The Brain Circuit that Wakes You Up

By Karis Tutuska ’18

Deep sleep is crucial for both mental and physical health.

A goodnight’s sleep is crucial not only for cognitive function, but for long-term physical health as well, which is why so much effort has gone into studying the mechanisms of sleep. While scientists have long known the key brain circuits that control NREM sleep (non rapid eye movement, associated with light sleep) and REM sleep (rapid eye movement, associated with deep sleep and dreams), they have been in the dark about the precise mechanisms behind sleep as a whole. Particularly, what mechanism terminates sleep and causes wakefulness?

Recently, a study by the Department of Clinical Research at the University of Bern has discovered a neural circuit in mice between the hypothalamus and thalamus. The researchers studied this circuit using optogenetics, a technique that allows scientists to control neurons with light pulses. When activated, the circuit terminated NREM sleep and when inhibited, it stabilized and deepened NREM sleep. The response was so strong that the activation of this circuit aroused the mice from anesthesia. The researchers found that transient activation caused rapid awakening from sleep and chronic activation caused prolonged wakefulness in the mice.

Continued research into this circuit could lead to tremendous advances not only in treating individuals who suffer from conditions such as insomnia and other forms of sleep perturbance, but also in waking individuals from vegetative states.



  1. Image Acquired from:
  2. University of Bern. How the Brain Wakes You Up. ScienceDaily.

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