Applications in Research

Question 1

define cognition

Answer 1

the mental action or process of acquiring knowledge and understanding through thought, experience and the senses

Question 2

why is it important to study cognition?

Answer 2

it may be impaired in a number of contexts, which can be distressing for patients

Question 3

give the overall hierarchy of cognitive processes and functions

Answer 3

see notes

(idea that cognitive mechanisms build on one another to give a more sophisticated function)

*the complete list of cognitive domains is big

Question 4

why is cognition so hard to measure

Answer 4

it’s very abstract/theoretical. Firstly, trying to measure something doesn’t mean you are actually measuring it, we are often using surrogate methods. In addition to this the mind itself is a highly theoretical/abstract concept, hence difficult to define

Question 5

what are 2 common cognitive tests?

Answer 5

1) trail making
2) letter fluency

Question 6

what does trail making measure?

Answer 6

processing speed and aspects of executive function

Question 7

what does letter fluency measure?

Answer 7

semantic abilities, primarily word generation

Question 8

outline trail making

Answer 8

• first round, subject given piece of paper with numbers or letters scattered randomly and the subject must start at beginning and trace in ascending order, not moving pen from paper. The time to do this is recorded.
• second round, subject given another piece of paper with letters AND numbers, the participant must again trace these in ascending order but alternating between letters and numbers. Also timed.

time taken to do pt 1 subtracted from pt 2 - gives measure of high cognitive function controlling for motor speed

Question 9

outline letter fluency

Answer 9

participant given a letter of alphabet and in time limit must name as many words starting with this aloud. No proper nouns, no modifying works they’ve already used. correct words counted up.

Question 10

what is normal distribution/ gaussian distribution/ bell-shaped curve/ parametric sample?

Answer 10

where there’s a clear trend for the value of most points to cluster around a central mean with increasing rarity moving away either side

Question 11

in normal distribution/bell-curve do data need to follow a perfect bell-shape to be determined as normally distributed?

Answer 11

no

Question 12

why is distribution important

Answer 12

if variables form a normal distribution, there are a number of mathematical assumptions we can make which determines how we analyse them statistically

Question 13

what does distribution largely boil down to (at its simplest)

Answer 13

if the mean value is a fair way of presenting the average

Question 14

draw +ve skew, symmetrical and -ve skew distribution charts labelling mean, median and mode for each

Answer 14

see notes

Question 15

what is variance?

Answer 15

the average difference of all individual data points from the mean (quantifies how closely data is clustered around the mean)

Question 16

what is standard deviation (SD)

Answer 16

variance is a version f our data after we square everything, so SD uses square root to re-convert variance back in proportion with data

Question 17

what is the relationship between mean and SD in normal distribution?

Answer 17

SD holds a consistent mathematical relationship with mean
as we travel away a number of SDs from mean, % data points included in range increase by a set amount

Question 18

draw a diagram of normal distribution, mean and SD

Answer 18

see notes

Question 19

more samples (N)=

Answer 19

more confidence in findings

Question 20

what is the letter of significance?

Answer 20

p

Question 21

what is the p-value

Answer 21

a number between 0 and 1, essentially a % probability that the data you have observed has happened by chance

Question 22

what is the p-value convention?

Answer 22

if something is p<0.05, there’s less than a 5% probability it happened by chance, it is statistically significant and we therefore can reject the null hypothesis

Question 23

what are the 2 common statistical designs?

Answer 23

1) compare value between groups or before/after - looking for difference (groupwise tests)
2) see how one value changes depending on another (correlation)

Question 24

if we are comparing a score between 2 groups with parametric data what stats test is used?

Answer 24

independent sample t-test

Question 25

with a t-test, what do we do once we get a t-value?

Answer 25

convert to p-value using degrees of freedom table (DoF N-1)

Question 26

if we are comparing before and after scores for the same group with parametric data, which stats test are we using?

Answer 26

paired samples t-test

Question 27

what is the parametric correlational states test?

Answer 27

Pearson's correlation

Question 28

how does a Pearon's correlation work?

Answer 28

we calculate covariance between 2 variables (x and y) to get an r- value between -1 and +1 -1 - perfect negative correlation 0- no correlation +1 = perfect positive correlation

Question 29

what is the non-parametric equivalent of independent t-test?

Answer 29

Mann-Whitney-U

Question 30

what is the non-parametric equivalent of paired t-test?

Answer 30

Wilcoxon Signed-rank

Question 31

what is the non-parametric equivalent of Pearson correlation?

Answer 31

Spearman rank correlation

Question 32

what is the main difference between parametric and non-parametric tests?

Answer 32

non-parametric first rank the data, whereas parametric doesn't

Question 33

overview multivariate models

Answer 33

used when looking at how multiple variables can effect an outcome at once (e.g. the affect of age, brain volume and years of education on cognitive performance) a single multivariate/multiple regression model is built to test this- this is not the same as separately running single variable analysis and putting together

Question 34

multiple comparisons problem?

Answer 34

the more times we run a test, as is the case in multiple comparisons, the more likely we are to get a significant finding by random chance (like the more you roll a dice more likely to roll a 3)

Question 35

what corrects for this multiple comparisons problem?

Answer 35

Bonferroni Correction divides 0.05 by the number of comparisons we're running to get a new threshold e.g. 0.05/20 runs

Question 36

what is experimental control?

Answer 36

removing the effect of confounding variables (e.g. testing an active drug against placebo to control for placebo effect)

Question 37

what are mixed study desgisn

Answer 37

looking at at least 2 groups in at least 2 conditions e.g. comparing control and placebo (between groups) and baseline and f/u (within groups)

Question 38

what are 2 examples of advanced fMRI designs?

Answer 38

- real-time fMRI - multivariate analysis

Question 39

when is it important to think about how you're going to statistically analyse data?

Answer 39

when you're designing your study

Question 40

what are the 2 overall types of fMRI experimental designs?

Answer 40

task-based fMRI and task free fMRI

Question 41

what are the 2 designs within task-based fMRI?

Answer 41

block design and event-related design

Question 42

what's the difference between block design and event related

Answer 42

event related is jittered- varying interval lengths between stimuli block design has stimuli generally for longer periods (longer blocks) event related allows you to look at more stimuli, but block is more robust for fewer stimuli types

Question 43

what 2 control factors are very important to appropriately choose in fMRI study design?

Answer 43

the choice of control condition and the choice of control group

Question 44

what is task-free fMRI

Answer 44

aka resting state participants lay still and told to not think about anything in particular, results in introspection/abstract cognition

Question 45

what have task-free/resting state designs shown?

Answer 45

that at rest, the brain is still active in coordinated ways often with same regions (networks) activating together hence important in functional connectivity analysis

Question 46

outline region-based functional connectivity study design

Answer 46

usually a region of interest is picked out and activity calculated over time frame and look to see which other areas have activity correlated with ROI time course

Question 47

what is an important factor to remember when undertaking correlational studies

Answer 47

that correlational is not equal to causation and may result in spurious correlation (factors shown to be significantly related with no causation)

Question 48

why is fMRI likely to show spurious correlation

Answer 48

because large numbers of voxels are being looked at so there is a high chance that 2 or more voxels may be shown to activate along same time frame even if they have no actual functional connectivity

Question 49

advantages of MRI:

Answer 49

- versatile- structural AND functional - simple statistic tests - in vivo - good for longitudinal studies - important in translational neuroscience (cognitive research with clinical applications) - safe

Question 50

limitations of MRI

Answer 50

- devoid of biological info- surrogate measure - also low temporal resolution - counterindications e.g. metal

Question 51

what 4 categories are most MRI studies one of:

Answer 51

Structural MRI: 1) brain volume 2) cortical thickness Functional MRI 3) task-based 4) task-free/resting state

Question 52

what is real time fMRI

Answer 52

more advanced fMRI technique allowing direct activity feedback, often to subject with rapid analysis and transfer of data within a few seconds of data collection

Question 53

give 2 applications of real-time fMRI feedback

Answer 53

- novel brain-machine interface - coupling conscious experience with brain activation - planning neurosurgical interventions - neural feedback

Question 54

give 2 applications of using BOLD signal from brain to feedback to control localised neural activation

Answer 54

- non-pharmacological therapy - overcomes limitation of other feedback methods - directly targeting specific brain areas

Question 55

outline research which has used this direct fMRI feedback

Answer 55

one study used real-time feedback relating to blood flow in right anterior insula (RAI) using a block-design of increasing and decreasing blood flow using tasks such as asking participants to remember arousing memories (increase BF) or count backward from 100 in 3s (reduce BF) showed that participants were able to control activity in these regions using feedback and tasks showing only activation changes in RAI in fMRI