So i think it’s official: everyone at Neuroanthropology has a copy of Doidge’s book. Paul and I were discussing it, too. And, yes, that whole discussion is why I asked Lord about deafferentiation of the feet. Thanks for reminding me of the ‘cobblestone mat’ example — I’ll have to include it in my eventual equilibrium chapter/paper (the one I’ll give at the AAAs if our panel gets accepted).

But overall, I think that balance is a great example — glad I’m not the only one. Since I’m also interested in the high-performance end of balance abilities, such as capoeiristas who achieve almost uncanny unbalance while walking on their hands and on Uighur kids who are taught to tightrope walk at a very early age, I’m intrigued by what other sorts of sensory input might also be brought into the ‘equilibrium synthesis,’ especially when some of the normal inputs are taken out of the equation. In other words, equilibrium is a great ability to deal with because, both in degenerate and exceptional forms, the ‘sense’ is making use of different sorts of sensory inputs, forms of self-monitoring, strengths, and behaviour patterns to keep the body balanced (which is itself a situatlonally defined standard, as different activities allow us to compensate in diverse ways — a tightrope walker has fewer action options to compensate for instability, for example).

But overall, it’s fun stuff. That’s why I’ve had such a great time getting stuck into it. Thanks, though, for the great reference. Lord’s research and work has been a great boost to my thinking, and I’ve barely scratched the surface on it. GD

I’ve been reading Doidge’s The Brain That Changes Itself, and he relates an idea from Michael Merzenich about the decline in “gross motor control” as we age. To quote: “Aside from a failure of vestibular processing, this decline is caused by the decrease in sensory feedback from our feet. According to Merzenich, shoes, worn for decades, limit the sensory feedback from our feet to our brain. If we went barefoot, our brains would receive many different kinds of input as we went over uneven surfaces. Shoes are a relatively flat platform that spreads out the stimuli, and the surfaces we walk on are increasingly artificial and perfectly flat. This leads us to dedifferentiate the maps for the soles of our feet and limit how touch guids our foot control. Then we may start to use canes, walkers or crutches or rely on other senses to steady ourselves. By resorting to these compensations instead of exercising our failing brain systems, we hasten their decline.”

In other words, the argument is that the lack of diverse sensory input from our feet leads to the “use-it-or-lose-it” phenomenon in neuronal processing. This can create its own sort of “sensory weakness,” similar to the muscular strength weakness in the legs. And Doidge’s point about the emphasis on compensation, rather than re-training the under-used parts of the brain, is one he repeats throughout the book, as it works well with the break-it-down-into-pieces research approach (provided individual variation is also considered).

Not surprisingly, Chinese medicine, with its emphasis on accupuncture and accupressure, seems to have realized this sort of thing long ago. One particular “intervention” was to walk along a path of rounded but uneven stones, thus stimulating the feet (and thus the overall body). In the US, this has been adapted to a “cobblestone mat” that has been clinically shown to be an effective intervention for balance and for blood pressure in people over 60. For more info, see here: http://massagetherapy.suite101.com/article.cfm/reflexology_and_cobblestone_mats