Bio Psych

• CAT scanning

  -computed axial tomography

  - CAT scans use X-rays and a computer to create detailed structural images of the inside of the body and the brain
• how CAT

  - The person lies inside a large scanner which is slowly rotated around them - Each image is a cross-section of the brain, when all of the 'slices' are put together they can build us a very detailed picture
• who CAT

  - Can be used on brain damage patients to discover extent of injuries, cannot be used on pregnant women as radiation could damage the foetus.
• strengths of CAT

  - useful for revealing abnormal structures in the brain such as tumours or structural damage the quality of the images provided by the scans are much higher than that of traditional X-ray
• weaknesses of CAT

  -require more radiation than traditional X-rays, the more detailed and complex the scan is, the more radiation exposure the patient receives. This means cat scans cannot be used often. Low ethics as repeated exposure could lead to cancer.

  -can only provide structural info, they do not give information about activity of the live brain unlike other scans, this means they have a limited use in researching links between brain areas and particular behaviours.
• PET scanning

  -Positron emission tomography

  -Measures metabolic activity in the brain, for example, showing areas that are the most active
• how PET

  -The patient is injected with a small amount of a radioactive tracer such as glucose the tracer provides small positrons which give signals that are recorded, as the glucose is used in the brain, this shows up as an area of activity

  -Recordings can be displayed as images which are then interpreted by understanding that the most active areas are coloured red or yellow whereas the least active areas are coloured blue
• PET strengths

  -PET scans provide evidence of localisation of function as they indicate the specific areas of the brain that are involved in experience. For example, the person can be asked to look at a picture or do a jigsaw puzzle and the linked brain area can be identified
• PET weaknesses

  -Ethical issues related to the injection of the radioactive tracer used in the scans as radioactive substances con cause damage to the tissues of the body, this means the technique can only be carried out once every six months, this further limits the use for psychological research.
• who PET

  -can be used in the study of schizophrenia to see which parts of the brain are working

  -epilepsy can also be studied by looking at blood flow in the brain
• fMRI

  -functional magnetic resonance imaging
• fMRi how

  -Uses radio waves to measure blood oxygen levels in the brain

  -The areas of the brain which are most active use the most oxygen and therefore blood is directed to the active area, this is a haemodynamic. response.

  -This activity or response is picked up through radio signals, these radio signal produce a series of successive slices which are then turned into a 3D image by a computer.
• fMRi relies on

  blood flow and neuronal activity are linked
• fMRI who

  -looking for onset of Alzheimer's

  -mental health issues to see effects on brain functioning

  -not good for claustrophobics or people with pacemakers
• fMRI strengths

  - Doesn't rely on radiation

  - If administered correctly, virtually risk-free, non-invasive and straightforward

  - Produces images with high spatial resolution, depicting detail by the millimeter and providing a clear picture of how brain activity is localized
• fMRI weaknesses

  - Expensive

  - Only establishes a clear picture if person lays completely still

  - Poor temporal resolution, 5 second lag time which can create issues when tryingh to interpret the information received

  - Only measures blood flow, not individual activity, therefore, it is difficult to tell what brain activity is being represented
• raine et al (1997)

  used PET scanning to measure the size of brain areas to see if murderers who were pleading NGRI in the areas known to link to aggression
• betts (2009)

  suggested that a case where a man strangled his wife could have been due to brain damage, CAT scans were used to gather evidence and they showed some damage and a widened sulci
• Axial

  Refers to the angle of the 'slices' in CT scanning, perpendicular to the area being scanned
• Helix shape

  A modern approach in CT scanning, advantageous over slices, used to study different angles of an area of interest
• Cognitive tasks

  Activities such as speaking, reading, or thinking used to study brain functioning in PET scanning
• Meta-analysis

  A study pooling data from various sources to provide a comprehensive overview of a research area
• Vasopressin

  A neuropeptide linked to moderating aggression, studied using fMRI

  brunnlieb et al (2013) - carried out a study to see if taking vasopressin would moderate aggression using fMRI