Natalie Hauglund at the University of Copenhagen and her colleagues implanted imaging tools and electrodes into mice to monitor their brain activity when they were awake and asleep. The authors ...

sleep, when the brain is as active as when we’re awake, but our voluntary muscles are paralyzed. We know that all mammals and birds sleep. A dolphin sleeps with half its brain awake so it can ...

hearts — maybe all the body’s major systems — are influenced by sleep. In the brain, our memory, creativity and ability to learn are, too. But for something that’s so entwined with our ...

Sleep and wake: They're totally distinct states of being that define the boundaries of our daily lives. For years, scientists have measured the difference between these instinctual brain processes ...

scans to investigate the brain activity of 85 healthy adults, half of which had experienced a healthy night sleep in the sleep lab, and the other half stayed awake all night. They were asked to ...

But it’s not a coma-like state, as in stage 4. Our brain during REM sleep is fully active, guzzling as much energy as when we’re awake. REM sleep is ruled by the limbic system—a deep-brain ...