fMRI– Functional magnetic resonance imaging detects changes in blood oxygenation and flow that occur due to neural activity in specific brain areas- when a brain area is more active it consumes more oxygen and blood flow is directed to the active area (haemodynamic response)- fMRI produces as 3D image showing which parts of the brain are active and therefore must be involved in particular mental processes
Strength- non-invasive- unlike other scanning techniques (e.g. PET), fMRI does not rely on the use of radiation and is safer. Another strength is that it produces images with high spatial resolution- showing detail by the millimetre- this means fMRI can provide a clear picture of how brain activity is localised
Limitation- It’s expensive compared to other techniques and can only capture a clear image if the person stays still. Another limitation is it has poor temporal resolution because of a 5 second lag between initial neural activity and image- This means fMRI may not truly represent movement-to-movement brain activity
EEG– Electroencephalogram- measures electrical activity within the brain via electrodes using a skull cap- the scan recording represents brainwave patterns from millions of neurones- shows overall brain activity- linked with sleep
Strength- diagnostic tool- e.g. epilepsy- can detective unusual arrhythmic patterns- also helped with our understanding of the stages of sleep- EEG has extremely high temporal resolution- EEG can detect brain activity at a resolution of a single millisecond
Limitation- Info received from thousands of neurones- EEG produces generalised signals from thousands of neurones- difficult to know the exact source of neural activity- can’t distinguish the activity of different but adjacent neurons
ERP– Event-related potentials- use electrodes that are attached to the scalp, as with EEG. However, the key difference is that a stimulus is presented to a participant (for example a picture/sound) and the researcher looks for activity related to that stimulus- ERPs are types of brainwave that are triggered by particular events- research shown different forms of ERPs are likely linked to cognitive processes (e.g. attention)
Strength- ERPs are more specific than what can be achieved using raw EEG data- specific measurement of the neural process- also ERPs have excellent temporal resolution- less expensive than fMRI
Limitation- lack of standardisation in methodology between studies- makes it difficult to confirm findings in studies involving ERPs- also, background nose and extraneous material must be completely eliminated- not always easy to do
Post-mortem examinations– a technique involving the analysis of a person’s brain after death- areas are examined to establish the likely cause of a deficit or disorder that the person suffered in life- may involve comparison to a neurotypical brain
Strength- provided the foundation for understanding the brain- Broca AND Wernicke both relied on post-mortem studies- also has helped improve medical knowledge- generate hypothesis for further study
Limitation- causation may be an issue- observed damage in the brain may not be linked to the deficits under review but to some other related trauma or decay- also post-m studies raise ethical issues of consent from patient before death- may not be able to provide informed consent