AQA A-LEVEL: Biopsychology - Researching the Brain

RESEARCHING THE BRAIN


POST MORTEM 

  • A person's body + brain is examined after death. Done to see where the damage had occurred in the brain and to see if behaviour done by individual prior to death can be explained.
  • The brain can be sliced into thin sections and studied under a microscope to detect abnormalities.
DETAILED EXAMINATION
  • You can see anatomical aspects which can't be seen w/ non-invasive techniques, we can look at deeper regions of the brain
RESEARCH SUPPORT - Harrison 2000
  • This method was important for our understanding of schiz. He suggested structural and neurochemical abnormalities linked to schiz were first identified using post-mortem 
METHOD IS RETROSPECTIVE
  • The problem with comparing function to before death is that there is little info about how the individual functioned before they died. Researchers cannot follow up on potential brain abnormalities and cog function
BRAIN CHANGES after death
  • Because of this, the findings may lack accuracy, especially if there is a time delay between death and analysis. As soon as oxygen is cut off from brain it's structure changes.

FMRI

  • Measures the energy emitted from haemoglobin as it reacts with oxygen when it is picked up.
  • If an area of the brain has a lot of oxygen it is very active.
  • Difference in amount of energy released from haemoglobin is detected and the change is measured
  • Results in a dynamic moving picture has a 1-second time delay, accurate to 1-2mm
NON-INVASIVE
  • No insertion of instruments or exposure to radiation so it is ethical
DYNAMIC and DETAILED
  • A moving picture of the brain rather than bland physiology is highly valuable when trying to research brain function 
Overlooks NETWORK NATURE of brain 
  • Only looks at localised activity. Communications between regions of the brain are critical to mental functioning as the scanner can not reduce that.
Scan is DIFFICULT to INTERPRET
  • Due to the complex brain activity it takes expertise and time to interpret the scan

EEG

  • Electrodes are placed on scalp which records the size and frequency of electrical activity in the brain and recognises patterns for certain states which help to find abnormalities easier
  • Measure the activity of cells immediately - more the electrodes, fuller the picture
PRACTICAL APPLICATIONS
  • Can be used in clinical practice for sleep disorders, disturbed brain activity and for a diagnosis
CHEAPER, a better alternative to other methods

Scan is DIFFICULT to INTERPRET
  • Due to the complex brain activity it takes expertise and time to interpret the scan
METHODOLOGICAL ISSUES
  • Electrical activity can be picked up by neighbouring electrodes

ERP

  • Same equipment of ERP but data is recorded when there is activity in a response to a stimulus introduced by the researcher
  • To identify small specific responses, recordings are taken from numerous presentations which are averaged out to get an ERP
It's NOT RETROSPECTIVE
  • Results are live and you can look at neural activity and conscious cognitive processing
METHODOLOGICAL ISSUES
  • Only detects strong voltage readings
Scan is DIFFICULT to INTERPRET
  • Due to the complex brain activity it takes expertise and time to interpret the scan

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