Brain Scans

Question 1

structural scans

Answer 1

identify size and damage of certain brain areas

magnetic resonance imaging (MRI)

P placed in large circular magnet- causes H atoms to move in body

when magnet turned off- revert to original positions producing electromagnetic signal that’s translated by computer into pics of brain tissue

Question 2

functional scans

Answer 2

investigate activity levels of different brain areas

positron emission tomography (PET)

radioactive tracer combined with sugar, hormone or protein and injected into P

after period of time- P placed into computer scanner

positrons smash into electrons releasing gamma rays- detected by scanner

positions are plotted + varying levels of activity in brain are recorded

Question 3

example of structural scan

Answer 3

McCarley et al (1999)

showed enlarged ventricles in brains of individuals with schizophrenia with MRI

Question 4

example of functional scan

Answer 4

Raine (1997)

investigated brain activity of people pleasing NGRI using PET

Question 5

strengths of brain scans

Answer 5

+ allows for objective assessment of brain structure/function

+ allows investigation of live brains rather than waiting for post mortem

+ MRI best suited for cases when individual is to undergo the scan several times in short term- doesn’t expose patient to hazards of radiation

+ PET scans reveal chemical information that’s not available with other imaging techniques

Question 6

weaknesses of brain scans

Answer 6

• scans take a long time and can be uncomfortable- claustrophobia
• extremely costly
• PET can only be used a few times- radiation
• only limited range of activities can be investigated due to limitations of being stuck in a machine