ways of studying the brain Flashcards
what are the 4 brain scanning techniques?
•post-mortem examination
•fMRI
•EEG
•ERP
what is a post-mortem examination?
a surgical procedure which dissects a corpse to determine the cause of death. for psychology, the brain is examined to determine whether behaviours in a persons lifetime can be linked to abnormalities in the brain.
what are strengths of post-mortem examinations?
•evidence obtained was vital in providing a foundation for understanding key processes in the brain
•broca and wernicke used this technique to establish links between language, brain and behaviour before neuroimaging
•improves medical knowledge
what are weaknesses of post-mortem examinations?
•observed damage to the brain may not be linked to the defects under review but to some other unrelated trauma or decay
•issues of causation
•raises ethical issues of consent
what is an fMRI?
using an MRI scanner to measure activity of the brain while the patient performs a task. it uses radio waves to detect oxygen function, which is then rendered as an image using software.
what are strengths of an fMRI?
•it doesn’t rely on the use of radiation
•virtually risk-free, non-invasive and straightforward
•produces images with very high spatial resolution
•provides a clear picture of how brain activity is localised
what are weaknesses of an fMRI?
•very expensive
•can only capture a clear image if the person stays perfectly still
•poor temporal validity/ resolution because there is a 5 second time-lag behind the image on screen and the initial neural activity
•fMRI can only measure blood flow in the brain, it cannot home in on the activity of individual neurons so it can be difficult to tell exactly what kind of brain activity is being represented on screen
what is an EEG?
recording tiny electrical impulses produces by the brains activity using small senses which target particular areas of the brain
strengths of an EEG
•it has proved invaluable in the diagnosis of conditions such as epilepsy
•it has contributed to much of our understanding of the stages involved in sleep
•EEGs have extremely high temporal resolution
•non invasive with few risks
weaknesses of an EEG
•the main drawback lies in the generalised nature of the information received (that if many thousands of neurons)
•it is not useful for pinpointing the exact source of neural activity
•cannot provide information on what is happening deeper in the brain
•poor spatial resolution
•does not allow researchers to distinguish between activities originating in different but adjacent locations
what is an ERP?
a statistical aggregate of measured brain response that is the direct result of a specific sensory, cognitive or motor event from an EEG
strengths of an ERP
•they bring much more specificity to the measurement of neural processes than could ever be achieved using raw EEG data
•non-invasive and virtually risk free
•high temporal validity
weaknesses of an ERP
•lack of standardisation in ERP methodology makes it difficult to confirm findings
•poor spatial resolution
•background noise and extraneous materials must be completely eliminated, and this may not always be easy to achieve
