Brain plasticity in amputees
Brain plasticity is the ability of brain cells to adapt to new situations when deprived of their usual stimuli. The project PLASTICITYINAMPUTEES studied plasticity in terms of two major drivers for reorganisation of brain functioning: sensory deprivation and adaptive motor behaviour. In their first study, researchers looked at the relationship between brain plasticity and phantom pain - i.e. uncomfortable sensations where the limb once was. Researchers found that amputees suffering from more phantom pain show more normal brain structure and activity in the former hand area. Furthermore, the brain's response to phantom hand movements was indistinguishable from that seen in people with intact limbs. However, brain function is not normal. Communication between the hand and other brain areas responsible for interaction with the external environment appears to be disrupted. The second study looked at how amputees adapted to their disability. Researchers found that people born without one hand (congenitally deprived) tended to use their stump more than those who lost their hand later in life (acquired deprivation). These strategies are reflected in the brain, showing that adaptive plasticity is contingent on how the limbs are used. The third study focused on how local brain reorganisation affects the entire brain. This work showed that the area affected by the amputation decoupled from its network of origin (that responsible for movement) and became part of the network responsible for processing internal sensations. Researchers hypothesised that this shift may be the cause of phantom pain. Drawing on this knowledge, scientists used non-invasive brain stimulation and behaviour therapy to treat phantom pain. They were able to help a group of 12 amputees. This project is one example of how such work can benefit amputees. As shown by the research, the adult brain is more flexible than previously thought. Based on these findings, new rehabilitation programmes can be designed accordingly.
Keywords
Brain, amputee, plasticity, phantom pain, sensory deprivation, adaptive behaviour
