First (Postdoc) Paper; Jetlag, Sleep Loss, and Inflammation

This data took nearly four years to collect. Needless to say, I am pretty proud of this publication. This is one of the first projects that I worked on (and completed) as a postdoc. It also presented an opportunity for undergraduates to become involved in biomedical research too. This study was an extension of a previous study ResearchBlogging.orgout of our Neuroscience Institute (Castanon-Cervantes et al. 2010; Journal of Immunology) which aimed to verify (if you will) that elevated immune responses are manifest from a change in the light-dark cycle and not explained by sleep loss. To address this, we first measured changes in daily sleep amounts across a 3 month protocol of jet lag in which the light-dark cycle was advanced by 6 h at the beginning of each week. As shown in this graph, the weekly decrease in sleep was highly variable, peaking on day 3 (even after wake, NREM and REM sleep processes re-entrained) and returning to baseline amounts by the end of the week. Despite this significant amount of sleep loss mid-week, there was no change in sleep pressure derived from measures of slow wave activity in the EEG.
Weekly Changes in Sleep with Experimental Jetlag

In a follow-up experiment, we tried to mimic the amount of sleep loss found under a protocol of jetlag (while also accounting for recovery from daily sleep loss). At the end of this experiment, we challenged the blood of animals that were controls, systematically sleep-deprived, or underwent 4 weeks of jet lag with LPS (an endotoxin that induces an immune response). We found that only the group subjected to the jet lag protocol showed an elevated immune response, recapitulating the findings of Castanon-Cervantes et al. 2010. We also found that both systematic sleep loss and experimental jetlag increased neuronal activity (relative to controls) in arousal-promoting and sleep homeostatic areas but to a different extent. In conclusion, it appears that the detrimental effects of jet lag on the body extend well beyond a loss (or change) in sleep. Frequent travelers beware.
Effects of Systematic Sleep Loss and JetLag on Brain Areas

Brager AJ, Ehlen JC, Castanon-Cervantes O, Natarajan D, Delisser P, Davidson AJ, & Paul KN (2013). Sleep loss and the inflammatory response in mice under chronic environmental circadian disruption. PloS one, 8 (5) PMID: 23696854

National Postdoc Appreciation Week!!!

National Bosses Week, National Secretaries Week, and now National Postdoc (Factory Worker) Week in which all graduate students, undergraduates, and PIs are supposed to appreciate our newly (degree)-granted arrogance, and whines of “how we used to do it in this lab,” and at times, our ability to introduce a new writing style, methodology, or usual perspectives on data analyses here and there.  Oddly enough, I have put in more hours of work this week than any week of my postdoc yet. To celebrate, the postdoctoral association at Morehouse School of Medicine has organized a series of panels and a seminar with the author (and Emory University department chair, Jeremy Boss), Academic Scientists At Work.

Throughout this week, I’ve learned about how to market oneself in today;s job market; that is, if you don’t have a Science, Nature, or Cell publication then utilize your networking skills, emphasize any extramural and intramural funding, and come with a solid, innovative research plan that could produce long-term results. Dressing for the occasion (ladies, limit form-fitting clothing; men, tone down the pastel colors) helps too. And interestingly enough, we it comes to spousal hires, which seems to be an urban legend nowadays, following the “don’t ask, don’t tell” policy is recommended.

Best of luck to all of us postdocs out there!

The Importance of a Career Development Plan

This infographic has gone viral across the past few days, and for a very good reason. Many PhD candidates in biology aspire to have the life of their mentor in graduate school. I will even admit that it seems like utopia except for the time away from the bench. I hope to never be that hands off. Three things are striking to me on this infographic derived from an NIH report published in 2012 on enrollment, retention, and short- and long-term success in academia. First, the high dropout rate of 37% across the average length of time that it takes to get a PhD in biology which is about 7 years is higher than other professional degree programs: law school, business school, and med school. Although this can easily be explained by the lack of financial commitment. Most PhD candidates are paid enough to not have to take out loans or find another job whereas those in other professional degree programs feel the need to bite the bullet if they are already $100k + into paying for their program. Second, PhD candidates say they want to get a PhD because they want to be in a faculty position. The NIH portfolio reveals, however, that a tenured faculty position is a rare gem, reserved only for 8%. This statistic is likely lower for women and minorities because let’s face it, even in 2014 academia still greatly struggles with recruiting more than just frat boys. Lastly, I was shocked to learn that postdocs really aren’t as mistreated as I previously thought. The average length of one is 4 years and only about 30% do a second postdoc. Maybe I am hanging out with the wrong crowd. At any rate, this infographic emphasizes the importance of planning ahead in the short- and long-term by means of having a Career Development Plan. Fill one of these out and post it to your bulletin board. It is helpful, trust me.

from getting a Phd to having your own lab

Best of Dormivigilia in 2013

This year was incredible–scientifically, athletically, and personally. I had a lot of firsts that will, in some cases, likely never be seconds. I got both NIH grants that I first applied for in 2012 and then re-applied for in 2013; an F32 to investigate skeletal muscle regulation of sleep and metabolic processes and a loan repayment grant which will pay 50% of my educational loans over the next two years to examine biological sex regulation of sleep. I had two first-author papers published in PLoS One and Behavioural Brain Research with the former being my first publication as a postdoc and the latter being my last publication from graduate school. Athletically, my teammates and I qualified for the Reebok Crossfit Games where we competed against teams across the globe and picked up many sponsorships in the process. Words can’t describe the year of training, discipline, and commitment required for achieving this goal, but the payoff of competing with world-class athletes and being filmed for ESPN production was well worth the sacrifices. Personally, Montegraphia and I tied the knot!

Usually, I begin my annual best of blogging with January. This year, I’m going to travel backwards.

December: I’ve spent most of December abroad. Montegraphia and I went on our honeymoon to Western Europe. We took an 8-day cruise from Rome and traveled to Northern Italy, Barcelona, Marseilles, the ancient city of Carthage in North Africa, and Sicily. Here is a collage of photos from my favorite places in each country. Scientifically, I have recently become interested in the discovery of a “new” sleep center: the nucleus accumbens. The nucleus accumbens is historically known as a reward center. But how can you experience pleasure without concurrently being awake?

Rome

Rome

Vatican City

Genoa, Italy
Genoa, Italy

Genoa, Italy

Marseilles, France

Marseilles, France

Sagrada Familia, Barcelona

Sagrada Familia, Barcelona

 

Carthage, North Africa

Carthage, North Africa

Palermo, Sicily
Palmero, Sicily

Palmero, Sicily

 

November: Like every November, I attended the annual Society for Neuroscience meeting. For the fifth year in a row, I was selected as the representative Neuroendocrine and Homeostatic Systems blogger for the annual meeting. It was fairly evident that viral vector-mediated techniques are saturating basic sleep research; over 50% of basic sleep-related posters used optogenetics or DREADDS. Back home, my postdoctoral laboratory published a (methods) paper in SLEEP that described a means to quantify physiological sleepiness with better temporal resolution

Trip to wine country in Ensenada, Mexico during SfN 2013

Trip to wine country in Ensenada, Mexico during SfN 2013

 

Lunch on Coronado Island during SfN 2013

Lunch on Coronado Island during SfN 2013

October: Montegraphia and I tied the knot in my hometown of Youngstown, Ohio. There was a considerable amount of sleep and circadian papers to review this month. One of the more salient papers that I discussed (per comments from readers) was in regards to the surprisingly lack of sleep disruption after binge drinking caffeinated alcoholic beverages. I also conducted a case study with a proprietary protein blend directed towards accelerating recovery while you sleep. The CEO of the company actually called me after seeing my blog post to discuss future products aimed towards recovery and performance that are underdevelopment.

Montegraphia and Dormivigilia tie the knot

Montegraphia and Dormivigilia tie the knot

September: This month, I found out that I got both of my NIH grants. Not only do I have three more additional years of job security, I finally can travel a bit more for training and professional development activities. I also talked about a circadian study that made the pages of Current Biology in which research subjects were recruited to camp in the Rockies for a few weeks. Not a bad idea.

Macedonian convention in Pittsburgh with family

Macedonian convention in Pittsburgh with family

August: August was a month of recovery from the Crossfit Games and the summer research program. This month, I learned about the death of Google Reader which I daily used since the days of graduate school to stay up-to-date on research. Oh well. Feedly is just as cool.

Bachelorette party at Put-N-Bay, Ohio

Bachelorette party at Put-N-Bay, Ohio

July: This month was cuckoo and crazy between mentoring our undergraduate summer fellows and training and then competing in the Crossfit Games! Scientifically,  a rad study that identified biological clocks in a variety of garden vegetables was published.


June: I went to the Society for Behavioral Neuroendocrinology meeting which happened to be here in Atlanta. It was weird reuniting with my friends, colleagues, and attending a major conference while sleeping in my own bed every night.  I also learned that I was going to be a spokesperson for 23andme—a corporate genotyping company–after filling out a product review that piqued their curiosity! Since then, I’ve signed a press release allowing them to use the material collected from phone and Skype interviews that I have done for product promotion. One of my more popular posts that month speculated on the death of Michael Jackson. Top-rate researchers project that a lack of sleep, particularly REM sleep, was largely responsible for the death of this pop star.

Sponsorship promotion for Crossfit Games

Sponsorship promotion for Crossfit Games

May: This was one of the most memorable months of the year. First, we competed in the Southeast Crossfit Regionals in Palm Beach, FL. We finished third, advancing us to the Crossfit Games! It was wonderful to have my family in attendance cheering us on. I also had my first postdoc paper published in PLoS One on the impact of jet lag on sleep and inflammatory responses. My lab also had a second paper published in PLoS One biological sex regulation of sleep. Hilariously enough, Montegraphia ended up on a manuscript in my own postdoctoral laboratory before me by serving as a statistical consultant.

Third Fittest Team in the Southeast

Third Fittest Team in the Southeast

April: This month, my last paper from graduate work was published in Behavioural Brain Research. It examined how mice lacking the Per2 gene responded to cocaine in the presence of light or how the circadian system responded to cocaine. I also attended a wonderful animal behavior conference at Indiana University. It happened to coincide with the March Madness finals when Indiana was knocked out of contention. There were lots of somber, drunken souls wandering around campus one morning…

Another sponsorship promotion for our team

Another sponsorship promotion for our team

March: A few unusual circadian studies arose that examined behavioral and physiological rhythms in the camel. A separate study examined the frequency of Facebook posting. Another study has kept us on our toes because they reported how changing the expression of a gene in the skeletal muscle influences the ability to recover from sleep deprivation. Luckily for us, this was done in a non-mammalian species. It’s exciting that their results are in agreement with ours, but nonetheless nerve-wracking about the possibility of being scooped.

Camels we saw in Tunisia on our honeymoon

Camels we saw in Tunisia on our honeymoon

February: Every February, we have our in-house research symposium. This year, a neuroscientist from Duke University–Erik Jarvis–was invited. His research is fascinating because he studies “echo” communication in mice. Researchers are often warned by their IACUC about euthanizing animals in the presence of others because it elevates stress. Erik Jarvis’s research certainly supports this. I also wrote a blog post about a study that linked daily sleep durations with diet. I was fascinated to learn that the paleo diet which is rich in leafy greens and proteins was highly correlated with shorter sleep durations.

New Orleans for the Super Bowl!

New Orleans for the Super Bowl!

January: January was kind of lame for sleep and circadian research. There wasn’t much published, but there was one study that found seasonal changes in adenosine signaling–a neurochemical biomarker of physiological sleepiness.

Facebook rendition of 2013

Facebook rendition of 2013

As 2013 ends, I am grateful for the continuing support of Dormivigilia. Thank you! The action won’t stop in 2014. Also, I hope to have a couch read for you by the end of 2014.

 

Nanosymposia: Cocaine, Clocks, and Calcium

My interests lie in sleep, circadian timekeeping, and drug addiction. This has been the focus of my graduate work (circadian clocks, cocaine, and alcohol) and current work (sleep, jet lag, and metabolism). Today I attended two nanosymposia related to both my graduate and postdoctoral work: for years, cocaine addiction researchers have focused on the neocortex and stress-related signaling cascades. Today, I saw tons of expansion on focus and methods. Researchers used a variety of pharmacological approaches in order to prevent the release of biological substrates such as lactate from astrocytes as well as to selectively activate certain receptors with specific drugs. This approach known as DREADDS involves the transfection of  (viral) designer receptors into specific brain areas to selectively active these certain receptors with specific drugs. It’s cool stuff and honestly, less behaviorally limiting than optogenetics-a very hot research area at the moment-if behavior is the desired, measurable outcome. There is no question that restriction of movement with optogenetics could be confounding for cocaine-seeking and tests of conditioned place preference. In the circadian symposia, there was an emphasis on calcium which is a major “between neuron” communicator within the master biological clock. In this symposium, calcium was found to guide the release of neuropeptides from certain regions of the master clock in response to light or other non-photic environmental cues. By blocking, initiating, or temporarily shutting down calcium signaling, the clock doesn’t function well or is essentially broken.

I also attended a poster session focused on circadian rhythms research. You can find a recap of my top-three posters here. Until tomorrow. Good night, San Diego!

Joint Lab Publication: Novel Means to Quantify Physiological Sleepiness

My postdoctoral laboratory has been on an upswing for publications in 2013; two publications in PLoS in the spring and now this publication in Sleep. For years, sleep researchers have characterized physiological sleepiness observed by EEG through one measure: slow wave activity. Slow wave activity is fairly ResearchBlogging.orgstraightforward to identify and represents EEG waves of a very small  frequency (0.5-4.0 Hz) that essentially look like a roadside view of the Rocky Mountain Range. The amount of slow wave activity is directly proportional to the length of time that an animal is awake meaning that slow wave activity dominates the EEG after long periods of wake or sleep deprivation. While  slow wave activity has helped determine how a host of environmental, physiological, and genetic factors influence the ability to recover from sleep loss, it is limiting because it does not accurately quantify how an animal feels during sleep loss. And so, our lab teamed up with another electrophysiology lab that studies epilepsy to provide a means to quantify physiological sleepiness as it occurs, not after.

This was achieved through a period-amplitude analysis which looks at a single EEG within a specific time frame, say 10 seconds, rather than all EEG waveforms within a specific time frame.   With this period-amplitude analysis, the number of slow wave peaks were counted across sleep loss with the mice being deprived of sleep for up to 24 hours. Early into the sleep deprivation, there were slow wave peaks here and there.

 

Early into Sleep Deprivation

But as time passed, particularly after the animal had been deprived of sleep for 6 hours, slow wave peaks began to dominate the EEG and persists until the end of 24 hours of sleep deprivation.
Late into Sleep Deprivation
We also found that the number of slow wave peaks was negatively correlated to the time it took the animal to fall asleep, in particular NREM sleep, which makes up 85-90% of total sleep and is the first type of sleep that an animal has unless the animal is narcoleptic. This relationship between slow wave peaks and time to NREM sleep corroborates the previously identified negative relationship between slow wave activity and time to NREM sleep.
Number of Slow Wave Peaks With Continued Sleep Deprivation
Finally, we found a time-dependent difference in the quantity of slow wave peaks based on whether the animal got sufficient sleep or was recovering from sleep loss. With sufficient sleep, slow wave peaks were more common during the light or rest/sleeping period of a nocturnal rodent. There were also more slow wave peaks during the middle of the night when most nocturnal rodents nap. This distinctive rhythm in slow wave peaks was absent in a mouse recovering from sleep loss. This is largely because there were more slow wave peaks during the night than that present with sufficient sleep.
Loss of Rhythm of Peaks After Sleep Deprivation

This study provides a means to better characterize changes in sleep and wake with inadvertent or involuntary sleep deprivation. But if we extrapolate these findings to humans, they also reveal the scary reality of even a few hours of sleep loss-a moving body in a brain that is essentially asleep.

Ehlen JC, Jefferson F, Brager AJ, Benveniste M, & Paul KN (2013). Period-Amplitude Analysis Reveals Wake-Dependent Changes in the Electroencephalogram during Sleep Deprivation. Sleep, 36 (11), 1723-35 PMID: 24179307

 

Dormivigilia and Montegraphia Tie the Knot!

For my regular readers, Montegraphia may be familiar to you. His real name is Justin Montemarano and today we tied the knot after nearly seven years of dating. Like most academics, we met in graduate school so we’ve seen each other at our worst–when long-term experiments went awry, when our mentors were being unreasonable or unavailable, or when the prospects of getting a postdoc/faculty position in the same city or state were unlikely–but also at our best–when we’ve gotten grants that we’ve spent hundreds of hours on instead of with each other or  when a paper was finally accepted. We collectively began our blogging endeavors midway through graduate school with me choosing to focus on circadian rhythms and sleep and Justin choosing to focus on wetland ecology.w

 

At Last, NIH Funding!

I don’t usually use my blog as a means to brag about my professional accomplishments, but I can’t help but contain this news. In the past two months, I have been able to secure NIH for two things; 1. to have three years of job security by means of a National Research (postdoctoral) Service award that will pay my stipend and provide related funds for travel and equipment; and 2. to have a significant portion of my student loans paid back via the Loan Repayment Program. It’s apparent that the NIH has generated an interest in sleep…I happened to recently come across this PSA they generated. Woo hoo!

NIH PSA

Chromosomes, Sex, and Sleep

This week, our lab published a paper that we’ve been working on for some time (and one that I’m continuing). It’s also kind of hilarious that Montegraphia made it onto a paper from my postdoctoral lab (see acknowledgments section) before me! He only beat me by a few weeks though….
ResearchBlogging.org
Our lab is interested in sex differences in sleep/wake before and after short-term sleep deprivation. In fact, my mentor has previously shown that males with circulating androgens sleep more often during the dark (active) period than females with circulating sex steroids. Removing the circulation of sex steroids, simply through castration or an ovarectomy, removes these sex differences. However, sleep rebounds following a period of short-term sleep deprivation were less sensitive to hormonal removal and replacement, suggesting that there are other physiological substrates that determine one’s sex that contribute to sex differences in sleep. One candidate is sex chromosomes.

This was essentially the specific aim of our recent paper–to differentiate between hormonal versus chromosomal sex differences in sleep. To accomplish this, we used the four core genotype mice which I described in a very recent post. These mice have been used to differentiate hormonal versus chromosomal sex differences in circadian timekeeping (though subtle) and alcohol drinking behaviors (extremely compelling). To recap, the sex chromosome opposes the gonadal makeup due to a spontaneous deletion of the testes-determining gene Sry. Through a complicated scheme of Mendelian genetics, hermaphroditic mice are produced–XY females and XX males. The mice in this study were also castrated and ovarectomized in order to remove the additional confound of circulating sex steroids. In reproductive physiology research, this will also help determine if some trait is possibly organized by hormones (ie. hard-wired) or activated by hormones.

Prior to sleep deprivation, there was only one time point in which the amount of sleep varied across a 24 hour period;  midnight. Here, normal and hermaphroditic (XXM) males had significantly more sleep than typical females (hermaphroditic females were somewhere in the middle). Further, after the animals were sleep-deprived, the hermaphroditic males had a greater propensity to sleep (deeply), particularly during the dark phase. This suggests that the chromosomal ‘male’  sleep homeostat is set higher (sucks for them).

Sleep in normal and hermaphroditic mice journal.pone.0062205.g003 (1) journal.pone.0062205.g002

While we did not report the neural substrates and mechanisms of these sleep phenotypes in this paper, we do have some evidence, but you’ll have to wait until the Society for Neuroscience meeting in San Diego to find out.

 

Ehlen, J., Hesse, S., Pinckney, L., & Paul, K. (2013). Sex Chromosomes Regulate Nighttime Sleep Propensity during Recovery from Sleep Loss in Mice PLoS ONE, 8 (5) DOI: 10.1371/journal.pone.0062205

Indiana University Animal Behavior Conference

I spent the latter part of last week in basketball country; Bloomington, Indiana. Aside from cursing over the loss of Indiana to Syracuse (only to preserve my first place ranking in the fantasy college basketball), I attended an animal behavior conference that was very multidisciplinary. Most of the presenters were graduate students and postdocs but their disciplines ranged from ecology, to computational biology, to neuroscience. The keynote speaker of the conference was Dr. Frances Champagne from Columbia University who does some really exciting (and media-friendly) research in epigenetics. She examines how behaviors linked to anxiety and depressive-states in rodents (high licking) can be passed on to several generations by means of pathological changes in the genetic architecture. One of the most common pathologies studied by her lab is DNA methylation which involves the addition of a methyl group to a cysteine or adenine, causing a change in gene expression and subsequent change in cell division or development. Dr. Champagne’s research has also been featured on one of my favorite science-based podcasts: Radiolab.

In addition to Dr. Champagne’s talk, I learned a substantial amount about social aggression and stress in hamsters; male hamsters have a very complex hierarchy of winners and losers with losers showing high levels of anxiety for a month after they have been defeated. The mechanism behind this social stress likely involves the monoaminergic pathway (serotonin, dopamine, norephinephrine), particularly in structures of the midbrain and hindbrain. I had the unfortunate opportunity to see this type of male-on-male (and even female) aggression in graduate school (though unprovoked). I say unfortunate because my fingers lost the fight (don’t worry, only a bite or two!).

I also had the opportunity to visit the Kinsey Institute when I was on campus. Alfred Kinsey was the pioneer of research on human sexuality and as expected, had been a target for many right-winged, religious groups given that he viewed homosexuality to be under the influences of both one’s biology and social environment. He also adopted a viewpoint that every human is bisexual in some regard with women displaying more bisexual tendencies than men. I often give students in my neuroendocrine course this study published by the Kinsey Institute to read as it examines the powerful influence of pheromones on reproductive (in some sense) behavior.

Overall, I enjoyed my trip. I’d like to thank my mentor and the Center for Behavioral Neuroscience at Georgia State for providing travel funds.

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from getting a Phd to having your own lab