The Science of the Forgotten Dream
By Naomi Stapleton, Psychology, 2016
Picture the scene: You burst through the door for your 8 a.m. class, just in time. You feel the relief wash over you — but no, that’s not relief. That prickling, trickling feeling is sweat. With a shock, you come to the conclusion that you are stark naked. Luckily, just before your professor opens his mouth to ask your intentions, you wake up panting in your bed, very much clothed and confused.
Many people are haunted by the horrifying, the mundane, and the just plain weird situations that the brain imagines during the night, whereas others remain blissfully unaware of these midnight musings. Scientists can still only speculate about the function of dreams, but they are getting closer to understanding why humans exhibit drastically different levels of dream recall.
In INSERM’s (Institut national de la santé et de la recherche médicale) Brain Dynamics and Cognition Team’s recent sleep study, researchers used Positron Emission Tomography (PET) to analyze the brain activity of 41 participants during sleep and wakefulness.
These subjects were distinguished based on their dream recollection: “high dream recallers” who recall dreams an average of 5.2 mornings per week and “low dream recallers” who recall an average of 2 per month. The PET results highlighted clear differences in the participants’ brain activity throughout the night.
High dream recallers awoke more often while sleeping, and were generally more reactive to external auditory stimuli during both sleep and wakefulness.
The high dream recallers exhibited higher spontaneous activity in the temporo-parietal junction and the medial prefrontal cortex in the brain. These areas serve as information-processing centers and are involved in transferring the brain’s attention to external stimuli.Therefore, increased activity in this area could be what promotes increased wakefulness between sleep cycles.
A brief awakening after a dream is likely what facilitates high dream recallers’ greater encoding of the dream memory, since “the sleeping brain is not capable of memorizing new information; it needs to awaken to be able to do that,” said INSERM Research Fellow Perrine Ruby.
It is clear that the increased activity in the temporo-parietal junction contributes to a higher likelihood of dream memorization, but it is not yet certain whether the degree of dream production could also be a factor. The team at INSERM, a public health and biomedical research institution in France, hopes to expand their research in the Lyon Neuroscience Research Center in the future to account for and examine the dream production’s role in dream recall.
This article was originally published in NUSci Issue 19.
