Research methods in Neuroscience 10.02.23

Question 1

Are X-Rays good for neuro?

Answer 1

Not really. The brain is mushy and so doesn’t show up well. However, they can be good to confirm locations of foreign objects for medical purposes

Question 2

What are contrast X-ray techniques?

Answer 2

• Use an injected substance (called a contrast agent)
• They provide image contrasts between different bodily compartments
• Usually between the intravascular compartment (within blood vessels) and the extravascular compartment (everything else)

Question 3

What is an MRI?

Answer 3

• Magnetic Resonance Imaging
• Put energy in via radio frequency waves
• Energy is absorbed and then emitted in a way that gives information about the chemical properties of the tissues
• So MRI allows detailed picture of brain structure (sensitive to different tissue types - grey and white matter)

Question 4

What is an fMRI?

Answer 4

This is a functional MRI
- Only difference is that you ‘tune’ your scanner to be sensitive to something that disturbs the way the energy is absorbed and emitted (e.g. blood)
- Can be made very sensitive to the effect of iron

Question 5

What is a PET scan?

Answer 5

• Positron Emission Tomography
• Make a contrast agent that is specifically targeted to the biological process we want to image
• Get a chemical that binds to the target
• attach a radio-isotope to that chemical
• Inject the tracer
• Detect the emitted radiation and use computer to see where they are coming from

Question 6

What is an EEG?

Answer 6

• Electroencephalogram
• Gives indication or regional brain activity underlying electrodes
• Good resolution
• good for detecting signs of epilepsy
• Analysis is complex and takes a lot of time
• can be used to look at brain responses to a specific stimulus

Question 7

What is an MEG?

Answer 7

• Magnetoencephalography opposite to EEG
• Electrical current of cells and white matter (axons etc…) induce a magnetic field that can be detected by this machine
• MEG signals are small and hard to detect
• Less interference

Question 8

How can we stimulate the brain?

Answer 8

TMS and TDCS
- Induces an electrical current in brain tissue which disrupts the ongoing activity
- Used to turn off parts of the brain so that their role and function can be assessed

Question 9

What are the three guiding principles for all research involving animals?

Answer 9

Replacement (can another method be used)
Refinement (can it be done in a better way)
Reduction (can it be done with a smaller number of animals)

Question 10

What are the possibilities with using animals for invasive methods?

Answer 10

1. Make direct measurements of the activity of brain cells
2. Determine the connectivity between structures, flow of information
3. Disrupt connectivity between structures to determine effects upon circuit function
4. Lesion specific structures to inform us about their function

Question 11

What are pharmacological research methods?

Answer 11

• Psychoactive drugs such as caffeine, alcohol and other illegal compounds often have complex actions on many brain regions
• So they use these to test how they might mimic neurotransmitters/ blocking receptors etc…

Question 12

How have genetic manipulations been used in research?

Answer 12

They have been able to add or take out specific genes in animals for example the serotonin gene so the levels of this are elevated

Question 13

What are optogenetics?

Answer 13

We can make specific brain cells sensitive to light, so that we can control them
- Currently an invasive technique used for research animals