Neuroscience methods 2

Question 1

What is a T1 image

Answer 1

An image of brain anatomy.

Resolved from an MRI when hydrogen protons return to normal magnetism

Question 2

What is DTI used for

Answer 2

Mapping white matter & brain connectivity

Question 3

What is fMRI used for

Answer 3

Mapping brain activation

Question 4

What is MRS used for

Answer 4

Mapping metabloic activity

Question 5

How does TMS work?

Answer 5

A coil induces a magnetic field that induces an electrical field in the brain and causes ells to fire

Question 6

What is TMS

Answer 6

Trans-magnetic stimulation.

A non-invasive method of stimulating cortical tissues by administration of a brief magnetic pulse to the scalp

Question 7

What is BOLD

Answer 7

Blood Oxygen level dependence.

A measure of ration of oxygenated to deoxygenated blood

Question 8

What is a T2 image

Answer 8

An image of connectivity through the fluid (CSF) in the brain resolved when the hydrogen protons relax their spinning

Question 9

Does EEG have better spatial or temporal resolution

Answer 9

Temporal

Question 10

Does fMRI have better spatial or temporal resolution

Answer 10

Spatial

Question 11

What connections does fMRI measure

Answer 11

functional connections between brain regions

Question 12

What connections does DTI measure

Answer 12

Structural connections between brain regions

Question 13

What is temporal resolution

Answer 13

The time course of various neural events

Question 14

What is spatial resolution

Answer 14

Ability to discern elementary units of activated brain networks

Question 15

Who should not use TMS

Answer 15

• People with a history of seizures
• People with metal in the head
• People with history of serious head injury

Question 16

Explain the trade-off in network connectivity in the brain

Answer 16

Regular networks have low metabolic cost but low efficiency

Random networks have high metabolic cost but high high efficiency

Question 17

What is spatial normalisation

Answer 17

Averaging out individual differences in brain structure

Question 18

What is a limitation of voxel-based morphology

Answer 18

Limited to locating abnormalities. Can not explain them (e.g. neurons or synapse loss)

Question 19

Are tracts in DTI axons?

Answer 19

No, they are estimates of the trajectory of a fiber pathway

Question 20

What are explanations for variation in tract diffusion in DTI?

Answer 20

• altered fibre integrity/myelin
• altered organisation
• noise

Question 21

What is a limitation of DTI

Answer 21

• not a direct physiological meaningful measure of connectivity
• cannot distinguish efferent/afferent connection

Question 22

What does DTI measure

Answer 22

Water diffusion in the brain

- anisotropic diffusion along axons

Question 23

What is radial diffusivity?

Answer 23

Less diffusion - an index of myelin integriy

Question 24

What is axial diffusivity?

Answer 24

Breakdown of fibre organisation

Question 25

What are the limitations of fMRI?

Answer 25

- BOLD response may reflect neuronal exhitation/inhibition or a combination - BOLD response is much slower than neuronal activity

Question 26

What is does fMRI measure

Answer 26

The ratio of oxygenated to deoxygenated blood

Question 27

What is a block design?

Answer 27

Trial with a condition are presented together

Question 28

What is a event-related design?

Answer 28

Randomised presentation of trials

Question 29

Which has higher power: block or event-related design

Answer 29

Block

Question 30

What have animal studies revealed about the BOLD measure

Answer 30

It is correlated with input into a brain region (local field potential) not output (multi unit activity)

Question 31

What does resting state fMRI measure

Answer 31

Brain activity in the absence of a task

Question 32

How much energy consumption is from base activity in the brain?

Answer 32

80%

Question 33

How long does it take for the brain to return to baseline after task

Answer 33

Up to 15 minutes

Question 34

What is a connectome

Answer 34

A comprehensive map of neural connections

Question 35

What is graph theory

Answer 35

A mathmatical field that looks at how networks interact with each other

Question 36

What neurotransmitter is involved with TMS measurement of cortical inhibition

Answer 36

GABA

Question 37

In TMS, what frequency is used to create a virtual lesion

Answer 37

1Hz

Question 38

In TMS, what frequency is used to enhance brain activity

Answer 38

5Hz or greater

Question 39

What is the therapeutic application of TMS to schizophrenia

Answer 39

An inhibitory pulse is used to treat auditory hallucinations in schizophrenia

Question 40

What is the therapeutic application of TMS to depression

Answer 40

An excitation pulse is used for treatment resistant depression