Bruna Rezende
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Lucid dreaming: a way to better understand REM-sleep and consciousness
In neuroscience, the simple act of sleeping is surrounded by mystery and unsolved questions.
Why do we sleep?
How does the brain work during deep sleep?
More puzzling than the act of sleeping is dreaming. Are we conscious in deep sleep? Why don’t we remember all parts of our dreams?
Even though it’s been decades since dreaming has been validated as a neurophysiological phenomenon, the neurobiology behind it remains poorly characterized. In lucid dreams, people can be physiologically asleep but are aware that they are dreaming. Because of this, they are able to perform actions and even remember parts of their “real life” while dreaming. Although the modern nomenclature for lucid dream was formally adopted in 1913 by Frederick Van Eeden, there are numerous reports on literature about lucid dreams dating back to Aristotle.
It’s not difficult to find someone who has had a lucid dream (it’s not even hard to be that person yourself either!) even though, it was only in the early 80s that lucid dreams were validated as a verifiable phenomenon that occurs during REM sleep. The movement and direction of the eyes during the sleep episode is the evidence of the experience of a lucid dream.
Recently, the interest in studying lucid dreams has increased, mainly due to rising of new technologies and debates about consciousness. For these studies, EEG has been one of the most used tools to investigate the brain activity during a lucid dream.
In a review that analyzed numerous EEG studies it showed that there is a certain degree of discrepancy between data from different sources. It is not possible to observe a strong pattern between different episodes of lucid dreaming.
This may be due to some factors, such as:
1. limited electrode montages and evaluation of different EEG frequency bands.
2. Each person experiences the dream in a different way, activating different memories, emotions and reactions
Another interesting aspect is that if a person is experienced in having lucid dreams, their brain activity will be different than a person who is less experienced. This happens because a person that is more experienced seems to interact more with the dream and are able to sustain longer dreams. On the other hand, the less experienced one seems to have shorter dreams and interact less. Because of this, the EEG may differ mainly due to the aspect of neural activity necessary to maintain the state of the dream.
With these findings, it’s clear that there’s a lot more to understand about the inner workings of lucid dreams and how it affects cognition. There is a need for larger study samples and different methodologies. Neuroimaging studies have shown to be a great pathway to follow; currently there is only one fMRI study contrasting lucid and non-lucid REM sleep and it’s a case study.
This study supports the hypothesis that there is a difference in the brain activity of more experienced people compared to less experienced people in lucid dreams, which has been confirmed by other studies using EEG. Initial results indicate that regions of anterior prefrontal, parietal and temporal cortex are involved in lucid dreaming.
Better comprehending lucid dreams seems to be an excellent way to better understand REM sleep and, consequently, create a better picture of how conscious we are during sleep.
If you want to know more about cognitive neuroscience of sleeping and dreaming, check Sleep and neuroscience.
Referências
If you want to know more about cognitive neuroscience of sleeping and dreaming, check Sleep and neuroscience.
Referências
Baird, Benjamin, et al. “The Cognitive Neuroscience of Lucid Dreaming.” Neuroscience & Biobehavioral Reviews, vol. 100, 2019, pp. 305–323.,
