03: Chasing the Phantom

Chasing the Phantom is an article about phantom limbs. Phantom limbs are the sensation that an amputated or missing limb is still attached to the body. The article discusses two main types of phantom limbs; those that feel like they are moveable, and those that are paralyzed that cannot be moved. Firstly he questioned what caused these phantom limbs in the first place.

He interviewed a girl named Mirabelle. At first he questioned whether they actually felt anything or if it was a desire to fit in. Mirabelle gave evidence to actually feeling something because she felt her phantom arm was shorter than her prosthetic. Because she never had an arm he assumed that there had to be a genetic aspect to phantom limbs.

Another man named John McGrath had a phantom hand that was attached to his arm with nothing in between. If you tell him to grab a cup with his phantom limb and pull the cup he felt pain. Ramachandran says that simple hand movement starts in the primary motor cortex with complex movement starting in the supplementary motor area. The difference in feeling for hands and forearms can be explained by this. The supplementary motor area acts as a master of ceremonies, passing specific instructions about the proper sequence of required movements to the motor cortex. The signal continues to travel down the spinal cord to reach the muscles that need to be stimulated. When a command goes from the supplemental motor area to the motor cortex, not only does it send command signals to the muscle, it sends the signals to other areas in the brain, such as the parietal lobe and the cerebellum. This could explain why there is a limb is felt.

He then thought that maybe paralysis of the phantom arm is caused by a learned paralysis of an injury. He built a box which contained a mirror and reflected an image of his other hand. He then had his patient practice with it a few weeks, and to his surprise the patient lost all feeling in part of his phantom limb. Along with the feeling of his phantom limb, the patient also lost all pain that resided in the area. This shows that your perception of yourself can distort how you receive feeling and pain.