Localization

Question 1

Define localisation

Answer 1

The theory that certain areas of the brain correspond to certain functions. i.e. behaviours, emotions and thoughts originate in the brain in specific locations.

Question 2

Case study of HM

Answer 2

Milner 1957, hippocampus removal

Question 3

Hippocampus

Answer 3

• situated in the medial temporal lobe under the cerebral cortex.
• mainly associated with memory, especially the long-term memory.

Question 4

Aim

Answer 4

to investigate the removal of hippocampus in relation to localisation of the brain.

Question 5

Procedure

Answer 5

• HM suffered from epileptic seizure.
• the neurosurgeon removed his hippocampus and adjacent area of his brain (responsible for LTM retrieval).
• in-depth case study lasts over 50 years

Question 6

Results

Answer 6

• H.M. could not create new episodic (memory of autobiographical events) and semantic memories (long-term memory that are not drawn from personal experiences) but was able to learn a few procedural memories (motor skills) after the operation. His personality remained unchanged and there was no general intellectual impairment.
• this was confirmed by Corkin et al. (1997)’s MRI scan of HM’s brain as they found parts of the temporal lobe including hippocampus were missing.

Question 7

Conclusion

Answer 7

• Hippocampus is important in memory processing and particularly in the storage of new memories.
• The fact that H.M. had deficits in one part of the memory system but not in others is evidence that the brain has several memory systems, and that these are supported by distinct brain regions.

Question 8

Evaluation

Answer 8

• High ecological validity: study of a real life case.
• longitudinal research: contributed to the understanding of memory processing in relation to specific brain areas.
• results can not be generalised because the case is an individual.
• ethics: the patient cannot remember all the times he participated in research