Sleep Revolution—In The Blink Of An Eye
We spend approximately one-third of our lives asleep. Many speculate that this time could instead be used to improve our memory and brain functionality. A good night’s sleep has well-known restorative functions and is also critical for memory reinforcement and emotional refining. A booming community of sleep scientists have been studying aspects of the impact of sleep on the human body. In the process, they have conducted various experiments to determine a method to manipulate sleep to the benefit of humans. The researchers describe this technique as Sleep Engineering.
Sleeping is an incredibly complex process—the brain doesn’t just switch off when we fall asleep. In fact, some areas of the brain are more active during sleep than when the person is awake. Sleep doesn’t arise from a single structure within the brain but is instead a network property that involves a series of oscillating sleep stages. Sleep engineering involves the manipulation of these sleep stages through auditory and electrical stimulation, and the manipulation of memory by targeted memory reactivation in sleep. Thus the understanding of each stage is essential to understand the growth of this rapidly expanding field in science and technology. To simplify the understanding of sleep and its complexities, sleep researchers divide sleep into four stages—wake, hypnagogia, light sleep, and REM. Each of these stages serves a different purpose.
The first stage of sleep, where the mind and body begin to slow down, is known as wake. It is one of the shortest stages, lasting for five to ten minutes on average. In the second stage of sleep, referred to as light sleep, the pattern changes—it slows down, and the amplitude of brain waves gets slightly higher, showing marginally higher synchrony. In this stage, we start to see occasional bursts of high-frequency activity called sleep spindles. These spindles don’t occur across the whole brain but rather are only observed in localised areas at any particular moment. These spikes in brain activity are thought to play a role in long term memory consolidation, making this a crucial stage.
Hypnagogia is the dream-like or semi-lucid state that occurs in the transition between wakefulness and sleep. It usually lasts a few minutes at most and is associated with creativity and problem-solving. As we go deeper into the sleep cycle, the activity slows down even further. We start to see high amplitude slow oscillations called slow waves. These waves showcase a high degree of synchrony. And if we go deeper still, we go into a sleep stage called Rapid Eye Movement Sleep. This stage is named for the way the eyes move under closed lids during its occurrence.
Among the five different types of brain waves, alpha waves are present during deep relaxation, and theta waves emerge during the REM dream state. The coexistence of these two brain waves during hypnagogia may account for a bizarre imagery and auditory experience, otherwise termed as dreams. Beethoven, Tesla, Salvador Dali, and other famous personalities all claimed to use a creative technique that involved accessing their dreams to decipher concepts and bring them into the conscious world. For example, Thomas Edison took short naps that he spaced throughout the day, holding steel balls in his hand during these naps. If he fell asleep, his grip would relax during the hypnagogic state, causing him to drop the balls and wake up. Immediately upon awakening, Edison would grab a pen and paper and note down his thoughts.
The idea of separating wakefulness and unconsciousness, and promoting creative thought through the brain has lead to the invention of devices that act as an interface to the stages of sleep. Researchers at Massachusetts Institute of Technology are trying to build on the process with an interface for dreams. Their invention is called Dormio—an electronic glove that contains sensors to monitor when you enter hypnagogia and when you are moving into real sleep. Dormio gently nudges you with an audio cue. The subtle noise is meant to bring you back into hypnagogia without waking you up. The team found that the chosen word, which serves as the audio cue, often gets incorporated into the user’s lucid dreams and reinforces its memory.
Sleep is vital for forming new memories, strengthening memories and integrating those memories. As we age, our sleep patterns change as the high amplitude slow oscillations, responsible for memory control, gradually flatten out. After the age of sixty-five, it is quite common not to get any slow-wave sleep at all. Recent research that involved playing the sound of a click near the peaks of high amplitude slow oscillations suggested that these clicks boost the amplitude and improve memory the next day. This works very well in healthy people at a young age. Sleep scientists are working on developing a preventative treatment that could help maintain slow wave sleep as a person ages. This could potentially improve memory and be a step in the direction for a cure for memory disorders that occur during old age.
Targeting one or more sleep stages explores ways to find a secret door to our subconscious. The challenge is to do so without waking a person up. Signals and stimuli do just that. Several studies have explored the use of scent to help induce sleep. Project BioEssence by the MIT Media lab demonstrated that certain smells could be used to influence the emotional valence of dreams. In this case, researchers used a 60 cm tube to connect the nose to an olfactometer. Once the user is asleep, this device releases a smell that has already been associated with a specific memory. This process allows easier access to the memory and refreshes certain regions of the brain. In particular, it was found that smell also affects the nature of dreams. The scent of roses during sleep yielded more positive dreams, while the smell of rotten eggs resulted in negative ones.
Another sphere of sleep engineering is to derive the relationship between sleep and mental health illnesses. Studies prove that those with mental health problems are more likely to have insomnia or other sleep disorders. Neuroimaging and neurochemistry studies suggest that sleep helps foster both mental and emotional resilience, while sleep deprivation sets the stage for negative thinking and emotional vulnerability. Yet the mutual relationship between sleep and mental health is not completely understood. Several primary research studies have experimentally manipulated sleep and then measured mental health outcomes. None of these experiments could estimate the magnitude of the effect of sleep on the quality of the results. Therefore, it is currently challenging to draw firm conclusions that mental health problems can be tackled using interventions that have been designed to improve sleep.
Admittedly, studies from this new wave of interest are still underway. Until now, they reflect a growing trend towards understanding sleep as a link between dreams and improved memory and creativity. Being one of the favourite picks of sleep scientists and psychologists, sleep engineering may give rise to a number of new research subjects, inventions, and other major breakthroughs in the near future.
Featured Image Credits: Jason Beaubien