Localization of function

Studies

Maguire (2000) Terms to define

• Localization

• Hippocampus

Maguire (2000) Aim

To investigate whether changes could be detected in the brains of London taxi drivers and to further investigate the functions of the hippocampus in spatial memory

Maguire (2000) Procedure

• Natural experiment

• The participants were 16 male, right-handed male London taxi drivers

• Their MRI’s were compared with MRI’s of another 50 male non-taxi drivers (control group)

• Researchers were trying to see if there was a relationship between the number of years driving and the anatomy of the brain

Maguire (2000) Results

• The posterior (back) hippocampi rewas significantly larger in thaxi drivers

• The anterior (front) hippocampi was smaller in taxi drivers than in control subjects

• The hippocampal volume of the right hippocampus in each taxi driver correlated with the amount of time spent driving (the back part of the right hippocampus grew larger and the front part shrank)

• The larger posterior hippocampi made the taxi drivers more proficient at spatial memory and navigation

Maguire (2000) Evaluation

• Demonstrates the plasticity of the hippocampus in response to environmental demands

• The changes in hippocampal grey matter, at least on the right, are acquired

• The environmental demands of being able to navigate a complex structure of streets led the taxi drivers to develop more pronounced posterior hippocampi than the control subjects

Draganski (2004) Terms to define

• Localization

• Mid-temporal area (related to visual memory)

Draganski (2004) Aim

To see whether learning a new skill (juggling) would have an effect on the brains of participants

Draganski (2004) Procedure

• 24 volunteers all non jugglers

• Divided into two conditions: 1. Juggles, 2. Non jugglers (control condition)

• Both conditions had an MRI to start with

• After, the jugglers were tought how to juggle and notifiy the researchers when they had mastered it

• The jugglers had a second MRI Were told to stop practicing juggling

• They had a third MRI three months after stopping

• To analyse the MRI scans they used voxel-based morphometry to determine if there was significant differences in neural density (grey matter) in the brains of jugglers vs non-jugglers

Draganski (2004) Results

• From the baseline (first) scans, taken before the study began, there was no significant regional differences in grey matter between the two conditions

• At the end of the first part of the study, jugglers showed more grey matter in the mid temporal area

• After the jugglers stped practicing, the amount of grey matter decreased

• There were no changes in the control condition

Draganski (2004) Evaluation

• Juggling relies more on visual memory than on procedural memory

• Procedural memory would more likely show change in the cerebellum or basal ganglia

Localization of function and studies general evaluation

• Localization research is often limited to very specific behaviors (e.x. spatial memory, habits, etc)

• Memory as a whole is distributed throughout the brain

• Most of the research is correlational research (like most quasi-experiments)

• The studies draw indirect conclusions about the specific role of certain areas of the brain (correlation is not causation)