Outline how one study demonstrates localisation of function in the brain.

Localisation is the theory that different areas of the brain correspond to different functions and behaviours. Hence if one such area becomes damaged, the function that it carries out will no longer be performed. This view has received considerable support, especially from individual case studies. One such case study is that of HM as described by Milner and Scovill (1957). Following a fall, HM experienced epileptic seizures of increasing severity. After trying medication with no success, HM decided to undergo surgery to control his seizures. During this surgery HM’s hippocampus and surrounding cells were removed. As a consequence of this removal, after surgery HM experienced anterograde amnesia. This form of amnesia describes when a person can remember long term memories but has difficulty forming new memories. Thus HM could remember details from before his surgery but had difficulty remembering events that had occurred after his surgery. For example, years after his surgery in 1953, HM still recalled the year as 1953 and his age as the same as when he had had surgery. Despite the large changes in his memory, HM’s IQ did not change significantly and his personality remained the same. While experiencing some loss of long term memory, the main effect of the removal of his hippocampus was an inability to process short term memories into long term memories. This case study supports the localisation of different functions of memory. Under the multi-store memory model, memory is considered to be formed of sensory memory (which lasts for less than a second), short term memory (which lasts for less than a minute) and long term memory (which can last a lifetime). The study of HM suggests that the function of converting short term to long term memories was produced by the hippocampus, thus when this brain area was removed this function was lost. Consequently, HM could remember events before his surgery but could not form memories, and such remember events, after his surgery. Hence the correlation displayed between the removal of the hippocampus and loss of memory function in HM suggests that this area of the brain was responsible for this function. This therefore demonstrates localisation of function in the brain.