong environmental control and regions toward the back of the brain under stronger genetic control.
Funding: This research was supported by the Jacobs Foundation.
Source: David Barnstone – SfN
Publisher: Organized by NeuroscienceNews.com.
Image Source: NeuroscienceNews.com image is credited to Rusterholz et al., JNeurosci (2018).
Original Research: Abstract for “Nature and Nurture: Brain region specific inheritance of sleep neurophysiology in adolescence” by T. Rusterholz, C. Hamann, A. Markovic, S.J. Schmidt, P. Achermann and L. Tarokh in Journal of Neuroscience. Published September 24 2018.
Nature and Nurture: Brain region specific inheritance of sleep neurophysiology in adolescence
Sleep specific oscillations of spindles and slow waves are generated through thalamocortical and cortico-cortical loops respectively, and provide a unique opportunity to measure the integrity of neuronal systems. Understanding the relative contribution of genetic factors to sleep oscillations is important for determining whether they constitute useful endophenotypes that mark vulnerability to psychiatric illness. Using high-density sleep EEG recordings in human adolescent twin pairs (n=60; 28 females), we find that over posterior regions 80 to 90% of the variance in slow oscillations, slow wave and spindle activity is due to genes. Surprisingly, slow (10 to 12 Hz) and fast (12 to 16 Hz) anterior spindle amplitude and sigma power are largely driven by environmental factors shared amongst the twins. To our knowledge this is the first example of a neural phenotype that exhibits a strong influence of nature in one brain region, and nurture in another. Overall, our findings highlight the utility of the sleep EEG as a reliable and easy to measure endophenotype during adolescence. This measure may be used to measure disease risk in development prior to the onset of a psychiatric disorder; the location within the brain of deficits in sleep neurophysiology may suggest whether the ultimate cause is genetic or environmental.
Two cardinal oscillations of sleep, slow waves and sleep spindles, play an important role in the core functions of sleep including memory consolidation, synaptic plasticity and the recuperative function of sleep. In this study, we use a behavioral genetics approach to examine the heritability of sleep neurophysiology using high-density EEG in a sample of early adolescent twins. Our findings reveal a strong influence of both environmental and genetic factors in shaping these oscillations, dependent on brain region. Thus, during a developmental period when the brain is in flux, we find that the sleep EEG is among the most heritable of human traits over circumscribed brain regions.