ways of studying the brain Flashcards
how does a fMRI work
detects changes in oxygen levels in the blood to see activity in specific brain areas - there is increased blood flow and thus increased oxygen during brain activity
when is an fMRI used?
used to identify the specific brain areas which are active during processes
what does a fMRI produce?
produces a 3D image of where the brain is active during a specific task - activation map
strength of fMRI
safer technique of studying the brain to alternative methods
why are fMRI’s more safe? + comp
they are non invasive as they do not use radiation to identify specific brain areas during activity,
this is unlike PET scans which use a small amount of radiation which although may be low levels can still cause potential harm
strength link fMRI
increases the appropriateness of fMRIs as a method of studying the brain
weakness/strength of fMRI (temp +spatial res)
low temporal resolution
high spatial resolution
why does fMRI have high spatial resolution
high spatial resolution is important feature of brain scan since it can accurately identify areas of the brain which are active during activity
provides detail by mm which creates a clear image of how the brain is localised
why does fMRI have low temporal resolution
there is a 5 second time lag behind the image on screen and the initial firing of neuronal activity
fMRIs may not truly represent moment by moment brain activity
how does an EEG work
EEG detect small electrical changes in the brain caused by activity of brain cells
they attach electrodes to the scalp by using a skull cap
what does an EEG produce
electrical signals are graphed over a period of time to show general brain activity
when is an EEG used
used to detect sleep patterns and states such as arousal and sleep to help diagnose conditions such as brain tumours and epilepsy
strength of EEG
high temporal resolution
why does an EEG have high temporal res and what does it allow - comp
it provides the researcher with a real time recording of brain activity as an oppose to a still image which is the case with fMRIs.
allows researcher to accurately measure and identify brain activity during specific tasks and greater insight into the brain’s processes during states such as sleep
strength link EEG
thus increasing validity of the EEG as a way of studying the brain
weakness of EEG
low spatial resolution
why does an EEG have low spatial resolution - comp to ERP
it only provides information on general brain activity - cannot pinpoint exact source of neuronal activity in the brain
unlike ERPs which allow researchers to identify specific brain areas associated with a task
what is an ERP?
ERP’s work in the same way as EEG as they use electrodes attached to a skull cap onto the scalp but shows the brain’s response to a specific stimulus
the stimulus is repeatedly shown to the individual but is measured in the same way as an EEG
how is an ERP different to an EEG?
It filters out an extraneous brain activity from the original EEG recording and only shows the brain’s response to the presentation of a stimuli
what does an ERP produce?
It is graphed with a base line measure against the test line to show the difference in brain activity in response to the stimuli
when is an ERP used?
it is used to study a range of mental cognitive processes such as memory, perception and attention in response to a stimuli
strength and weakness of ERP
high temporal resolution
low spatial resolution
weakness of ERP
hard to obtain meaningful data
why does an ERP have high temporal resolution?
compared to fMRI, it shows brain activity by the millisecond which means researcher can see brain activity in real time.
why does an ERP have low spatial resolution?
it can only show brain activity in general brain areas rather than identifying brain activity in specific locations. Thus limiting validity of ERP’s as a way of studying the brain’s mental processes
what is a post mortem?
when the brain is dissected and examined to check for any structural or physical abnormalities
this is usually done on people with brain defects or damage
this is then compared to a neurotypical brain which does not exhibit these behaviours or mental processes to see the differences
when is a post mortem used?
identification of the broca’s area in understanding its importance for speech production
strength of post mortem
only invasive way of studying the brain
why is post mortem being the only invasive way to study the brain a strength
it allows researchers to conduct a more detailed examination which would not be possible by solely using a brain scan. It has allowed researchers to study deeper areas of the brain such as the hypothalamus in understanding brain functioning in a range of different behaviours
strength link post mortems
increases the validity of using post mortems as a method of studying the brain
weakness of post mortem
hard to establish cause and effect
why’s it hard to establish a cause and effect in post mortem studies
there are many extraneous variables which cannot be easily controlled such as how long the person has the disorder for, the age at the time of death or whether they were receiving treatment for their disorder. Therefore, it can be hard to interpret the role of specific brain areas in behaviour
weakness link post mortem
thus limiting appropriateness of using post mortems in studying the brain and the validity of findings in post mortem studies
