A03 Ways Of Investigating The Brain

• fMRI Strengths


  Unlike other scanning technology like PET scans, it does not rely on the use of radiations. If administered correctly, it's usually virutally risk-free, non-invasive and straightforward to use. Also produces images that have very high spatial resolution depciting details by the mm, producing a clear picture of how brain activity is localised.
• fMRI weaknesses


  Expensive compared to other neuroimaging techniques and can only capture a clear image if person stays perfectly still.

  Has poor temporal resolution as there is a 5 second time lag between image on screen and initial firing of neuronal activity.
• Lack of clarity in fMRI (fMRI weaknesses)

  Also, it can only measure blood flow in the brain, it can't hone in on activity of individual neurons making it difficult tell what kind of brain activity is being represented on screen.
• EEG strengths


  Provided invaluable in the diagnosis of conditions like epilepsy which is characterised by random bursts of act in the brain that can be easily detected on screen.
• Contributions to understanding (EEG strengths)


  Also, it contributed to the understanding of the stages of sleep (ultradian ryhthms). Unlike the fMRI, EEG technology has extremely high temporal resolution and can accurately detect brain activity at a resolution of a single millesecond
• EEG weaknesses


  Main limitation is the generalised nature of the information received as is it not useful for pinpointing exact source of neural activity and does not allow researchers to distinguish between activity originating in different but adjacent locations
• ERP strengths


  Limitations of EEGs are partly addressed through ERPs. It brings much more specificity to the measurment of neural processes that could never be achieved using raw EEG data.
• Temporal resolution (ERP strengths)

  ERPs are derived from EEG measurements, they have excellent temporal resolution, especially when compared to neuromimaging technology like fMRI and this led to widespread use in the measurement of cognitive functions and defects.
• Different types of ERPs (ERP strengths)

  Researchers have been able to identify different types of ERPs and describe the precise role of these in cognitive functioning. For example, the P300 component is though to be involved in the allocation of attential processes and the maintenance of working memory.
• ERP weaknesses


  There is a lack of standardization in the methodology between different research studies which makes it hard to confirm findings. In order to establish pure data in studies, background noise and extraneous variables/materials must be eliminated and this is not always easy
• Post-mortem strengths


  Its evidence is vital in providing a foundation for early understanding of kep processes in the brain. Broca and Wernicke relied on post-mortem studies in establishing links between language, the brain and behaviour decades before neuroimaging became a possibility. Post-mortem studies improve medical knowledge and help hypotheses for further study.
• Post-mortem weaknesses


  Causation is an issue as observed damage to the brain may not be linked to the defecits under review but to some other unrelated trauma/decay. Post-mortems raise the ethical issue for consent from individuals before death. They may not be able to provide informed consent like HM who lost the ability to form memories and therefore, couldn't provide consent.