Name the 5 devices that record functionality of brain
fMRI
EEG
MEG
ECOG
PET
What is magnetic field strength measured in?
Teslas = 10,000 Gauss
Where is the B0 field ?
inside the MRI scanner bore while magnet is at rest.
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.
What is the spatial and temporal resolution for PET?
Spatial: 1-3 mm
Temporal: 6+sec
What is the spatial and temporal resolution for MEG?
Spatial: 1-3 cm
Temporal: ms
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
H2O relaxes at how many seconds?
2.5 seconds
T1 scan measures
no water signal
T2 scan prominently measures
water signal
on a T1 MRI, water shows up as
Dark
on a T2 MRI, water shows up as
Bright white
a PET scan's duration is determined by what?
radioactive half-life of particular tracer
Name the tracer used for each measurement
B) FDG: Glucose
O15: Blood flow
PIB: Amyloid
FMT: decarboxylase involved in dopamine synthesis
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
How does blood appear on a CT scan after injury?
Bright white (MRI can't do that)
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
What does trial averaging do?
dampens the noise to reveal signal
causes noise to sum to ZERO
What is an evoked potential (EP)?
brain response to sensory stimuli
What is an ERP?
Evoked related potential
measures cognitive/perceptual task
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
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
T2 scans are good for seeing
pathology
What is brightest on the T1 scan?
Fat/White matter
T1 scan measures
the rate that the longitudal component of magnetization relaxes back to the b0 field direction
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
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.
PET is great for looking at what?
neurotransmitters
Which field has better signallign results?
open field
What does phase inversion help with?
points to local source-when you see flip in ploarity (inversion), you see there is an abnormality.
What is an example of MEG?
SQUID
If the geometry of an EEG source are the same (+) (+), what kind of field is it? and (-)(+)?
Open(+)(+)
Closed (+)(-)
________ allows an experimenter to pull out a true physiological signal fromthe noise when analyzing EEG data.
B) signal averaging
Order the following recording techniques according to their temporal resolution (most to least precise): fMRI, EEG, PET, CT
B) EEG, fMRI, PET, CT
CT scanning relies most directly on:
B) the differential absorption of Xraysby tissue types of varying density.
In fMRI, we measure an INCREASE in signal when:
A) there is an increase in the ratio of oxygenated to deoxygenated hemoglobin
EEG primarily measures signal from:
B) pyramidal neurons in an open configuration
Doing a Fourier Analysis of a continuous signal will give you what information about that signal?
B) It allows you to determine the frequencies present in your signal
Which is of the following is used as a measure of communication between brain regions?
A) A and B
Coherence and Phase locking
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
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
Which of the following historical figures is INCORRECTLY matched to hiscontribution to neuropsychology?
C) Paul Broca – described a brain area that was involved in understanding language
language PRODUCTION
The temporal and spatial resolution of fMRI is on the order of _________ and__________, respectively:
E) seconds, millimeters
Which of the following statements about MRI is incorrect?
