It’s still 1927, sometimes: Women in Science

What is unique about the picture taken in 1927 at the Solvay Conference: a gathering of the elite physicists and chemists of the time?

This is the gender diversity of most faculty departments, even ones close to home


Close up

There’s one lone female. In 1927, that was impressive, but if you look a many group photos from university departments in science, math, and engineering today, there is likely to be just one female for the same number of people as the 1927 Solvay Conference. Now that is pathetic.

Eleanor Roosevelt and Marilyn Monroe often said that “well behaved women rarely make history.” It’s true, even in an academic setting. Fortunately, academic departments make it easy for women to be viewed as misbehaved or notable. Often times, if I consider alternative interpretations and approaches from senior scientists, I’m viewed as “lacking in confidence ,” but if I become overly passionate about an issue and don’t change my opinion after hearing alternative viewpoints, “I’m being defensive.”

Some of the more ludicrous commentary that I have heard about from female colleagues is being begged by administration to not have children so as not to increase risks for postpartum depression.

And then of course there is sexual misconduct. One world-renowned neuroscientist made himself “Instagram/Twitter/Facebook famous” at the Society for Neuroscience annual meeting in NOLA in 2012 by lamenting about the lack of attractive females at the meeting. It may had been the booze and easy access to prostitution talking or the fact that we shared the convention center with a boating trade show, but still. A recent report in PLoS found that at least 50% of women encounter some form of sexual harassment, verbal or physical, at some point in their professional career.

Now how can we overcome?  My colleague and mentor of mine, Dr. Jenny Marcinkiewicz, who has served on STEM- and women in science-related tasks forces recommends the following, “We can educate both our male and female colleagues about the dangers and inequity of unconscious bias. We can continue to fund ADVANCE grants from NSF that work to advance the careers of women in science. We can push to create women’s taskforce groups that identify actions to be taken and then make sure these are implemented. IMHO, asking women to work harder and stop making excuses is part of the problem, not part of the solution. It serves to drive capable women out of the sciences. Last, but not least, postpartum depression is not a choice and cannot be solved by simply willing ourselves out of it or working ourselves out of it.”

Vampire Diaries: Tales of Sleep

Blood is making a comeback in neuroscience and psychology research. Centuries ago, Galen thought that personality and behavior were governed by the four “humors” with blood being one of them. A few months ago, blood gained some credibility in neuroscience when a study published in Nature found that the donation of blood collected from a young mouse to an old mouse forestalled neurodegeneration while donation of blood collected from an old mouse to a young mouse accelerated neurodegenetaion. Read the full details in this blog post.

ResearchBlogging.orgAs for how the blood may carry sleep-promoting factors that cross the brain and act on sleep regulatory areas, there may be a few. Recently, researchers at UPENN have undertaken an extensive study where they collected the blood from individuals sensitive or resistant to sleep deprivation. The researchers deprived the subjects of sleep for 38 hours and figured out just how sensitive or resistant the subjects were to sleep deprivation through a simple, reliable test of mental alertness and lapses: the psychomotor vigilance test. Performance on the PVT was compared against the blood genome of these individuals. The results were striking in that it pointed out that most of the genes were more sensitive to time-of-day, a circadian effect, rather than the environment challenge of sleep deprivation, a homeostatic effect. Separating circadian and homeostatic influences on daily sleep amounts is a constant struggle. In this study, the researchers were able to identify circadian vs. homeostatic influences without even controlling for these processes through a unique protocol called forced desynchrony. There were two genes that showed sensitivity to sleep loss in that their gene expression increased across a protocol of sleep deprivation, but for the most part, the genes peaked in the mid-night or mid-day which conveniently correspond with biologically driven dips in core body temperature. However, the rhythms of this waxing and waning of gene expression was dampened in the lucky bastards who are resistant to changes in mental performance with sleep deprivation.

And so while this study has narrowed down some possibilities, the quest for a single, peripheral regulator of sleep centers in the brain continues. Hopefully I am the first to find it.

Vampire Diaries is a bore

Arnardottir, E., Nikonova, E., Shockley, K., Podtelezhnikov, A., Anafi, R., Tanis, K., Maislin, G., Stone, D., Renger, J., Winrow, C., & Pack, A. (2014). Blood-Gene Expression Reveals Reduced Circadian Rhythmicity in Individuals Resistant to Sleep Deprivation SLEEP DOI: 10.5665/sleep.4064

Sleep Position Matters.

Today, I got a deep tissue massage in an attempt to accelerate recovery from the Pensacola Beach Brawl. It is no surprise that I favor my right side; it is my dominant side. Even so, my massage therapist provided some insight that is so obvious yet so neglected and likely explains my long-term aches and pain on my right side; I may be sleeping wrong. Duh! If you are like me who needs lots of restorative, deep sleep in an attempt to recovery for a hard day of training, then your body doesn’t really care what position it sleeps in because it is too busy getting this restorative, deep sleep. Therefore, we have to prepare our bodies to sleep in a healthy position before we sleep and are immobile for nearly 8 hours. Fortunately, Kelly Starrett, pioneer of mobility WOD, has addressed this:

Pensacola Beach Brawl: Pain in the Sun, Sand, and Surf

It’s time for some self promotion mixed with science. Sorry. This weekend, I competed in the Pensacola Beach Brawl which also presented me with the opportunity to compete in my first (Crossfit-style) triathlon. Sure, we swam (and saw a bull shark on the pier the morning of the swim), but then we sat on a stationary bike to be one with our thoughts, a remarkable view of the Gulf coast, and the dinging of the bike in an attempt to forget how few calories we had biked and how much further we had to go: 150 calories in total. From there, we hopped over a small wall and began the worst part of the tri; a seemingly endless run for a mile in the soft sand that is difficult to walk in let alone run in. It really jacked up our heart rates.

And we are off

Kill Em

The final push

I finished 5th overall which I was extremely happy with because it was my first legitimate ocean swim.

After a night of recovery, it was on to a standard Crossfit competition on Saturday. Unlike most Crossfit competitions in Georgia, this was outdoors. The rain even held off for us. Not only did I tie my current PRs for my Olympic lifts (clean and snatch), but I did really well in the metabolic conditioning workouts that tested our latencies to forearms and bicep fatigue as well as how much pain we could handle after a long, enduring weekend. We also had to NFL combine style testers; max bench press reps at bodyweight and the standing broad jump. I would have been embarrassed if I didn’t place top three in the broad jump. Luckily, I did place first, helping secure a 6th place overall finish for the weekend.

New hang snatch PR

Tie of clean PR

Thrusters to start


Deep concentration

The last workout

On Sunday, I was part of a local Georgia team from Crossfit Perimeter. The workouts were seriously modified due to the poor weather but honestly, I was thankful. We took full advantage of the beach by doing a mile run as a team as well as dragging an #80 sled 125 m each. It was nasty. Like most heavy, longer sled pulls, it is best to go slow and steady instead of going “all out.” Once your body switches over to fat metabolism, there is a serious compromise in power. This decline in power usually results from giving 100% effort in the beginning because you burn through your creatine and glucose reserves quickly.

Quad Squad

Overall, I had a fantastically grueling yet entertaining weekend competing, laughing, and hanging out with fellow Southeast athletes. Much thanks to the continued support of Boxstalker and Pure Strength –as we continue our journey to the podium in the 2015 Reebok Crossfit Games. The Pure Strength rig at the competition was awesome. And now it is back to lab bench.

The elite ladies

Panda Rage

In case you didn't know

History of Sleep by the Father of Sleep, Himself

Last week, my undergraduate advisor, Dr. Mary Carskadon, who could arguably be called the “mother of sleep” given her long-standing contributions as a female scientist, sent me the following article.

The article is about the life’s work of William C. Dement who many regard as the “father of sleep medicine.” I won’t spoil the contents of the article, but Dr. Dement should be any scientists’ idol, not just for those who study sleep. He has done basic science, translational science, clinical science, and is one of the most effective advocates for funding. Believe me, his numerous stories about trips to Capitol Hill are very humorous and could make for their own memoir. I first met Dr. Dement during the summer of my junior year (of college) as a Dement Fellow in Dr. Carskadon’s laboratory at Brown University. The advice he parted about the history of our field, doing science, and being a scientist have stuck with me today. I have passed along many of his stories and experiences to my own students at Morehouse College. So please, read Dr. Dement’s story. It will inspire you, scientist or non-scientist.

Dr. Dement with the 2006 Dement Fellows

For Sleep but Sleepless in Lake Arrowhead, California

For the past week, I have been residing in high altitude at the UCLA-owned resort of Lake Arrowhead, California in the San Bernardino Forest (and mountains) near LA. I was attending a scientific and professional development workshop devoted to sleep research, grantsmanship, responsible conduct of research, and networking. The theme of the workshop was “translational validity in sleep research” meaning that the focus was on appropriate animal models of sleep and disease states. The workshop has been going on for nearly 30 years organized, funded, and hosted through the efforts of Dr. Michael Chase of UCLA. Holy cow was it spectacular. I can see why my undergraduate advisor, Dr. Mary Carskadon, uses Michael’s retreat as a model for her annual retreat.

The trip began with a short trip to Manhattan Beach, its epic dining, and the Santa Monica Pier where I showed those beach boys that they really aren’t as strong as their muscles make them out to be.

When we arrived in Lake Arrowhead, we immediately began to dive into intellectual discussion. We went over and critiqued common methods to sleep deprive animals. We weighed the pros and cons of common animal models of sleep and disease, namely the fly, rat, mouse, and even cat. We even talked about the pros and cons of staying ahead of the curve. The general consensus is that it is never good to put the cart before the horse; that optogenetics and chemogenetics, two sexy approaches in neuroscience that I have discussed previously, are worthless in time and money if you do not have a sufficient hypothesis and supporting rationale. Also, using these tools is not a priori for getting funded. We also learned about some transfection techniques for activating neurons and measuring neuron activity by transfecting a rabies virus or using a recording electrode covered in a lipophilic (fat-loving) material, enabling it to be sucked up by the neuron’s membrane.

On the morning of the second day, I organized a morning boot camp. One of the workshop’s organizers, Dr. Mark Opp, had the brilliant idea to do our workouts on the zen deck. Not a bad view, eh? The zen deck was the meeting spot for our morning boot camp/bro sessions for the rest of the meeting. On the second day, I also got too cocky (and stupid) in the pool and smashed my nose on the bottom of the deep end after doing a perfect front tuck into a dive.

The Zen Deck

The scientific sessions of the workshop continued with discussions of appropriate measures of sleep homeostasis. The obvious candidates are NREM sleep saturated with slow wave activity, but Dr. Ron Szymusiak presented evidence for physiological phenomena relevant to sleep homeostasis that have been overlooked. Basically, his lab examined the firing rates of neurons in two sleep-promoting nuclei of the hypothalamus, the ventrolateral and median preoptic nuclei. Typically, these nuclei are less active during wake and even forced wakefulness, and more active during spontaneous sleep or recovery sleep after sleep deprivation. Thankfully, Ron found that this is not entirely true because a tipping point from low to high rates of firing in these nuclei can occur across an episode of forced wakefulness. I am thankful for this data set because it addresses a concern that I have had with a data set of mine that I am hoping to be publish soon.

We also had an evening discussion on ethics. Each discussion began with a short skit. Here is the skit that my group and I performed to exaggerate very inappropriate relationships between mentor and mentee.

About halfway through the conference, we were introduced to the EUREKA grant writing proposals. Basically, we were given 36 hours to write AND present an R21 (NIH system) grant that would allow for two years of work and $250,000 in allowance (excluding whatever indirect costs the university took which is normally around 50%). The committee did a fantastic job of spreading out areas of research focus, or maybe it was just a coincidence. Our group had an interesting mix of expertise and personality. However, we were able to overcome an initial mental block in proposing a hypothesis-driven research question. Our proposal aimed to investigate how sleep deprivation could further worsen brain connections and cognitive and motor learning after a stroke. At the end of the day, our grant proposal won, although all of the proposals were impressive for the short time allotted! For our winning efforts, we got a bottle of Glenvelvet.

Presenting our grant

Winners of the EUREKA grant with their prize!

Without a doubt, this workshop was one of the best smaller conferences in animal research that I have ever attended. It presented many opportunities to ask questions, respectfully refute opinions, and to remove the typically intimidating barrier between PIs and trainees.  The countdown til the next workshop is on.

A non-invasive system to replace EEG/EMG recording of sleep

This week, we resumed our biweekly journal club in sleep and circadian rhythms for the year. I presented a paper published last week in the journal Sleep. It was more of a methods papers, but still important because non-invasive tools for measuring sleep have become best-sellers: FitBit, Zeo, and other Nike/iPod-based physical activity software. This new technology that I talked about in journal club is reserved only for rodents although the researchers state that it could eventually transform the human sleep laboratory. The system, known as the piezoelectric system, has been around for about a decade, but has really only been used by selective groups. However, now that the system is commercially available (Signal Solutions), there may be more papers using it to record sleep. Hopefully, these researchers are cautiously doing so as I will explain why.

ResearchBlogging.orgThe hardware of the piezo system is fairly straightforward. There is a polymer “mattress” placed under a light layer of bedding on which the animals move around, groom, sleep, eat, drink, etc on. This polymer is connected to a box that encases the animals’ cages. The box also contains many tiers of infrared beams to measure general locomotion. Basically, the amount of mechanical pressure generated from movement and breathing is proportional to the amount of electric signal generated. These two variable–mechanical pressure and electrical signals–are assigned a score that is above or below a “wake” threshold shown here. The lower the positive score, the deeper the stage of sleep and the higher the negative score, the more intense the stage of wake.

Basically, these researchers found that the temporal distribution of sleep and wake across multiple days is largely in agreement between this system and the traditional EEG/EMG system that also requires someone to score each individual epoch of recording, a process that can take hours to days.

Decision Statistic determining sleep or wake

There were some concerns about over-reporting sleep during the light or rest phase of rodents as well as the system being a poor measure of particular EEG waveforms characteristic of each state of sleep and wake.

Temporal distribution of sleep and wake with EEG and this new non-invasive piezo system

But for the most part, I do think this is an ideal system for high-throughput research requiring quick sleep-wake analysis in hundreds of mice. It also removes human error of scoring sleep records out of the equation. Obviously, there are some limitations as to what types of studies should rely on the piezo system alone. Personally, I think it is ideal for high-throughput studies of drug screens. If you are interested in gross changes in sleep from baseline levels, then sure. But if you are trying to identify a new model of sleep dysfunction then this system may not be sufficient enough to accurately identify brief awakenings as sleep or wake. Regardless, I do hope to see more studies using this type of recording technology soon.

Mang GM, Nicod J, Emmenegger Y, Donohue KD, O’Hara BF, & Franken P (2014). Evaluation of a piezoelectric system as an alternative to electroencephalogram/ electromyogram recordings in mouse sleep studies. Sleep, 37 (8), 1383-92 PMID: 25083019

Galen may have been (partly) right.

You may recall learning bits and pieces of ancient psychiatric history in some physiology or psychology course. I am referring to the four temperaments proposed by Galen who believed that four bodily fluids were uniquely responsible for some aspect of human behavior: blood, bile, black bile, and phlegm. After Galen, the medical and psychiatric community ResearchBlogging.orgbecame cerebral-centric, believing that most aspects of human behavior manifested from operations of the brain and feedback with other parts of the body. The best example would be reflexes and muscle memory which don’t really require the brain but simply the spinal cord.

Thankfully, some scientists have reverted back to hypotheses proposed in ancient medical texts. The most recent incidence was this year when scientists in California did blood transfusions and gave mice systemic injections of another mouse’s blood to study whether biological factors in the blood control the rate of neurodegeneration. Ponce de Leon would have been proud.

In this study, the researchers created a parabiotic mouse which means that these researchers made a post-natal Siamese mouse for the purpose of having a young adult mouse share a circulatory system with an aged mouse. I can only imagine the amount of surgical skill that it requires to do this in a mouse! In a second set of experiments, aged mice were injected with the blood of young mice. In both cases of blood transfusion or systemic injection of plasma, the rate of neurodegeneration was slowed in aged mice that had been introduced to young adult blood. Nothing happened when aged blood was introduced into another aged mouse. Because of the journal in which the study was published in–Nature–it is no surprise that this protection from neurodegeneration was confirmed at many levels, behaviorally, electrophysiologically, histologically, and molecularly.

Moreover, the experimental design of this study has paved a path to investigate many other neurological events that may be controlled by biological factors circulating in the blood. Even Steven Colbert agrees. You know you’ve made it in science when your sh*t ends up on the Daily Show or Colbert Report to be poked fun of.

The Colbert Report
Get More: Daily Show Full Episodes,Indecision Political Humor,The Colbert Report on Facebook 

Villeda, S., Plambeck, K., Middeldorp, J., Castellano, J., Mosher, K., Luo, J., Smith, L., Bieri, G., Lin, K., Berdnik, D., Wabl, R., Udeochu, J., Wheatley, E., Zou, B., Simmons, D., Xie, X., Longo, F., & Wyss-Coray, T. (2014). Young blood reverses age-related impairments in cognitive function and synaptic plasticity in mice Nature Medicine, 20 (6), 659-663 DOI: 10.1038/nm.3569

It’s Crossfit Games Week: #Pandanation, #AllBridgers, and #Jetlag

Years worth of training, competition, and trust come to fruition this weekend as my teammate, training partner, and friend competes for the title “Fittest on Earth.”  I’ve talked about the Crossfit Games and the journey that it takes to get there many times before. Last year, I had the opportunity to compete on a team with Emily in the Games. This year, I cheer on Emily Bridgers from Atlanta, regretting not being there in person to support (because science calls). Emily is going to impress everyone this weekend–fans, judges, coaches, other athletes, and the ESPN networks.

Pandanation celebrating Emily's Regionals win


While athletes are prepping for the Games, I bet many of them overlook one important variable: jet lag. The Games are in California but represent teams from around the world. Jet lag can have residual effects on rhythms of physiology and behavior beyond just a day. Depending on the direction and extent of travel, it can sometimes take a week to adjust, mentally and physically. With that, I provide an excerpt from my book that is due on bookshelves within the next year–Meathead. This particular chapter discusses the impact of jet lag on game day performance.

“There actually is a handful of information on jetlag, sleep deprivation, and their consequences on athletic performance. Most of the laboratory-based studies have focused on shifts in rhythms of melatonin and CBT, which are easy to measure with little invasiveness. As I discussed earlier in the chapter, the relationship between CBT, sleepiness, and mental and physical performance is intimate; drops in CBT increase sleepiness which lead to declines in mental and physical performances. With a new light schedule, especially one that is more than a few hours ahead or behind, the release of melatonin—the “hormone of darkness” that is sensitive to light— is suppressed and the normal afternoon and early morning dips in CBT occur earlier or later. Obviously, both of these physiological shifts wreak havoc on sleep and performance by keeping people up at night, waking people up too early, and causing a lack of focus and energy throughout the day. In fact, one study has compiled a breakdown of motor and mental skills that suffer from insufficient sleep driven by game day travel; for low-aerobic sports that require high levels of alertness and fine motor skills like sailing and archery, there’s more room for error. For team sports that require high levels of concentration, there’s poorer decision-making. For individual sports with a mixture of aerobic and anaerobic movements like swimming, mixed martial arts, and weightlifting, there’s a loss of power and quicker time to fatigue. Although these symptoms and changes in our body’s physiology from game day travel across time zones eventually disappear, the problem is that it takes at least a few days for the body to adapt. For professional baseball and basketball players, this is an unresolvable problem because many teams are already on their way to a new time zone to play another team. As an example, the 2012 NBA season, which was truncated by contract agreements, had more game-day travel than in year’s past to make up for lost inter-conference playing time. The season was also plagued by poor refereeing, increased amounts of injuries, and complaints of constant exhaustion. Although no empirical studies were undertaken, sports pundits and researchers like me believe that jet lag and constant weekday and weekend game travel were the culprits28.

In the field of sleep research, we often talk about “sleep debt” which refers to any negative deviation from your body’s desired amount of nightly sleep. So if your body requires 8 hours and 20 minutes of sleep a night (the human average), but you only get 7 hours, you will need to make up that 1 hour and 20 minutes at some point. If we short-change ourselves 1-2 hours of sleep for a few days once a year, this isn’t a big deal. We may be sleepy for a few days, but we will rebound quickly. But if we are depriving ourselves of 1-2 hours of sleep a few times a week for months or years, we aren’t getting quality sleep. This is largely because our body full of clocks keeps getting exposed to different light-dark cycles, which is a serious problem. Under these circumstances of chronic sleep deprivation, our sleep debt creeps up on us whenever we aren’t socially stimulated such as when we are driving, watching a movie, or standing around in the outfield. Even if we aren’t sleepy per se, our minds are slower due to individual neurons going offline at random intervals to “rest,” and our physiological rhythms of growth hormone which acts to repair damaged and maintain healthy tissue can be suppressed. This is one of many reasons why game travel in collegiate and professional sports communities should be re-evaluated or more carefully planned with the help of researchers in sleep and circadian rhythms.

Does the length and direction in which we travel also make a difference? That is, does performance suffer worse upon travel to the Pacific versus Mountain time zone from the East Coast, or do West Coast teams playing a night game at home have a physiological advantage over their East Coast opponents or vice versa? If you look at the regional distribution of professional NFL, NBA, and MLB teams across the US, nearly half the teams lie in the Eastern US time zone (Atlantic coast) while a majority of the others are in the Central or Pacific US time zones (Midwest or Pacific coast). Within a professional organization, there are two conferences that are not solely determined by region of the country; both the MLB and NFL are divided into American and National Leagues which each have teams on the West Coast(Oakland A’s for American and San Diego Padres for National) and East Coast (Boston Red Sox for American and New York Mets for National). This is particularly bothersome for Major League baseball players who play 2-4 games per week, sometimes in different time zones, versus a professional football player with one game on a Monday, Thursday, or Sunday. Luckily for us, researchers have investigated if the type of game (away versus home) and direction of travel (east versus west) impacts athletic and mental performance through careful examination of win-loss records, changes in individual statistics, and even a few questionnaires on sleep habits.

Even with mice and hamsters, the direction of travel makes a difference; mice have an easier time adjusting to delays in their light-dark cycle, whereas hamsters have an easier time adjusting to advances. This time zone preference actually isn’t random either, but rather explained by how closely biological clocks “tick” towards 24 hours. Because the biological clock of a mouse “ticks” slightly less than 24 hours, a delay in an environmental schedule would make their clocks “tick” at 24 hours. Meanwhile, because the biological clock of a hamster “ticks” slightly more than 24 hours, an advance in an environmental schedule would make their clocks “tick” at 24 hours. Human biological clocks are similar to those of a hamster in that they “tick” slightly longer than 24 hours. This is why most humans have an easier time with Western versus Eastern travel. Athletes are no different. One of the first studies to investigate athletic performance following East versus West Coast travel was determined from archived data of the 1996 collegiate (NCAA) football season; the University of Florida Gators were national champions that year. Overall, teams that traveled more than one time zone eastward performed consistently worse than teams traveling more than one hour westward: they scored fewer points, allowed more points, and had greater point spreads even when controlling for progress of the game: 1st quarter versus 4th quarter29.

In terms of whether travel to the Pacific coast versus Midwest for a New York Yankee matters, it does. In 2008, I learned about such a concern at our annual sleep conference held in Baltimore, Maryland through Dr. W. Christopher Winter at the University of Virginia who happened to have a research poster next to me. Dr. Winter and colleagues entered the scores of over 24,121 MLB games into a database that controlled for number of time zones travelled. Independent of direction, 60% of games were lost if the baseball player traveled three zones and 52% were lost for travel through two time zones. An 8% difference may not seem significant, but in the world of professional sports that can be the difference between finishing last in the league (and subsequently getting first pick in the next year’s draft) and vying for a pennant. These results–that athletic and mental performance suffer more as the number of time zones travelled increases–make biological sense because that extra hour of light (or dark) for one more time zone would mean that your body would need an extra day and sometimes more to adjust. However, there are many strategies for adapting quicker to a new time zone of which I’ll discuss next.

As for whether certain coastal teams have an advantage during night games–the games with the highest viewer ratings–this also matters. The sleep community of Stanford University conducted a carefully controlled examination of win-loss records across forty years of play in the NFL to determine if East Coast teams had a biological advantage over West Coast teams during a night game played on the East Coast or if West Coast teams had a biological advantage over East Coast teams during a night game played on the West Coast. Unlike previous studies, these researchers also factored in the Vegas point-spread which is carefully calculated: it is based on win-loss record, injury reports, historical matchups between the teams, weather, and whether it is an away versus home game plus many other variable. Therefore, a “win” in this Standford study was defined as winning the actual game and beating the Vegas point-spread. Unfortunately, East Coast teams are always at a disadvantaged when playing a night game with West Coast teams winning 70 out of the 106 night games played regardless of whether it was an away or home game. So even if an athlete is at a biological disadvantage to performing at their best due to game day location, can modern science and medicine help?



Neury Thursday: Mitochondria, neuron health, and sufficient sleep

This paper came out in the Journal of Neuroscience while I was at the Gordon Conference a few months ago. This week, a group did a summary of it in a unique section of the journal called journal club. Basically, it offers a different perspective/interpretation of the data without a loss of content.
In this study, the authors were interested in a structure of the brain stem that regulates sleep-wakefulness: the locus coreleus (LC). Neurons of the LC are considered wake-promoting. To see what happens to the health of these neurons with extended wakefulness, mice were woken up three hours on one day (acute) or eight hours earlier for three days (chronic); mice have a robust and predictable activity period around the lights-on/lights-off transition. Typically, sleep deprivation is done at the end of the night (lights-off/lights-on) so this approach is unique in itself.

With this experimental approach, the biomarker of neuron health that the researchers were concerned about was reactive oxygen species (ROS). Increases in ROS are indicative of harmful physiological stress and likelihood of neurodegeneration. As expected, a gradient of extended wakefulness increased ROS and a near 30% loss of neurons.

Obviously, we can include that sufficient sleep is important for neuron health. But what’s the mechanism? In follow-up experiments, the researchers were concerned with Sirt3–a biological factor of mitochondria–that shuttles byproducts of cellular respiration, namely NAD+. Mice lacking sirt3 had a neuron phenotype similar to mice deprived of sleep; increased ROS and 30% loss of LC neurons.

To conclude, this study adds to the body of evidence showing the neurobiological pathologies and mechanisms related to restricted sleep.

Fifel, K. (2014). Sirtuin 3: A Molecular Pathway Linking Sleep Deprivation to Neurological Diseases Journal of Neuroscience, 34 (28), 9179-9181 DOI: 10.1523/JNEUROSCI.1848-14.2014

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