✓ Ways of Studying the Brain (AO1 + AO3) Flashcards
What are the 4 ways to study the brain?
fMRI
EEG
ERP
post-mortems
How does an fMRI work?
when a brain area is more active it consumes more oxygen so more blood flow is directed to that area
a fMRI detects these changes & the resulting 3D image produced shows these active areas of the brain
Positives of a fMRI?
- doesn’t rely on radiation
- non-invasive
- safe procedure (unlike PET)
- produces high spatial resolution imagery w great detail
- objective, scientific method
Negatives of a fMRI?
- costly compared to other techniques & only produces clear image if person stays still
- poor temporal resolution bc of 5 second lag
- not directly measuring neural activity just blood flow to the area
- focus on specific areas can overlook the network of brain activity
How does an EEG work?
measures electrical activity in the brain via electrodes using a skull cap
the scan recording represents the brainwave pattern generated from millions of neurons & shows overall brain activity
EEG is often used as a diagnostic tool (detects unusual patterns of activity which often indicate abnormalities like epilepsy or sleep disorders)
Positives of EEG?
- useful for diagnosing & understanding stages of sleep
- high temporal resolution, detects activity to the millisecond, recordings in ‘real time’
- cheaper than other imaging techniques
Negatives of EEG?
- produces generalised signal from thousands of neurons
- makes it difficult to know the exact source of neural activity
- doesn’t detect activity in ‘deeper’ brain regions e.g. hippocampus
How does an ERP work?
ERPs are what we have left when all extraneous brain activity is filtered out from an EEG recording
ERPs are types of brainwaves that are triggered by particular events or stimuli
various different forms of ERPs have been identified & linked to cognitive processes e.g. perception & attention
Positives of an ERP?
- more specific than EEGs
- excellent temporal resolution (espc. compared to fMRI)
- cheaper than other imagery techniques; system less expensive to maintain
- non-invasive procedure
Negatives of an ERP?
- ERPs undergo statistical processes to filter out extraneous brain activity
- difficult to completely eliminate & difficult to confirm findings (low reliability)
- need to do lots of trial to increase reliability (time-consuming)
- can’t measure ‘deeper’ brain areas
How does a post-mortem work?
analysis of a person’s brain after their death
areas of the brain are examined to establish the likely cause of a deficit or disorder that the person suffered in life
this may also involve comparison to a neurotypical brain to assess the extent of the difference
Positives of a post-mortem?
- Broca & Wernicke relied on post-mortems & HM also post-mortem
- helped to identify change in NT levels in depression, schizophrenia etc.
- improve medical knowledge & help generate future hypotheses
- brain tissue can be examined in greater detail & ‘deeper’ structures too
Negatives of a post-mortem?
- observed damage may not be linked to the deficits under review but due to other trauma or decay (major confounding variables)
- also age/drug use
- also need consent from patient before death & may not be able to give fully informed consent (like HM)
- only retrospective data, too late to test cognitive function
