biopsychology- studying the brain

Question 1

methods of studying the brain

Answer 1

-fMRI
-EEG
-ERP
-post-mortem

Question 2

What are the 2 types of resolution that are important for imaging?

Answer 2

-spatial
-temporal

Question 3

how does temporal imaging work?

Answer 3

-accuracy of the scanner in relation of time or how quickly the scanner can detect changes in brain activity

Question 4

how does spatial imaging work?

Answer 4

-smallest features or measurement that a scanner can detect

Question 5

how does fMRI work?

Answer 5

-highlights ACTIVE AREAS of brain
-measures blood oxidation not neural activity
-measures difference between oxygenated blood and de-oxygenated blood as they have different magnetic properties, as active areas of the brain consume more oxygen.
-produces a 3D image showing which parts of the brain active and so must be involved in particular mental processes

Question 6

What are the strengths of fMRI?

Answer 6

-high spatial resolution
-non-invasive (unlike PET scan which have radioactive tracer to track glucose)

Question 7

What are the limitations of fMRI?

Answer 7

-low temporal resolution
-expensive- underpowered as too few subjects for hypotheses due to cost
-indirect- measures blood flow as indirect measure of neural activity
-movement artefacts- patient can’t move
-accessibility- certain populations it’s not appropriate for- pacemaker or pregnancy

Question 8

How is EEG measured?

Answer 8

-measures ELECTRICAL ACTIVITY via electrodes that are fixed on the scalp using a skull cap.
-works on the assumption that info is processed in the brain as electrical activity in the form of action potentials
-scan recording represents wave patterns from thousands of neurons, shows overall brain activity

Question 9

What is the basis for the EEG signal?

Answer 9

-small electrical charges are detected by the electrodes and graphed over a period of time indicating the level of activity.

Question 10

What are the 4 types of EEG waves, and how do they differ?

Answer 10

-alpha
-beta
-theta
-delta

Question 11

How are EEGs used?

Answer 11

-Often used by clinicians as a diagnostic tool as unusual arrhythmic patterns of activity (no particular rhythm) may indicate neurological abnormalities such as epilepsy tumours, or disorders of sleep.

Question 12

What are the advantages of EEG?

Answer 12

-high temporal resolution- in the mm range
-non-invasive- no radioactive tracer
-low cost- much larger samples as a result so more validity for conclusions
-wide range of populations- no claustrophobia
-direct neural measure- unlike fMRI
-contributed a lot to sleep research
-diagnosis of conditions i.e. epilepsy and can be widely applied

Question 13

What are the limitations of EEG?

Answer 13

-low spatial resolution
-susceptible to artefacts- if blink the ocular activity picked up as electoral activity
-limited to surface activity- cortical surface measurements
-interpretation- relationship to frequency band and cognition is debated

Question 14

What are ERPs?

Answer 14

-uses statistical averaging techniques, that filters out extraneous brain activity from the original EEG recording
-ERPs are a type of brain wave thats triggered by particular events
-way of isolating specific neural responses associated w/ sensory, cognitive, and motor events

Question 15

What are the advantages of ERPs?

Answer 15

-high temporal resolution- data in the millisecond timeframe, led to use in measure of cognitive functions and deficits
-non-invasive
-relatively low-cost as same EEG machine
-sensitive to condition- time-locked to the event unlike EEGs
-somewhat better spatial localisation- partly solves issues of EEGs

Question 16

What are the limitations of ERPs?

Answer 16

-still low spatial resolution- compared to fMRI and PET
-low signal-to noise ratio
-limited to surface activity

Question 17

How is post-mortem data used in psychological research?

Answer 17

-acquire actual tissue
-analysis of brain after death
-areas of damage examined as a means of establishing likely cause of deficit or disorder suffered
-looks at structure in relation to function
-may involve comparison w/neurotypical brain to see extent of difference

Question 18

who is subject to post-mortems?

Answer 18

likely to be those with rare disorders and who have experienced unusual deficits in mental processes or behaviour

Question 19

What are the advantages of post-mortem research?

Answer 19

-detailed analysis
-access to human tissue
-validate imaging data
-identify disease mechanisms

Question 20

What are the limitations of post-mortem research?

Answer 20

-limited availability
-selection bias- can’t compare to those not dead as don’t have access to tissue
-time-dependant changes
-ethical considerations- informed consent needed by donor or next of kin

Question 21

ao3 of fMRI: risk-free and high spatial revolution

Answer 21

-unlike other techniques (e.g. PET) doesn’t use radiation as is safe
-also produces images w/high spatial resolution, showing detail by mm
-means can safely provide a clear picture of how brain activity is localised

Question 22

ao3 of fMRI: expensive and poor temporal resolution

Answer 22

-expensive compared to other techniques
-has poor temporal resolution as 5s lag between initial neural activity and image
-so may not truly represent moment-to-moment brain activity

Question 23

ao3 of EEGs: practical uses and high temporal resolution

Answer 23

-contributed to understanding of stages of sleep
-high temporal resolution- brain activity in 1 millisecond
-shows real-world application of the technique

Question 24

ao3 of EEGs: info generalised and source not pinpointed

Answer 24

-produces a generalised signal from thousands of neurons
-difficult to know the exact source of neural activity
-EEG can’t distinguish the activity of different but adjacent neurons

Question 25

ao3 of ERPs: specificity and good temporal resolution

Answer 25

-measures of neural processes more specific with ERPs than EEGs
-ERPs gave excellent temporal resolution better than fMRI
-means ERPs are frequently used in cognitive research

Question 26

ao3 of ERPs: lack of standardisation and background ‘noise’

Answer 26

-lack of standardisation makes it difficult to confirm findings in studies involving ERPs
-background ‘noise’ and extraneous material must be completely eliminated
-issues are a problem as they may not always be easy to achieve

Question 27

ao3 of post-mortems: localisation and medical research

Answer 27

-Broca and Wernicke both relied on post-mortems
-used to link HM’s memory deficits to damage in his brain
-means they continue to provide us w/ useful info

Question 28

ao3 of post-mortems: knowing causation and ethics

Answer 28

-observed damage in brain may not be linked to the deficits under review
-P-Ms raise ethical issues of consent after death (e.g. HM)
-challenges their usefulness in psychological research