CAT, PET, fMRI

• describe PET scans


  - Pet scans are a slightly more invasive form of measurement of brain activity, that involves injecting a patient in the with as all amount of a radioactive tracer (FDG) added to a chemical such as glucose.

  - The tracer omits small, positively charged particles called positrons, which give signals, that are then recorded.

  - As the glucose is used in the brain, it shows up as an area of activity.

  - used to identify brain damage or tumour, showing levels of activity blue=low red=high

  - detect areas of damage by indicating which parts are showing abnormal levels of activity, helps researchers see where problems exist and predict what kind of issues they may face in relation to brain areas' activity
• a study that used PET scans

  - Raine et al used to investigate diff between brain activity in murderers and non-murderers

  - they were able to measure any abnormal brain activity in the murderers' group in areas of the brain associated with impulsivity and risk-taking bhv whihc may explan increased agg they found murderes had less glucose activity in some parts linked to violence
• strengths of PET scans

  VALID- can measure thing like where speech impairments are caused by broca's aphasia and can predict issues, where parts of brain are not functioning properly e.g. raine

  RELIABLE- standardised procedure e.g. patitent injected with FDG, given task which releases gamma rays picked up by scanner
• weakness of PET scans

  MOST INVASIVE- patients are injected with a radioactive tracer

  LONG TERM EFFECTS-patients are advised not to have too many as risk of long term effects

  NOT USEFUL- cannot pinpoint exact locations only shows general area of abnormal activity
• describe CAT scans


  - used to take images of any part of the body and brain, very quick to conduct (15-30 mins) and can give accurate detail of brain structure, helps guide clinicians in decision making regarding treatment or surgery

  - involve passing x-rays into the head, multiple beams are passed around the head from diff angles to gather more info

  - info from x-ray beams is interpreted by computer and detailed image of brain structure shown, useful for detecting areas of brain damage following accidents or positioning of tumours

  - the pictures are formed to pick up how the area being scanned reacts to the X-ray being passed through it, showing how far the X-ray is blocked

  - exposure to radiation and its advised that they are only used when possible benefits outweigh risks
• a study that used CAT scans

  - Betts study of herbert weistien, defence used CAT scan to show he had damage to the brain that might have led to agg (strangled wife) and scan showed damage, this evidence was used to persade jury that his actions were not thought through
• strengths of CAT scans

  QUICK- only takes 15-30 mins, means clincians can make quicke decision making about treatment, reducing risks regarding anaesthetics

  SCIENTIFIC- x ray beams focused on specific areas to produce an detailed image on computer, objective high quality images than MRI so useful to detect tumours/damage
• -The use of X-rays in CAT scans can pose a risk to patients as they involve exposure to radiation and it is advised that they are only used when the possible benefits in relation to diagnosis outweigh the potential risks.

  -They are, however, less risky than exploratory surgery.

  -Pregnant women are advised not to have CAT scans where possible as there is some evidence that exposure to X-rays can cause damage to new born babies.
• describe FMRI scans

  - fMRI (functional magnetic resonance imaging) scanning refers to functional MRI implying it looks at the functions of the brain.

  - Based on what task you are doing it can show what changes occur in the brain.

  - It uses radio waves to measure blood oxygen levels in the brain. Changes in the blood flow highlight neuronal activity and shows the cell use of energy. Oxygenated and de-oxygenated haemoglobin is looked at.

  - Blood flow in the brain refers to consumption or flow of glucose and different structures do that differently eg. The amygdala, basal ganglia, thalamus relate to the flow of glucose not its consumption. Those areas of the brain that are most active use most oxygen and therefore blood is directed to the active area. This is haemodynamic.

  - This activity is picked up through radio signals and these signals produce a series of images of successive slices which are then turned into 3D using a computer
• a study that used FMRI scans

  - li et al investigated how herion effects diff parts of the brain, they found in the cue induced task activation of the PCC and other brain regions in the herion group complared to control group
• strengths of FMRI scans

  MINIMAL RISK- doesn't use radiation, minimising risks of potential complications down the line

  RELIABLE- produces images with spatial resolution showing detail and clear image of how brain activity is localised, high inter rater reliability
• weaknesses of FMRI scans

  -Because of the use of high-powered magnetic fields in fMRI scanning, some people are unable to have these kind of brain scans. Eg, anyone with a cardiac pacemaker or who has had recent metal surgical implants would not be able to have one of these scans.

  -Anyone who is claustrophobic or unnerved by confined spaces or loud noises may become quite stressed during the procedure (as they have to lie flat and still in a large tube for the duration of the scan). This may not be suitable for all patients.
• Evaluation of using brain scanning techniques to investigate human behaviour

  -Meta-analyses are used, which draw on many different studies using different evidence and techniques, and when findings support one another this suggests reliability and scientific credibility. Reliable findings as studies have been repeated and the same results found, and drawing on many different studies has the same effect.

  -Brain scanning can be seen to be valid as it does measure brain activity and that is not denied.

  -The results are visible and measurable and it is generally accepted that brain scanning, such as fMRI, does show actual brain activity, including the sites of activity, although whether the responses in the brain measure validly the behaviour of interest is in doubt. For example, there may be a lack of validity in that tasks intended to generate aggression in someone might not lead to aggression- that is an assumption.

  Getting someone to feel aggression in a study is not easy- it might not be ethical and tasks may not yield aggression in all individuals.
• Quick

  CAT (Strength) - _____ to conduct, due to using X-rays and computer.
• abnormal


  CAT (Strength) - useful for revealing _____ structures in the brain, such as tumours or structural damage.
• Quality

  CAT (Strength) - quality of images is much higher ____ in comparison to traditional X-Rays.
• plan

  CAT (Strength) - the information provided from a CAT scan, can help a surgeon better ____ a procedure before surgery, by being allowed to see the layout of the brain, making it faster and more efficient, reducing risk.
• radiation


  CAT (Weakness) - the use of x-rays, pose the risk of exposing patients to ______.
• Radiation


  CAT (Weakness) - CAT scans require more _____ than traditional X-rays, the more detailed the CAT scan is the worst this can get.
• Structural

  CAT (Weakness) - CAT scans only provide ____ information. Unlike other scans, they do not provide information on brain activity such as PET scans. Limited uses.
• Radioactive glucose, tissues, cells, mutations

  PET (Weakness) - There are ethical issues. The injection of ______ _____ may cause damage to the ______, they may kill _____ or cause _______ in the DNA code in cells.

  
  

  (Answer: _____ _____, _____, _____, _____)
• Invasive


  PET (Weakness) - PET scans are more ____, compared to other scans, as it requires patients to be injected with a radioactive substance (even though this is a low amount)
• Conclusions


  PET (Weakness) - It is difficult to draw _____ on the results, due to people doing the same task showing different levels of brain activity, making it hard to know which brain areas are linked to which behaviour.
• action

  PET (Strength) - PET scans show the brain in _____, which is useful for psychological research.
• Cocaine


  PET (Strength) - Nora Volkow et al used PET scans to correlate the activity of dopamine transporters during a ______-induced "high". This means biological activity could be linked to behaviour.
• Detecting


  PET (Strength) - ____ areas of damage in the brain is possible, by seeing abnormal levels of activity, can help researchers predict issues the patients might face or see where problems exist.
• areas


  PET (Strength) - PET scans can indicated the specific ____ of the brain that are involved in experience.
• millimetre


  fMRI (Strength) - fMRI scans are clear and can show brain activity to the _____
• radiation


  fMRI (Strength) - Unlike CAT and PET scanning. fMRI does not use ______, and so it is a safe method.
• Pardini et al


  fMRI (Strength) - Name the case study that used fMRI scans to measure the volume of participants' amygdala levels and relation to observed levels of aggression.
• areas

  fMRI (Strength) - fMRI shows important information. Such as the specific ____ of the brain in used at one time. Pardini's experiment used this function to measure amygdala levels.
• expensive


  fMRI (Weakness) - Unlikes PET scans, fMRI scans are _____ to use.
• magnetic fields


  fMRI (Weakness) - Due to the use of high powered _____ _____, some individuals are unable to have this type of scan. (e.g. anyone with a cardiac pacemaker)
• claustrophobic


  fMRI (Weakness) - Anyone who is _____ or unnerved by confined spaces may be stressed during the scanning as they have to lie flat in a tube for the scan.
• Still

  fMRI (Weakness) - Technique is only effective if the participant remains completely _____. Therefore may not work on children. Limiting the use.
• delay


  fMRI (Weakness) - There is a 5 second ____, between brain activity and the image appearing on the screen. May cause difficulty interpreting.
• structural


  CAT scans use X-rays and computer to create detailed ______ images of inside the body.
• brain damage


  CAT scans used for detecting ____ ____ following an accident or positioning of tumours.
• beams


  CAT scans take images from different angles are taken by multiple ______ to gather information, each image is a cross-section of the person's brain or body.
• brain activity

  fMRI scans are used to get images of ____ ____ without radiation.