“Sleep that knits up the raveled sleave of care”
As the late and ever lovely Oliver Sacks said, “Waking consciousness is dreaming – but dreaming constrained by external reality.”
Dreaming — that fantastic, frank and, sometimes, quite fu—bizarre activity that we engage in on a nightly basis and yet we know so little about our unconscious conjured visions. Forget what Freud has disseminated into the winds of the zeitgeist about the images that are projected across our dancing eyelids. It’s much less about our unconscious desires and sexual lust for our paternal and maternal figures and more about our neurons oscillating between the humming hive like collective and the rolling waves bringing in the tide. Our brains are synching in and out of varying depths of unconsciousness and neuronal activity and we, helplessly, are along for the often-horrifying ride.
But dreams and their emotional provoking, fantastical narratives are only a small portion of the very absurd activity of sleep. We, generally speaking, attempt to avoid vulnerability at all cost while we are awake. We are vigilant of our surroundings, with a tendency to assess the likelihood of danger or disaster.
We look both ways before we cross the street. We may keep secrets shoved down deep in our throats, to avoid revealing ourselves in what would likely be a disastrous outcome. We evaluate the minute ways the body of a stranger moves when they approach and assess what this reveals about their intentions. Perhaps, we simply avoid public speaking at all cost. In everything we do, during our waking hours, we avoid putting ourselves in a compromising position.
And yet, when the sun goes down on the horizon and darkness inches his long fingers across the sky, we feel the strong, siren call from our beguiled bed. We shed our armoured day clothes and crawl beneath the cool sheets to stretch our limbs out across mattress and pillows. We tangle in blankets and, perhaps the arms of our lovers, relaxing our spines into the softness beneath. We close our eyes and the darkness of our bedrooms floods into the darkness of our skull. Our breathing becomes deeper and less guarded — that unmistakable heaviness of breath that comes when sleep crests and crashes over our bodies, sweeping us away in the undertow of unconsciousness.
Keeping with this watery theme, let’s explore a little deeper into the science of sleep and dreams.
Following, in Part Two, will be a look at what happens when the two become unattainable.
“The death of each day’s life”
Think of you brain like a free diver in the middle of the Pacific. We start at the surface, head above the waves, treading water with slow even rotations of one’s leg. We are awake and focused — surveying the horizon and the emptiness of the water that surrounds. This is an activated cortex — beta waves of unsynchronized neurons, crackling away at all the stimulus you are taking in.
Now our diver has perhaps pulled her goggles down over her eyes and secured the snorkel between her lips. She takes one last look out to the horizon as she slowly sucks air into her lungs until they reach their limited capacity. She slips beneath the waves and begins her descent. This is your brain, still awake, but relaxed. Here, alpha waves — deeper oscillations and less neuronal chatter.
It is in this state that you will, at some point, slip passed consciousness and into the arms of sleep. This is stage one, and our alpha rhythms will slowly give way to deeper waves, as our eyes roll from side to side beneath their lids.
The smooth strong kicks from our diver’s legs leaves a trail of bubbles as the rubber fins cut through the heaviness of water. Her movements are graceful, choreographed and designed to get her to where she needs to be. We have entered true unconsciousness and stage two of our sleep journey. Our neurons begin to synch up and start to generate something called a sleep spindle. This is produced by a structure buried in our deep brain– the master of sleep regulation– the mighty Thalamus.
The sleep spindle might be the most whimsical name for the electrical charge that ushers in sleep. It conjures to mind Sleeping Beauty, reaching her pale finger out to touch the cursed spinning wheel — pricking her porcelain skin on the sharp spindle and plunging herself into the supernatural unconsciousness.
The sleep spindle seems to be involved in looping through the landscape where our memories are consolidated — laid down and packed away for safe keeping. It is with these sleep spindles that our brain thumbs through all the activities of our day and stashes them away between sulci and gyri of the cortex. Tucking our day into folds and hiding events and newly learned skills in to hidden grooves, to be retrieved later when they are needed.
Back to our diver, she moves silently pass stage two and into stage three where we find very high spikes of electrical activity — it is here that we find our neurons are all humming together, and our body is absent of movement. She presses on, swimming towards the sea floor and entering into stage four. Large, slow delta waves roll across our skull as we lay still, silent and heavy in our beds. This can last for just over a half hour.
And then, just like our diver — when her lungs begin to yearn for air and the crushing pressure of the ocean becomes too great — we begin our ascent, passing through each stage again until we reach stage one. Our diver is here, just beneath the surface of the water; the tip of her snorkel crests through the lazy waves to draw in the oxygen from the world above. She stays here, in a liminal space between sea and sky.
This is the breast stroke of REM sleep. It is eerily similar to our waking physiology. Our blood pressure and heart rate had decreased as we descended into the depths of sleep. Our breathing slowed and our temperature dropped. Our metabolic rate followed suit.
With REM, all of these increased dramatically — mimicking that which regulates our waking form. But appearances are deceiving. Our body does not behave as though it is awake. In fact, despite our increased respiration rate and our eerily rolling eyes from behind their hooded homes — we are no longer in control of our bodies.
We are no longer capable of deliberate movement, or any movement for that matter. We are paralysed — if all the mechanisms are in working order.
“I love sleep. My life has the tendency to fall apart when I’m awake, you know?”
When we are reach REM sleep there is increased activity in the cluster of neurons in your brainstem — specifically a little ancient area called the pons. Within the pons there is a series of neurons releasing their specific neurotransmitters. These chemical messengers defuse from arm like projections, sending precise signals to other neurons. The net result of all this chemical chatter is the shutting down of the neurons in your spine that produce movement. Our brain wraps our muscles in restraints every night, preventing their activity.
Like a straight jacket, your brainstem prevents your limbs from flailing around as you reach your nighty destination in your mind’s dreamy landscape.
Of course, like nearly every mechanism within our fallible bodies, nothing is fool-proof. Mechanisms fail, pathways breakdown and the results can be far worse than any dream we can conjure up from the depths of our grey matter.
REM sleep behaviour disorder is one such example of how when shit goes wrong, it fails spectacularly. If something disrupts the conversation within our brainstem while it is in the process of shutting down our motor neurons, the inhibition fails, and the paralysis doesn’t stick.
We are no longer locked-in prisoners of our brain — hapless immobile limbs frozen in place.Our motor neurons are now in charge of this show and they cannot be trusted. Producing violent, hyperbolic movements we become catastrophic marionettes, doomed to act out our dreams with our motor neurons tugging blindly on the strings.
People have succumbed to this physiological failure by either gravely injuring themselves or the ones they love. Take the Welsh man who murdered his wife in 2009, while having a dream that he was battling with intruders (found HERE). Horrifyingly, his story is not unique — you can find dozens of ones quite similar all over the world.
Of course, there are occasions when our brainstem’s vise-like paralysis is too heavy handed and continues on after we have broken the surface of the water, our aching lungs gasping for air. This second failure of our clumsy brainstem will be explored in the depths of part two — which you can find HERE
“Sleep that knits up the raveled sleave of care” – Macbeth
“The death of each day’s life” – Macbeth
“I love sleep. My life has the tendency to fall apart when I’m awake, you know?” – Hemingway
Neuroscience: Exploring the Brain, Fourth edition. M. F. Bear