research methods in neuroscience

Question 1

what are some constraints on research?

Answer 1

• Expertise
• Facilities
• Time
• Money
• Ethics

Question 2

what can x-ray technique be used for?

Answer 2

not very useful in neuroscience

can confirm location of foreign objects

Question 3

describe contrast x-ray techniques

Answer 3

injected substance known as contrast agent, provide image contrast between different bodily compartments e.g. contrast between intravascular compartment and extravascular compartment – cerebral angiography

Question 4

describe magnetic resonance imaging (MRI)

Answer 4

put energy in via radiofrequency waves, the energy is absorbed and emitted in a way that gives information about the chemical properties of the tissues, so allows you to build up a picture of brain structure that is sensitive to the different tissue types

Question 5

Functional magnetic resonance imaging (fMRI)

Answer 5

‘tune’ scanner to be sensitive to something that disturbs the way the energy is absorbed and then emitted – blood (iron) – scanner picks up oxygenation of blood in the tissue, activated brain cells can call up more blood so it tells us about brain activity

Question 6

positron emission tomography (PET)

Answer 6

contrast agent in specifically targeted to the biological process we want to image, chemical that binds to target, attach radioscope to that chemical, inject, detect radiation, use computer

Question 7

EEG

Answer 7

gives indication of regional brain activity underlying electrodes – good temporal resolution, poor spatial resolution – good for detecting signs of epilepsy, complex and time consuming, frequencies separated into bands which relate to distinct neurophysiological processes

Question 8

MEG

Answer 8

The electrical current of large numbers of cells and white matter tracts (bundles of axons, think wires) induces a magnetic field that can be detected with a very large and odd looking machine, signals are small and hard to detect

Question 9

stimulating the brain - TMS, TDCS

Answer 9

Induces electrical current in brain tissue which disrupts the ongoing activity. Used in research to ‘turn off’ parts of the brain so that their role in a cognitive function can be assessed, Hard to target precisely, Some evidence of clinical potential (e.g. in treating depression)

Question 10

Three guiding principles for all research involving animals (3Rs)

Answer 10

• Replacement (can another method be used)
• Refinement (can it be done in a better way that further maximises the cost:benefit equation)
• Reduction (can it be done with a smaller number of animals)

Question 11

possibilities with invasive methods

Answer 11

1) Make direct measurements of the activity of brain cells.
2) Determine 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 what function that structure performs

Question 12

who can drugs affect the process of neurotransmission

Answer 12

o Some will mimic the neurotransmitter to act on the receptor
o Some will block the receptor
o Some will prevent manufacture of the neurotransmitter
o Some will block re-uptake

Question 13

optogenetics

Answer 13

o This is a process whereby we can make specific brain cells sensitive to light, so that we can control them (switch on or off) in very precise ways