Differentiation Builds Brain Maps

Extract adapted from
The brain’s way of healing: Stories of remarkable recoveries and discoveries
By Norman Doidge MD Scribe Books

Newborns, Feldenkrais observed,often make very large, poorly differentiated movements based on primitive reflexes, using many muscles at once, such as reflexively extending their entire arms. They also cannot discriminate among their fingers. As they mature, they learn to make smaller, more precise individual movements. But the movements do not become precise until the child can use awareness to discern very small differences among them. Differentiation, Feldenkrais would show, would be key to helping many people with strokes, children with cerebral palsy, and even autism.

Feldenkrais found, repeatedly, that when a body part is injured, its representation in the mental map becomes smaller or disappears. He relied on the work of the Canadian neurosurgeon Wilder Penfield, who showed that the surface of the body is represented in the brain by a map. Both the size of an individual body part in the brain map is proportional not to its actual size in the body but rather to how often and how precisely it is used. If the body part performs a simple function – the thigh, for example, mainly does one thing, moving the knee forward – the representation is small. But brain maps for the fingers, often used in precise ways, are huge. Feldenkrais understood that it is a use-it-or-lose-it brain, and that when parts are injured – and thus are not used often – their representation in the brain map decreases. By making very finely tuned – differentiated – movements of these parts and paying close attention while doing so, people experience them subjectively as becoming larger; they take up more of their mental maps, and lead to more refined brain maps.