Chapter 4: Methods and Ethics of Research Flashcards

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1
Q

What is a theory?

A

It integrates and interprets diverse observations in an attempt to explain a phenomenon, and it explains the results of many studies and observations

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2
Q

What type of language does science use? And why?

A

Tentative. Because studies may be flawed, therefore we support and disprove, we DO NOT PROVE, new data may change the interpretation of old studies, and the laws of probability suggests that the results could be random

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3
Q

What is an observational study? What are 4 different types?

A

Measuring and observing behavior/effects. Four types are naturalistic observation, case studies, surveys, experiments

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4
Q

What is an experimental study?

A

A study where the researcher manipulates the independent variable to produce change in the dependent variable. The experimenter tries to eliminate extraneous variables.

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5
Q

Experimenters often sacrifice realism for control. What does this mean?

A

This means that if you want a realistic study then you are probably unable to control all aspects of the environment. Control is usually more important therefore extraneous variable can be controlled, but this means doing an experiment in a lab which is unrealistic.

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5
Q

What is a correlational study?

A

Researcher observes whether two variables are related, cannot determine cause and effect only if there is a relationship, there is a chance on confounding variables, results are variable but require careful interpretation.

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6
Q

What are the four ways to image neuron?

A

Golgi stain, myelin stain, Nissl stain, retrograde stain?

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7
Q

What is the Golgi stain?

A

Randomly stains about 5% of neurons on a slide, good for seeing the structure of the neuron, first stain developed, creates picture of entire neuron

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8
Q

What is a myelin stain?

A

It is taken up by fatty myelin surrounding neurons, you can only see myelinated axons and nothing else, good for tracing and identifying neural pathways, you can see ALL axons in the slice

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9
Q

What is a Nissl stain?

A

It identifies cell bodies of neurons, ALL cell bodies in the slice

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10
Q

What is a retrograde stain?

A

It is taken up by neuron terminals and transported up into the axons of cell bodies, done on animals while they are still alive, the stain travels from axon to cell body therefore when we slice open the brain we can see what parts of the brain were sending info to the injection site.

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11
Q

What is autoradiography?

A

It stains and reveals which neurons are active, inject radioactive product (2DG) which is a radioactive glucose, so if there is more in a site, the more active it is. You inject the 2DG, get the animal to perform a behavior, then kill the animal and image the brain, all within an hour

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12
Q

What is immunocytochemistry?

A

This uses antibodies attached to a dye to identify cell components. It is essentially the same thing as autoradiography because it shows what cells were active right before death. More active cells produce more proteins therefore they will have more dyed antibodies and will light up more

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13
Q

What is the difference between autoradiography and immunocytochemistry?

A

You do not inject radioactive material in immunocytochemistry, and immunocytochemistry also targets proteins exclusively

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14
Q

Both autoradiography and immunocytochemistry can be grouped together under what heading?

A

After death fMRI. They target specific areas and see what parts of the brain are active (or neurons) after a certain behavior.

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15
Q

Does staining and imaging neurons show structure or function? or both?

A

STRUCTURE

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16
Q

What is in situ hybridization?

A

This is construction of DNA strands which complement an mRNA strand. This uses antibodies on mRNA (not actual antibodies, we are using the complementary strands)

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17
Q

What is a complementary strand? (used in in situ hybridization)

A

This is what fluoresces, it closes the mRNA therefore it does not get translated into proteins, it does the same function as antibodies?

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18
Q

Immunocytochemistry is to antibodies and in situ hybridization is to _____________

A

complementary mRNA strands

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19
Q

What is mRNA?

A

Stands for messenger ribonucleic acid, and it is the copy of one DNA strand carried from the cell nucleus into the cytoplasm

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20
Q

What technology do we use to look at the stained neurons?

A

Light and electron microscopy.

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21
Q

What is light microscopy? What is its limitations?

A

Used to look at neurons, can magnify up to 1500x, and you can only see clusters, you cannot see individual cells

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22
Q

What is electron microscopy? Why is it better than light microscopy?

A

It magnifies up to 250,000x and you can see individual neurons.

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23
Q

What does a transmission electron microscope do? Why is is better than electron microscopy?

A

It passes a beam of electrons through a thin slice of tissue, it magnifies up to 50 million times. You can see the internal structures of a cell/neuron

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24
Q

What are the two types of electron microscope?

A

Transmission electron microscope and scanning electron microscope.

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25
Q

What is a scanning electron microscope? How is it an enhancement of a TEM?

A

It is a beam of electrons that induces a specimen to emit electrons, magnifies up to 2-3 million times. It creates a 3D image which a TEM does not

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26
Q

What are two types of scanning electron microscope? How are they different from each other?

A

Confocal laser scanning microscope and two photon microscope. They differ in the types of particles they use to pass through tissue

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27
Q

What is an EEG?

A

Electroencephalogram. It is an electronic amplifier that detects electrical activity of all neurons between two electrodes (brainwaves)

28
Q

What is the temporal and spatial resolution of an EEG?

A

Its temporal resolution is that it can measure events as close as 1 ms apart. It spatial resolution is imprecise unless the electrodes are applied directly to the brain surface (EEG usually used on skull, therefore hard to know which brain region lies under the electrode)

29
Q

EEGs use event related potential. What is this? Why do we use it?

A

It is averaging many recorded responses to stimuli, it cancels out background noise and reveals the brains unique response to stimulus. It is computer based, and we use it so that we know for sure that all activity we see is significant.

30
Q

What is a stereotaxic instrument?

A

It is a device allowing precise positioning of a probe in the brain. Mostly used in animals, or humans while in surgery. It holds the head in fixed position so we can insert probes into the right lobe, the position is standardized so we can use a brain map. The probes are fine wire electrodes

31
Q

What is the purpose of using microelectrodes?

A

They can monitor and stimulate a single neuron, mostly used in animal research.

32
Q

What are optogenetic techniques? Are they used in humans? How do they work?

A

This technique is where light sensitive channels can be inserted into specific types of neurons, it is more precise then electrical stimulation. It uses gene manipulation, you take genes from cell/bacteria that has light gated channels and insert them into animals therefore when light shines on part of the brain, the channel opens and allows for more specific targeting of cells. ANIMALS

33
Q

What is chemical stimulation via cannulation?

A

You insert a tube into the brain so its end is sitting at the brain region of interest, then put the needle through the tube (cannula) and into the brain to inject the drug.

34
Q

What is microdialysis?

A

A more complex variation of cannulation, we do not inject a chemical, we draw out brain fluid and then remove the NT from this area to see what NT are present in this area.

35
Q

What are natural experiments?

A

Studying brain damaged patients. The damage may overlap different functional areas, damage may fail to affect the entirety of a functional area. These are case studies

36
Q

What is ablation?

A

Surgical removal of brain tissue. Only used for large areas because it is imprecise, hard to measure how much brain material you are removing. Often done by aspiration where you vacuum out the tissue

37
Q

What is lesioning?

A

Surgical damaging of neural tissue, it is precise and sometimes reversible. You inject acid into part of the brain therefore killing neurons there

38
Q

How do you make a reversible lesion?

A

You inject a drug/chemical into the brain or you make the brain very cold, and therefore it only loses function until the chemical wears off, or the brain regains normal temperature

39
Q

What is the name of the alternative method to lesioning that is used in humans?

A

Transcranial magnetic stimulation.

40
Q

What is transcranial magnetic stimulation? How is it performed?

A

A noninvasive technique using a magnetic coil to induce voltage, using a magnetic to increase or decrease firing in the brain, like a temporary lesion. You hold the device over the scalp and it pulses at varying rates

41
Q

How it TMS used therapeutically?

A

In stroke patients, to activate and inactivate specific areas to speed up recovery, and can be depression and anxiety treatment for those who cannot use regular meds

42
Q

What is a CT scan? What does it stand for and how does it work?

A

Computed tomography, it produces a series of x-rays from different angles and then composites them into a 3D image (black and white), false color’s can be added for contrast, and it shows different densities of blood vessels in the brain.

43
Q

Does a CT show structure of function or both?

A

STRUCTURE

44
Q

What is an MRI?

A

Magnetic resonance imaging, and it measures radiofrequency waves emitted by hydrogen atoms to magnetic field. It makes hydrogen atoms vibrate. Most hydrogen atoms are within water molecules (78% of brain) but now non-hydrogen elements can be measured.

45
Q

Does an MRI show structure, function or both?

A

STRUCTURE

46
Q

What is diffusion tenor imaging?

A

An MRI variant measuring the strength of movement of water molecules, shows pathways between different brain regions, so it shows a little bit of function

47
Q

What is a PET scan?

A

Positron emission tomography. Enables observation of brain regions through a radioactive substance injected into bloodstream. You drink a radioactive substance (2DG) and the PET scan measures how much is taken up into cells, more active cells have more 2DG. Scanner picks up emitted positrons to form a color coded image, and indicates relative activity of brain regions, cannot detect changes less than 30s in duration, DOES NOT IMAGE THE BRAIN

48
Q

Does a PET scan show structure, function, or both?

A

FUNCTION

49
Q

What is an fMRI?

A

Functional magnetic resonance imaging. It detects increases in blood flow and oxygen usage. Essentially an MRI that measures function, more active cells have more O2, and you get a general image of the brain. It is suitable for repeated measurements, good spatial resolution, it is an alternate to PET scans, COSTLY

50
Q

What are three limitations of brain imaging?

A

fMRI in particular is low sensitivity (harder to get p-values), their test-retest reliability if often low, and they are also prone to data snooping where researchers only record what was significant after looking at all the results

51
Q

What is a family study?

A

This type of study typically determines how a characteristic is shared among relatives.

52
Q

Heredity’s effects are typically confounded by the environment. How do we avoid this?

A

By studying families, their environments are the same.

53
Q

What are three types of relationship studies?

A

Family study, adoption studies, twin studies

54
Q

What are pros of a family study?

A

Can show that a characteristic follows family lines, and it confounds heredity and environment

55
Q

What is a con of adoption studies?

A

They are susceptible to confounding because the adoption variable is not manipulated

56
Q

What is a pro of a twin study?

A

Allows comparison of two levels of genetic similarity (50% and 100% DNA match in fraternal and identical twins)

57
Q

What does the correlational approach to studying heredity entail?

A

Family studies, twin studies and adoption studies

58
Q

What does the experimental approach to studying heredity entail?

A

Genetic engineering, knockdown and knockout, gene transfer and therapy

59
Q

What is genetic engineering and what are two examples?

A

Manipulating an organisms genes. The knockout technique is introducing a nonfunctioning mutation into a gene and then transferring it to embryos therefore the gene is turned off. Knockdown technique is silencing a gene by interfering with its expression, still get mRNA but no protein.

60
Q

What is antisense RNA and when is it used?

A

It is a complementary strand of RNA which binds to mRNA to block gene expression, it is used in knockdown technique.

61
Q

What is gene transfer?

A

When a gene from another organism is inserted into recipient cells, same as recombinant DNA

62
Q

What is gene therapy?

A

Treatment of disorders by manipulating genes to ideally figure out what genes are responsible for a disorder.. Use vectors which are often a disabled virus that carries the gene in the body and inserts it into cells

63
Q

What is plagiarism?

A

Theft of another work or ideas, failure to cite to copying a whole paper

64
Q

What is fabrication?

A

faking results, more serious than plagiarism, introduces erroneous information to the field, 2% of researchers admit to falsification

65
Q

What are two ethical considerations that one must think about when doing research with humans?

A

Informed consent (participants voluntary agreement with understanding of potential adverse effects) and deception (must tell all risks even if not telling what the study is actually measuring)

66
Q

What is a consideration when performing research on animals?

A

Speciesism which is the dual standard that the experimenters preference for inflicting discomfort or dangers on animals rather than humans

67
Q

What are some ethical concerns with gene therapy?

A

gene manipulation could effect reproduction, future generations cannot consent to this manipulation, extent to which gene editing should be permitted

68
Q

What is stem cell therapy and some ethical concerns with it?

A

application of pluripotent embryonic stem cells, and ethical concerns come from where do we get the stem cells from? the creation and intentional termination of human embryos for research is deemed morally repugnant by some, and nonapproved stem cell therapies can be very dangerous