Techniques to study the brain

Studies

Maguire (2000) Terms to define

• MRI

• Hippocampus

Maguire (2000) Aim

To investigate whether changes could be derected 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

Baumgartner (2008) Terms to define

• fMRI

• Oxytocin hormone

Baumgartner (2008) Aim

To investigate the role the hormone oxytocin may play in trust relationships

Baumgartner (2008) Procedure

• Laboratory experiment

• 49 participants had an fMRI

• They recieved either ocytocin (group 1) or a placebo (group 2) via nasal spray

• Participants were told to act as investors in several rounds of a trust game involving financial risk, with different trustees

• The investor must decide whether they want to keep or share an amount of money with a trustee

• If the sum is shared it will triple the amout and the trustee has to decide whether to pay the trust back by sharing half with the investor or violate it by keeping all the money

• In a second condition, they were told they were playing a ‘risk game’ with a computer instead of another human

• The experimenters gave them feedback saying that their decisions had resulted in poor investments as they broke the trust and then to make their next investment

Baumgartner (2008) Results

• Placebo participants, before they started playing were more likely to decrease their rate of trst after being breifed that their trust had been broken

• Participants who recieved oxytocin continued to invest at similar rates

• Apparently it did not matter to them that their partner had broken their trust

• Different brain areas were active in the two groups

• The oxytocin group showed decreases in responses in the amygdala and caudate nucleus

• The amyglada (has many oxytocin receptors) is involved in emotional processing and fear learning

• The caudate nucleus is associated with learning and memory and has a role in reward-related responses and learning to trust

• The results observed were only apparent when they played the trust game but not the risk game, meaning that oxytocin’s effects on trust are exclusive to human interaction not computer

• Oxytocin may facilitate the expression of trust even when it has been violated by lowering fense mechanisms associated with social risk, therefore decreases our ability to learn from mistakes made in trusting people

Baumgartner (2008) Evaluation

Techniques to study the brain and studies general evaluation

• fMRI’s have an imprecise nature

• The over-interpretatio of color coding

• Issues of artifacts (fMRI machines)

• Lack of ecological validity

• Due to the cost of using fMRI’s causes small sample sizes (questionable generalization)

• Lack of cause and effect

• The technology allows for global researcher triangulation

• Use of databasess makes it easier to obtain samples