Wide Awake

In the brain, neurons communicate by way of minute electrical signals, adding up to create distinctive patterns of electrical activity. Using electrodes, small metal discs placed on the scalp, we can monitor these patterns in a non-invasive way, to gain insights into the brain’s behaviour. The resulting recordings, called electroencephalograms (EEGs), can track differences in arousal, from wakefulness through the different phases of sleep, and help diagnose conditions like epilepsy. EEGs show brain activity as electrical waves of varying frequency and amplitude, or power: pictured, across a night’s sleep, higher peaks indicate higher frequency, and warmer colours greater power, with the white line representing overall changes in arousal. High frequency waves generally have lower power; recent research suggests measuring the relationship between these properties, known as spectral slope, can accurately determine patients’ level of wakefulness, a potentially valuable technique for monitoring responses to anaesthesia or patients in a coma.

Written by Emmanuelle Briolat

Emmanuelle Briolat

Writer

A researcher specialising in visual signals in Lepidoptera, camouflage and the effects of light pollution, Emmanuelle’s writing covers a range of topics, from biomedical research to children’s books about moth defences.

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• Image from work by Janna Lendner and colleagues
• Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USA
• Image originally published under a Creative Commons Licence (BY 4.0)
• Published in eLife, July 2020