What Happens in the Brain When You’re Dreaming
A mesmerizing dive into the latest science
The brain does something special during sleep. Instead of simply switching off, it activates patterns of activity that can lead to dreaming. But what exactly is happening to the brain during a dream? It’s a question that has puzzled scientists for a long time, and new research is revealing some answers.
In the sleeping brain, there are two major states: rapid eye movement (REM) and non-REM. Non-REM is split into separate stages, each occupying a progressively deeper phase of sleep. The first and lightest stage of non-REM sleep features slow eye movements and brain waves at a relatively high frequency of around 4 to 7 Hz. On the other end of the spectrum, the deepest stage of non-REM sleep is commonly referred to as slow-wave sleep, and features brain waves at lower frequencies (less than 4 Hz). During this deep stage, the brain is minimally reactive to external sounds, and people are less likely to wake up.
As its name suggests, one of the most distinctive features of REM sleep is that people exhibit quick and jerky eye movements. REM is not the only time people dream, but it does seem to be when people experience the longest, most vivid, and most bizarre dreams. In a bid to stop people from acting out these dreams while asleep, the brain…
