Recipe for a mad scientist – lab coat, rats, electricity

I spent some time as an undergrad in the University of Washington’s Department of Physiology and Biophysics conducting research on rats with incomplete spinal cord injuries.

Before I describe my experience, I’d like to explain some of the background for the study. My PI (principle investigator or “guy who runs the show”) was interested in a concept called Hebbian Plasticity.  This whole concept is a rather simple one, basically stating that the more times you use a certain neural pathway, the more “solid” it becomes. This theory is used to describe a dynamic concept in which neurons can adapt to repeated stimuli and “learn”.  You hear about “the science of neuroplasticity” on those Luminosity commercials, and I find it rather silly because it isn’t necessarily new science, it’s just learning by repetition – a concept we are all familiar with. Maybe some of you will disagree, but I recommend you save the money for something more fun. I digress. An important piece of Hebbian Plasticity is the timing of the signals. It is not enough to simply have neuron B receive a signal from neuron A to induce Hebbian Plasticity. If my memory serves me right, the appropriate window of time is between 20-50 milliseconds, outside of this window, a connection between A and B wouldn’t be any more solidified than if it were some random signal coming in from A two days later.  Keep this information in mind as I describe the research we did in the lab.

The research begins with a rat that is trained to reach through a slit to grab a pellet of food from a block with her arm and eat the pellet like an apple. This is a fun thing to do because we’re so used to seeing rats stuff their faces in to their food, but it does take quite a bit of time to train the rats to learn this behavior. The rats are given a score based on their performance in grabbing these pellets and once the rats are trained sufficiently, they are given a lesion on their spinal cord that considerably limits the use of the arm that was used for reaching.

After the rat is injured, it is allowed to heal and then a second, rather massive surgery is performed. A series of microelectrodes is placed into the spinal cord just below the lesion, wires are inserted into the forearm, biceps, and triceps of the affected arm, and a computer chip is attached to the skull of the rat, like some sort of morbid hat.

The wires in the arm of the rat are for EMG recordings, or recordings that gather electrical information every time the rat is able to use these muscles, indicating the rat is choosing to reach, even though it is severely limited because of the spinal cord injury.  The EMG signal is then sent to the computer chip on the rat’s skull, which relays the signal to a brain computer interface (bigger chip AKA neurochip) that will wait about 20 milliseconds to send a signal to the spinal cord electrodes. The microelectrodes in the spinal cord then send the signal down the normal pathway that the rat uses for reaching motion in efforts to strengthen the remaining neural pathways that weren’t damaged by the lesion. In essence, the neurochip tries to pick up the signal that was interrupted by the lesion on the spinal cord and sends that signal to the remaining pathways that extend past the lesion. Also, the signal that is sent down from the neurochip is not a signal strong enough to actually cause a muscle twitch. We call that being “below threshold.” We did this to make sure that the results we were seeing were not simply due to the magnitude of the electricity and to make sure we weren’t masking any real long-term progress or hindering any opportunities for true plasticity.

According to the theory of Hebbian Plasticity, if this signal is propagated properly in the right time window, we can increase the functional output from these remaining neurons and we can get a net result very similar to the result that would have been the case if the injury had never happened. Of course this is in the ideal theoretical world.

In my experience in the lab, I was lucky to be around long enough to see some preliminary results. The initial results were promising, showing an increase in the rats’ reaching scores when they received stimulation as opposed to the rats that did not receive stimulation.  

Like any study, this study has its limitations, but it was exciting for me because medicine seems to be pretty behind in terms of advancements for people with spinal cord injuries and other central nervous system traumas. People who live with spinal cord injuries have a set of problems that most uninjured people could never truly understand. I’ve heard people who were wheelchair bound just wish to have voluntary control of their bladder again. Or be able to make love. Regardless, if anyone is interested in central nervous system research, I really think it’s an area with plenty of potential for profound breakthroughs. I’m convinced that in ten years we will have some very sophisticated technologies available to us that have academic roots in the type of research I was able to do at UW and that you can be a part of too.

Deep within: The Role of Adenosine in GAD Symptoms

Deep within: The Role of Adenosine in GAD Symptoms

            According to the National Institute of Mental Health (NIMH), about 40 million Americans suffer from serious anxiety disorders. While there are many different anxiety disorders, each with its own set of symptoms, I’m going to focus on Generalized Anxiety Disorder (GAD; for several reasons, not the least of which is my close relationships with several of these 18% of Americans). There are many symptoms of GAD (including its hallmark symptom, constant worrying); however, in the interest of not writing a novel, I would like to focus two of these symptoms: fatigue and restlessness.

            If you have GAD, having both symptoms probably seems quite natural—you worry about everything all the time and you are, therefore, exhausted. However, for outsiders looking in, these symptoms may seem self-contradictory: how can someone be both amped up (restless) and tired at the same time?

            There are probably many ways to explain these symptoms, because many, many neurotransmitters are involved in creating the symptoms (especially the restlessness) that come with GAD. But, adenosine happens to relate to both symptoms; consequently, I am going to focus on this chemical. Adenosine is a diverse chemical—it is the precursor of adenine, it can be phosphorylated (twice) to make ATP, it is a product of hydrolysis as ATP (and then ADP) are used to make energy (which makes adenosine a good measurement of metabolism). Although it has many roles in the body, its most relevant job for our purposes is its role as a neurotransmitter.  

            Just as adenosine has diverse roles in the body, it also has diverse roles as a neurotransmitter. Research has shown that the effects of adenosine depend on where in the brain the adenosine acts. According to Ruby, Adams, Mrazek, and Choi in a meta-analysis of adenosine’s role in anxiety disorders, a deficiency of one of the adenosine receptors (the A_2A receptor) has been associated with anxiety in mice (2011). The researchers report that inhibiting one of the adenosine receptors can cause hyperactivity in the part of the brain that mediates stress response (the hypothalamic-pituitary-adrenal, or HPA, axis). Thereby, this action of adenosine deficiency in the HPA leads to a stress response that is always on (in terms of Why Zebras Don’t Get Ulcers, this would be the equivalent of the brain telling the body that you are always being chased by a saber-tooth tiger).

            So, that helps explain the restlessness—but what about the fatigue? It also turns out that, since it is a product of hydrolysis, adenosine accumulates throughout the day as your body breaks ATP into ADP, then into adenosine. This adenosine that accumulates throughout the day then binds to another kind of receptor (A₁) in the basal forebrain. This accumulation, then binding, causes drowsiness (Basheer, Strecker, Thakkar, & McCarley, 2004).

            In sum, adenosine binding to different receptors in different parts of the brain is one (although there are probably many) of the biological explanations of why people with GAD often feel amped up and dragged down at the same time.

References:

Basheer, R., Strecker, R. E., Thakkar, M. M., & McCarley, R. W. (2004). Adenosine and sleep-wake regulation [Abstract]. Progress in Neurobiology, 73, 379-396. doi: 10.1016/j.pneurobio.2004.06.004

National Institute of Mental Health. The numbers count: Mental disorders in America. Retrieved from: http://www.nimh.nih.gov/health/publications/the-numbers-count-mental-disorders-in-america/index.shtml

Ruby, C. L., Adams, C. A., Mrazek, D. A., & Choi, D. (2011). Adenosine signaling in anxiety. Anxiety Disorders, Vladimir Kalini (Ed.). Retrieved from: http://cdn.intechopen.com/pdfs/17570/InTech-Adenosine_signaling_in_anxiety.pdf

Five More Minutes Mom: Just About Everything Known About Sleep

Now that school is back in session you may be having a hard time waking up and find yourself leaning over to hit that snooze button once or twice like I do.  Since many of you are logging on for the first time to make sure that you are in the right blog, I thought I would throw up a second post for everyone to read. This post may be !!!!A LOT!!!! longer than the recommended length of most blogs found here, but I could not sleep last night and did some research on why I hit the snooze button five times every morning and now that I am a little bit sleep deprived I thought I would post just about everything that I found out.  If it makes you fall a sleep, maybe that is a good thing.  It starts off with a little bit of imagination. 

Imagine a time long before alarm clocks, a time where man still woke with the clock-a-doodle-do from a rooster call. I can see that man rolling over in the early morning, a little earlier than he would have wished as beams of sunlight were only thinking of crossing the horizon. Grasping for the stone just a little smaller than the size of his fist that he had methodically placed next to the spot of his slumber the night before and curving that stone right at the head of his rooster with the aim of a professional baseball player. Bang! The cries of morning glory that the rooster’s song so ungracefully pierced the atmosphere with ceases and a few more minutes of shut eye are able to be had. As time passes, the rooster, with consciousness slowly percolating back, clears its throat in preparation for its next verse and screams its song once again, the man is woken, but with that revered extra ten minutes of sleep. The snooze button is born.  

As I systematically scoured the internet for information on the snooze button I was a bit surprised to find very little information devoted to it, it seemed that there were more FarSide cartoon stills on the matter than scientific inquiries. A realization came over me that in order to understand why I use the snooze button three times a day, I would have to understand all aspects of sleep.  I figured I would start where the problem begins, with an alarm going off. 

According to Alarm Clocks and Lost Productivity (2005) the very first alarm clocks are credited to the ancient Greeks who had modified a water tank with a whistle, as water draining from the tank reached a certain level it would trigger the whistle to blow. The invention of more modern clocks, one that wouldn’t spring a leak and worked through cooperating mechanical gears would not come along until the 14^th century. The first clocks that could actually fit into a house were not developed until 1620 in the German village of Nuremburg, these clocks even had alarm mechanisms that were capable of sounding an alarm every twelve hours (History of Alarm Clocks 2007).

 
Finding out where the snooze button fit within this historical timeline of clocks came with a surprising answer, Ben-Hur. So Ben-Hur is not technically the right answer here, however according to Alarm Clocks and Lost Productivity (2005) the author of Ben-Hur, Lew Wallace, beyond his fame of writing the fore mentioned prolonged agony, earning the rank of Brigadier General during the Civil War, becoming a lawyer, holding a seat on the Senate as well as serving as Governor, is also credited with the invention of the snooze button sometime in the late 19^th century (Lew Wallace Wikepedia 2013), apparently the first man to snooze did not lose. However there is little information out there that would explain the workings of this original reset button, which I found to be "alarming." When the alarm as we know it today was first slammed with a sleepy fist several times in hopes of hitting the snooze button and not accidentally turning off the alarm first came in 1956 and was marketed by General Electric (It’s Alarming 2011).

 After the above history lesson, I thought I would get a quick census of what people think about the snooze button and where else would I turn than the blogging world. According to the most up to date and relevant online blogging sites the snooze button gets some mixed reviews. On one cutting edge blog site known simply as Discuz (“How Often Do You Hit the Snooze Button 2011), an author who identifies herself as Amy and uses an anonymous default white figure of a head with an orange background asserts, “I blame the snooze button for all life’s problems. I would love to meet the guy who invented it. I would kick him, wait four minutes and then kick him again.” Contrasting Amy’s hatred of the snooze button is the blogging conversation available at Yahoo answers, where Sharon, using her japanimation character of a young girl, tweets in to start a blogging session with, “Do you think it feels sooooo darn good to hit the snooze button???? I do….I love it. Just wanted to say that (Snooze Button 2011).” It appears that she is not alone because she is quickly answered by another user, jessp who is also using a japanimation character that responds, “OMG…OF COURSE!! It’s the best feeling ever…to get just those few minutes of extra sleep…its blisss….(Snooze Button Response 2011)” 
  
The unedited and apparently often abbreviated writings of the blog sites led me to think that some blogging posts are not the best scholarly sources (except for this one of course), so I turned my attention towards what actual experts on the matter might think about the snooze button, and like clockwork I quickly found my answer. As it turns out hitting the snooze button might just do more harm than good. An article in the Professional Safety Journal (2009) on sleep reports that the nine to ten minutes of sleep that a person gets after hitting the snooze button is not enough to reach REM sleep and that “the sleeper may be adding to his/her level of sleep debt instead of getting more solid snoozing.”  REM is an abbreviation of rapid eye movement sleep, and is the only stage of the sleep cycle where we dream, it accounts for about 20 – 25 percent a typical night’s sleep (“Rem Sleep,” Wikipedia 2013). 

Trying to find out what constitutes a sleep cycle I found an article through HelpGuide.com that explained the sleep cycle consists of five sleep stages that progress towards the final stage of REM sleep (Smith and Segal 2010). The first stage is transitioning into sleep characterized by slow eye movement, this is when you will wake up with the smallest amount of noise. The cycle continues into light sleep where eye movement stops, body temperature decreases, and heart rate slows, from this point most people will transition into deep sleep within 25 minutes. When a person goes into deep sleep they are very difficult to wake up, and will be slightly disoriented if they are awoken. The fourth stage is a more intense version of deep sleep where brain waves slow dramatically with blood flow is diverted from the brain and sent to the muscles to restore energy. On average people will enter the final stage of REM sleep 70 to 90 minutes after first falling asleep, although people can enter into REM sleep sooner if they are sleep deprived. REM sleep is where a person’s eyes will move very rapidly, their breathing will become extremely shallow, heart rate and blood pressure increase, and the arms and legs will become paralyzed (Smith and Segal 2010). While a person sleeps they are continually rotating through the cycles and that on average a person cycles into REM sleep about five times per eight hour period of sleep.
  
As I continued peering into sources I started searching for answers about why we actually sleep. I came to find out that not much is known about why we actually sleep and the experts are still sleeping on it. A recent article from Harvard Medical School Sleep Division (2008) explains that it might just be an unanswerable question, but some theories have been developed. One of the first theories developed is known as the inactive theory and took an evolutionary standpoint that asserted it would have been beneficial for us to sleep while it was dark ensuring that we would be still and quiet as to not attract things that go bump in the night.  Another theory explains that we sleep in order to conserve energy, research does show that metabolism is substantially reduced while sleeping. The restorative theory explains that we sleep in order to rejuvenate what we lose and conversely break down what we produce while awake. Things like “muscle growth, tissue repair, protein synthesis, and growth hormone release occur mostly, or in some cases only, during sleep (Why Do We Sleep Anyway? 2011).” 


Current experimentation being performed by Griffith and Rosbash (2008) suggest that sleep increases homeostatic control of synapse strength. Figuratively speaking every time a nerve or neuron fires it shoots a bullet, those bullets are neurotransmitters made up of synaptic proteins, so sleeping serves to reload the bullets. The more activity going on in the brain, the more the neurotransmitters need to be replenished, this explains why babies who are learning and making so many new connections within their brain need so much sleep. In order to keep the correct number of neurotransmitters available, also known as homeostatic plasticity, it is believed that our bodies measure the amount of Adenosine present within the brain (Griffith and Rosbach 2008), a substance that increases in concentration the longer we stay awake and induce feelings of tiredness. Subsequently caffeine and some other drugs are adenosine blockers, and by drinking caffeine you are blocking the receptors that measure the increase in adenosine, eliminating the symptoms of feeling tired.






After knowing as much as the experts on why we sleep, which is like saying, “I’m not entirely sure why,” I became interested in just how much sleep we need and shifted my research. Is eight hours enough sleep for most of us? Information from the National Sleep Foundation (How Much Sleep Do We Really Need 2011) recommends that most of us should really go to bed a little earlier than we do and the following amount of sleep is suggested depending upon age. Newborn babies up to the age of two months should have between 12 and 18 hours of sleep.  Infants younger than a year need an average of about 14.5 hours of sleep. Children up to the age of three should be getting close to 13 hours of sleep and preschoolers up to the age of five need about 12 hours. Elementary school children under the age of 10 are recommended to have between 10 and 11 hours. Preteens and teenagers should be getting on average nine hours of sleep and healthy adults should be turning in for anywhere between seven and nine hours of sleep. Knowing that I usually do not meet these guidelines I became interested in what happens when you don’t get enough sleep. 
  
While some people may be able to get away with less sleep than others, health-and-sleeptracks.com (7 Signs and Symptoms of Sleep Deprivation 2010) has developed seven signs of sleep deprivation that include, feeling tired during meetings, lectures, or driving, feelings of moodiness and irritability, needing an alarm clock to wake up and repeatedly hitting the snooze button, sleeping longer on the weekends, taking naps every day, the formation of dark circles or bags under your eyes. Well these criteria may not sound like such a big deal, research has shown that lack of sleep may cause, headaches, increased blood pressure, increased risk of developing diabetes, obesity, poor immune system functioning, lower levels of cognitive functioning, memory loss, and in the most extreme cases death (Brody 2007). 

During my research on understanding how much sleep that we need I came across a few articles that explained some alternative sleep patterns that have been used by several famous people. Leonardo Da Vinci, Benjamin Franklin, Thomas Edison, and Albert Einstein, four people who collectively developed and created ideas and inventions that have been the most relevant towards shaping our modern world, all had one thing in common, their sleep routine. The American Chronicle (Bisnar 2009) explains this sleep routine is known by several different names, polyphasic sleep, the Da Vinci sleep cycle, or the sleep of genius. A polyphasic sleep routine consists of taking 20 minute naps every four hours throughout a 24 hour period. When you do the math this accounts for about two hours of sleep, leaving 22 hours of wake time to be productive. If you are wondering if a person could be productive on so little sleep, just take a look at the accomplishments of the fore mentioned individuals and if that’s not enough it also explained through sleep science. 

A person who sleeps eight hours through the course of the night moves through the sleep cycle five times, receiving close to 30 minutes of REM sleep for each cycle, totaling about one and a half hours of REM sleep.  During polyphasic sleep, it is thought the body is able to adjust and go directly from stage one sleep into REM sleep, eliminating the other stages of what could be considered nonproductive sleep (Bisnar2009).  During a traditional sleep pattern of eight hours a night, REM sleep only accounts for 20 percent of sleep, polyphasic sleep induces REM sleep almost exclusively and REM sleep accounts for close to 100 percent of sleep, totaling close to two hours of REM sleep.  In an article appearing in the Washington Post, Dr. Stampi, a circadian physiologist warns that this sleep strategy is not for everyone and it can take two to three weeks for the body to adjust (Mallin 1990). However he also explains that subjects that have followed the routine closely do not show symptoms of sleep deprivation, but do lose the ability to dream and often feel very unsociable mainly due to simply not being on the same schedule as society.
  
On a final note, during the last stages of my research I came across an article that made me yawn and I wondered why that was. Like other mysteries surrounding some of the fundamentals of sleep, the truth behind yawns is still not fully understood. According to Dr. Barry Make (Little Mystery: Why Do We Yawn 1998) medical students are taught that we yawn because oxygen levels in our lungs are low, and that no correlation between tiredness and yawning exists.  Since normal respiration rarely completely fills our lungs with air, yawning helps to expand our lungs and to be sure that our entire lung become filled with air every once in a while so those portions of the lung not do not partially collapse. Other theories focus on a yawn helping regulate the temperature of the brain or equalizing pressure in the middle ear, while some theories just conclude that it is a residual effect of a past primitive instinct that no longer serves a purpose (9 minutes to snooze 2009). What is known is only socially aware animals yawn, which includes most vertebrate species including fish, birds, cats, dogs, chimpanzees, and humans. As for the contagious factor of yawning, children under the age of two as well as most children with autism (Little Mystery 1998) lack the contagious yawning response.  Like so many other aspects of sleep, the yawn has remained a mystery and scientist will continue to sleep on the answer, hit the snooze button and sleep some more.

Works Cited

“7 Signs and Symptoms of Sleep Deprivation.” SleepTracks.org.2010.

“9 Minutes To Snooze.” Professional Safety. 54.11 Nov. 2009: 48.

“Alarm Clocks and Lost Productivity (or How I Can’t Get No Satisfaction).” TheBlueSmokeBand.com. March 2005.

Amy. “How Often Do You Use the Snooze Button??” Discuz.Online posting. 11 Jan. 2011.

Bisnar, John. “Napping in the New year-The Da Vinci Sleep Cycle.” The American Chronicle. 14 Jan. 2009. LexisNexis Academic.

Brody, Jane E. “At Every Age, Feeling the Effects of Too Little Sleep” The New York Times. 23 Oct. 2007.

Griffith, Leslie C., Rosbash, Michael. “Sleep: Hitting the Reset Button.” Nature Neuroscience. 11.2 (Feb. 2008): 123-124. Academic Search Premier. 

“History of the Alarm Clock.” ClockHistory.com. 2007

“How Much Sleep Do We Really Need?” NationalSleepFoundation.org. 2011.

Jessp. “Snooze Button?” Weblog Post. Answers.Yahoo.com.

“Lew Wallace.” Wikipedia: The Free Encyclopedia. Wikimedia Foundation, Inc. 18 Mar. 20011.

“Little Mystery: Why Do We Yawn?” msnbc.msn.com. 15 Oct. 1998.

Mallin, Jay. “Sleep of Future: 15-Minute Naps.” The Washington Post. 6 July 1990: B7. 

McClelland, Cynthia A. “It’s Alarming.” Wamware.com. 2003-2011.

“Rapid Eye Movement Sleep.” Wikipedia: The Free Encyclopedia. Wikimedia Foundation, Inc. 16 Mar. 20011.

 

Sharon. “Snooze Button?” Weblog Post. Answers.Yahoo.com.

Smith, Melinda M.D., Segal, Robert M.A., “How Much Sleep Do You Need?” 2001-2010. HelpGuide.org. July 2010.

Jessp. “Snooze Button?” Weblog Post. Answers.Yahoo.com. Web. 18 Mar. 2011.

“Snooze Button?” Comment on Weblog Post of Snooze Button. Answers.Yahoo.com. Web. 18 Mar. 2011.

“Why Do We Sleep, Anyway?” HealthySleep.med.Harvard.edu. President and Fellows of Harvard College. 2008. Web. 18 Mar. 2011.