If a person loses an arm, what happens to the part of the brain responsible for control of this arm?
In: Biology
That part of the brain keeps doing what it’s supposed to, but now there’s nothing for it to actually act on. This causes some weird side effects, such as phantom limb syndrome where the person continues feeling the limb even though there’s nothing there.
Often, that phantom limb will feel uncomfortable or in pain and the amputee isn’t able to undo the sensation. The treatment is unbelievable though. They use a mirror to reflect the good limb and make it look like the other is still there. The brain actually believes the illusion, even when the conscious mind knows it’s a reflection, so that the uncomfortable sensations cease.
Sometimes, it kind of freaks out and convinces the body that the limb is still there and it is in pain. If that doesn’t happen, that part doesn’t atrophy or anything, it’s most just gets taken over by some other function. Your brain is good at allocating resources.
Imagine your brain as a big, busy city, where different areas have different jobs, like a park, a library, or a shopping mall. Now, imagine there’s a part of this city dedicated to controlling and feeling each of your limbs—your arms and legs. What happens if suddenly one of those limbs isn’t there anymore, like if someone lost an arm? It’s a bit like closing down the park. People (or in the brain’s case, the “brain cells”) that used to hang out in the park now don’t have their usual place to go.
But here’s the cool part: the brain is super adaptable, much more than a city. The areas of the brain that were dedicated to the missing limb don’t just stay empty or unused. Instead, they start to get visits from the brain cells that control and feel other parts of the body. So, if the “park” was for the arm that’s no longer there, the brain’s “visitors” from other areas, like the one for the face or the remaining arm, might start using that space. This means the brain area for the missing limb can become active again, but in a different way, helping with the sensations or movements of other body parts.
This ability of the brain to change and adapt is called “neuroplasticity.” Sometimes, this can lead to something called “phantom limb sensation,” where a person feels like their missing limb is still there. This happens because the brain’s map is still figuring out how to adjust to the change. Over time, the brain learns and adapts, showing just how flexible and amazing it is at dealing with changes.
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