Brain Imaging Technology

PET scans

Inject subject with radioactive glucose/most active parts of brain use most glucose/computed map of brain activity/more active = red

MRI scans

Magnetic field used to track flow of oxygenated blood within brain/more active parts need more oxygen/blood flow is more concentrated in more active areas/fMRI takes many images in a short period of time

Uses of brain technology

• Compare brain activity between two groups of people

• Investigate which parts of the brain are involved in specific thoughts and behaviors

Evaluate PET scans

A: less catastrophic (open ring) / minor movements do not affect results

D: lower resolution / injection of radioactive substance

Evaluate MRI scans

A: high resolution / no additional equipment required

D: small movements can region the scan / claustrophobic

Raine

A: brains of violent murderers

P: comparison of two groups of people/ngri and normal non violent people/41 murderers had brains scanned/41 control

F: murderers had less activity in prefrontal cortex (associated with controlling impulsive behavior)/shrunken amygdala (associated with emotion and fear)

C: may explain why people become murderers/difficult to control violent impulses and lack of empathy and remorse

Evaluate Raine

Findings are consistent/not generalizable/correlational study (can’t be sure that the brain abnormalities are the reason for murder)

Limitations of PET and MRI

• multiple areas of the brain light up in any situation, making interpretation difficult

• Brain areas activate for multiple reasons

• Results are correlational

• fMRI measures changes in oxygenated blood flow, not neural activity

• Brain scans are not a natural environment, low ecological validity