We carry a map of our bodies around in our brains. It’s not a literal picture, but an organised pattern of brain activity. So, touch different fingers and different parts of the brain respond. Remarkably, this arrangement is highly consistent from person to person.

Known as the somatopic map, where somato means “body” and topo means “place” in ancient Greek, this is one of the oldest and most recognisable ideas in neuroscience. But we still do not fully understand why the brain has a body map, or how important its precise organisation is.

A new study by my colleagues and I looks at whether the brain’s hand map changes after surgical repair of a nerve in the hand. We found that it does, which could have useful implications for rehabilitation.

Touch your thumb, index finger or little finger and each produces a pattern of activity in the part of the brain involved in our sense of touch: the primary somatosensory cortex, or S1. Neighbouring parts of the body tend to activate neighbouring parts of the brain. The orderly spatial arrangement that this creates is what we mean by a somatotopic map.

It dates back to the 1930s, when Canadian-American neurosurgeon Wilder Penfield stimulated different parts of the exposed brain during surgery. This showed that different locations corresponded to sensations in different parts of the body.

Similar body maps have been found........

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