People who have the ability to recall their dreams five mornings per week, on average, have more spontaneous activity occurring in certain parts of their brains than others. The parts of the brain that host these increased levels of activity are called the temporo-parietal junction, which is an information-processing hub, and the prefrontal cortex, which is responsible for the expression of personality as well as the planning of complex cognitive behaviors. And, interestingly, this escalation in liveliness is higher during both wakefulness and sleep, so says a study of 41 people recently published online February 19 in the journal Neuropsychopharmacology. The activity in the brains of the people in this study were measured by Positron Emission Tomography while they were awake and sleeping. What do these findings tell us?
In combination with previous research from one of the study’s authors, Perrine Ruby, the findings tell us why some people remember their dreams and some do not. Ruby co-authored related research that was published last year in the journal Cerebral Cortex, which showed that people who have the ability to regularly recall their dreams are also more reactive to sounds when they are both asleep and awake. Ruby made some comments in a recent statement that synthesized the findings for both of these studies. Ruby stated that the brain needs to awaken from sleep in order to memorize new information. This, said Ruby, may explain the reason that those who react more to environmental stimuli can remember their dreams better; they simply are awakened more often and can therefore better encode into memory their dreams than others who are less reactive to sounds. In addition, the researchers said that people who often recall their dreams may also have more dreams than “low-recall” dreamers.
While these two studies tell us that some people, whether awake or asleep, are more reactive to sounds and have more activity happening in specific areas of their brains and therefore are able to remember their dreams more often than others, the studies stop there. Is the increased activity in the temporo-parietal junction and the prefrontal cortex along with the increased reactivity to sounds a good thing or a bad thing?
The key is whether or not people who recall their dreams have more dreams than “low-recall” dreamers. Many studies have linked dreams to depression. People who are depressed dream up to three times as much as people who are not depressed. Dreams have specific psychological and biological purposes, according to the latest scientific research. They are the brain’s way of neutralizing a concern’s charge. Once our brain is aroused from a concern, it must complete a cycle of arousal. If it is not completed during waking hours, it will be completed in dream sleep, also known as the REM stage of our sleep cycle. Because depressed people have more emotional arousal to neutralize, they have to dream more than non-depressed people. And when the brain devotes more time to dreaming, less time can be allocated to slow-wave sleep, also known as the most physically recuperative stage of sleep.
Rosalind D. Cartwright has researched sleep for fifty years and authored a book titled The Twenty-Four Hour Mind: The Role of Sleep and Dreaming in Our Emotional Lives. She says that brain imaging technology shows higher activity in depressed people in the emotion areas of the brain during REM sleep than it does non-depressed control subjects. Cartwright says “dreaming diffuses the emotional charge…and prepares the sleeper to wake ready to…make a fresh start.”
Are Ruby’s studies connected to Cartwright’s? Perhaps. Ruby’s research team states that people who often recall their dreams may not only have increased reactivity to sounds and be more active temporo-parietal and prefrontal cortex areas, but they also may have more dreams to recall. Without brain imaging technology, measuring how much one’s sleep cycle is devoted to dreams is near impossible. The closest thing is knowing whether or not one has “high-” or “low-recall” with regard to dreams.