At the Gates of Sleep

497736998_45c09a136e_oNow that my daughter is about to reach her first birthday, I’m in the mood to reflect on the year that just passed. Unfortunately, my recollections of it are a little fuzzy, probably because I can count on one hand the number of times I’ve enjoyed a good night’s sleep over the past year. Some people have babies who regularly sleep through the night and I am happy for them. Truly, I am. But clearly I was not meant to be in their ranks.

Still, the never-ending parade of nighttime awakenings has taught me something about my own brain. It is precisely tuned to hear my baby. Although I sleep blithely through my husband’s thunderous snoring and the loud buzz of his alarm clock – multiple times a day, thanks to the snooze button – I awaken at the faintest sound of my daughter’s sighs, coos, or grumbles. When she cries, I am immediately awake while my husband sleeps on beside me, undisturbed.

People are generally able to sleep through minor sounds and sensations thanks to a subcortical structure in the brain called the thalamus. This structure receives incoming signals from our senses and relays them to cortical areas devoted to processing sensory information like sounds or tactile sensations. When we’re awake, the thalamus faithfully relays nearly every sensory signal on to the cortex. But when we’re asleep, neurons in the thalamus participate in strong, synchronized waves of activity that squelch incoming signals. As a result, about 70% of these signals never make it to the cortex. This process, known as sensory-gating, is how we manage to sleep through the roar of rainstorms or the brush of the sheets against our skin each time we turn in bed. It is also how we sleep through our husband’s room-rattling snores.

Yet some sensory information does get through to the rest of the brain during sleep. These signals do get processed and can even wake us up if they are either intense (like a loud noise) or personally relevant. A clever study illustrated the importance of personal relevance by exposing sleeping subjects to a loud presentation (via tape recorder) of their own name spoken aloud. The scientists played the recording either normally or backwards and found that subjects awoke in less than half the time when they heard their names presented in the recognizable form.

So did my daughter, in effect, sleep train me by training my brain to recognize her sounds as personally relevant? It’s a plausible explanation, but one that is ultimately lacking. It cannot explain that first night when I slept beside my baby at the hospital nearly one year ago. Although I had labored through the entire night before and had not slept in the ensuing day, I awoke constantly to every little sound my mewing newborn made, not to mention the cries that told me she wanted to nurse. She’d had no time to train me; I had come pre-trained. Just as my breasts were primed to make milk for her, my brain was primed to wake for her. We seemed to be engineered for one other, mother and child, body and brain. And we spent that first long night discovering how clever a designer Nature can be, while my husband slept peacefully on the couch.

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Photo credit: planetchopstick

Daily Death, Part 2

I’ve blogged about sleep before, specifically how I didn’t get any and how sleep is a very strange phenomenon when examined closely. Now, in Part 2, I write about sleep from a different perspective: that of someone who gets enough.

Everyone knows sleep is important. Neuroscience research has shown that sleep allows the ‘replaying’ of neural activity that took place during wakefulness, strengthening pathways relevant to the prior day’s events. And a plethora of psychology experiments have shown that the human capacity for learning and memory goes down the toilet when people are sleep deprived.  A recent medical study has added evidence to the claim that sleep deprivation hampers our immune response.

When I worked as a neuroscience researcher, I averaged about five hours of sleep. Sometimes it was as little as three. My lack of sleep was caused by a combination of busyness and stress. Now that I write full time, I get seven or eight hours of sleep pretty much every night. Since then, I’ve noticed a dramatic change in my cognitive abilities, but the changes are different for logical and creative thought.

The clarity with which I can reason and attend have improved substantially since I started spending quality time with my bed. No longer do I listen to the end of someone’s sentence and realize I’ve forgotten how the sentence began. (Yes, after really sleepless nights that could happen.)

The effect of sleep on creative writing has a subjectively different feel. Some writers feel that they are most creative when they are half-asleep or when they’ve just awoken (see this essay by one of them.) My writing teacher describes his routine of waking at dawn and immediately writing by candlelight. He doesn’t wear his glasses because he doesn’t want to read the words, just let them flow. He claims that his best lines and descriptions come from those sessions.

I’ve tried a few times to do the same thing and have come up with fun lines myself. My favorite so far is, “a helicopter julienned the morning sky.” When I was sleep deprived and drowsy all day, I found it easier to come up with creative uses of language. Now, as a well-slept gal, I find it easier to explore larger-scale situational, plot, and character issues, but harder to toy with words. What to do? What to do?

As with mental illness, the unhinged-ness of the drowsy mind may give artists greater flexibility and inventiveness with language, metaphor, and description. A rare upside to sleep deprivation? Maybe. But for me it was small consolation for having to ask people, “how did that sentence begin?”

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