Studying The Brain Flashcards
What are the 4 main types of studying the brain?
- FMRI
- EEG
- ERP
- Post mortems
How does an FMRI studying the brain?
It record energy released by haemoglobin
How does an FMRI work?
- Haemoglobin reacts differently with O2 then without O2
- FMRI detects haemoglobin with and without O2
- When an area is more active it uses more O2
- The FMRI detects and measures the energy released
Describe the pictures produced by FMRI’s
- moving picture
- delayed by about 1 second
- 3D map that shows what areas are involved in certain things
- red = high activity
- blue = low activity
When are FMRI’s used on participants?
- when they’re resting
- then again when completing different tasks to activate different areas
Describe a key researcher who used FMRI’s
- emmorey (2006)
- used FMRI’s to measure Broca’s area
- p’s used could express themselves using spoken and sign language
- findings : regardless of the type of Lang Broca’s area was always active
What are the 2 strengths of FMRI’s?
- non invasive
- high spatial resolution
How are FMRI’s non invasive?
- nothing is inserted into body
- doesn’t require exposure of brain to radiation
- more ethical
- p’s more willing to participate
- makes repeatedly testing a p easier
How do FMRI’s have high spatial resolution?
- spatial resolution of 1-2mm
- more accurate as to where there is increased O2 in the brain
- precise at researching localisation
What are the weaknesses of FMRI’s
- low temporal resolution
- impractical
How does FMRI’s have low temporal resolution?
- delayed by around 1 second
- not accurate
- difficult to establish the extent to which a task has influences the activity in the brain
Why are FMRI’s impractical?
- expensive
- can only capture a clear image if the person is still
- can be uncomfortable
- noisy
- if the person isn’t still the image is useless
- reduces sample size
- lack population validity
How does an EEG measure brain activity?
- electrodes are placed on a scalp
- these detect small electrical changes
- electrical signals are shown on a graph
What are EEG’s used for?
- measure electrical energy in the brain
- measure abnormalities in the brain
- e.g epilepsy or sleep disorders
Describe key research using EEG’s
- Dement and Kleitman (1995)
- used EEG’s to monitor sleep patterns in 9 p’s
- sleep lab
- everyone had periods of REM sleep
- if they woke during REM they were more likely to remember dreams
What are the strengths of EEG’s?
- high temporal resolution
- cost
How do EEG’s have high temporal resolution?
- shows a recording in real time
- data is recorded to the millisecond
- can accurately measure a particular activity in the brain
- more accurate at detecting brain activity
Why is the cost of EEG’s a strength?
- cheaper than FMRI
- uni’s more likely to have their own EEG
- easier to carry out research
- larger sample size
- increase population validity
What are the weaknesses of EEG’s?
- low spatial resolution
- surface measurements
How do EEG’s have low spatial resolution?
- only give a general overview
- can’t pinpoint the exact source of energy
- only picks up activity close to electrode
- can’t help as much with localisation
How is surface measurement a weakness of EEG’s
- only detects energy in superficial regions
- can’t reveal what happens in deeper regions
- e.g hypothalamus or hippocampus
- limited to what it can study
What is an ERP?
- researchers use statistical averaging to filter out extraneous brain activity from original EEG recordings
How does an ERP work?
- a stimulus e.g sound is shown to p
- look for electrical responses to stimulus
- same stimulus is repeatedly shown
- this allows for change in brain activity to be detected
Describe key research using ERP’s
- Costa (2003)
- showed p’s nude pics of both genders 19 - 29
- asked p’s about arousal levels to opposite gender
- ERP showed higher rate of arousal than p’s self reports
What are the strengths of ERP’s?
- high temporal resolutions
- reduces demand characteristics
How do ERP’s have high temporal resolutions?
- provides a continuous measurement
- can show how processing is affected by specific manipulations e.g stimuli
How do ERP’s reduce demand characteristics?
- measures responses without p actually giving a response
- e.g can measure a response as p reads a sentence rather than waiting until they finish the sentence
- reduce social desirability bias
- p’s can’t control brain responses
What are the limitations of ERP’s?
- low spatial resolution
- surface measurement
How does ERP’s have low spatial resolution?
- only give a general overview of electrical activity
- can’t pinpoint exact source of energy
- only picks up energy close to electrode
- can’t really help with researching localisation
How is surface measurement a weakness of ERP’s?
- only detect activity of a certain strength
- only detects energy at scalp surface
- can’t detect energy deeper
- e.g amygdala which controls emotions
- info is missed
Describe what and how post-mortems examinations happen?
- not scans
- carried out after death
- brain is sliced into very thin pieces
- can be used to see where damage has occurred
On who and why are post - mortems carried out?
- on p’s who have rare disorders or experience abnormal mental processes or behaviour
- can identify the causes
- brain will be compared to healthy controls
Describe key research using post mortems
- post mortem done on tan’s brain
- tan had a large lesion in the frontal lobe specifically Broca’s area
What have post mortems specifically found about disorders?
- found a link between psychiatric disorders (e.g schizophrenia and depression) and underlying brain abnormalities
What are the strengths of post mortems?
- full access to the brain
- precise
How do post mortems have full access to the brain?
- detailed analysis of brain that’s not possible through other methods
- can examine deeper areas
- e.g hypothalamus and hippocampus
How are post mortems precise?
- direct access to brain
- can see specific neural circuits and groups of neutrons
- not possible through other methods
- spatial resolution in post mortems is extremely high
- gives more detailed info
What are the weaknesses of post mortems?
- Lack of control
- retrospective
Why is their a lack of control in post mortems?
- multiple confounding variables e.g:
- cause of death
- length of time between death and post mortem
- drug treatment
- age of death
- difficult to make comparisons
- lack validity
How are post mortems retrospective?
- issue establishing causation
- person is dead so can’t follow up with anything that arises
- any damage might not be a result of suspected cause
- difficult to draw conclusions
