Psychology Today | 24.09.2026 22:48
Have you ever wondered what happens to your brain while you sleep? Could it be that your brain turns off just as the rest of your body shuts down for the night? For quite some time, scientists and physicians believed that to be the case. But this view changed with the invention of the electroencephalogram, or EEG, a device that records our brain’s electrical activity. In the 1920s and 1930s, when scientists first recorded the sleeping brain using EEG, they were shocked to discover that the brain was anything but quiet at night. Rather, the brain was considerably busy, cycling through distinct patterns of activity. Today, we know that sleep is anything but a passive process; instead, it’s composed of carefully orchestrated sleep stages, each with its own unique brain-wave patterns and health implications.
