Clinical Neuroscience Techniques Flashcards Preview

CMSD5290 Intro to Neuroscience > Clinical Neuroscience Techniques > Flashcards

Flashcards in Clinical Neuroscience Techniques Deck (42)
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1
Q

What are 6 techniques for studying brain structure and function?

A
  • Computerized Tomography (CT)
  • Magnetic Resonance Imaging (MRI)
  • Electroencephalogram (EEG) / Event Related
    Potentials (ERP)
  • Positron Emission Tomography (PET)
  • Functional MRI (fMRI)
2
Q

When was Computerized Tomography develop?

A

Developed in 1970’s

3
Q

What images does CT scan provide?

A

Static anatomical images of the brain

4
Q

What does the X-ray source do in a CT scan?

A

X-ray source emits a series of narrow x-ray beams and
rotates around the head

5
Q

What positional information can we get from the CT scan?

A

Many positions and reconstructs a 3-D image of brain using mathematical techniques

6
Q

In computerize tomography image is produced because different substances ______________________________________.

A

absorb different amounts of X-rays

7
Q

CT scan shows that dense tissue:

A

absorbs a lot of rays -> light image
e.g. Bones
Acute blood

8
Q

CT scan shows that soft tissue:

A

absorbs fewer rays -> dark image
CSF
Brain tissue (density of gray matter > white matter)
Infarct
Cysts

9
Q

What can be used in CT scan to increase contrast for the images?

A

Intravenous injection of dye may be used to increase contrast (may allow blood vessels, tumors to be seen)

10
Q

What are the advantages of CT scan? (4)
* Provides what?
* Can be used in?
* Indicates?
* Invasiveness?

A
  • Provides structural image of brain in vivo
  • Can be used in healthy and clinical subjects
  • Indicates areas of brain abnormality
  • Relatively non-invasive
11
Q

What are the disadvantages of CT scans? (3)
* Resolution?
* Doesn’t provide what?
* Price and requires what?

A
  • Relatively poor spatial
    resolution
  • Provides measure of
    structure, not ongoing
    activity
  • Expensive and requires
    highly trained specialist
    staff
12
Q

MRI and CT scans have in common that they provide:

A

Static “slice” images of brain,
but in even greater anatomical detail

13
Q

In MRI, the images result from effects changing __________________________________________________.

A

strong magnetic fields applied to brain tissue

14
Q

What happens with the nuclei of certain atoms in brain tissue in MRI?

A

Nuclei of certain atoms in brain tissue
(usually hydrogen) align themselves in
orientation of field when the subject is placed in the magnetic field.

15
Q

What happens with hydrogen atoms when specific radio frequency (RF) is INTRODUCED during the procedure?

A

Causes hydrogen atoms to
resonate and change axis of alignment

16
Q

What happens with hydrogen atoms when specific radio frequency (RF) is REMOVED during the procedure?

A

Hydrogen atoms
“relax” and return to original alignment

17
Q

What occurs in MRI with hydrogen atoms and RF? (3)

A
  • During realignment, hydrogen atoms discharge the RF energy that they had absorbed
  • Because hydrogen (i.e., H2O) composition of different brain structures varies, the RF energy
    given off is distinct for different structures
  • Computer analyses construct 3-D image of brain based of differential energy emissions
18
Q

Rate at which hydrogen atoms realign and return to a lower energy state is called __________ in MRI.

A

relaxation

19
Q

What are the two types of relaxation in MRI?

A

T1 and T2 which result in 3 main types of images

20
Q

In MRI T1 images provide: (2)

A

Dark CSF, light tissue
Pathologies generally behave like CSF (i.e., dark on T1 and bright on T2)

21
Q

In MRI, T2 images provide: (2)

A

Light CSF, dark tissue
Pathologies generally behave like CSF (i.e., dark on T1 and bright on T2)

22
Q

What are the advantages of an MRI? (4)
*Resolution?
* Visualization of brain?
* No use of what material?
* invasiveness?

A
  • Excellent spatial resolution (about 1 mm; determined
    mainly by magnet strength)
  • Brain can be visualized in any plane
  • No X-rays or radioactive material used
  • Safe, painless, non-invasive
23
Q

What are the Disadvantages of an MRI? (4)
* Price?
* Where?
* Can’t be used with who?
* What measure does it not provide?

A
  • Even more expensive than CT
  • Special housing required for magnetic field
  • Cannot be used in patients with metallic devices (e.g.,
    pacemakers, vessel clips)
  • Provides measure of structure not ongoing activity
24
Q

What does EEG stand for?

A

Electroencephalogram (EEG)

25
Q

What does the EEG record?

A

Records electrical activity of brain by
electrodes placed on scalp

26
Q

In EEG, the signal is generated by ________________ activity of millions of _____________ cells of layer V and Vl . Signal is amplified and seen as ____________.

A

Post-synaptic activity of millions of
pyramidal cells
Seen as waveforms

27
Q

In EEG, beta rhythm of an alert participant (_____________, ________________) will have waveforms of _____________________ amplitude

A

Awake, Excited
Low amplitude

28
Q

In EEG, alpha rhythm of an calm participant (_____________, ________________) will have waveforms of _____________________ amplitude

A

Relaxed, Resting
high amplitude

29
Q

Why do we use EEG?

A

Used to diagnose epilepsy and other brain
abnormalities

30
Q

Event-Related Potentials ERP show:

A

change in EEG signal in response to sensory
or cognitive stimulus

31
Q

What are the advantages of EEG? (5)
* Non-invasive or invasive?
* Resolution?
* Record of brain activity?
* Can measure what?
* Price?

A
  • Non-invasive
  • Excellent temporal resolution
  • Can be used to record brain electrical activity in real time
  • Can be used to measure brain’s response to a number
    of sensory or cognitive variables
  • Relatively cheap
32
Q

What are the Disadvantages of EEG? (4)
* Localizing functions?
* Record of neurons?
* Brain activity?
* Susceptible to what?

A
  • Poor at localizing function
  • Activity is recorded from millions of groups of neurons
  • Brain activity may fluctuate unpredictably
  • Susceptible to movement artifact
33
Q

What does Positron Emission Tomography (PET) provide?

A

images of brain function

34
Q

What is the subject injected with for the PET scan?

A

radioactive substance (e.g.,
2-deoxyglucose)

35
Q

In PET scan, ________________ transported by blood to brain and metabolically-active areas will use more ________________ and become more ____________

A

Glucose
Glucose
Radioactive

36
Q

In PET scan, amount of gamma radiation
is represented in ____________ images which
indicate those regions which are__________
in metabolism

A

color-coded
high or low

37
Q

Which method is used in PET and other functional techniques to make conclusions on brain activity?

A

Subtraction method

(Brain is always active
so need to subtract
normal background
activity (i.e., control)
from activity
measured during task
(i.e., stimulation))

38
Q

What are the advantages of PET? (3)
* Measure of?
* When can we use it?
* Resolution?

A
  • Measure of regional
    brain activity in vivo
  • Can be used to measure
    brain activity during task
    performance
  • Relatively good spatial
    resolution (3-8 mm)
39
Q

What are the disadvantages of PET? (4)
* Invasive or non ?
* Resolution?
* Tasks?
* Price?

A
  • Invasive
  • Poor temporal
    resolution (blood flow is
    slower than neural
    transmission)
  • Tasks must take longer
    than 1 minute
  • Expensive
40
Q

What does fMRI measure?

A

Uses MRI technology, but measures brain activity

41
Q

What happens in fMRI? (3)

A
  • Active brain areas receive more oxygenated blood
  • Concentration of oxygen affects magnetic properties
  • MRI can detect functionally induced changes
    in blood oxygenation
42
Q

Compare fMRI to PET and EEG. (2)

A
  • Compared to PET, fMRI has better spatial and temporal resolution
  • Poorer temporal
    resolution than EEG)