We’re dreaming every night (or at least most nights), although it’s not always clear to us what our dreams are really about, or even why we dream. Over the years there has been a lot of research into dreaming, and it’s long been known that we can determine if someone is dreaming if their eyes appear to be darting from side to side or place to place in what is known as rapid eye movement sleep, or REM sleep, a period involving fast brain activity similar to that when awake. But dreaming has also been reported in non-REM sleep, creating confusion among researchers.
Research into dreaming
Recent research seems to indicate that using REM sleep alone to measure how much and how often we dream may not actually be nearly as accurate as was thought. Francesca Siclari of the University of Wisconsin-Madison, along with the rest of her research team, have discovered that a decrease in low-frequency brainwaves in an area at the back of the brain (the posterior cortical region) is a far more accurate indication of dreaming.
“This zone was a little bit more awake, showing high-frequency brainwaves more common during wakefulness,” she says. And she asserts that activity in this one region seems to be all that’s necessary for dreaming.
Her team conducted research on 46 people, carefully mapping brain activity during sleep using high-density electroencephalography. Their findings were a revelation; there was such a strong correlation between dreaming and reduced brain activity in this particular region that they could predict whether a person was dreaming with roughly 90% accuracy.
Each of the participants had their brain activity recorded while they slept, via up to 256 electrodes attached to their scalps and faces. Each of the subjects was woken at various points during their sleep and questioned as to whether they had been dreaming, and the details of the dreams (if they could recall any). Throughout the research, there were over 1,000 awakenings, and they revealed whether the dreams (where there had been any) had involved faces, physical activity, or thinking, or whether it had been a vivid sensory experience.
The team also found that dreaming about certain things correlated with brain activity normally associated with recognition of those things. For example, dreaming about faces or facial expressions produced brain activity in the region usually involved in facial recognition. As Ms. Siclari says, “This is proof that dreaming really is an experience that occurs during sleep, because many researchers up until now have suggested that it is just something you invent when you wake up.” And as she points out, the dreaming brain and the waking brain are more similar than might have been imagined, since they seem to recruit the same regions to deal with similar experiences.
The secrets of dreaming might be about to be uncovered
Experts in the field are welcoming this research as highly important. Mark Blagrove, director of the sleep lab at Swansea University, says “It is comparable really to the discovery of REM sleep, and in some respects it is even more important.” The researchers claim that the study could help shed light on the nature of consciousness, which is of great importance since there are so many complicating factors involved in comparing wakefulness to, for example, an anaesthetised state.
Mark Blagrove points out that the research is important in that it could reveal the purpose of dreaming, and whether it has a function concerning memory. It’s long been thought that the function of dreaming is at least partly to help the brain process the events of the previous day, and to help consolidate memories.
Regardless of this research, we should all be aware that memories are formed, or consolidated, during our hours of sleep, and getting a good night’s sleep is important, particularly if you’ve been studying during the day. Never underestimate sleep’s importance, no matter how tempting it might be to skimp on it; it’s too valuable to dismiss as merely a time when we’re unconscious. There’s far more to sleep than that, and sleep’s secrets are gradually being revealed to us.
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