In the earliest dream I can recall, I was being held captive in a cave, handcuffed to a giant. Upon awakening, I wondered how handcuffs that fit a giant would also fit me. Couldn’t I just slip out of them? Even as a kindergartener, I was intrigued and baffled by the phenomenon of dreaming.

Since that memorable nighttime vision, I’ve tried to decipher my dreams. I’ve kept written and pictorial dream journals and belonged to dream groups, and yet, most dreams remain opaque to me. Occasionally one seems to resonate with life events, but so many are like bits of cottonwood seeds drifting past me as I stir. Others seem important, and are even recurring but are hard to connect with anything. And then there are the really weird ones that make as much sense as a Dali painting inserted into the middle of Good Night Moon

So it was with great interest that I read When Brains Dream: Exploring the Science and Mystery of Dreams. While any theory is necessarily incomplete, Antonio Zadra and Robert Stickhold present a clear framework for the purpose of dreams, and though they note many areas in need of further research, their theory addresses many of my queries. Both longtime dream investigators, Zadra Is a professor at Universite de Montreal and researcher at the Center for Advanced Research in Sleep Medicine; Stickgold is a professor at Harvard Medical School and director of the Center for Sleep and Cognition. Their theory, NEXTUP, is an acronym for Network Exploration to Understand Possibilities, and as the name suggests, they hypothesize that dreams are the brain’s attempt to navigate the world – but not in the straightforward way we might expect. 

While any theory is necessarily incomplete, Zadra and Stickhold present a clear framework for the purpose of dreams.

The book begins with a history of the science of dreams and sleep, from Freud’s “groundbreaking” work on condensation, where latent and repressed ideas return in hidden symbols (an idea that was actually appropriated from other psychologists) to the discovery in the 1950s of rapid eye movement (REM) and other stages of sleep.  With neural electrode technology, sleep labs could investigate what occurs in the brain while we dream, and the relationship between different sleep levels, dream types and the function of each. The authors’ definition of dreaming includes any memory or event that occurs during any stage of sleep– a story, an image, a word, a sound. Dreams that occur during REM are generally the most salient, emotional and bizarre, while hypnogogic dreams, those that occur as we are drifting into unconsciousness, are generally a blend of current events and non-real situations.

There are two overarching questions that guide the authors’ theory on dreaming. First, even when we are totally in the dark as to their meaning, why do dreams sometimes feel like they are trying to tell us something significant? Second, if dreaming is in some way beneficial for our survival or wellbeing, why do we remember so few of them?

Regarding the first question, the authors explain that the production of serotonin—a neurotransmitter in the brain that regulates mood— decreases during sleep and is blocked during the REM stage. The result, they explain, is similar to that of LSD and other hallucinogens that deactivate serotonin receptors: a bias that announces “This is important.” In the same way we might feel enlightenment while under the influence of a hallucinogen, a dream might feel important, even if it’s just a series of seemingly absurd and unrelated images. The perceived importance may help the brain store the associations for future use.

Regarding the second question, if dreams have survival value, why do we struggle to remember them? And while we’re at it, why are they not more tangible if they are communicating something to our conscious mind? NEXTUP’s hypothesis is that the recall of REM dreams is not necessary to their function, which is to subconsciously explore weak associations between our memories and recent events, especially emotional experiences. The neurotransmitter noradrenaline is the brain’s version of adrenaline, which helps the mind to focus. But during REM sleep, it is not produced, encouraging our focus to wander among weak associations and allowing the brain to investigate different possibilities that may be useful in the future. These are associations that you would be unlikely to make while awake, but that might prepare you for future events, regardless of whether you recall the dream.

Put these two ideas together and some aspects of dreaming make more sense. They feel important because of the neurochemistry of sleep, and yet they are difficult to recall because weak and unexpected associations are made between memories and current events in our life rather than clear and strong connections. 

So, are dreams actually important? The authors theorize that dreaming, and especially REM dreaming, has an evolutionary basis for problem solving and survival in exploring nonlinear possibilities. Importantly, it’s not necessary that we recall our dreams for them to serve this purpose. This is not to suggest that remembering and analyzing your dreams is not useful— several chapters in the book discuss topics such how to approach your dreams, organize an effective dream group, and facilitate lucid dreaming. This active analysis can be useful to your personal development, insight, and problem solving, as well as interesting and fun. But the brain seems to be doing its own thing with our dreams as well. 

The book also investigates how dreams can be used to enhance creativity, tame nightmares, treat PTSD and sleep disorders, and whether dreams might be predictive or linked to telepathy (the jury is still out on this matter.) If you are interesting in learning more about the fascinating topic of the purpose of dreaming, I would certainly recommend checking out When Brains Dream!


  • Bill Carroll

    Bill Carroll is a retired mathematics and astronomy high school teacher with a PhD in Educational Processes. Currently, he volunteers at the Field Museum in lichen, botany, and education outreach and with Little Brothers Friends of the Elderly. He also tends a native garden in the traffic circle near his home in Chicago.

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Total Solar Eclipse on April 8, 2024

Total Solar Eclipse on April 8, 2024

On April 8th, 2024, a total solar eclipse will sweep across North America, from Mexico to the Maine-Canadian border. For those who experienced the spectacular solar eclipse of 2017, this one will be similar, crossing the United States from west to east and passing through or near several major metropolitan areas. And while its path is quite different this time, Carbondale, Illinois, a reasonable destination for Chicago-area residents, will once again be on the line of totality.    

Just a little background on eclipses:  Lunar and solar eclipses are not uncommon – they each occur about twice a year when the moon is crossing the ecliptic, the path of the sun in the sky.

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