Dendritic Pathways and Retirement

September 22, 2019

I have been wrestling with a big bear of a book called Behave:  The biology of humans at our best and at our worst, published in by Robert M. Sapolsky, who, according to the inside cover, “is a professor of biology and neurology at Stanford University and the recipient of a MacArthur Foundation genius grant.”   In other words, he is pretty smart.

I won’t kid you.  The book is tough going.  The cover blurbs call it “immensely readable”, and it is, if you find sentences like “Moderate, transient stress (or exposure to the equivalent glucocorticoid levels) increases spine number in the hippocampus; sustained stress or glucocorticoid exposure does the opposite” to be immensely readable.

But I’m fighting my way through it because there is so much good stuff in it.  One of the most interesting discussions is about the discovery of what is called “adult neurogenesis,” which is the formation of new neurons in adults (and the accompanying creation of new dendritic processes, which, as I understand it, enable the learning of new skills).  In other words, you can teach an old dog at least some new tricks.

I’ve been thinking about this while spending time at French school.  As I mentioned, most of students here are our age or a bit older.  Yet they are all spending time and money (albeit in a highly pleasurable environment) to learn something quite difficult — the French language with all its twists, turns and quirky pronunciations.  Few of us will truly master French, but all of us will benefit from new neurons.

It is a cliche, but the brain really is like a muscle.  It gets stronger, or at least gets less weak, the more you use it.  That, in part, is why I have taken up the piano, singing in a choir, and learning bridge in the past few years.  (I’ve been fooling around with French for a long time).

As Dr. Sapolsky says, “Hippocampal neurogenesis, for example, is enhanced by learning, exercise, estrogen, antidepressants, environmental enrichment, and brain injury, and inhibited by various stressors.”  I’m skipping the estrogen, antidepressants and brain injury, at least for now, but I’m all for learning, exercise and environmental enrichment.

I’m also thinking — and I want to learn more about this — that civic and/or charitable activity creates dendritic pathways.

Speaking of learning and environmental enrichment:  Yesterday we drove a lot and visited Chambord (which I thought was an enormous monstrosity, built without any sense of taste or proportion) and the lovely small city of Beaugency, right along the Loire.

Among other things to recommend it, Beaugency is home to the spectacular 12th century Notre Dame church, in which Eleanor of Aquitaine’s marriage was annulled, so that she could marry Henry II and so that the movie The Lion in Winter could be made.  It also has a 56-meter tower, which we duly climbed, despite the narrow stairs and the pigeon droppings.

That gave us the resulting view of the Loire and the wonderful Beaugency bridge, with most of its 23 arches captured on W.’s phone camera:




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