Methods of studying the brain

• the brain is the main focus of neuroscience
• studying the brain gives important insights into underlying foundations of our behaviour and mental processes
• a range of methods are used to study the brain including scanning the living brain to look at patterns of activity associated with particular tasks
• methods of studying the brain

  • post mortem examinations
  • functional magnetic resonance imaging (fMRI)
  • electroencephalogram (EEG)
  • event related potentials (ERPs)
• post mortem examinations are used to establish underlying neurobiology of particular behaviour observed when patient was living (looking at a dead persons brain)
• an example of post mortem examinations includes Brocas area
• using post mortem examinations as a method of studying the brain has led to identification of brain structures involved in memory such as HM was used to identify hippocampus
• using post mortem examinations there has been established links between psychiatric disorders and brain abnormalities
• functional magnetic resonance imaging (fMRI) measures changes in blood flow in areas of the brain which indicates neural activity

  • active areas within the brain have increased demand in oxygen which leads to increased blood flow
  • whereby it then maps out areas of the brain involved within certain functions
• the fMRI takes slices of the brain showing activated areas through magnetic and electrical fields

  • the lit up areas are those neurons being activates

  
• electroencephalogram (EEG) measures electrical activity within the brain

  • using electrodes on scalp to detect small electrical charges resulting from activity in the brain
  • signals are mapped out over time to produce EEG
• EEG data can be used to detect various brain disorders or diagnose those that influence brain activity (Alzheimers)
• there are 4 basic patterns on an EEG

  1. alpha waves
  2. beta waves
  3. delta waves
  4. theta waves
• when a person is awake alpha waves are recorded
• when person is physiologically aroused there will be low amplitude and fast frequency beta waves found
• as an individual falls asleep the alpha waves decrease and are replaced with lower frequency theta waves and the delta waves
• in sleep the beta waves are found in REM sleep - this is where individuals eyes more rapidly back and forth
• evaluation for using fMRI as method of studying the brain - STRENGTHS

  • non invasive and does not expose the brain to harmful radiation (PET scans do)
  • offers objective and reliable measure of psychological processes where verbal reports cannot be done
• evaluation for using fmri as method of studying the brain - LIMITATION

  • no direct measure of neural activity because it measures the blood flow only
  • argued it overlooks networked nature of brain activity due to it focusing on only localised activity
  • does not measure communication - can be argued as essential or crucial for the brain to function
• evaluation for EEG as method of studying brain - STRENGTH

  • provides recording in real time so accurately measures task or activity and brain activity associated with it
  • useful in clinical diagnosis as it can be used to diagnose epilepsy because normal EEG readings will suddenly change due to disturbed brain activity
• evaluation for using EEG as method of studying brain - LIMITATION

  • cannot reveal deeper regions without implanting electrodes which can only be done to non humans due to ethical implications
  • can pick up neighbouring electrode activity making it harder to identify exact source - can be seen as unreliable
• evaluation of using ERP as method of studying the brain - STRENGTH

  • continuous measure of processing in response to stimulus - determine how processing is affected by specific experimental manipulation
  • is able to measure processing of stimuli even in absence of behavioural response
• evaluation of using ERP as method of studying the brain - LIMITATION

  • requires large number of trials to gain meaningful data
  • only sufficiently strong voltage changes generated across scalp are recordable
  • electrical activities occurring deep in brain are not able to be recorded - restricted
• evaluation for using post mortem examinations as a method of studying the brain - STRENGTH

  • allows more detailed examination which is not possible through scanning techniques
• evaluation for using post mortem examinations as way of studying the brain - LIMITATION

  • time and matter of death can impact the brain
  • length of time between death and mortem can also impact
  • retrospective because can only be done following persons death
  • may be limited individuals who give away their brain once dead for examination