Brain Scans

Question 1

How is an MRI taken?

Answer 1

• Magnetic Resonance Imaging

• Uses a magnetic field which causes hydrogen atoms in the body to move

• When the magnet is switched off , these atoms revert back to their original positions , producing an electromagnetic signal

• Signals are detected and produce cross-sectional images

• 2D images of brain structure

Question 2

Advantages of MRI

Answer 2

• Doesn’t use radiation

• Allows for the objective (scientific) investigation of brain activity

Question 3

Disadvantages of MRI

Answer 3

• Must stay completely still

• Can take a long time & be uncomfortable

Question 4

How is a PET taken?

Answer 4

• Injects radioactive tracer & sugar , the brain controls positrons which move around in the brain & collide with electrons -> produce gamma rays

• More active parts of the brain will have more movement which produces an image of the brain

Question 5

Advantages of PET

Answer 5

• 3D images

• Less claustrophobic than MRIs

Question 6

Disadvantages of PET

Answer 6

• Not advised for pregnant women (baby exposed to radiation)

• Can still be claustrophobic

Question 7

How is an EEG taken?

Answer 7

• Electrodes are placed on the scalp which record electrical impulses in the brain and create a visual display of electrical activity in the brain

Question 8

Advantages of EEG

Answer 8

• No radiation

• Cheaper

Question 9

Disadvantages of EEG

Answer 9

• Unable to scan deeper areas of the brain

• Poor spatial resolution