the problem of where

a minipost

 

Wandering around in a field we seem to know roughly where we are and can make a plan to get from here to there.  This sense of location takes place deep in the hippocampus and the neighboring entorhinal cortex (full disclosure - I couldn't remember that one and had to look it up).  The hippocampus has place cells that fire individually at different locations.  Grid cells and head direction cells are in the entorhinal cortex and create a virtual map of triangles that provide the hippocampus with additional information of location and heading.  It's a full navigation system that receives additional sensory information from sight and hearing.  

 

Some of us make better use than others.

 

I've been wondering about the "court sense" seen in some elite athletes where it's important to know the position and motion of the ball as well other relevant players at any moment.  Soccer, hockey, rugby and beach volleyball come to mind. Using beach volleyball as an example the best players create an evolving mental map of the other three players including one that may be behind you.  They can't take the time to think about it.   It's interesting talking to a player.  They may be unaware of the uniform or other details of the other players, but are very aware of a few pieces of dynamic spatial information. 

 

Toddlers often take indirect paths getting distracted by any number of interesting waypoints on their path.  As adults we tend to take what we think is the easy path from A to B and these days that information comes from the GPS in our phone or car.  GPS navigation isn't infallible, but the same is true for human navigation.  Are we getting worse at human navigation by relying on these satellite consultations so much or is it just a computational extension of our brain?

 

fMRI experiments have been done with people navigating virtual cities and forests with and without GPS.¹   Compared to those who navigated using their own mental maps there was much less hippocampus activity in those who navigated by following external directions.   The virtual map generated by the hippocampus seems to appear only when you are actively engaged in the act of navigation.  It's like we're bypassing part of our brain when we use a GPS.  It has also been shown that enhanced use of personal active navigation increases the size of the hippocampus while inactivity causes atrophy.²  

 

Make it a game to turn off your GPS and navigation on your own for awhile.  There are numerous natural signs and signals that help you find your orientation and path.  Which side of the tree has moss? What is the sun angle and shadow direction?  Which direction is North at night? .. and hundreds more.  Try it in a city too.  If you get lost you can always pull out your phone for a quick look.  You might even find the fun of discovery that a toddler gets by observing their surroundings more carefully.    There's even some evidence that exercising the hippocampus by building up rich maps through cafeful observation lower dramatic stress.  Perhaps give up the GPS function, but sketch or carefully photograph was you see.  Straight up play and you might be doing your brain a favor. 

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¹ Several studies exist.  Here's a fascinating fMRI study taking place in virtual London.

² London taxi drivers have to spend a large amount of time building a mental virtual map of much of the city.  Brain scans show highly developed hippocampus regions.  Some preliminary work with people genetically disposed to early onset dementia has found people with highly developed hippocampuses may be protected from decline.