Brain circuit in mice switches body from rest to warmth and wakefulness
The body does not regulate temperature through shivering and sweating alone. New mouse experiments show that a specific brain signal triggers the shift from rest to activity, including warming up the body.
Researchers studied a group of neurons in the hypothalamus, a brain region that governs bodily processes, that produce the hormone oxytocin. These neurons are active during social thermoregulation, such as huddling. But they also turned out to be active in non-social settings.
What the mouse experiments showed
The study, published in eLife, combined multiple measurement methods. Using fiber photometry, the researchers tracked the activity of oxytocin neurons in real time. Their activity aligned with transitions from rest to thermogenesis and behavioral arousal, in both social and non-social contexts.
The researchers then artificially stimulated the oxytocin neurons using light pulses (optogenetics). When this was done while mice were in a low-temperature resting state, body heat production increased, followed by heightened activity. Timing was critical: stimulation at other points in the rest cycle had less effect.
A switch between rest and activity
Based on these findings, the researchers propose that these oxytocin neurons help facilitate state transitions in body temperature regulation. They may act as a switch that helps determine when the body moves from an energy-saving rest state to a more active one.
Whether it is oxytocin itself that drives this effect, or another substance co-released by the same neurons, was not fully resolved in this study. The findings are based on mouse experiments and their relevance for humans requires further investigation.
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