Functional Neuroimaging

Question 1

Imaging of functional activity can be done ______ or ______.

Answer 1

direct or indirectly

Question 2

What does the indirect imaging measurements quantify?

Answer 2

cerebral blood flow, blood oxygen levels, or oxygen or glucose consumption

Question 3

Is electric and magnetic signals direct or indirect?

Answer 3

direct measurement of neural activity

Question 4

Electroencephalography (EEG)

Answer 4

electrical potential produced by large populations of neurons are measured by electrodes placed on the scalp

Question 5

EEG provides continuous recording of what?

Answer 5

recordings of overall brain activity

Question 6

What are the recorded measured signals of an EEG referred to as?

Answer 6

Electroencephalogram

Question 7

Predictable EEG patterns are associated with different behavioral states; Why would you compare EEG readings to neurotypical patterns?

Answer 7

in order to detect abnormalities

Question 8

What is the quality of EEGs?

Answer 8

Good temporal quality, poor spatial quality

- Signal can be distorted as it passes through the tissue

Question 9

Magnetoencephalography (MEG) measures….

Answer 9

neural activity by capturing the magnetic fields produced by active neurons

Question 10

What is the quality of MEGs?

Answer 10

similar temporal quality as EEG, but better spatial resolution due to lack of signal distortion

Question 11

How are MEGs applied?

Answer 11

during neurosurgery

Question 12

Why are MEGs useful?

Answer 12

for identifying cortical functionality

Question 13

Is measuring metabolic signals direct or indirect?

Answer 13

indirect measurement of neural activity

Question 14

Positron Emission Tomography (PET) measures….

Answer 14

local changes in cerebral blood flow

Question 15

Areas of increased blood flow on a PET scan = what?

Answer 15

increased neural activity

Question 16

What is required for PET scans?

Answer 16

Radioactive tracer injected into the bloodstream (tracer emits photons/gamma rays)

Question 17

How does a PET scanner detect blood flow?

Answer 17

detects the location of emitted gamma rays

Question 18

When are PET scans employed?

Answer 18

• 1st during a control condition (subject at rest)

- 2nd during experimental condition (subject engaged in a cognitive task)

Question 19

What will brain areas of heightened neural activity emit?

Answer 19

will emit the highest levels of gamma rays due to increased blood flow in those regions

Question 20

What are results of PET scans reported as?

Answer 20

as a change in regional cerebral blood flow (rBCF) between two conditions

Question 21

What are the downsides of PET studies?

Answer 21

requires injection of radioactive isoptope

• Invasive procedure
• Limited number of tests due to exposure

Question 22

Functional Magnetic Resonance Imaging (fMRI) relies on what?

Answer 22

relies on the magnetic properties of hemoglobin

Question 23

fMRI measures

Answer 23

the ratio of oxygenated to deoxygenated hemoglobin in the bloodstream

Question 24

What is the ratio of oxy vs. deoxy hemoglobin referred to as?

Answer 24

blood oxygenation level-dependent (BOLD) effect

Question 25

As a brain region becomes more active (during fMRI) what happens to the BOLD effect ratio?

Answer 25

Cerebral blood flow to those areas increases thus the ratio of oxygenated to deoxygenated hemoglobin in that region increases

Question 26

Why is fMRI a preferred neuroimaging technique?

Answer 26

• Non-invasive and can be repeated
• Found in most hospitals and require less staff to run
• Spatial resolution is better than PET
• Improve temporal resolution is possible with fMRI due to the rapid measurement of the BOLD signal

Question 27

Previous view of evolving brain theory?

Answer 27

• Neural circuitry is static
• Cognitive function and memory are localize
• Information processing involves only serial processing
• Brain function(s) vulnerable to single site injury
• Clinical supporting evidence limited

Question 28

Current view of evolving brain theory?

Answer 28

• Neural circuitry is plastic
• Cognitive functions and memory are distributed
• Information processing involves serial, parallel, and reciprocal
• Brain activity is driven by internal, intrinsic cycles of network activity (intrinsic and extrinsic interaction)
• Brain function(s) resistant to degradation by single site injury
• Clinical supporting evidence strong

Question 29

Cognitive network neuroscience is a branch of neuroscience that studies what?

Answer 29

how brain dynamics within the human brain networks support cognitive function

Question 30

What are single-source divergent networks?

Answer 30

functional neural pathways comprised of neurons within specific nuclei found that release one type of signaling molecule that influence numerous other target brain areas

Question 31

Cognitive network characteristics

Answer 31

• Appear early during embryonic development
• Support all cognitive functions of the brain
• Constantly modulate neural activity and are referred to as “brain state modulatory controls”
• Organized in a hierarchy (local division of labor within the network)
• Exhibit functional stability in the face of local network damage
• Are created and altered by synaptic plasticity processes
• Consist of many long-reaching axonal branches
• Categorized by the neurotransmitter utilized