Brain scanning strengths and weaknesses

CAT scans Strengths

-useful for revealing abnormal structures in the brain such as tumours or structural damage. The quality of the images provided by cat scans is much higher than traditional x-rays

-quick to conduct

-help surgeons better plan a procedure before surgery takes places by being able to accurately see the layout of brain structures- may make the procedure faster and more efficient

CAT scans weaknesses

-CAT scans require more radiations than x-rays and the more detailed and complex the CAT scan is, the more radiation exposure the patient receives. This means that CAT scans cannot often be used.

-cat scans only provide structural information. Unlike other scans, such as PET scans, they do not five information about the activity of the ‘live’ brain, they just produce still images. This means that they have limited use in research linking brain areas to particular behaviours.

PET scans strengths

-PET scans show the brain in action, which is useful in psychological research as biological activity can be linked to behaviour

-pet scans indicate the specific areas of the brain that involved in experience (ie. Localisation of function)

PET scans weaknesses

-sometimes the results are not easy to interpret. Eg. Pet scans on people doing the same task has shown different brain activity in different people. This makes it difficult to draw conclusions about which brain areas are linked to which behaviour

-the precise location of active areas in relation to brain structures is difficult to pin point

-there are ethical issues due to the injection of radioactive glucose as used in PET scans. Radioactive substances cause damage to the tissues of the body

-expensive to use

FMRI strengths

-as with pet scans, fmri shows important information about which areas of the brain are being used at any one time eg. Parading used fmri scans to measure the volume of participants amygdala and how it relates to aggression

-unlike PET and CAT scans, fmri does not use radiation and so is a safe method of studying the brain

-non-invasive and does not involve injections

-the images produced by fmri are extremely clear and can show brain activity to the millimetre

Fmri weaknesses

-expensive to sue

-the technique is only effective is the person whose brain is being investigated stays perfectly still and this may be a problem for some people eg. Children. This limits the use of the fmri

-there is around a 5 second time lag between brain activity and the image appearing on the screen which can cause problems when trying to interpret the information revived

-because of the high powered magnetic fields, some people are unable to have this kind of brain scan eg. People with a pacemaker of metal surgical implants