Working in Movement

The subject of human brain plasticity shows up fairly regularly in these pages. My understanding of the basic idea of plasticity is something like this. The self (or body) shows up as an image in the brain and it is this image that the brain acts upon in movement. For the most part, this image is changeable (or plastic), sometimes easily so. A past post that refers to this is here.

A recent study in the UK sheds some more light on how this plastic thingy works, suggesting a kind of hierarchy of sensory information that can produce some pretty unusual results. How the Brain Feels False Limbs reports on the study in which people came to recognize a rubber hand as their own.

The people studied put one of their hands under a table where they could not see them. Researchers placed a realistic rubber hand on the surface that the subjects could see. The researchers then stroked the real hidden hand and the rubber hand at the same time. The subject's were also scanned with magnetic reasonance imaging (MRI) at the same time. In a few seconds, the subjects reported feeling the rubber hand as their own. The MRI images showed lots of activity in the premotor cortex.

The premotor cortex gets its information about the body from three sources; vision, touch and proprioception. What interesting about this study is that it suggests that vision takes precedence when there is an inconsistency. Explaining the plasticity, lead researcher Henrik Ehrsson said:

"This study shows that the brain distinguishes the self from the non-self by comparing information from the different senses. In a way you could argue that the bodily self is an illusion being constructed in the brain."

The information from this study has implications for working with people with self-perception issues, from stokes, phantom limbs or other disorders.

But this idea of plasticity, that they body image can change so quickly, can also prove useful in non-therapeutic everyday situations. The ability to quickly differentiate and then reintegrate the musculo skeletal system could benefit people who want to improve their stability, for example. Or the athlete or performer who wants to change some related aspect of their movement might find these ideas quite useful.