Nobel Prize: A Poem

This week is Nobel Prize week!  On Monday, the prize for Physiology or Medicine was awarded to Yoshinori Ohsumi of the Tokyo Institute for Technology (Here’s his website.  I think..it’s in Japanese).  More than 25 years ago, Dr. Ohsumi and his lab took the yeast cultures they were growing, starved them of nutrients, and noticed the starved yeast accumulated small spherical structures inside.  Through their experiments they determined that the starved yeast were recycling parts of themselves.  This process, never-before described in yeast or animal cells, is “autophagy”.  Or self-eating (ooooo, sounds “Halloween-y doesn’t it?).

It’s a hot topic in science, so I thought I would educate myself by reading Ohsumi’s original publication.  A couple of things:  When I first went searching for the paper, I didn’t realize that 25 years ago meant 1992.  I was expecting it to be dated 1975 or something.  I may have had a bit of a panic attack when I fully realized it’s 2016.  Almost 2017.   Second, if you want to read the paper yourself, here’s the link .  It’s free.

And last, here’s a blackout poem for you made from the abstract.  I don’t know why I did this.  I guess I’m a weirdo.  Or, maybe it’s just hard to just sit down and read an article all the way through sometimes–so think of it less as a “poem” and more like a post-doc attention span simulator.

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Did you remember to change your internal clock with Daylight Savings?

I consider myself a morning person, and am always a little sorry the morning of the March daylight savings time change. I feel like somehow, having woken up so many mornings in the dark that I have “earned” those sunrises and to have them abruptly taken away on Sunday feels like a rip-off. Otherwise, I hardly notice the change because I hardly ever know what time it is anyway.

But that’s where I’m wrong. Even though I don’t consciously perceive it, each sunrise is unconsciously sending signals via light-sensitive cells in my eye back to my brain that put my circadian rhythms in sync with the break of daylight and the setting of the sun. Circadian rhythms are changes in gene and protein expression that vary throughout the day that help your body keep time. They control sleepiness, alertness, hunger and hormones. They are responsible for changes in body temperature and surges of glucose. Outside of the TSA and flight delays, they are what make international travel so dang hard. And, it’s why you might have had trouble going to sleep after you changed your (external) clock this week.

This is not my area of expertise, but I find it fascinating. For an approachable discussion of circadian rhythms by people who know what they are talking about, try this podcast or maybe this less formal one.   Or, if you are so inclined and bothered by my lack of citations, here’s nice scientific review article for you.

Probably because I have been reading a lot of science fiction lately, it makes me wonder just how adaptable our circadian rhythms are. They are amazingly flexible—which is why you can travel to the other side of the planet and adjust to that timezone—but also inflexible in that it takes time to make this adjustment (about a day) and in the absence of other signals (like light) people still generally have about a 24 hour circadian rhythm. My limited understanding of this is that the rate at which the genes and proteins involved in these clocks get expressed, made, and destroyed during this timeframe is roughly equivalent to 24 hours.

So…if you moved to a planet with a 32 hour light-dark cycle would you adjust to it? Or would you end up recreating a 24 hour Earth day on another planet?   Some people claim to have longer or shorter “rhythms” anyway and so maybe it wouldn’t be a big deal.  But, I would argue that extensive studies in shift workers and in people whose clocks are artificially set out of whack (by being placed in isolation rooms with odd light cycles) seems to indicate that this ultimately wouldn’t work well. At least in these groups, it looks like body chemistry changes so that systems don’t work as efficiently.  Also, there are strong links between altered circadian rhythms and obesity, diabetes, disorders like depression, and even neurological diseases (including Alzheimer’s—but it is still unclear whether altered rhythms cause the disease or the disease causes the altered rhythms).    Of course how much of this is something we are born with and something we gain with age? After all, babies are notorious for not having set circadian rhythms and the 24 hour sleep-wake cycle only seems to emerge with development. So maybe if you were born on another planet you might be better adapted and protected from some of the effects of change that we experience here?

I don’t know the answer to these questions. But if you’re still thinking about how much you hate the time change, think instead about how cool it is we all share the experience of having our internal circadian rhythms forced out of sync biannually.

And then think about how we can do away with this dumb daylight savings thing.

 

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It’s A-Mazing!

A-Mazing

A Maze.

I’m going to avoid making the obvious comparisons between life as a postdoc and this maze. That’s not why I made it. I made it simply because mazes are fun—can we just stop and have fun for a minute?

Actually, what I think of when I see this maze is the brain (but what doesn’t remind me of the brain?). Our ability to navigate our everyday environments is really amazing. In fact, so amazing that John O’Keefe, May-Britt Moser, and Edvard Moser shared the 2014 Nobel Prize in Physiology or Medicine for their joint discovery of the cells encoding position in the brain: place cells and grid cells. Place cells are found in a region of the brain called the hippocampus and were first described by O’Keefe in the 1970s. These neurons each send out signals every time you cross a specific point in space—like little proximity sensors they start screaming “FRONT DOOR!” or “KITCHEN SINK!” every time you are in a particular spot.  Grid cells, which were discovered by the Mosers in the early 2000s in a part of the brain called the entorhinal cortex, are more like having a world map in the corner of your screen while you play a video game. With grid cells, each single neuron sends out signals in a kind of checkerboard pattern as you walk around a room and, like a GPS, these signals help you to figure out where you are.

I have been thinking a lot lately about this because in Alzheimer’s disease both the hippocampus and the entorhinal cortex are severely affected, and spatial navigation is an ability that is lost early on.   One interesting paper I re-read recently was published in the Proceedings of the National Academy of Sciences in 2000 which use MRI to measured hippocampus size in London taxi cab drivers (http://www.pnas.org/content/97/8/4398.full). And guess what? Cab drivers, who spend most of their day navigating a major metropolitan city, had larger posterior hippocampi (yep, that’s plural, you have two of them) than people who don’t drive taxis!  And the longer they had been drivers, the larger it tended to be!  A later study in 2006 then tracked participants in the four-year London taxi cab driver licensing process and confirmed that those who passed the test basically “grew” this region of their brain over four years.  When you think about this, this is astonishing—it means what you do is altering the very structure of your brain!

Yes, I have heard that this works in other parts of the body as well—say, your muscles—though I don’t think I have personally experienced this phenomenon.   But think about it, what you are doing right now could be reshaping the soft putty of your brain and altering how you process information. Of course, when tested, the cab drivers also had worse visual memory.  So basically, there’s only so much space in your head and I have to wonder how being a postdoc may be “crowding out” other potentially useful areas of my brain…

Oh well!   The point is, take a minute. Solve a maze. Have fun and think about how useful those little cells in your brain are.

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