Ways of studying brain

• Scanning and other techniques

  Techniques for investigating brain often used for medical purposes in diagnosis of illness

  Purpose of scanning in psychological research is often to investigate localisation - determine which parts of the brain do what.
• Functional magnetic resonance imaging

  • (fMRI) works by detecting changes in both blood oxygenation and flow that occur as result of neural activity in specific parts of brain
  • When brain area is more active consumes more oxygen and to meet this increased demand, blood flow is directed to active area (known as haemodynamic response).
  • fMRI produces three dimensional images showing which parts of brain are involved in particular mental process - important implications for our understanding of localisation of function.
• Electroencephalogram

  Measures electrical activity within brain via electrodes that are fixed to an individuals scalp using skull cap.

  Scan recording represents brainwave patterns generated from action of thousands of neurons providing overall account of brain activity

  EEG often used by clinicians as diagnostic tool as unusual arrhythmic patterns of activity may indicate neurological abnormalities such as epilepsy, tumours or some sleep disorders.
• Event related potentials

  EEG - In its raw form- crude, overly general measure of brain activity

  Within EEG data are neural responses associated with specific sensory, cognitive and motor events - useful -Researchers isolate these responses:
• ERP

  Statistical averaging technique -all extraneous brain activity from original EEG recording filtered out leaving only responses that relate to presentation of a specific stimulus or performance of a specific task.

  Remains- event related potentials - types of brainwaves that are triggered by particular events

  Research has revealed many different forms of ERP and how eg these are linked to cognitive processes such as attention and perception.
• Post mortem examinations

  Analysis of persons brain following their death - psychological research, individuals whose brains are subject to a post mortem examination likely to be those who have a rare disorder and have experienced unusual deficits in cognitive processes or behaviour during their lifetime.

  Areas of damage within the brain examined after death as means of establishing the likely cause of affliction the person experienced

  May also involve comparison with neurotypical brain in order to ascertain the extent of difference.
• fMRI S:


  Unlike PET, does not rely on use of radiation - if administered correctly it is virtually risk free, non invasive and straightforward

  Also produces images that have very high spatial resolution depicting detail by the milimetre and providing a clear picture of how brain activity is localised

  --> meaning fMRI can safely provide clear picture of brain activity.
• fMRI limitatioon

  Expensive compared to other neuroimaging techniques

  Poor temporal resolution bc around 5 second time lag behind image on screen and initial firing of neuronal activity

  --> may not truly represent moment to moment brain activity
• Electroencephalogram (EEG)


  Useful in studying stages of sleep and in diagnosis of conditions such as epilepsy, disorder characterised by random bursts of activity in the brain that can easily be detected on screen

  Unlike fMRI, EEG technology has extremely high temporal resolution

  Can accurately detect brain activity at a resolution of a single millisecond

  --> real world usefulness
• W: EEG


  Generalised nature of info received

  EEG signal is also not useful for pinpointing exact source neural activity - does not allow researchers to distinguish between activities originating in different but adjacent locations.
• S: ERP


  Limitations of EEGs addressed through the use of ERPs - bring much more specificity to measurement of neural processes than could ever be achieved using raw EEG data.

  Excellent temporal resolution especially when compared to neuroimaging techniques such as fMRI

  --> ERPs frequently used to measure cognitive functions and deficits such as allocation of attentional resources and maintenance of working memory.
• W: ERP


  Lack of standardisation in ERP methodology between different research studies which makes it difficult to confirm findings

  Further issue - in order to establish pure data in ERP studies background noise and extraneous material must be completely eliminated - not always easy to achieve.
• S: Post mortem examinations


  PM evidence vital I providing foundation for early understanding of key processes in brain

  Broca and Wernicke both relied on post mortem studies in establishing links between language, brain and behaviour decades before neuroimaging ever became as possibility

  Also used to study HM's brain to identify areas of damage which could then be associated with his memory deficits

  --> provide useful info
• W: PM


  Causation issue

  Ethical issues of consent