To Sleep, Perchance to Dream: Some Ways of Our Brain Functions.

 What Happens When We Are Sleeping.

Comedian Mike Birbiglia was having trouble with sleep. Though not with the actual sleeping part. One night, while staying in a hotel, he dreamed that a guided missile was on its way to his bed, and in his dream, he jumped out of the window to escape it. Unfortunately, he also did this not in his dream, from the second floor, and the window was not open. This little episode cost him 33 stitches and a trip to a sleep specialist. Mike now sleeps in zipped-up mummy bags for his own safety. The lesson here? is not some break time when your brain or your body just goes dormant. Far from it. In truth, sleep is just another state of consciousness. And only in the past few decades have we begun to really plumb its depths. 

From why we sleep in the first place, to what goes on in our brains when we do, to what happens when we can't sleep. And there is a lot that science has to say about your dreams. Talk about weird, it's like Sigmund Freud meets Neil Gaiman. So even though it may seem like you're dead to the world when you sleep, your perceptual window remains slightly open. And kind of like Mike Birbiglia's hotel room window, a trip through it can make for a pretty wild ride. But for your safety and enjoyment, I'm here to guide you through this state of consciousness where you'll learn more than a few things about the human mind, including your own. And here's hoping you won't need any stitches when we're through. 

How Do We Sleep?

Technically speaking, sleep is a periodic, natural, reversible, and near-total loss of consciousness, meaning it's different than hibernation, being in a coma, or in, say, anesthetic oblivion. Although we spend about a third of our lives sleeping and we know that it's essential to our health and survival, there still isn't a scientific consensus for why we do it. Part of it probably has to do with simple recuperation, allowing our neurons and other cells to rest and repair themselves. Sleep also supports growth, because that's when our pituitary glands release growth hormones, which is why babies sleep all the time. Plus, sleep has all kinds of benefits for mental function, like improving memory, giving our brains time to process the events of the day, and boosting our creativity. 

But even if we're not quite sure of all of the reasons why we sleep, technology has given us great insight into how we sleep. And for that, we can thank little Armand Aserinsky. One night in early 1950s Chicago, eight-year-old Armand was tucked into his bed by his father. But this night, instead of getting a kiss on the forehead, little Armand got some electrodes taped to his face. Armand's dad was Eugene Aserinsky, a grad student looking to test out a new electroencephalograph, or EEG machine, that measures the brain's electrical activity. That night, as his son slept peacefully, he watched the machine go bonkers with brainwave patterns, and After making sure that the machine wasn't somehow broken, discovered that the brain doesn't just power down during sleep, as most scientists thought.

Rapid Eye Movement

Instead, he had discovered the sleep stage we now call REM, or rapid eye movement, a perplexing period when the sleeping brain is buzzing with activity, even though the body is in a deep slumber. Aserinsky and his colleague Nathaniel Kleitman went on to become pioneers of sleep research. Since then, sleep specialists armed with similar technology have shown that we experience four distinct stages of sleep. each defined by unique brainwave patterns. Say you're just going to bed. All day, your endocrine system has been releasing awake hormones like cortisol. But with nightfall comes the release of sleepy melatonin hormones from your pineal gland. Your brain is relaxed but still awake, a level of activity that EEGs measure as alpha waves. You're feeling sleepy, your breath slows, and suddenly, you're asleep. 

This exact moment is clearly evident on an EEG reading, as those alpha waves immediately transition to the irregular non-rapid eye movement stage one. NREM1 waves. It's in this first stage of sleep that you might experience hypnagogic sensation, those brief moments when you feel like you're falling and your body jerks, startling you. As you relax more deeply, you move into NREM2 stage sleep, as your brain starts exhibiting bursts of rapid brainwave activity called sleep spindles. You're now definitely asleep, but you could still be easily awakened. NREM3 comes along with slow-rolling delta waves. We now know that you can have brief and fragmentary dreams in the first three stages of sleep, But eventually, you'll get to the most important stage, full REM sleep. That famous stage of sugarplum slumber that makes eyeballs go nuts, grants vivid visual dreams and provides the namesake for certain famous rock bands. 

REM sleep is kind of paradoxical. Your motor cortex is jumping all over the place, but your brain stem is blocking those messages, leaving your muscles so relaxed that you're basically paralyzed. Except... for your eyes. That whole sleep cycle repeats itself every 90 minutes or so, transitioning back and forth between the stages of sleep. Obviously, sleep is super important, and lack of sleep is terrible for your health, mental ability, and mood. In fact, it's a predictor for depression and has been linked to things like weight gain, as your hunger-arousing and suppressing hormones get out of whack. Sleep deprivation also causes immune system suppression and slowed reaction time, which is why should not drive sleep. Of course, a bad night's sleep here and there is part of life, but there are a host of bona fide sleep disorders out there that can make your life pretty terrible, or, in Mike Birbiglia's case, land you in the emergency room. 

We've got insomnia, which is persistent problems falling or staying asleep, and kind of its opposite, narcolepsy, whose sufferers sometimes experience brief, uncontrollable attacks of overwhelming sleepiness called sleep attacks. This, as you can imagine, can get in the way of all sorts of things that you might enjoy doing, like driving, Eating? Pole vaulting? Narcolepsy may have several different causes, including a deficiency in the neurotransmitter hypocretin, which helps keep you awake. But in rare cases, brain trauma, infection, and disease may contribute to it as well. So that's pretty rare, but you probably know someone with sleep apnea, the disorder that causes sleepers to temporarily stop breathing until their decreased oxygen levels wake them up. Biglia, meanwhile, turned out to have a REM sleep behavior disorder, which we don't fully understand yet but appears to be associated with a dopamine deficiency. 

Then, We've got night terrors, which are as terrible as they sound, spurring increased heart and breathing rates, screaming and thrashing that's seldom remembered upon waking. Night terrors are most common in children under seven, and may be spurred by stress, fatigue, sleep deprivation, and sleeping in unfamiliar surroundings. Much like sleepwalking and sleep talking, night terrors occur during the NREM3 stage of sleep, and are not the same as nightmares, which occur, like most dreaming, during REM sleep. But oh, in REM sleep. what dreams may come. There you are, running naked as your teeth fall out, being chased down the beach by a Matt Damon centaur. You wake up, feeling around your mouth, thinking, what? What? What? What? Welcome to your dreams, those vivid emotional images racing through your sleeping brain, often providing a backdrop so bizarre that it may seem like David Lynch, Terry Gilliam, and Tim Burton are trying to out-weird each other at a film festival, a really, really long film festival, considering the average person spends about six years of their lives 

dreaming. So yeah, sometimes you have really crazy dreams, but mostly your average dream just sort of unpacks and reshuffles what you did that day. For example, last night I dreamt about Tumblr because I spent a lot of time on Tumblr yesterday. If you played Tetris all afternoon, you might dream of blocks falling from the sky. If something traumatic happened to you, your brain might provide you with a nightmare to help extinguish your daytime fears. Thanks, brain. And again, you might be unable to stop dreaming about the trauma, which we'll look at in the future. when we discuss post-traumatic stress disorder. Our two-track minds, of course, allow us to register more stimuli than we outwardly acknowledge during the day, and in that way, the sounds of car alarms or stinky dog farts that you might not even have noticed get incorporated into your dream, too. 

And that's all interesting and weird and sometimes a little gross, but what's the real purpose of dreaming? Why do we do this? As you might have guessed, there's more than one idea out there. The study of dreams is a mix of neuroscience and psychology known as oneirology. Oneirus is Greek for dream, and if you're a Neil Gaiman fan, you might recognize it as one of the Sandman's many names, the one that comes with a toga in Orpheus's head. But Sandman aside, if you want to talk about dreams, you might want to start with our old friend Freud. In his landmark 1900 book, The Interpretation of Dreams, Freud proposed that our dreams offer us wish fulfillment. He thought a dream's manifest content, the stuff you remember in the morning, was a sort of censored and symbolic version of whatever inner conflict was really going on in that dream's unconscious or latent content. 

Not surprisingly, the wish fulfillment theory lacks scientific chops and has, for the most part, fallen out of favor because, really, you can interpret a dream any way you want. Like, sometimes A cigar is just a cigar. Luckily, we have some other theories to consider. The information processing theory proposes that our dreams help us sort out and process the day's events and fix them into our memories. 

Why We Do Dream?

This may be particularly important when it comes to learning and remembering new information. And some studies show that people recall new tasks better after a good REM sleep full of dreams. But if brainwave readings show us anything, it's that a lot is going on in your brain when you dream. And the physiological function theory suggests 

That dreaming may promote neural development and preserve neural pathways by providing the brain with stimulation. When our brains are stimulated, they expand their connections more. So babies, for example, spend much of their sleep time dreaming, perhaps in part to help their brain circuitry develop more quickly. This is similar to the idea that dreams are part of our cognitive development. By this model, dreams draw on our knowledge and understanding of the world, mimicking reality and engaging those same brain networks that light up when we daydream. Finally, some theories focus on the way REM sleep triggers neural activity and the idea that dreams are just sort of accidental side effects. The brains attempt to weave a story out of a bunch of random sights, emotions, and memories. 

which is how, in dreamland, I might actually marry that Matt Damon centaur and give birth to a baby with banana fingers and a raccoon tail. For now, scientists continue to debate the function of dreams, but one thing we know for sure is that REM sleep is vital, both biologically and psychologically. But hey, do you think your dreams are not far? Next week, we're looking at other altered states of consciousness, where you'll learn what your brain really looks like on drugs, and whether you can actually hypnotize someone to do your evil bidding. or just act like a chicken. For now, if you stayed awake during this episode, you learned about the four stages of sleep, REM 1, 2, and 3, and REM itself, as well as some of the major theories for the psychological purpose of dreaming, including information processing, physiological function, cognitive development, and neural activity models.