Brain Scanning Techniques

Question 1

Describe fMRI brain scans

Answer 1

• Functional magnetic resonance imaging (fMRI) measures brain activity
• Detects changes in blood oxygenation and flow that occur in response to neural activity (when a brain area is more active it consumes more oxygen, blood flow increasing to meet increased demand)
• Can be used to produce activation maps showing which parts of the brain are involved in particular mental processes

Question 2

Describe PET brain scans

Answer 2

• Positron Emission Tomography (PET) uses trace amounts of radioactive material to map functional processes in the brain
• A positron is emitted during radioactive decay, picked up by the detector
• High radioactivity associated with high brain activity in a particular area

Question 3

Describe CAT/CT brain scans

Answer 3

• Computed tomography (CT) scans build up a picture of the brain based on the differential absorption of x-rays
• Subject lies on a table that slides in and out of a cylinder containing an x-ray source riding on a ring inside the tube around the patient’s head
• Images are made using x-rays depending on the absorption of the beam by the tissue it passes through