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Whether or not you remember your dreams, everybody has them. There are some people, who can remember their dreams every morning, while there are others who rarely recall their dreams. According to a new study, the temporo-parietal junction, an information-processing hub in the brain, is more active in people who more frequently remember their dreams. More activity in this part of the brain might help attention orienting toward external stimuli and promote intrasleep wakefulness, which would facilitate the encoding of dreams in memory.
While dreaming is a well-known phenomenon, its reason remains a mystery for the researchers who study the difference between “high dream recallers” and “low dream recallers”. Back in 2013, a team led by Perrine Ruby, inserm researcher at the Lyon Neuroscience Research Center, made these two observations: high dream recallers have twice as much time of wakefulness during sleep as low dream recallers, and their brains are more reactive to auditory stimuli while asleep and awake. This increase in brain activity could promote awakenings during the night, which in turn would make it easier to remember dreams.
In this study, the researchers worked to identify which parts of the brain differentiate high and low dream recallers. They used Positron Emission Tomography (PET) to measure the spontaneous brain activity of 41 volunteers during periods of sleep and wakefulness. Volunteers were put in 2 different groups: 21 high dream recallers, who remembered dreams for on average 5.2 times a week, and 20 low dream recallers, who remembered on average just 2 dreams a month. High dream recallers showed stronger spontaneous brain activity in the medial prefrontal cortex (mPFC) and in the temporo-parietal junction (TPJ), an area of the brain involved in attention orienting toward external stimuli.
According to Ruby, this might explain why high dream recallers react more strongly to environmental stimuli and are better at encoding dreams than low dream recallers. The sleeping brain is not able to memorize new information. The research team has concluded that high and low dream recallers differ in dream memorization, but don’t exclude that they also differ in dream production. It is possible that high dream recallers simply dream more than those who are low dream recallers.