methods in cog neuro science

Question 1

How does information travel around the brain

Answer 1

Dendrites receive the neurotransmitter from a neighbouring neurone. If it’s an excitatory neurotransmitter the neuron fires. The electrical signal passes down the axon to the terminal buttons where another neurotransmitter is released.

Question 2

How does MRI work

Answer 2

Hydrogen atoms align when in a scanners magnetic field. Radio waves make the atoms relax and face a their original direction. They e it energy which is what the scanner uses to create an image. Hydrogen atoms have different relaxation times in different tissue to allow us to identify tiny different areas.

Question 3

Advantages of MRI x4

Answer 3

1. ) excellent spacial resolution
2. ) allows multiple angles to be viewed
3. ) non invasive
4. ) excellent for looking at soft tissue

Question 4

Disadvantages of MRI x4

Answer 4

1. ) poor temporal resolution
2. ) noisy, have to stay still, claustrophobic
3. ) expensive
4. ) can’t have any metal on you

Question 5

How does fMRI work

Answer 5

Blood contains haemoglobin which is magnetic due to iron in it. Deoxygenated blood is more magnetic than oxygenated blood. Active areas of the brain have more oxygen rich blood. The difference between the two types of blood is the blood oxygen level dependant respires (BOLD)

Question 6

Advantages of fMRI x4

Answer 6

1. ) excellent spacial resolution
2. ) reasonable temporal resolution
3. ) non invasive
4. ) tells us which parts of the brain are active

Question 7

Disadvantages of fMRI x4

Answer 7

1. ) BOLD isn’t a direct measure of activity
2. ) noisy, have to stay still, claustrophobic
3. ) expensive
4. ) can’t have any mental on you

Question 8

How does PET scans work

Answer 8

Measures blood flow in the brain by tracking where a mildly radioactive drug goes in the brain

Question 9

Advantages of PET x4

Answer 9

1. ) reasonable structural resolution
2. ) direct reflection of activity
3. ) no motion artifacts
4. ) more comfortable than MRI / fMRI

Question 10

Disadvantages of PET x4

Answer 10

1. ) no temporal resolution
2. ) expensive
3. ) ethical issues of radioactive drug
4. ) may need a CT or MR scan too

Question 11

How does EEG work

Answer 11

Measures electrical signals generated in the brain by electrodes placed on the scalp. EEG signals are produced by partial synchronisation of cortical field activity (when one neurone fires the other neighbouring neurons also fire) and are measured as changes in voltage over time.

Question 12

Advantages of EEG x3

Answer 12

1. ) good temporal resolution
2. ) direct reflection of activity
3. ) not claustrophobic

Question 13

Disadvantages of EEG x3

Answer 13

1. ) poor spacial resolution
2. ) motion effects
3. ) can’t be sure which brain regions generated the electrical activity

Question 14

How does MEG work

Answer 14

Pyramidal cells of the cortex generate magnetic fields when active. MEG records these

Question 15

Advantages of MEG x3

Answer 15

1. ) excellent temporal resolution
2. ) direct reflection of activity
3. ) good spacial resolution (not distorted by scalp and for whole brain)

Question 16

Disadvantages of MEG x2

Answer 16

1. ) expensive

2. ) how can we be sure which areas of the brain generate electrical activity

Question 17

Which of EEG, MEG and fMRI has the best spacial resolution

Answer 17

fMRI best then MEG and EEG worst

Question 18

Which of EEG, MEG and fMRI has the best temporal resolution

Answer 18

EEG and MEG best, fMRI worst

Question 19

Which of EEG, MEG and fMRI measures frequency of neural oscillations

Answer 19

EEG and MEG

Question 20

Which of EEG, MEG and fMRI is portable

Answer 20

only EEG

Question 21

How does TMS work

Answer 21

Uses changing magnetic field to indue weak electrical currents in the cortex causing depolarisation or hyper polarisation producing a temporal lesion preventing function of that area

Question 22

Advantages of TMS x2

Answer 22

1. ) near portable

2. ) can stimulate temporal lesion

Question 23

Disadvantages of TMS x2

Answer 23

1. ) difficult to specify precise regions

2. ) only surface regions