It’s 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 ( 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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