Neuroimaging

Question 1

What are the advantages and disadvantage of EEG ?

Answer 1

Advantages:
- good time resolution
- portability
- affordable
- silent (can be done during auditory processing)
- can be combined with other methods

Disadvantages ?
- low spatial resolution
- artifacts

Question 2

What are the advantages and disadvantages of MEG ?

Answer 2

Advantages:
- good time resolution
- reduced preparation time
- signal unaffected by skull and scalp

Disadvantages:
- expensive
- low spatial resolution
- subject cannot move
- not portable
- sensitive only to neurons in sulci

Question 3

What can cause artifacts on EEG ?

Answer 3

• Eye lid movement
• scalp muscle activity
• pacemakers
• movement (= change in impedance)
• electrode-wire contact
• poor grounding
• sweating

Question 4

What are brain oscillations ?

Answer 4

Rhythmic fluctuations of repeated electrical activity generated by the activity of neurons.
Can be spontaneous or in reaction to a stimulus.

Question 5

What is neurofeedback training ?

Answer 5

Expected or desired aspects of cortical and subcortical activation can be achieved or modified through sensory (visual and auditory) stimulation, controlled by a biofeedback system that rely on EEG information.

Question 6

What are the types of neurofeedbacks ?

Answer 6

• univariate : blood oxygen level dependent
• decoded : multi voxel activity pattern
• connectivity : functional connectivity between regions

Question 7

For which conditions has NFT been proven efficient ?

Answer 7

• ADHD
• ADH
• epilepsy
• neurocognitive disorders
• ABI in connection with facilitation, sensory augmentation and functional training

Question 8

What are the advantages of MRI compared to CT ?

Answer 8

• no use of ionizing radiation
• contrasts have less side effects
• comparable resolution but not the same tissues
• more detailed even without contrast

Question 9

What are the disadvantages of MRI compared to CT ?

Answer 9

• Claustrophobic patients
• limitation to weight and size of patient
• very noisy
• long time of procedure (not suitable for emergencies)
• sequential (no generalization possible)

Question 10

What are the characteristics of T1 weighted image ?

Answer 10

White matter appears brighter than grey matter:

Hypointense signal:
- cerebro spinal fluid
- edema
- tumor
- infection
- inflammation
- hemorrhage
- calcification

Hyper intense signal:
- chronic hemorrhage
- fat
- protein rich fluid
- slow flowing blood
- contrast

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- melanin
- blood
- fat and slow blood flow
- proteins and paramagnetic substances
- cholesterol and contrast

Question 11

What are the characteristics of T1 weighted image ?

Answer 11

White matter appears brighter than grey matter:

Hypointense signal:
- cerebro spinal fluid
- edema
- tumor
- infection
- inflammation
- hemorrhage
- calcification

Hyper intense signal:
- chronic hemorrhage
- fat
- protein rich fluid
- slow flowing blood
- contrast

Question 12

What will cause unbalanced delta waves ?

Answer 12

Slowest in the human brain

Too much:
Dépression

Too little:
Sleep disorders and dissociation

Question 13

What will cause unbalanced Theta waves ?

Answer 13

Too much:
Lack of focus

Too little:
Memory disorders

Question 14

What will cause unbalanced alpha waves ?

Answer 14

Strongest EEG brain signal

Too much:
Anxiety

Too little:
Exhaustion

Question 15

What will cause unbalanced beta waves ?

Answer 15

Too much:
Obsession

Too little:
Dépression and anhedonia

Question 16

What will cause unbalanced SMR waves ?

Answer 16

Sensorimotor rhythm

Too much:
Dépression

Too little:
Attention disorders

Question 17

What will cause unbalanced gamma waves ?

Answer 17

Fastest brain wave

Too much:
Paranoïa

Too little:
Reasoning and perceptual deficits

Question 18

What are the characteristics of T2 weighted images ?

Answer 18

Grey matter appears brighter than white matter.

Hypointense signal will reveal: CSF, edema, infection, inflammation, subdurral or subacute haemorrhage and calcification.

Hyperintence signal will reveal: calcification, fibrous tissue, iron and melanin.

Question 19

What is FLAIR used for ?

Answer 19

Fluid Attenuated Inversion Recovery.
Efficient in the evaluation of vascular injuries, SDH and multiple sclerosis.

Question 20

What are the purposes of T1WI ?

Answer 20

• Intracerebral bleeding
• structures with high fat concentration
• small anatomical details

Question 21

What are the purposes of T2WI ?

Answer 21

• Edema
• Demyelination
• Infarction
• Chronic haemorrhage

Question 22

What are the purposes of FLAIR ?

Answer 22

• Edema
• Demyelination (most specific)
• Periventricular and pericortical hemorrhage

Question 23

What are commissural fibers ?

Answer 23

Connection between hemispheres.
- Corpus callosum
- Anterior commissure
- Fornix

Question 24

What are the projection fibers ?

Answer 24

Connection from/to the cortex:
- optic and acoustic fibers
- thalamocortical fibers
- internal capsule
- cortico pontine
- corticospinal tract

Question 25

What are the association fibers ?

Answer 25

Connexions within hemispheres:
- short U fibers (between adjacent gyri of the brain)
- inferior longitudinal fasciculus
- inferior fronto occipital fasciculus
- middle longitudinal fasciculus
- uncinate (from prefrontal to temporal cortex)
- Cingulum

Question 26

What is the role of the superior longitudinal fasciculus I ?

Answer 26

Connects prefrontal regions with parietal regions and is involved in higher cognitive functions, planning and analysis and spatial awareness.

Question 27

What is the role of superior longitudinal fasciculus II ?

Answer 27

Connects prefrontal regions with parietal and occipital regions. Integration between processed visual information and cognitive functions related to decision making and prospection.

Question 28

What are the functions of superior longitudinal fasciculus III ?

Answer 28

Connecting prefrontal regions with contralateral occipital regions. Involved in visual attention and tracking.