WHY THIS MATTERS IN BRIEF
- We already have the nascent technology that allows us to stream live movies from people’s minds but streaming dreams has been illusive because we didn’t know where they originated, until now
Throughout the Millennia our dreams, and our ability to dream, has fuelled everything from the Australian Aborigines “Dreamworld” to beliefs that our dreams are in fact bridges to other parallel universes – something that who knows, could be true after all…
Scientists have long associated dreaming with a phase of sleep known as Rapid Eye Movement, or REM sleep for short, a sleep stage in which the resting brain paradoxically generates “high frequency” brain waves that closely resemble those of when we’re awake.
Dreaming isn’t exclusive to REM sleep though, and a series of reports has found that dreaming also happens during non-REM sleep when the brain is dominated by “slow wave” activity – or the opposite of an alert, active, conscious brain. But now, thanks to a new study published in Nature Neuroscience, we might be getting closer to solving the riddle of dreaming.
By closely monitoring the brain waves of sleeping volunteers, a team of scientists at the University of Wisconsin (UW) have pinpointed a local “hot spot” in the brain that fires up when we dream – regardless of whether the person is in non-REM or REM sleep.
“You can really identify a signature of the dreaming brain,” says study author Dr. Francesca Siclari.
What’s more, using an Artificial Intelligence (AI) algorithm the UW team developed, the team found that they could accurately predict when a person was dreaming with almost 90 percent accuracy, and while that’s amazing, what’s more amazing is the fact that they were also able to, albeit roughly by setting the AI loose on the volunteers EEG recordings, interpret the content of the dreams too.
For the most part this latter breakthrough comes about because when the brain is dreaming it draws on the same parts of the brain we use when we’re awake – and we’ve already managed to stream images and movies out of people’s heads. For example, if you’re dreaming then you’re likely dreaming about a person’s face in which case the part of your brain responsible for remembering faces fires up, and the same goes for places, language and all manner of other dream content.
“What we found is that maybe the dreaming brain and the waking brain are much more similar than one imagined,” says Siclari.
“The importance beyond the article is really quite astounding,” says Dr. Mark Blagrove at Swansea University in Wales, who was not involved in the study.
During a full night’s sleep we cycle through different sleep stages which are characterised by distinctive brain activity patterns, and the team used EEG’s to precisely capture each sleep stage, which involved placing 256 electrodes against a person’s scalp to monitor the number and size of brainwaves at different frequencies.
When we doze off for the night, our brains generate low frequency activity that sweeps across its entire surface, and these waves signal that the neurons are in their “down state” and unable to communicate between brain regions – that’s why low-frequency activity is often linked to the loss of consciousness.
These slow oscillations of non-REM sleep eventually transform into high-frequency activity, signalling the entry into REM sleep, the sleep stage traditionally associated with vivid dreaming – a connection that up until now was either ignored or thought of as being a quirk.
During the study the 32 volunteers were woken up periodically throughout the night and asked what they were dreaming about – it’s like having children, but in lab coats… and rather than seeing a global shift in activity that correlated to dreaming the team, surprisingly, uncovered a brain region at the back of the head, a posterior “hot zone,” that dynamically altered its activity based on the occurrence of dreams.
Dreams were associated with a decrease in low frequency waves in the hot zone, along with an increase in high frequency waves that reflected high rates of neural firing and brain activity, a sort of local awakening, irrespective of the sleep stage or overall brain activity.
“It only seems to need a very circumscribed, a very restricted activation of the brain to generate conscious experiences,” says Siclari, “until now we thought that large regions of the brain needed to be active to generate conscious experiences.”
That the hot zone leaped to action during dreams makes sense, explain the authors.
Previous work showed stimulating these brain regions with an electrode can induce feelings of being “in a parallel world.” The hot zone also contains areas that integrate sensory information to build a virtual model of the world around us – our own virtual reality center.
The hot zone as it turns out is, in fact, a “dreaming signature,” and the team were able to use their AI agent to predict when a person was dreaming.
“We woke them up whenever the algorithm alerted us that they were dreaming, a total of 84 times,” the researchers say.
Overall, the agent nailed it 90 percent of the time, and even nailed cases where the participants couldn’t remember the content of their dreams but knew that they were dreaming.
Since the hot zone contains areas that process visual information, the researchers then wondered if they could get a glimpse into the actual content of the participants’ dreams simply by analysing the EEG recordings.
Dreams can be purely perceptual with unfolding narratives, or they can be more abstract and “thought-like,” the team explains, “faces, places, movement and speech are all common components of dreams and processed by easily identifiable regions in the hot zone, so we decided to focus on those aspects.”
Remarkably, volunteers that reported talking in their dreams showed activity in their language related regions, and those who dreamed of people had their facial recognition centers activate, and so on.
“All of this suggests that dreams recruit the same brain regions as experiences in wakefulness for specific contents,” says Siclari.
While there is still more work to be done, it may not be too long before we see the time when we can stream our own dreams to YouTube – after all, we’ve already streamed movies, and if dreams draw on the same centers of the brain then it might not be too big a leap.