brain and neuropsychology

• Describe the advantages of modern brain scanning techniques.

  Brain scanning techniques can be performed on 'live' brains. They can identify brain damage or disease.
• KEY WORD: what is a CT scan?

  Computerised Tomography image: a machine scans the body or the brain using a series of X-rays and then creates a detailed 3D image.
• Describe how CT scans can be used to learn about brain functioning.

  Large doughnut-shaped scanner rotates around the person to take lots of X-rays of the brain. Images are taken from different angles and are combined to build up a detailed picture.
• Describe the strengths of CT scans.

  Useful for revealing abnormal structures like tumours. Quality of the images provided is higher than traditional X-rays.
• Describe the weaknesses of CT scans.

  Requires more radiation than X-rays. Only produces still images.
• KEY WORD: what is a fMRI scan?

  Functional Magnetic Resonance Imaging: a machine scans the brain using radio waves to measure blood supply and identifies the magnetic activity of water molecules in active brain cells to show which parts of the brain or body are functioning at that time.
• Describe how fMRI scans can be used to learn about brain functioning.

  Measure changes in blood oxygen levels in the brain. Brain activity displayed as 3D images produced on a computer screen.
• Describe the strengths of fMRI scans.

  Shows brain in action. Clear images. No radiation.
• Describe the weaknesses of fMRI scans.

  Expensive. Person must stay very still. Time lag between activity and image appearing.
• KEY WORD: what is a PET scan?

  Positron Emission Tomography: measures the activity of cells in different parts of the body by detecting a radioactive dye which is absorbed by tissue and organs after being injected or swallowed.
• Describe how PET scans can be used to learn about brain functioning.

  Patient is injected with a radioactive substance like glucose. Brain activity shown on a computer screen.
• Describe the strengths of PET scans.

  Shows brain in action. Shows localisation of function when person asked to perform a specific task.
• Describe the weaknesses of PET scans.

  Expensive. Images difficult to interpret. Ethical issues due to the injection of radioactive substance.