cog neuroscience

Question 1

whats useful about a damaged brain

Answer 1

helps us understand how a healthy brain works

Question 2

N400 electrophysiological signal [how locating processes is valuable]

Answer 2

the N400 electrophysiological signal is triggered when we hear a completely unexpected word in a sentence; this is useful for language psych in measuring when prediction occurs in speech comprehension/planning

Question 3

recording study method

Answer 3

a study in which behaviour is changed or manipulated, and the effect on the brain is measured
- CORRELATIONAL technique

Question 4

strength of recording study technique

Answer 4

greater design flexibility and control, offers high temporal and spatial resolution of brain activity

Question 5

inference studies

Answer 5

changing the state of the brain and measuring the effect on behaviour [EX: comparing brain damage ppts to control group]
- CAUSAL inference

Question 6

limitation of inference studies

Answer 6

in brain damage, the brain often reorganises itself and has high plasticity, meaning that the function may not be completely impaired, and will be unique for every ppt

Question 7

two types of stroke

Answer 7

ischemic - blockages in blood vessels cut off blood supply to the brain
hemmorrhagic - the wall of a blood vessel bursts, disrupting flow to brain

Question 8

single dissociation

Answer 8

looking at one case of impairment; weak inference for exploring if two processes are different

Question 9

double dissociation

Answer 9

two contrasting cases of impairment; strong inference for concluding that two processes are independent and can also help locating

Question 10

association

Answer 10

cases with similar performance on all tasks (whether this is impairment or normality)

Question 11

fractionation assumption

Answer 11

the assumption that brain damage can selectively affect different cognitive and neural systems

Question 12

transparency assumption

Answer 12

the assumption that brain lesions can affect existing cognitive systems but do not create new ones

Question 13

universality assumption

Answer 13

the assumption that all cognitive systems are basically the same

Question 14

critique of transparency assumption

Answer 14

neural plasticity is common, so new pathways are often formed after brain damage

Question 15

critique of universality assumption

Answer 15

individual differences are too prominent to assume that cognitive systems are the same - ppl have variation in cognitive ability & cognitive strategies

Question 16

two proposed models of reading irregular words

Answer 16

connectionist ‘triangle’ model - to read irregular words, we use their semantics
dual-route cascaded model - to read irregular words, we use their lexical representation, not their semantics

Question 17

lesion-symptom mapping

Answer 17

find ppts with similar impairments, acquire structural brain scans, identify specific areas & create a lesion overlap map

Question 18

lesion overlap map

Answer 18

map of the brain where the areas with the most correlation between ppts is darker (works on a gradient)

Question 19

lesion overlap map in reading

Answer 19

study looked at specific reading deficits; found that poor irregular word reading was correlated with damage to the anterior temporal lobe

Question 20

how are lesion overlap maps useful in a clinical setting

Answer 20

can predict the statistical probability of specific brain injuries causing specific deficits

Question 21

limits of using natural lesions (3)

Answer 21

• can only use between-subjects design, which can be influenced by individual differences
• brain damage frequently extends to multiple areas
• neural plasticity = possible reorganisation of function, so ppts may not have completely lost certain functions

Question 22

transcranial magnetic stimulation

Answer 22

a rapidly changing magnetic field is applied to the head, and temporarily disrupts brain functions
= temporary virtual lesions

Question 23

what principle does transcranial magnetic stimulation work off of

Answer 23

electromagnetic induction
= the electric charge of one coil creates a magnetic field which induces an electric charge in the second coil (second coil = brain)

Question 24

strengths of transcranial magnetic stimulation (3)

Answer 24

• ppts can act as their own control in within-person design, reducing the effect of individual differences
• we can know and test what their normal brain function is like’
• no complications from damage or plasticity

Question 25

limits of transcranial magnetic stimulation (3)

Answer 25

• only stimulates 2-3cm below skull = cannot reach deeper structures
• higher cognitive functions have less noticeable effects, so exps need careful design
• cannot study long term processes such as learning

Question 26

how do atoms communicate

Answer 26

by passing on action potentials

this is called firing or spiking

Question 27

how do EEGs work [electroencephalography]

Answer 27

records changing action potentials

measures microvolts, which are the response of many neurons firing at once

Question 28

limitations of using EEG (2)

Answer 28

poor spatial resolution (measures when rather than where)

it’s hard to filter out noise from random firing

Question 29

how do ERPs work [event-related potential]

Answer 29

records positive and negative changes in voltage;

these events are named based on their polarity and extent

Question 30

how do MEGs work [magnetoencephalography]

Answer 30

similar to EEG but maps brain activity using a magnetic field instead

Question 31

strength of MEG

Answer 31

better spatial resolution than EEG

Question 32

how does a PET scan work

Answer 32

positron emission tomography
a radioactive tracer is injected into the blood stream, this then flows to where brain activity is taking places and the decay emits positrons which are measured

Question 33

limits of PET scans (3)

Answer 33

ppts become exposed to radiation
expensive and complex
the task has to last at least 1 minute for decay to be recorded

Question 34

how does a structural MRI work

Answer 34

protons within atoms are always spinning
a magnetic field is used to align them
to take a pic, a frequency is sent out to knock them out of place
we then measure where and how quickly they realign

Question 35

how does a functional MRI work

Answer 35

active neurons require more oxygenated blood, an fMRI measure the ratio of oxygenated : deoxygenated blood to see where activity is occurring
- this is called BOLD imaging
the brain is split into a grid of voxels to locate the BOLD contrast

Question 36

limit of fMRI

Answer 36

poor temporal resolution as it is a slow process

Question 37

blocked design in MRI

Answer 37

showing ppts stimuli in blocks (can lead to them expecting the stimuli and changing behaviour)

Question 38

event-related design in MRI

Answer 38

changing the stimuli each time it is shown to reduce expectations and provoke a more realistic response

Question 39

subtraction analysis for fMRI

Answer 39

the average of the brain’s ‘on’ activity minus the average of the brain’s ‘off’ activity

Question 40

default mode network

Answer 40

the brain network activity while resting; it deactivates during specific tasks

Question 41

multi-voxel pattern analysis (fMRI)

Answer 41

using algorithms to differentiate between patterns of activation to classify subsets of activity
= can tell us WHAT info is being coded (not just where/when)