It is hard to fully understand how the human brain functions. Often, people feel different sensations in their missing limbs, after the amputation of their hand or leg. Phantom limb pain has not been studied enough yet. However, many relevant researches have already been made, in order to get the opportunity to understand what phantom limb pain can teach us about the human brain.
Neuroscience gives us the opportunity to understand the complexity of the human brain, and to understand how it functions. Scientists study human brain and its functions from different angles. Some scientists try to completely unravel the structure of the human brain. Some scientists study the functions of the brain. First, they study parts of the brain separately, and then they study interactions between these parts.
People often feel some sensations in their missing limbs. They can feel that their hand, which has been amputated, is still connected to their body. People can also hear voices. These voices can be some voices of their friends, or the ones they once heard in a movie. Human brain can also make people hear voices that do not even exist. The brain can make different noises sound like human voices to people. People can also see things that other people do not see. They can experience all this only because of the complexity of the human brain. People feel the pain in the missing limbs, because of the damage of specific parts of their brain. The reactions in the brain are processed in the wrong way, thus they lead to the wrong functioning of the brain, so people feel something that does not exist.
If an arm or a leg has been lost in some kind of an accident or has been amputated, but it still exists in the mind of a person, and this person can feel this arm or leg, then it is called a phantom limb. People often feel pain in their phantom limbs, even after several years have passed, since the loss of the limb. In fact, 90% of people, who had amputation, experience phantom pain in the missing limb. The brain of a person has a specific body image in the mind. This image is set in the human brain by the genes. Thus, even after amputation of the limb, human brain tries to reshape the primary body image. Thus, because the reshaped limb is still missing in reality, person experiences the phantom limb pain.
Our brain makes referred sensations from the phantom, such as the sensations of a touch that are produced by the phantom limb. For example, if a person touches his/ her face, this person can experience the sensations in the fingers of the phantom arm. If a person feels pain or itch in his phantom hand, he can also feel how his phantom hand touches his face. If an object touches the face of the person, the person will not only feel the object on the face, but will also feel the sensation of the touch in the missing hand. By touching the cheek, people can map the phantom hand of the person on his face. If something cold is being put on the face, the person will also feel the cold sensation in the phantom limb. The process of touching the face with different things can refer to the missing limb.
All parts of the body are mapped onto the cerebral cortex of the human brain. The brain is divided into different parts that are controlling different processes and have different functions. Somatosensory cortex processes the information received from the skin of the whole body. The brain cells of this brain part refer to the patches of skin on the body. Thus, when this patch of skin is being touched, it refers to the specific part in the brain. The part of the brain that refers to the face is placed near the hand part. After the amputation of the hand, the brain area that referred to the hand achieves all signals from the neighboring areas and perceives them as the signals from the missing hand.
In normal condition of the body, when it is intact, only the signals from the face part of the skin refer to the face part of the brain. However, when a person is missing a part of the body, the reactions to the signals can sometimes be wrong, and lead to the different results. The signals from the skin are misinterpreted by the referring part of the brain, and body starts to think that the signals come from the phantom limb. Phantom pain is treated as pathological. Some people can even feel how they move their missing limb. According to the relevant research, 99% of people, who had amputation of the limb, feel sensations in their missing arms or legs. Around 80% of them feel the pain in their missing limbs. This pain teaches us a lot about the human brain. For example, it shows us that there is nothing imaginary about the pain from the missing limb. It is just a wrong perception of the sensation coming from the body by the sufficient brain part. According to the relevant study, the residual representations of the arm or a leg in the brain lead to the phantom pain after the amputation of the limb.
To sum up, after an arm or a leg amputation, most people still feel sensations in the missing limb, and still have the perception of their missing limb in their mind. Phantom pain is experienced by the 80% of the people who had limb amputation. Phantom pain in the missing limb can be very strong. It is the result of the wrong processing and perception of the sensation in the body by the specific referring brain part. Phantom limb pain teaches us that the human brain is divided into several parts, which process different information from the body. If the limb is missing, the brain part that refers to it is not receiving the signals. Thus, the referring brain part of the missing limb processes the signals from the neighboring parts of the body as the signals from the missing limb.
See an article about wolfgang and ferracuti if this post appealed to you.