20,000 leagues above dreams – Impact Campus

I structured the magazine with the subjects that had been submitted to me, it was quite varied, more than usual, except that youurns out, none of us had decided to work on the dream itself, like the ones we have while sleeping. I swapped my first topic for dreams knowing in advance that the only thing that brought me closer to neuroscience was my high concussion count. That said, I think curiosity is already a good starting point.

By Emmy Lapointe, Editor-in-Chief

A sleepy brain, how do we understand that?
Unsurprisingly, the simplest and oldest method scientists use to study dreams is to ask the sleeper what they dreamed of when they woke up. Although quite rudimentary, this technique allowed William Domhoff, a professor at the University of California, and his team to create a database of dreams. So far, the database contains over 20,000 dreams. As a clearing of the subject, the database has allowed other studies to better understand the function and mechanisms of dreams. Among other things, these studies have enabled us to discover that dreams contain twice as many negative emotions as positive emotions. Only 2% of dreams in adult men are erotic and 0.5% in adult women (I couldn’t find any stats for people with non-binary gender identities).

After that, it remains quite limited as a way of investigating the world of dreams, if only because of the forgetfulness of many of them and the vagueness with which they are described; MRI and EEG have therefore become the new gateway.

In 2012, researcher Tomoyasu Horikawa and his team created dream decoding software using functional magnetic resonance imaging (FMI). Basically, what they did was they took awake subjects and showed them hundreds of images to see which brain regions were activating for each one. They arrived at a certain mapping of the cerebral cortex. The next step consisted of putting the patients to sleep, waking them up regularly and asking them if they were dreaming about such and such a thing depending on the region of the brain that had been activated on the screen. The predictions came true in 55-90% of cases.

How does our brain dream?
Already, at the base, you should know that sleep is a drop in the state of consciousness. We then lose our alertness and muscle tone. Sleep can be divided into three types, and each night we go through 3 to 6 cycles. We find more deep slow-wave sleep in the first part of the night, while in the second, it is rather light slow-wave sleep and paradoxical sleep.

Slow-wave sleep, whether light or deep, is characterized by slow waves, the cerebral metabolism is slowed down. We always start the nights with a phase of light slow sleep after falling asleep. Light slow sleep will return regularly during the night, it is at this time that we are most easily “awakened”. Then comes deep slow sleep. It is during this cycle that our body recovers the most.

For its part, paradoxical sleep, the third and last type, is the one that houses the greatest number of dreams, the most intense and the most concrete above all. If the body is perfectly still thanks to the pons of Varole (a small structure of the brainstem), cerebral activity is at its peak (hence the qualifier paradoxical).

Francesca Siclari, a professor at the University of Wisconsin, conducted a study with her team in 2017 about the waves in our brain during sleep. Basically, she invited people to sleep in the lab to measure brain activity in different areas of the brain during sleep. Participants were frequently awakened during the night and asked if they were dreaming. The team was therefore able to compare brain activity when the subject is dreaming with when he is not dreaming.

Already, researchers have been able to confirm that we do not dream only during REM sleep. They also discovered an area that they consider to be the brain core of the dream, an area that they named the “posterior hot spot” because it is located in the back half. This point mainly covers visual sensory areas, but also the cingulate cortex and the precuneus, areas known for the integration of sensory information. According to Siclari’s team, these parts of the brain are quite adept at creating an immersive world.

To test their discovery, the researchers observed the real-time brain activity of a sleeper | sleeper and woke him whenever there were rapid waves in the posterior hot spot to ask him if he was dreaming. 90% of the time it was. For its part, the prefrontal cortex, that is to say the part responsible for critical sense, judgment and reasoning, is practically inactive during dreams, which explains, among other things, why they often have neither head nor tail. . The amygdala (the one in the brain, not in our throat) is on the contrary often very stimulated which, this time, explains the intensity of our dreams.

Why do we dream?
Between the messages of the gods of Antiquity and the repressed repressed desires of Freud, unsurprisingly, we want to know (since the dawn of time) why we dream. Already, the idea that our dreams could have a universal significance (loss of teeth = loss of money for example) is unfortunately rejected by most scientists.

Unlike the days of Freud or Pliny the Elder, we now know that dreams are of paramount importance for cognitive functions. First, dreams make it possible to memorize events by replaying them in a modified way. Obviously, we don’t exactly relive our days, but certain elements are sprinkled in fragments in our dreams. Reshaping events would also play on our creativity. Thus, many scientists argue that dreams help find solutions to problems in addition to promoting learning. According to a study carried out at Harvard, the elements learned before sleep and found in our dreams are three times more consolidated.

Why do some people remember their dreams and others don’t?
In a study led by Perrine Ruby at the University of Lyon, the team of researchers decided to compare the brain activity of those who remembered their dreams and those who did not. Those who remembered their dreams had higher brain activity at the temporo-parietal junction. As its name suggests, this junction is found at the borders of the temporal and parietal lobes. This junction is involved in directing attention to external stimuli. The great dreamers | dreamers, those who remember their dreams when they wake up are therefore more easily awakened. On average, big dreamers | dreamers wake up twice as often as others during a night. To memorize a dream, one must therefore have a certain degree of consciousness. However, that does not mean that little dreamers | dreamers dream less than adults.

The Dream and Time
How do we perceive time when we dream? Honestly, big question. According to several studies, time in dreams passes almost the same as in wakefulness. In 1958, an American researcher, William Dement, carried out a study using what are called sensory milestones. He exposed subjects to doorbells and flashes from light. Then he woke them up ten minutes later. Most of the subjects had incorporated these stimuli into their dreams. Dement questioned the subjects about what had happened in their dream between the stimulus and the awakening. In most cases, their dream scenario took place over a period of about 10 minutes.

Since this study, the techniques have obviously been refined. Researchers use lucid dreaming, among other things. In lucid dreaming, the subject can make choices and take actions deliberately. It can also set time intervals. The team of a study carried out in Switzerland appealed to these dreamers | lucid dreamers. Scientists asked them to count to 10, to 20, and to 30 while awake and while dreaming. They also asked them to walk 10, 20 and 30 steps while awake and in their dreams. During the dream, the subject had to signal the start of the action with an eye sign so that the team could note the duration of the task. They found that tasks, especially physical ones, took longer in dreams than in wakefulness. On average, counting to 20 took 17 seconds while awake and 22 seconds while dreaming. While walking 30 steps awake took 19 seconds and 29 seconds in a lucid dream. Of course, that’s when it comes to lucid dreaming. Some people do it regularly, others wait patiently for their only lifetime lucid dream to come.