Brain Scans

Question 1

Structural imaging

Answer 1

• Produces a static image of the brain
• Deals with the structure of the nervous system
• CT

Question 2

Functional imaging

Answer 2

• Produces images of what the brain is doing or which areas of the brain are active during certain tasks
• PET/fMRI

Question 3

CAT scan
(mechanism of the scan, risks, measurement, usefulness and limitation)

Answer 3

• Uses X-ray that pass through the brain in multiple angles and the computer creates an image
• Potential risks due to X-ray radiation
• It measures what areas of the brain are damaged or positioning of tumours but doesn’t tell us about how the brain is functioning
• Very quick to conduct showing accurate details of the brain and the quality of the images can show tumours or structural damage that could lead to better understanding of the area
• It cannot tell you about how the brain is functioning, only provides structural information, therefore limited use in research linking brain areas to specific behaviours

Question 4

Positron Emission Tomography (PET) scan
(mechanism of the scan, risks, measurement, usefulness and limitation)

Answer 4

• Patients are injected with a radioactive tracer that is absorbed into the bloodstream and binds to glucose molecules in the blood
• High concentration of gamma rays can be found in areas of high activity and images produced by PET scans will show these
• Low risk but it is unclear of long term effects
• It measures glucose usage in the brain and the more glucose usage, the more active the brain area is
• PET scans indicate specific areas of the brain involved in an experience, they can provide area of localisation of function in the brain when the ppts are doing tasks
• The radioactive tracer has potential to damage cells and tissues in the body, so the scan can only be done once every six months

Question 5

Functional Magnetic Resonance Imaging
(mechanism of the scan, risks, measurement, usefulness and limitation)

Answer 5

• A powerful electromagnet is used, which contains hydrogen in water molecules in your brain will algin with the magnet, blood cells with oxygen will repel the magnetic field whereas the blood cells with no oxygen will follow the magnetic field, these changes in magnetic field are measured by a computer
• There are little risk but people who have metal surgical implants and pacemakers cannot go through an MRI
• Areas of the brain that use more oxygen are more active by looking at oxygen levels of the blood you can see which areas are being used
• fMRI scans indicate the specific areas of the brain involved in an experience and can provide localisation of function in the brain when ppt are doing tasks
• fMRI scans is only effective when the person being investigated stays perfectly still, meaning it may be problematic for young children or people will motor disorders, therefore there is limited usage of fMRI scans in investigating children

Question 6

Overall benefits of using brain scans

Answer 6

• Reliable and objective ways to measure brain activity
• By comparing measurements against observed behaviours we can establish connecting between brain areas and behaviours

Question 7

Overall issues of using brain scans

Answer 7

• The tasks in brain scans are generally low in mundane realism they may not trigger or activate the brain in the same way where a real behaviour would
• Therefore finding on brain activity in these studies may not be applicable