It is not uncommon to see a person without one limb. Although in many cases it is a result of some kind of injury or a disease, many people are simply born this way. And one can only wonder, what do their brain areas, typically responsible for moving that particular limb, do? A new study from UCL looked into this question and revealed a surprising answer.
Researchers wanted to see what the brain area, responsible for moving a limb, does when a person is born without it. One would think that it simple does nothing, as the limb is not there. But this new study showed that it actually helps controlling lips, feet or arms, if the person is born without one hand. And it does kind of make sense – people with only one hand have to use other body parts to accomplish some everyday tasks. It is also interesting how scientists approached this subject.
They invited 17 people who were born without one hand and 24 two-handed controls. They had to complete some simple tasks such as opening a bottle, folding laundry or taking cash out of a wallet. Of course, for two handed people they were easy, but people with only one hand had to use their arms, feet, lips or other body parts. Then they were asked to move these body parts while fMRI scanner was monitoring their brain. And sure enough, “hand area”, responsible for missing limb, was very active.
This is the first study to show multiple body parts benefiting from the same cortical area in the brain. It serves as an example, how flexible human brain really is. And it changes our understanding on different brain areas and how their functions overlap. Dr Tamar Makin, senior author of the study, said: “We call this area of the brain the ‘hand area’, but perhaps it’s not really the hand area, but the area controlling whichever body part enables us to interact with our environment”. Our behaviour sculpts the basic structure of our brain.
A powerful region in the brain cannot stay doing nothing just because a person does not have a hand. Brain is using its resources as efficiently as it can. It means that organization of the brain is not pre-determined by some objective factors – it is flexible.
Scientists say that they are hoping to use this knowledge to inspire more research about best methods to integrate assistive and augmentative technology. It could help developing a new generation of prosthetic limbs, which would be more useful for people without one hand or other limbs.