by Emma Nagel
art by Mina Kamara
Any busy student knows that time always seems to slip away–there just aren’t enough hours in the day. As the night dwindles on, it is a fairly common experience for students to trudge back from the library after an all-night grind, cursing themselves for needing sleep. While it is necessary to function, sleep can feel like a waste of time because we aren't in control of our conscious selves. Well, at least some of us aren’t. A phenomenon called lucid dreaming allows one to have full consciousness and awareness of being in a dream while they are technically asleep [1]. Experiences like flying, traveling to different planets, facing your biggest fears, and so much more are suddenly just a thought away.
Before we get into what lucid dreaming is and how it affects the brain, it is important to first define sleep. The brain’s electrical activity is a crucial aspect of what distinguishes rest from wakefulness [2]. Brain cells are constantly communicating through organized electrical impulses that vary in energy levels and speed, creating repetitive cycles of electrical brain energy known as brain waves [2]. Different waves are distinguished based on their speed or frequency levels, measured in hertz (Hz), which represents the number of wave cycles passing through the brain per second [3]. There are five main types of brain wave frequencies: Gamma (>35 Hz), Beta (12-35 Hz), Alpha (8-12 Hz), Theta (4-8 Hz), and Delta (0.5-4 Hz). These brain waves are firing constantly, but they shift in frequency throughout our time awake and asleep – the lowest frequencies are associated with sleep or relaxation, and the highest frequencies with wakefulness and concentration [3].
As we sleep, we oscillate between two states: non-rapid eye movement (NREM) and rapid eye movement (REM) [4]. Both of these states play crucial roles in allowing the brain to experience deep rest and rejuvenation. The NREM stage reflects the period in which we fall asleep and begin to enter deep sleep [5]. In this stage, there is a decrease in body temperatures, heart rate, breathing, and muscle tone, as well as the amount of tension in our muscles [5]. The culmination of NREM produces delta waves, significantly decreased brain waves [4].
REM sleep is characterized by theta and alpha waves, which are closer in frequency to wakefulness than NREM [4]. However, REM sleep also causes muscles to stop moving, causing temporary body paralysis with the exception of cardiac, respiratory, and ocular muscle movement [5]. There is a long history of dreaming being associated with the REM stage [6]. This association was first found by Aserinsky and Kleitmann in a study done in 1953 where people were awoken at various stages of their sleep cycle and asked to recount their dreams [7]. A significantly higher number of people could recall their dreams following REM sleep than at any NREM stage [7]. Nowadays, it is known that dreaming can occur during all stages of the sleep cycle, predominantly during REM [8]. Scientists study and measure this electrical activity by using an electroencephalogram (EEG), a neural test where small electrodes are placed on different parts of the head that extract different waves from the recording and display them in real-time on a screen or paper [2, 3]. It is unknown whether dreaming can occur during both high and low-frequency waves, and it has been suggested that when dreaming occurs during NREM, it is really just disguised REM with lower frequencies, not picked up on the EEG [8]. Since it is also difficult to distinguish whether dreams were absent or forgotten when subjects didn’t report them, scientists recognize dream recall experiments may not accurately assess whether someone actually experienced dreaming [8].
What REM sleep is most famous for is rapid eye movements [9]. Compared to when one is awake, eye movements that occur during REM are produced using less brain energy and are more frequent. The reason for the rapid eye movements is unclear, and many believe it is a random response regulated by the brain stem; however, there is data to suggest that rapid eye movement reflects the movement of eyes scanning the dream reality [9]. A study examining the head directional (HD) cells, neurons responsible for guiding the head’s direction as it navigates its environment, supports this claim. Since mice sleep with their eyes open, researchers were able to study their eye movements during REM sleep, while analyzing the HD cell activity. It is important to note that no head movement actually occurs during REM because the parts of the nervous system responsible for triggering head movements are inactivated, along with all the other voluntary muscles. The HD cells that would fire in response to movement fire constantly, regardless of whether or not the head moves. The HD cells of a conscious mouse and a mouse in REM had similar correlational structures, meaning HD cells that fired together when awake also fired during REM sleep. HD correlational structure serves as evidence that there may be ‘virtual navigation’ during REM sleep [9].
So, now that we understand sleep and regular dreaming, what is lucid dreaming?
Lucid dreaming, a type of dreaming occurring during the REM stage, is when the dreamer experiences awareness of being in the dream as they are dreaming [10]. This phenomenon is not as fantastical as it appears and is much more common than people realize. Around half of the adult population has experienced lucid dreaming at least once in their lifetime and 23% of people lucid dream regularly, at least once a month [10]. It is worth noting that there is a high correlation between lucid dreaming and sleep disorders like narcolepsy, a disorder where people are unable to regulate their sleep-wake cycles resulting in excessive daytime sleepiness. In a study assessing the experience of lucid dreaming, 78% of narcoleptics reported having done so on average twice per week [11]. Additionally, age may play a key factor in the spontaneous origination of lucid dreaming. According to a study that surveyed 344 lucid dreamers, spontaneous lucid dreaming originates most frequently from ages 12-14, and the onset is triggered by nightmares, recurring dreams, or strange features within the dream [1]. This higher probability for lucid dreaming in younger ages may be due to their increased REM sleep. A newborn's sleep consists of 8 hours of REM while adults only need around 2 hours [12]. Since there is a decreased amount of REM sleep after age 25, spontaneous lucid dream origination is much less common [1].
While the idea of lucid dreaming has been around for centuries, the first laboratory study on lucid dreaming wasn’t conducted until the 1970s, when scientists first discovered observable evidence of a lucid dream occurring [13, 14]. Scientists Keith Hearne and Stephen LaBerge both independently discovered that lucid dreaming could be proven and studied. They found that lucid dreamers could signal to the researcher through a specific pattern of left-to-right eye movements throughout the lucid dream. These eye movements are recorded through a REM polygraph monitor, a machine that analyzes physiological changes during sleep like eye movements and can be distinguished from normal REM eye movements because the unusual pattern of left-right eye signals is done deliberately by the lucid dreamer [13, 14]. This led to the beginnings of lucid dream research and was an essential step in figuring out what happens in the brain during this state. Despite this discovery, lucid dreaming is still difficult to study because it is a relatively rare and subjective experience. Most studies have low statistical power and interpretation issues, meaning that the data is not fully objective, which makes it difficult to compare the studies. There are many questions about lucid dreaming in terms of brain function left to be answered as the field of lucid dreaming develops.
Since discovering a way to determine when lucid dreaming occurs, scientists have been able to study the physiological brain differences that distinguish it from regular dreaming during REM sleep. When scientists compared EEGs of typical, non-lucid REM to lucid REM, they discovered that lucid dreaming exhibits traits of both normal REM sleep and wakefulness [15]. The fact that lucid dreamers can signal eye movements while they sleep is indicative of lucid dreaming being its own distinct neurological state. The dreamer recognizing that they are in a dream and being able to control their eyes, both in their dream reality and in real life, is an action associated with consciousness. Yet, their electromyographic activity, electrical brain activity in response to nerve stimulation of certain muscles, was consistent with REM measurements and significantly lower than a conscious person’s activity while performing the same movement with their eyes closed [15].
Overall, lucid REM dreaming is very similar to normal REM, as shown by both low-frequency brain wave activity that controls the muscle relaxation common to both states. However, there was a major difference in the frequencies of gamma waves, which are related to the fastest brain activity, in the frontal regions of the brain. For lucid dreamers, these waves reach frequencies similar to levels when the brain is awake, rather than the lower frequency waves more common in REM sleep. This increase in frequency power further suggests that lucid dreaming is indeed different from REM sleep, creating a unique brain state during sleep [15]. The frontal regions of the brain activated when lucid dreaming takes place are known for being associated with self-consciousness and exercising voluntary control, leading scientists to conclude that this brain area is responsible for a person’s self-reflection and their ability to acknowledge a dream state [15, 16].
People who have never experienced lucid dreaming may never experience it spontaneously; however, lucid dreaming can be an acquired skill. There are two ways to induce it: either through training yourself to recognize in the dream that you are dreaming, or to use techniques to help you enter a lucid dream directly [10]. Using the reality test method, participants in a study were most successful in inducing lucid dreaming by performing several reality tests over the course of the day. They questioned if they were dreaming while awake to train themselves to do the same when they were actually dreaming. They also read literature before bed explaining what they should do if they actually lucid dream. The most effective method the participants used, however, was the mnemonic induction of lucid dreams (MILD) technique. MILD is a technique where the dreamer wakes up five hours after going to sleep and repeats the phrase, “the next time that I’m dreaming I will remember that I’m dreaming” [10]. There appears to be no difference in the brain physiology of someone who started lucid dreaming spontaneously without any prompting and one who trained themself to induce it [1].
This alternate brain state of lucid dreaming, while fascinating, has been glorified by the media and public and there are many myths to debunk. Often, lucid dreamers cannot completely control their dreams and instead only possess a range of influence [1]. Sadly, you can’t surf the internet or read textbooks in your dreams, and while it is possible to review material for exams in lucid dreams, no new knowledge can be attained through lucid
dreaming. Another prevalent myth is that two lucid dreamers can share a dream. Even if two dreamers agree to ‘meet up’ in a certain location and have the same ‘experience’, there is no evidence to support that the dream was actually shared [17]. Time also doesn’t necessarily move any faster in lucid dreams [18]. An experiment analyzing the difference between lucid dream time and real-time found that seconds counted by those in a lucid dream reflected approximately the same amount of real-time. Even more interesting, tasks like performing squats actually took around 10 more seconds for the lucid dreamers asleep than it took them to physically do the same amount of squats while conscious [18]. Another study expanding on this found an increase in time spent during lucid dreaming on tasks involving mobility, like walking or gymnastics, but for tasks that didn't involve movement, like counting, no difference was observed [19].
While not as extraordinary as it appears, there are many possible benefits to lucid dreaming including skill refinement. Specifically for athletes, lucid dreaming has been used to practice specific sports skills. A study on German athletes found that 9% of the participants actively used lucid dreaming to practice and of those 9%, 77% found it improved their performance [20]. Japanese athletes showed similar statistics where 9% of the participants used lucid dreaming and the majority found an improved sports practice [21]. Lucid dreaming also shows promise as a possible treatment for phobias and nightmares. In an online survey, 71% of 55 participants exhibited strong fear before lucid dreaming and 61% reported that their fear lessened after experiencing that fear in a lucid dream [22]. Research that studied lucidity as a treatment for nightmares in five case studies found that lucid dreaming techniques, regardless of whether the subject could induce a lucid dream, gave their participants more control and allowed them to alter their recurrent dreams. Dreamers' sudden ability to affect the nightmare and change the result proved to be crucial in eliminating it [23].
Though there are benefits in the ability to lucid dream, there are associated dangers when it comes to inducing them. The methods for inducing lucid dreaming, like waking up in the middle of the night inherently diminishes sleep [24]. Specifically, the reality test method has been predicted to increase symptoms associated with dissociation and schizophrenia, mental illnesses in which people have trouble distinguishing reality from fantasy [25]. Given these risks, is lucid dreaming worth it? Most of the research on lucid dreaming has focused on the positive effects of inducing it while failing to account for the harmful side effects [26].
The field of lucid dreaming is just emerging and brimming with potential. Whether conducting research that may help determine what causes lucid dreaming or studying the ways it can serve as a treatment for nightmares, there are countless aspects of lucid dreaming to delve into and new ground is still being broken. Due to the novelty of this research, lucid dreaming may hold a plethora of answers for many unanswered questions surrounding sleep. Who knows what this research will be utilized to achieve!
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