Methods of cortical specialisation

Methods of studying cortical specialisation are divided into two groups: the invasive, and the non-invasive. The invasive methods are those, in which something is injected into the brain, to find out what the problem is. The non-invasive methods are more ethical, as there are no changes in the brain area, therefore no damage can be done to it. One of the invasive methods of cortical specialisation is neurosurgery. It involves manipulating with the structures within the brain. There are two main ways of performing neurosurgery: ablation, which is a surgical procedure used to remove certain areas of the brain, and lesioning, which is cutting neural connections within the brain. An advantage of using neurosurgery, is that it allows for a lot of control and detail in the location of faults within the brain. On the other hand, cutting neural connections, or removing certain parts of the brain, may damage other ones, which may lead to a more severe consequence. Another invasive method is electrical and chemical stimulation. It is a very important technique, which involves electrical stimulation of certain parts of the brain. There is also the Wada test, which is a chemical test used to establish which functions correspond to which hemisphere of the brain, which is done by injecting an anaesthetic into one hemisphere at a time in order to stop any language or memory functions in that hemisphere. A strength of this method, is that stimulating the brain is less harmful than surgery, therefore making it more ethical, however, the research conducted on animals, cannot be applied onto humans, which may cause unreliable results. Post-mortems, are another method. They are used to compare brains to look for faults. A patient, who has a rare affliction, is examined after his death. The part of the brain that is damaged is then associated with the affliction. Before the introduction of scans and X-rays, this was one of the only ways to study cortical specialisation. It