Localization + plasticity

Localization

Localization of function is the theory that specific parts of the brain are responsible for specific behaviors or cognitive processes.

Neuroplasticity

Plasticity refers to the brain’s ability to alter its own structure following changes within the body or in the external environment.

Mac guire study

• quasi experiment (researchers are comparing the sata of taxi drivers and non-taxi drivers. Researchers have no control of the IV bc naturally occuring)

• Participants: 16 right handed taxi driver ad 50 non taxi drivers (Matched pair design via age, gender and heandedness)

• Aim: Investigate the extensive use of the area of the brain responsible for spatial awareness causes structural changes in the brain

• Procedure: Scans were carried out and analysed by one experienced individual who was blind to whether they were taxi drivers or not

• Results:Posterior hippocampi of taxi drivers was significantly larger relative to those of control particiapnts. There was no difference between the gorups in terms of the overall volume of the hippocampus but there was a significant redistribution of grey matter from the anterior to the posterior hippocamplus in the brains of taxi drivers

• Conclusion: Brain changes structure in response to environmental demands

H.M

Aim: to determine the extent of HM's memory deficiency

Longitudinal case study: An observational research method in which data is gathered for the same subjects repeatedly over a period of time; can extend over years or even decades

Procedure: Neurosurgeon, Dr. Scoville, performed a experimental surgery taking out most of the hippocampus and tissue from the medial temporal lobes; HM was 27

Results: Concluded that the hippocampus wasn't the site of memory storage, but the site where it turns short term to long term memories

Conclusion

-HM strongly affirms the idea of localization of function in the brain
-asserting that the function of organization of memory is localized in the hippocampus

What can be learned about localization of function of brain in relation to memory from the case study of H.M.?

-Procedural memory is not stored through the hippocampus
-The brain has several memory systems
-Processes of memory are very complex
-The hippocampus is not the only structure involved in the process.

weakness of longitudinal study

-need larger sample size
-extremely time consuming

strengths of longitudinal study

-show clear variable patterns over time
-allow for clear focus and validity

localization of function: The idea that different parts of the brain do different things

Draganski (plasticity)

Aim: Find out whether the human brain can change structure in response to environmental demands

Procedure: Random sampling design, self-selected sample
Randomly allocated a sample of volunteers into 2 groups
One : jugglers
Two : non-jugglers
Made sure that both groups had no experience of juggling before the start of the experiment
First MRI performed
Participants in the juggler group subsequently spent three months learning a classic juggling routine with three balls
Second MRI performed
Participants in the juggler group spent three months where they were instructed not to practice juggling

Results

Prior to the start of the experiment there was no difference in brain structure
Second scan the juggler had more gray matter in some areas of the cortex mostly the mid-temporal area
Third scan differences decreased but jugglers denser gray matter

Conclusion

If we practice something then our brain will increase and when we stop practicing then it will decrease again, but often not to its original state

Strengths

No researcher bias - random sampling
Replicable
Cause/Effect relationship

Limitations

Low ecological validity
Participant bias - self-selected