Me Talk Pretty – Hypnic Jerk

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One day I will grow the Soul Train afro of my dreams.

Pre-season’s greetings my fellow information seekers! No no, I’ve missed you more. We’re shining this week’s E-Hollywood spotlight on the “hypnic jerk”. While it may sound like a funky, dance from the 70’s, it describes a far more psychedelic physiological phenomenon. Can you dig it? I knew you could.

When I first heard about the “hypnic jerk” I was…

17 years old or so, nodding off in statistics class to that dream where I’m giving my Nobel Prize speech and no one in the audience is laughing at my jokes because I’m not wearing any pants. Anyway, in the dream the floor of the stage suddenly collapsed and I fell into this bottomless pit of my subconscious. At that very moment I was in fact sliding out of my desk. My arms and legs flailed wildly, like a cat trying not to take a bath, knocking my textbooks onto the floor and waking me from my pants-less slumber. What I didn’t know then was that this phenomenon is actually experienced by many people (the falling feeling, not the no pants thing).

Hypnic Jerk

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The Mayo Clinic recommends not taking naps near the Jacuzzi.

In the movie “Inception” (kick-ass movie btw) they refer to it as “the kick,” that moment while asleep when the sudden sensation of falling jolts you awake. Most of us have experienced this at some point and the feeling is anything but pleasant. What I experienced that day in high school was actually a rare scenario of dream incorporation.

The funny thing about R.E.M. is…

You may not know this but during the surprisingly brief stage of R.E.M sleep, where all of our dreaming takes place, your body is temporarily paralyzed. It’s quite normal, and when you think about it, evolutionarily advantageous not to be able to act out your dreams. Otherwise, we would be jumping out the window every time we’re chased by zombie hordes in our sleep. In fact the only motor function that doesn’t seem to be impaired during this stage of sleep is our eye movement. This is how the R.E.M. stage or rapid eye movement gets its name.

Of course, the line separating the dream state from the waking state is notoriously blurry and it is proposed that the hypnic jerk phenomenon occurs during that awkward intermediate stage where the region of our (brain beneath the cortex) most active when we are awake intrudes on our sleepy-time region of the brain (ventrolateral preoptic nucleus, or VLPO) that manipulates our sleep. I will affectionately refer to this region of the brain as “Vilpo” that’s right,…Vilpo Baggins.

Stay with me this gets interesting…

The VLPO region of the brain is practically next door neighbors with the optic nerve (anterior of the hypothalamus). Why so close? The theory is that during the day Vilpo is busy collecting information from our eyes about light levels (time of day) and it uses this solar sense of time to direct our sleep cycle. Yeah..sounds good, but more importantly it is neurotransmitters like serotonin and adenosine that activate the VLPO. These crafty neurotransmitters accumulate throughout the day until they reach a concentration that causes us to turn in for the night. While we sleep the VLPO releases it’s own neurotransmitters that inhibit the neurons that are most active and frisky when we’re awake so that we can stop being so frisky and get some rest. So neurotransmitters encourage sleep and neurotransmitters keep us asleep.

Sleep is not passive. To sleep and to wake means that there is always some element that must actively be kept under control. 

While we are awake the VLPO is inhibited by opposing neurotransmitters. When we are awake our reticular activating system, R.A.S is awake. This region of the brain is BFF’s with the cortex, hypothalamus, and cerebellum which control basically every conscious and semi-conscious thing we do (walking, eating, SEX, etc.). So one cluster of neurons inhibits another cluster of neurons in a daily battle of sleep and wakefulness where both sides win and both sides lose.

So here’s the deal…

Hypnic jerks seem to occur as a kind of involuntary hiccup of motor control during the crossing over phase into sleep paralysis. The mechanism behind this is still poorly understood but it is the last gasp of waking motor function. It is a paradoxical, involuntary muscle reflex (Myoclonus) and it is pretty common in healthy people. We do know that these episodes can be triggered by persistent stress and anxiety, which is never good. It is also indicated that strenuous activity throughout the day can trigger an episode. It may sound paradoxical but you can actually be “too tired” to get a good night’s sleep and you can cheat your body out of its natural progression into the stages of sleep by being either too exhausted or too wired before you cut out the lights.

Let’s say you let 6 hours of YouTube videos play on your laptop while you typed up a research paper, opened 20 website browsers, and then shut your computer without shutting anything down. It may sound like a lousy way to treat your computer but we do it to our brains all the time…we don’t “go to bed” we just slam our laptops shut without “shutting down” first.

Hypnic Jerks seem to serve as a haunting reminder of the gaps in our understanding of the mechanism of sleep.

Human beings make straight lines and sharp angles. Our buildings have perfect triangles, solid walls, and mathematically proportional rectangles and squares. We believe in boundary lines and cut off points but the human brain itself, with its mosaic of soft tissue and blood vessels, is not confined by the same boundaries. You have to consider that perhaps no one portion of the brain is designated strictly to sleeping or waking but that these two states of consciousness are far more intimately connected, perhaps even dependent on each other. The phenomenon of sleep could be nothing less than an infinitely complex culmination of subtle details and relationships within the vast landscape of the brain.

Stay curious, stay classy, and never stop learning my friends 🙂

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Me Talk Pretty – Syndromes

Hello party people! I know it’s been many moons since I’ve posted an article but hey, let’s not dwell on the past. It’s bad for your complexion. In this episode of Me Talk Pretty I would like to introduce a topic that has wandered the deserts of obscurity for eons in need of clarity, and today we’re gonna make it rain. For many of us, the definition of a syndrome is as elusive as the lyrics to Tiny Dancer (hold me closer Tony Danza..I’m cold). Let’s clear a few things up shall we.

Syndrome versus Disease…FIGHT!

The classifications for diseases and syndromes are so closely related that they could be wearing the same underwear (like 100% cotton with no room to breath). There is a somewhat reliable consensus that a disease is classified as – having recognizable signs and symptoms which have a consistent anatomical or physiological effect on the body and are linked to a KNOWN CAUSE, a.ka etiologic agent. For example, Bacterial Meningitis is the inflammation of the protective layer of the brain in response to some nasty ole bacterial infection in the blood stream.

A) This disease has a known cause – playa hating bacterial infection by the bacteria Neisseria meningitidis (or any number of known pathogens)

B) This disease has a recognizable physiological effect on an organ/organ system – inflammatory response within the meninges of the brain and infiltration of cerebrospinal fluid leading to systemic central nervous system infection.

C) This disease has consistent, recognizable pattern of signs and symptoms – mind numbing headaches, neck stiffness, fever, altered mental state.

Here’s where it gets tricky…

I would like to tell you that a syndrome is distinguishable from a disease by – having recognizable signs and symptoms which have a consistent anatomical or physiological effect on the body but have NO KNOWN CAUSE. However, we know that Acquired Immunodeficiency Syndrome (AIDS) is linked to an infection with HIV (Human immunodeficiency virus) which attacks our CD4 T-cells. AIDS is classified as a syndrome because the condition has such a broad spectrum of symptoms and complications resulting from the breakdown of the immune system that it can not be classified as a single disease process. On the other hand, Carpal Tunnel Syndrome (the chronic pain and impaired functionality of the hand and wrist associated with the constriction of the medial nerve of the wrist) has a consistent pattern of symptoms and physiological effects BUT the causes of carpal tunnel are highly debatable.

So I would like to be so bold as to say that as a general rule of thumb – what makes a syndrome a syndrome is in the complicated nature of identifying a single, consistent cause for a pattern of signs and symptoms that typically appear together.

I know I know…this one is a little messy. So let’s think of it abstractly.

One afternoon I walk outside and notice that everyone is wearing bright green t-shirts, and walking in groups along the sidewalks with four leaf clovers painted on their faces, carrying mugs of bubbly green liquid. As I walk past restaurants I see lunch specials for corned beef and cabbage. Based on these signs and symptoms I immediately check the calendar (March 17th) and quickly diagnose the phenomenon as St. Patrick’s day. It has been well established that these patterns of behavior only occur together on this particular day. So based on what I’ve told you, would you classify this holiday as a disease or a syndrome?

How about this one – One afternoon I walk outside and there’s a parking ticket on my windshield. Later that day I crack the screen to my smart phone and can no longer make calls which causes me to miss a crucial text message about a party that night. Based on these signs and symptoms I immediately look at the calendar (Friday 13th) and I quickly diagnose the phenomenon as Bad luck. The association of these patterns of behavior are both poorly understood and highly debatable. If bad luck were an illness would you classify it as a disease or a syndrome? (yeah I know that’s a lousy example but humor me)

Stay curious, stay classy, and never stop learning my friends 🙂

Me Talk Pretty – Pyrexia

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Maybe you should lie down…

That’s right, it’s time for another super sexy physiology term. Pyrexia (known on the streets as a fever) is one of the most well known signs that “something ain’t right.” Here’s an obnoxiously obvious statement to start your day; the human body is all about balance. For example, our body is only really happy if it’s core temperature is maintained within roughly 36.5-37.5 C or 97.7-99.5 F. That’s a pretty tight range for a lot of metabolic processes to take place. You’ll find more leg room flying coach. We have a temperature set point that our body is practically calibrated to. When we are experiencing hypothermia or hyperthermia the temperature of the environment we are in has affected our core temperature and pushed us beyond our cozy little set point. HOWEVER, a fever occurs when something triggers the body to temporarily raise it’s set point. That “something” is typically an infection (bacterial, viral, etc.). When this happens our immune system is making a declaration of war on the offending pathogen, turning up the heat.

Fevers happen when a pyrogen (thing that triggers a fever) causes the release of potent chemical messengers (produced by our cells) called prostaglandins that work on our hypothalamus. If you recall, our hypothalamus is our brain’s team captain of homeostasis with such popular hits as hunger, thirst, hormonal control, and temperature regulation. We love the guy but probably wouldn’t invite him to hang out very often because he would want to control EVERY little thing.
On the one hand, a fever creates a less cozy temperature range for the pathogen to thrive and reproduce. It has also been shown that the activity of immune cells like neutrophils (your marines on the ground) and T-cells (CIA operatives providing intelligence on the enemy) is greatly enhanced. This is basically the fight they’ve been training for their entire, short little lives. On the other hand, raising the body’s set point takes a lot of energy. When our temperature rises the small vessels at the surface of our skin constrict to conserve heat for the sake of our core. We start to shiver, which generates heat by our muscles while demanding more energy from our already weakened body. As we begin to adjust to our new set point we get warm and sweat to cool back down, losing water and salts. It’s no suprise that you feel so wiped out after you’ve recovered from a fever. So is a fever worth all that trouble or is it simply an evolutionary relic, a souvenir of our adaptive immunity’s epic saga of trial and error? It’s interesting that such a metabolically demanding process that can often spiral out of control (reaching temps of 105 F in cases of severe infection or autoimmune response) would stay with us. Despite it’s cost or contribution to our body’s war on bio-terror, we are not the only chosen ones on this planet to get the shakes and the sweats. Many other vertebrates and invertebrates from Rottweilers to Iguanas have been shown to exhibit fever-like responses to infection. Oh yeah, pyrexia gets around and it looks like she’s here to stay.

Stay curious, stay classy, and never stop learning my friends.

 

Me Talk Pretty – Nociceptive flexion reflex (NFR)

SU11_GTY_sb10064912a-001_a_hzKnown on the streets as the withdrawal reflex, NFR refers to our body’s involuntary, ninja-quick neuromuscular response to pain. It’s our super sexy physiology term of the week and quite possibly our spiciest one yet. I even like saying it out loud (sometimes in a French accent).

Isn’t it nice to know that our body has our best interests in mind despite our worst judgment? If you’ve ever not been paying attention for a moment and let your hand stray a little too close to a hot stove (like who hasn’t) then it’s highly likely that you’ve witnessed your NFR in action. You probably yanked your hand away at what felt like the same instant you experienced pain. We perceive pain and withdraw from it simultaneously and our body does this seamlessly. If you’re the least bit skeptical just think back to that scolding hot bowl of chili con queso you dropped. YOU didn’t drop it. Your hands let go of it.

What experience could be more direct than pain? In reality, pain may not be as direct a phenomenon as you might think. When it comes to our involuntary withdrawal from pain there are at least 3 stages that occur. Once any part of your body is injured nerves in the vicinity transform that moment into a lightning quick electro-chemical signal. That signal has to take a journey from the site of the injury to the spinal chord. A new signal is sent from the spinal column to the appropriate muscles to flex and manipulate that stray body part away from the pain stimulus. Perhaps one of the reasons this process is so blindingly fast is the fact that the nerve control center in this case is the spinal chord and not the brain.

Let me set the scene…

It’s a perfect July afternoon. The grills are out. The air is saturated in honeysuckle flowers and spicy, charcoal kissed meat. You’re barefoot in the grass, loving life in your favorite shorts and a barbeque stained t-shirt. Oh yeah, you know what I’m talking about. You have a half-eaten bratwurst in one hand. Your other arm is free, innocently reaching out to grab the Frisbee that your friend just tossed to you (you crazy kids). She tossed it high. You take a step back unaware that laying in wait in the grass is a jagged piece of gravel just begging to be stepped on by bare feet. You plant your foot on the rock…

1) Tiny, branching pain receptors suspended within the epidermal layer of your heel, like tree roots, transmit an electrical signal up a long network of neuron fibers that form an intricate junction at the spinal column not unlike a downtown D.C. intersection.

2) Once the message reaches the spinal column an alpha motor neuron sends a signal back down your leg.

3) The signal from the alpha motor neuron reaches a neuromuscular junction in the hamstrings of your leg, initiating their contraction. This flexes the knee, pulling your foot off of the ground to minimize damage to the soft tissue of your foot so you can frolic in the grass another day.

Stay curious, stay classy, and never stop learning my friends 🙂

Me Talk Pretty-blood brain barrier

Hello! No, you look great today.

This week’s super sexy, fancy pants physiology term is…

Blood brain barrier

Every organ in your body is supplied in some fashion with blood. Yes, I know I haven’t said anything too shocking yet. However, as far as
the body is concerned the brain is like Queen Mother and requires the extracellular fluid (fluid without the cells) to be separated from the circulating whole blood by a royal guard of specialized endothelial cells. Just like I pointed out in another article, True Blood, blood is a pretty wild mixture and not everything in that mixture is useful or even safe for the precious, fine tuned neurons of the Central Nervous System (CNS). A network of painfully tiny capillaries form an intricate spider web mesh that filters out big nasty things (microscopically speaking) like bacterial cells, microscopic fungi, and cellular debris as well as large hydrophyllic molecules like proteins, and a buffet of potentially bad news chemical compounds.
The Blood Brain Barrier has the mad skills to allow vital compounds like CO2 and O2 to slip through while actively transporting (uses membrane protein channels) glucose, hormones, and amino acids. Remember that the blood vessels of the body have elastic qualities and those vessel walls become more permeable (leaky) during inflammation.
When doctor’s perform spinal taps, drawing up CSF (cerebrospinal fluid) from within the patients spinal column with a syringe, the
fluid tells a story. In healthy patients spinal fluid should be a ghost town…clear, colorless, and devoid of red cells, white cells, and just about everything else. Patients with active infections of their CNS may show white cells, red cells, increased protein, glucose (like in Tuberculosis cases) and discoloration of the fluid sample. The inflammation or infection in that case has overwhelmed the BBB’s ability to filter. Sometimes you truly understand the value of a thing when it stops working.

Stay curious, stay classy, and never stop learning my friends 🙂

 

Me talk pretty – Vestibulo-ocular reflex

Hello and welcome to the first segment of “me talk pretty” where I bring you tongue twisting terms from the most remote corners of physiology. This week’s super sexy, fancy-pants physio term is….

“Vestibulo-ocular reflex (VOR)”

This is a highly adapted eye reflex in humans that keeps images fixed or stablized on the retina (in the center of your visual field) by allowing the eyes to move in the opposite direction of head movement like a compass needle that points to magnetic north no matter how much the ship tosses on the waves. Your VOR is incredibly fast (fraction of a second) and it needs to be in order to compensate for even the most subtle head rotation along an axial plane (vertical, horizontal, or diagonal). It is what makes clear vision possible. If you were a catcher for the Yankees and your VOR were a fraction of a second off you would be grabbing for blurry fast balls at 90+ mph, but hey, who wants to live forever? (No one should be grabbing for blurry balls) So the next time you’re trying to read your Vanity Fair magazine on a Chinatown bus with bad suspension, finish a sudoku puzzle on a plane while someone’s devil spawned child is throwing a fit and kicking the back of the seat, or just trying to check out the fit brunette jogging by out of the corner of your eye, remember to thank your VOR for keeping that image nice and clear.