Biopsychology- brain scanning techniques

Question 1

What is fMRI?

Answer 1

Functional magnetic resonance imaging

Question 2

What does fMRI measure?

Answer 2

oxygenated haemoglobin blood flow in the brain i.e. brain activity

Question 3

Why is oxygenated blood measured?

Answer 3

has a different resonance than deoxygenated blood

Question 4

How does fMRI work?

Answer 4

-The blood flow reacts to the scanner’s magnets
-Deoxygenated blood is present in less active/non-active regions of the brain
-The blood flow equates to activity in the brain which in turn indicates which specific structures are working hard at that point in time

Question 5

What happens the scan?

Answer 5

-A computer transforms the information into a brightly coloured 3D image which is mapped using voxels (each voxel = thousands of neurons)
-Active areas of the brain can then be compared with areas that are lower in activity which is indicated on the fMRI scan image via the degree of bright colour

Question 6

What usually happens during an fMRI scan?

Answer 6

-Person performs a task
-Neurons in the brain need energy to perform the task
-Energy requires glucose and oxygen

Question 7

What is the temporal resolution of fMRI?

Answer 7

-Images show activity 1-4 seconds after it occurs

Question 8

What is the spatial resolution of fMRI?

Answer 8

-Images are accurate within 1-2 mm

Question 9

What does EEG stand for?

Answer 9

Electroencephalogram

Question 10

What does EEG involve?

Answer 10

-Placing of electrodes on the scalp which record brain activity
-Usually between 22-34 electrodes are used but there can be any number from 2-100 depending on the age and size of the participant and what the aim of the research is
-The electrodes are fitted to a cap that is placed on the participant’s scalp along with a conductive gel
-The electrodes measure the activity of the cells directly below them
-The more electrodes there are, the more detailed information and a comprehensive picture of the brain can be derived
-Graphed over a period of time indicating the level of activity

Question 11

What can EEGs be used for?

Answer 11

Investigating sleep disorders, seizures, memory problems

Question 12

Brain activity is shown via brain waves, the 1._____ shows the brain intensity and the 2._____ shows the speed of activation

Answer 12

1.amplitude
2.frequency

Question 13

What do EEGs measure?

Answer 13

Electrical activity through electrodes attached to the scalp

Question 14

What are the 4 types of EEG patterns (waves)?

Answer 14

-Alpha
-Beta
-Theta
-Delta

Question 15

Which waves are associated with lighter sleep?

Answer 15

Alpha

Question 16

Which waves are associated with deeper sleep?

Answer 16

Theta/delta

Question 17

What is the temporal resolution of EEG/ERP?

Answer 17

Every millisecond

Question 18

What is the spatial resolution of EEG/ERP?

Answer 18

Only detect activity in superficial, general areas of the brain/ cant detect activity in the hypothalamus/ amygdala

Question 19

What are ERPs?

Answer 19

Event-related potentials

Question 20

What is a similarity between ERPs and EEGs?

Answer 20

use the same apparatus and technique

Question 21

Define event related potentials

Answer 21

tiny voltages generated in brain structures in response to specific events or stimuli

Question 22

How are ERPs stimulated?

Answer 22

sensory, cognitive or motor events

Question 23

Define latency

Answer 23

The time or interval between the presentation of the stimulus and the response is referred as latency

Question 24

What do post-mortem examinations involve?

Answer 24

examining the brain after death to determine the cause of behaviour(s) or dysfunction experienced when the patient was alive

Question 25

Are the findings of PME typically correlational?

Answer 25

Yes

Question 26

Give an example of where PM has been used?

Answer 26

Broca and Wernicke’s area

Question 27

Why are PME useful?

Answer 27

Allow for a more detailed examination of anatomical and neurochemical aspects

Question 28

Give an evaluation point for PME

Answer 28

-Issues surrounding consent
- The person is deceased so cannot give informed consent
-If they did give consent for this to be done they may not have been fully competent
-Ethical concerns
-However PME allow for a more detailed explanation of anatomical and neurochemical aspects

Question 29

Give an evaluation point for EEG in comparison to FMRI (Temporal resolution)

Answer 29

-EEG has good temporal resolution
-Temporal resolution refers to the accuracy of the scanner in relation to time/ how quickly the scanner can detect changes changes in brain activity
-EEG scanners take readings every millisecond meaning it can take readings in real time opposed to looking at passive brain
-However FMRI scans have temporal resolution of 1-4 seconds which is worse than other techniques
-This suggest that EEG can provide a high degree of accuracy when examining the onset of brain activity, allowing psychologists to make accurate conclusions in relation to the timing of neural activity in comparison to fMRI

Question 30

Give an evaluation point for FMRI in comparison to EEG (spatial resolution)

Answer 30

-One strength of FMRI in comparison to EEg is that it has good spatial resolution
-spatial resolution is the smallest feature/measurement that a scanner can detect, greater spatial resolution allows psychologists to discriminate between different regions of the brain with greater accuracy
-EEG om the can only detect the activity in the superficial regions of the brain
-Therefore psychologists can determine the activity of different brain regions with greater accuracy when using FMRI, in comparison to EEGs Which makes fMRI and ideal choice when trying to pinpoint specific brain regions

Question 31

Give a strength of fMRIs and EEGs (non invasive)

Answer 31

-One strength of fMRIs and EEGs are both non invasive techniques
-For example both brain scanning techniques used imaging scanning techniques such as EEG, ERP and fMRI scans do not involve inserting instruments into the brain or using radiation unlike post mortem exams or Xrays
-This is a strength as it means the procedure is more likely to be risk free