Nuggets of information from past papers

Question 1

What is counterbalancing?

Answer 1

Giving slightly different treatments to different groups to control the effects of nuisance variables (different orders between subjects and between groups)

Question 2

What is a replication study?

Answer 2

One that repeats a previous study using the same methods but different subjects and experimenters

Question 3

Why are a range of doses used in some studies?

Answer 3

To investigate selective/specific effects, comparison with different studies, comparison with clinical doses, and to aid interpretation of different results

Question 4

How can non-specific behavioural effects be controlled for?

Answer 4

By using different doses, by using multiple different measures, using local infusion of drugs, and by using food rewards

Question 5

What is an interaction term in a two-way ANOVA?

Answer 5

It informs whether the effect of one of the independent variables on the dependent variable is the same for all values of your other independent variable.

Question 6

What can limit the representativeness of the results of in vitro binding studies?

Answer 6

The fact that many are carried out at room temperature, rather than body temperature

Question 7

How should the aims be stated in a paper?

Answer 7

Not just verbatim. Show that you understand the central aims in the context of the paper

Question 8

When justifying the choice for the key figure, can you also point out limitations?

Answer 8

Yes!!

Question 9

What does CellTrace Violet bind?

Answer 9

Binds to free amines inside and on the surface of cells

Question 10

What can CellTrace Violet be used for?

Answer 10

Proliferation tracking and cell tracking

Question 11

What is often an assumption of ELISA?

Answer 11

That the measured factor is not degraded in the supernatant

Question 12

What are some limitations of scientific papers?

Answer 12

Lack of summary statistics, lack of explanation of statistics, inconsistency in results not explained, mechanisms not always explained, conclusions not always supported

Question 13

What is the DIO system?

Answer 13

The DIO system is a vector for Cre where Cre expression both inverts a reversed opsin system, then cleaves one of a double lox sequence to overall turn on gene expression.

Question 14

Why is the DIO system used?

Answer 14

It is much more effective at avoiding transcriptional leakage compared to a floxed stop codon.

Question 15

What is a DREADD?

Answer 15

Designer Receptor Exclusively Activated by Designer Drugs - chemogenetic tools with receptors designed using normal endogenous GPCRs but mutated so only an engineered ligand activates it.

Question 16

What are the advantages of DREADDs?

Answer 16

Activation of DREADDs is minimally invasive, very repeatable, allows anatomical control, compatible with behavioural tasks, and easy to do.

Question 17

What controls should be used for DREADDs?

Answer 17

DREADD with CNO or vehicle, GFP with CNO or vehicle

Question 18

What is a repeated measures design?

Answer 18

A research design that involves multiple measures of the same variable taken on the same or matched subjects either under different conditions or over two or more time periods

Question 19

What is ordinal data?

Answer 19

Ordinal data is a categorical, statistical data type where the variables have natural, ordered categories and the distances between the categories are not known

Question 20

What is nominal data?

Answer 20

Data that fits into different categories that cannot be measured or ordered

Question 21

What are the 3 types of categorical data?

Answer 21

Dichotomous, nominal, and ordinal

Question 22

What is DeepLabCut and what does it allow?

Answer 22

A software package that uses human training inputs and pose estimation to teach neural networks about when an animal is exhibiting a certain behaviour.

Question 23

What is probably the key thing to consider regarding stats in paper 3?

Answer 23

Whether assumptions for statistical tests have been satisfied.

Question 24

How many advantages/disadvantages should be listed per mark?

Answer 24

At least 1

Question 25

What are the advantages to within subject tests compared to between subjects tests?

Answer 25

Within subjects comparisons are more powerful as less variability

Question 26

What are the disadvantages to between subject tests versus within subjects tests?

Answer 26

Less powerful than within subjects tests, ethically a waste of organisms, assumes behaviour is stereotypical between organisms.

Question 27

Why might authors choose to target embryonic genes during their investigations into later behaviours?

Answer 27

To use them as fate mapping genes or to manipulate genes in embryonic cells.

Question 28

What is a disadvantage of BAC transgenic mouse lines?

Answer 28

They are not as reliable as knock-ins - expression can be ectopic, and can vary over time.

Question 29

What are some advantages of using c-FOS as a marker of neural activity?

Answer 29

c-FOS is a transient early marker of cell differentiation and proliferation in response to extracellular stimuli.

Question 30

What are some disadvantages of c-FOS as a marker of gene activity?

Answer 30

Not clear how it detects sub versus supra-threshold activity, could be upregulated due to intrinsic neural activity.

Question 31

If data are presented as percentages, what should be noted about their statistical analyses?

Answer 31

They may be discrete rather than continuous data. An appropriate transformation should be used.

Question 32

What are the limits of detection for ELISA?

Answer 32

Around 100pg/ml of substance.

Question 33

What is the enzyme/substrate system for standard ELISA?

Answer 33

Horseradish peroxidase and TMB (tetramethylbenezidine)

Question 34

What online tool can do power analyses?

Answer 34

G power

Question 35

What should be used to transform percentage data to allow ANOVA?

Answer 35

Arc sine transformation is often used but some argue for a logit transformation instead.