Dreaming fascinates everybody with a mind. However, despite this nearly universal curiosity, we know relatively little about the science behind the land of nod.
Luckily, a new study published this week in the journal Nature Neuroscience has uncovered more about dream states and the parts of the brain that contribute to it.
Neuroscientists from the University of Wisconsin-Madison studied the dream state of 46 people by hooking them up to EEG brain activity monitors while they slept. When they woke up, the researchers asked them to report the experience of their dream (if they could remember it).
In general, imaging of the brain during dreaming showed that the activity mimicked the activity of an awake brain. For example, if their dreaming experience contained faces, imaging of their brain activity showed the same activity that you would expect of an awake person engaging in facial recognition.
As study author Dr Francesca Siclari explains, this means you can effectively predict what somebody is dreaming about by monitoring which regions are activated.
“This study has managed to identify the brain regions that are involved in dreaming,’’ Dr Siclari said in a statement. “We’ve also been able to identify the brain areas that correspond to specific dream contents (like faces, spatial setting, movement, and speech) during well-established sleep.”
The study has further busted a misconception about the nature of rapid eye movement (REM) sleep. Namely, they found that dreaming does not just happen during the REM phase, but can also take place in non-rapid eye movement (NREM) sleep. However, individuals are more likely to recall the experience of the dream when there's a higher level activity in the prefrontal cortex, which itself is associated with memory and personality.
However, there were a few differences between an awake brain and a dreaming brain.
The team found that there was always a spike in high-frequency activity within the so-called “hot zone” in the posterior cortex of the brain when a person is dreaming. This area of the brain is typically involved in visual, spatial, and certain sensory experience. Essentially, by looking for this activity in the hot zone, the researchers can predict whether a person is dreaming or not.
In a sense, this means that a dream is like a simulated world. Dr Lampros Perogamvros, the study’s co-author, told the Australian Broadcast Corporation (ABC) that this region active region during sleep makes sense as you can stimulate this hot zone during wakefulness to "induce a feeling of being in a parallel world or in a dream-like state."