2- Methods

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Author:
carolinc
ID:
84566
Filename:
2- Methods
Updated:
2011-05-08 20:59:18
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MRI fMRI
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Description:
types of imaging
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  1. Name the devices that record structure of brain
    • MRI(magnetic resonance imaging)
    • CT (computerized tomography)
    • Histology
  2. Name the 5 devices that record functionality of brain
    • fMRI
    • EEG
    • MEG
    • ECOG
    • PET
  3. What is magnetic field strength measured in?
    Teslas = 10,000 Gauss
  4. Where is the B0 field ?
    inside the MRI scanner bore while magnet is at rest.
  5. The R in MRI refers to the resonance of what with what?
    resonance of hydrogen protons with radio frequency pulse delivered by gradient coils inside scanner.
  6. What is the spatial and temporal resolution for PET?
    • Spatial: 1-3 mm
    • Temporal: 6+sec
  7. What is the spatial and temporal resolution for MEG?
    • Spatial: 1-3 cm
    • Temporal: ms
  8. T then Number ie) T1, T2 represents..
    • pulsing time of MRI study of a nucleus in magnetic field
    • T1= 0.5 sec T2= 2.5sec
  9. H2O relaxes at how many seconds?
    2.5 seconds
  10. T1 scan measures
    no water signal
  11. T2 scan prominently measures
    water signal
  12. on a T1 MRI, water shows up as
    Dark
  13. on a T2 MRI, water shows up as
    Bright white
  14. a PET scan's duration is determined by what?
    radioactive half-life of particular tracer
  15. Name the tracer used for each measurement

    FDG:
    O15:
    PIB:
    FMT
    • FDG: Glucose
    • O15: Blood flow
    • PIB: Amyloid
    • FMT: decarboxylase involved in dopamine synthesis
  16. How does a PET scan work?
    Positron hits electron-->2 photons emitted at 180 degrees, travel at speed of light-->sensor pick up 2 opposing photons --> compute map
  17. How does blood appear on a CT scan after injury?
    Bright white (MRI can't do that)
  18. How does a CT scan work?
    2 x-rays emitted simultaenously, imaged towards detectors on opposite side-->computer combine time and info to form a map
  19. What does trial averaging do?
    • dampens the noise to reveal signal
    • causes noise to sum to ZERO
  20. What is an evoked potential (EP)?
    brain response to sensory stimuli
  21. What is an ERP?
    • Evoked related potential
    • measures cognitive/perceptual task
  22. What is the difference between near-field and far-field?
    • NF=neuron firing generated near scalp where EEG can measure it.
    • FF=neuron firing generation located FARTHER from electrodes
  23. In ECOG, electrodes are placed on..
    the surface of the brain, therefore, skull not in the way and are NOT LOW PASS FILTERED by presence of bone
  24. T2 scans are good for seeing
    pathology
  25. What is brightest on the T1 scan?
    Fat/White matter
  26. T1 scan measures
    the rate that the longitudal component of magnetization relaxes back to the b0 field direction
  27. In an action potential, the region trailing the wave of depolarization has a net ____ charge, while the region in front has a net _____. This creates a ______
    • positive charge, negative charge,
    • dipole when it reaches the surface of the scalp
  28. Doing a Fourier Analysis of a continuous signal will give you what information about the signal?
    tells you how much frequency is present in original signal, changes continuous time series into info about amplitudes and frequencies.
  29. PET is great for looking at what?
    neurotransmitters
  30. Which field has better signallign results?
    open field
  31. What does phase inversion help with?
    points to local source-when you see flip in ploarity (inversion), you see there is an abnormality.
  32. What is an example of MEG?
    SQUID
  33. If the geometry of an EEG source are the same (+) (+), what kind of field is it? and (-)(+)?
    • Open(+)(+)
    • Closed (+)(-)
  34. ________ allows an experimenter to pull out a true physiological signal fromthe noise when analyzing EEG data.

    A) Fourier analysis
    B) signal averaging
    C) source localization
    D) coherence analysis
    B) signal averaging
    (this multiple choice question has been scrambled)
  35. Order the following recording techniques according to their temporal resolution (most to least precise): fMRI, EEG, PET, CT
    A) EEG, fMRI, PET, CT
    B) fMRI, CT, PET, EEG
    C) CT, EEG, PET, fMRI
    D) EEG, PET, fMRI, CT
    A) EEG, fMRI, PET, CT
    (this multiple choice question has been scrambled)
  36. CT scanning relies most directly on:
    A) the differential radioactivity in the X‐ray range by different tissuetypes.
    B) the differential absorption of Xraysby tissue types of varying density.
    C) the different magnetic shielding properties of different tissue types.
    D) the fact that different tissue types have different resonance frequencies.
    B) the differential absorption of Xraysby tissue types of varying density.
    (this multiple choice question has been scrambled)
  37. In fMRI, we measure an INCREASE in signal when:
    A) there is an increase in the ratio of oxygenated to deoxygenated hemoglobin
    B) there is an decrease in the ratio of oxygenated to deoxygenatedhemoglobin
    C) a radiotracer decays, emitting gamma rays
    D) A and C
    e) None of the above
    A) there is an increase in the ratio of oxygenated to deoxygenated hemoglobin
    (this multiple choice question has been scrambled)
  38. EEG primarily measures signal from:
    A) basal ganglia neurons in the far field
    B) pyramidal neurons in a closed configuration
    C) pyramidal neurons in an open configuration
    D) basal ganglia neurons in the near field
    C) pyramidal neurons in an open configuration
    (this multiple choice question has been scrambled)
  39. Doing a Fourier Analysis of a continuous signal will give you what information about that signal?
    A) It allows you to determine the frequencies present in your signal
    B) It allows you to determine whether there is a dipole source close toyour electrode
    C) It allows you to remove noise because it will average out, thanks to its random nature
    A) It allows you to determine the frequencies present in your signal
    (this multiple choice question has been scrambled)
  40. Which is of the following is used as a measure of communication between brain regions?
    A) Phase inversion
    B) A and B
    C) Phase locking
    D) Coherence
    B) A and B

    Coherence and Phase locking
    (this multiple choice question has been scrambled)
  41. ECOG
    a) Has better temporal resolution than fMRI
    b) Measures signals from the scalp
    c) Allows you to measure high frequency brain activity
    • A and C
    • Better temporal resolution than fMRI and allows you to measure high frequence brain activitity
  42. Theta‐Gamma coupling:a) reflects coupling between the phase of theta and the amplitude ofgammab) can be measured with electrocorticography
    • reflects coupling between phase of theta and amplitude of gamma
    • can be measured with ECOG
  43. Which of the following historical figures is INCORRECTLY matched to hiscontribution to neuropsychology?
    A) Paul Broca – described a brain area that was involved in understanding language
    B) Karl Brodmann – developed detailed cytoarchitectonic maps of the brain
    C) John Harlow – described a brain area involved in social and emotional control
    D) Franz Josef Gall – studied the relationship between skull features and personality traits
    A) Paul Broca – described a brain area that was involved in understanding language

    language PRODUCTION
    (this multiple choice question has been scrambled)
  44. The temporal and spatial resolution of fMRI is on the order of _________ and__________, respectively:
    A) minutes, millimeters
    B) seconds, millimeters
    C) seconds, centimeters
    D) milliseconds, centimeters
    E) hours, millimeters
    B) seconds, millimeters
    (this multiple choice question has been scrambled)
  45. Which of the following statements about MRI is incorrect?
    a) The strength of the magnet is measured in Hounsfield units
    b) The B0 magnet aligns hydrogen electrons
    c) T1 and T2 refer to the strength of the B0 magnet
    d) All of the above are incorrect
    d) All of the above are incorrect

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