“Life is too short to sleep on low thread-count sheets”

The average American gets 6.8 hours of sleep on a weekday. The most recent survey by the National Sleep Foundation revealed that only 26% of Americans get 8 hours of sleep on weekdays. Seven years ago, 35% of Americans got 8 hours of sleep on weekdays. On weekends, the situation improved considerably with about 49% of them getting 8 hours or more. If today is a weekday, then 1 in 4 Americans will get 8 hours of sleep. When it comes to sleep, the odds of a good night’s sleep look awfully bleak. If you are reading this right now, you are uncluttering your mind for a tranquil pillow; everyone knows that a ruffled mind gets no sleep.

Wakefulness is controlled by the reticular activating system of the rostral braintem, which projects to the thalamus and the cortex. If you inhibit these projections, you will sleep well tonight. If you want to be able to narrate your dreams tomorrow morning, with all its permutations and combinations that you deem fit, then you’re all in for REM (Rapid Eye Movement) sleep tonight, which is generated within the tegmentum of the pons. What modulates REM? Norepinephrine and serotonin-containing neurons of the locus ceruleus and the dorsal raphe nucleus. These events are generated in the pontine reticular formation, propagate through the oculomotor and visual system during REM sleep, simultaneously with rapid eye movements. What suppresses these waves? These very same modulators, or norepinephrine and serotonin; what stimulates these waves? Cholinergic neurons. So REM sleep and that exquisite melodrama you’re about to tell, within a few hours of waking up is all dependent on the fine intricate balance of inhibitory Bad Cop Norepinephrine and Serotonin and Good Cop Acetylcholine. You better hope the cholinergic system is up and partying tonight!

Stages of sleep can be defined by an EEG or electroencephalogram and behaviourally. Sleep includes NREM (non REM sleep) and REM sleep. If you are awake, with eyes open, as I expect you to be currently, alert, with active mental concentration, then your EEG should read Beta waves, highest frequency, lowest amplitude. While you listen to your ipod, swaying side to side to soft eccentric lyrics, with your eyes closed, your beta waves now give way to alpha waves. You slowly drift away, and before you know it, the lyrics are history and you are now in stage 1 of sleep, or light sleep; your EEG now reads theta waves. Light sleep corresponds to about 5% of the total sleep time in young adults. As the sleep deepens, you enter stage 2, and the theta waves are now being replaced by sleep spindles and K complexes and here you rest for 45% of your total sleep time. We have now transitioned from stage 1 (theta) to deeper (sleep spindles and K complexes) stage 2, to stage 3-4, where you remain 25% of your entire sleep cycle and you are now in Delta zone, lowest frequency, highest amplitude. This is the deepest of all the stages. This is where you encounter sleep walkers, night terrors and bed-wetters.

Switching to REM gear, where you’re likely to stay in for 25% of your sleep cycle, this is it! You dream, you lose all motor tone, you possibly process memory. There is some evidence that procedural and declarative memory consolidation occurs during REM sleep. REM sleep time increases after task training. After episodic learning, memory consolidation is accomplished during slow wave sleep by rapid reactivation of the hippocampal neurons previously activated by the place or event to be remembered. Alternatively, it has been hypothesized that dream sleep functions as a random stimulator of the cortex to remove weak memories, and thus permit only stronger memories to be retained. This is where your brain oxygen use increases. REM sleep has a wide array of happenings from an increase and variable pulse, to variable blood pressure, penile and clitoral tumescence, occurring every ninety minutes, with increasing duration throughout the night. Acetylcholine runs the show.

Now that we’re through with correlating sleep and waves, what about disorders of sleep? Most sleep complaints fall into four categories: hypersomnia (excessive daytime sleepiness), insomnia (trouble falling or staying asleep), circadian rhythm (biological clock) disorders, and parasomnias (complex behavior arising during the sleep period). Narcolepsy, which is a disordered regulation of sleep-wake cycle often includes hypnagogic (just before sleeping) and hypnopompic ( just before awakening) hallucinations. The night starts off with REM sleep. Cataplexy or loss of all muscle tone, following strong emotional stimuli occurs in some. Hypocretins or orexins are sleep neuropeptides made in the lateral hypothalamus, with projections to the raphe nucleus, locus ceruleus and the thalamus, which modulate the release of excitatory and inhibitory neurotransmitters.  If you interrupt this pathway or become deficient, you are now narcoleptic and may require amphetamines.

Sleep disorders can be assessed with subjective tests such as a sleep diary, kept over a period of 2-3 weeks or rated on the EPWORTH sleepiness scale, where you are faced with a situation, for instance, as a passenger in a car, for an hour without a break or watching TV and you are asked about how likely you are to doze off, (would never doze off=0, slight chance of=1, moderate chance of=2, high chance of=3). Most objective tests include polysomnography, multiple sleep latency tests and actigraphy, in which a small, wrist-mounted device records activity plotted against time-usually over a period of 1 to 3 weeks. Children have growth hormone spurts when they are asleep and adults process memories in REM mode. Now, how about we get some and “grow” wiser. Good night ya all.

Cite this article as:
Rayda Aaishah Joomun, MD, "Connection between the sleep and EEG," in Medicalopedia, January 9, 2019, [Permalink: https://www.medicalopedia.org/7155/connection-between-the-sleep-and-eeg/].