Unit 4 (Chapter 7) - The Methods and Ethics of Research in Neuroscience (Questions)

What are the types of observational studies?

Naturalistic observation, case studies, surveys

What are the pros and cons of experimental research?

Pros: experimenter attempts to eliminate extraneous variables → can reach causal conclusion, which isn’t possible in observational research

Cons: experimenters may sacrifice realism for control, where strict lab conditions may not be applicable to or reflect a real life scenario

What are the pros and cons of correlational studies?

Pros: results are valuable as they reflect real world situations, allow for studies that normally are not ethically permissible (ex. comparing a group of people with brain injuries)

Cons: observational so cannot determine cause and effect, chance of confounding variables due to not controlling extraneous variables

Which stain techniques are structural, and which are functional?

Structural: golgi, nissl, retroactive, myelin

Functional: autoradiography, immunocytochemistry, in situ hybridization

What are the pros and cons of using a golgi stain?

Pros: able to see a full, clear picture of an entire single neuron without being overlapped by millions of others

Cons: tissue must be dead (in a slide)

What are the pros and cons of using a myelin stain?

Pros: able to see myelinated neurons over the entire brain, comprising a large area

Cons: cannot be used for individual neurons

What are the pros and cons of using a nissl stain?

Pros: able to see grey matter/cell bodies over the entire brain, comprising a large area

Cons: cannot be used for individual neurons

What are the pros and cons of using a retrograde stain?

Pros: able to see the connectivity of neurons (used in live brains) based on where they send information to

Cons: cannot be used for individual neurons, not for dead tissue

What is the key defining feature of using autoradiography?

Able to see which neurons are active during certain activities (location)

What is the key defining features of using immunocytochemistry?

Able to see where cells produce a certain protein (location) as well as how many produce it (number)

What is the key defining features of using in situ hybridization?

Able to see where cells produce a certain protein (location) as well as how many produce it (number)

What is the main pro of using an electron microscope?

High zoom for relatively cheap

What is the main pro of using a transmission electron microscope? What is the main con?

Incredible zoom (50 million), expensive to run and use

What is the main pro of using a scanning electron microscope? What is the main con?

3D image produced, sacrifices some zoom (2-3 million)

Explain and describe how a stereotaxic instrument can be used to monitor and measure brain activity.

Instrument holds the brain in a precise position such that fine-wire electrodes in a probe can be inserted, and microelectrodes that stimulate single neurons of a larger structure in the brain

What is the main pro of optogenic techniques to measure and manipulate brain activity?

Light is a very precise stimulator (more than microelectrodes)

What is the main pro of chemical stimulation via a cannula to measure and manipulate brain activity?

Only the area within the cannula responds to the chemical treatment → precise locational selection

What is the main pro of using microdialysis?

Able to measure the chemicals already present in the brain, but not manipulating it

What is the main pro of using natural experiments? What are the main cons?

Can use specific case studies to discover circumstances that otherwise would not be possible

Damage may overlap functional areas or fail to affect the entirety of an area, and thus experimentation is unable to attribute a specific behavioural change/observation to one part

What are the main cons of using ablation as a way of manipulating brain activity?

Large area removed → imprecise

What are the main pros of using ablation as a way of manipulating brain activity?

Precise, can be reversible (if hormone-blocking substance or other is used)

What are the main pros and cons of using EEG as a way of measuring brain activity?

Pros: very high temporal resolution

Cons: imprecise spatial resolution

Compare and contrast how TMS is used in research compared to therapeutically via duration and intended effect.

In research: one session with the intent to turn off a brain area temporarily, with no lasting effect

Clinically: 6-12 sessions over the span of time with the intent to cause lasting change. Can treat symptoms of Parkinson’s, schizophrenia, chronic pain, etc.

What are the main pros and cons of positron emission topography for measuring function of the brain?

Pros: cheap

Cons: poor spatial (not shown on the brain itself) and temporal resolution (cannot detect real time changes)

What are the main pros and cons of fMRI for measuring function of the brain?

Pros: good spatial and temporal resolution, good for repeated measurements

Cons: very costly to use, low in sensitiviy

Test-retest reliability in brain imaging is (high/low).

Low, repeated measurements unlikely to give exact same result

Explain how the results of twin studies differ between fraternal and identical twins.

Identical twins are 100% similar: any difference must be due to environment

Difference between fraternal twins could be genetic or environmental

Comparing genetic similarities is a (observational/experimental) approach, while genetic engineering is a (observational/experimental) approach.

Observational, experimental

Explain the difference between knockout and knockdown techniques.

Knockout: replaces the working gene with a nonfunctional mutation of the gene. Gene is present but not working from the start

Knockdown: the working gene is silenced using antisense RNA but is still functional and present in the cell

How can deception be used ethically? When can it not be used?

Strategic deception to prevent bias from the participant, but they must be informed afterwards

Cannot be used when there is significant risk, pain, or harm

What are the ethical concerns surrounding gene therapy?

Gene manipulation could affect reproduction → future generations cannot consent to this manipulation

Extent to which gene editing should be permitted → may be used in subjective ways (strength, beauty, etc.)

What are the ethical concerns surrounding stem cell therapy?

Stem cells must be taken from the human embryos → creation and intentional termination of human embryos for research in mass is problematic

Dangers posed by non-approved stem cell therapies offered in private clinics → stem cells from unapproved or unsafe methods can cause a wide array of health issues

Even approved stem cell therapies have a nearly 50% increase in cancer rate at the injection site