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psych 345 quiz 3 Questions and Answers
(Expert Solutions)
Q: structural brain imaging, 🗹🗹: -Visualizes static anatomical structure of the brain
-Does not require a live subject
-Structural brain imaging allows us to assess damage and/or structural abnormalities in
neural architecture
-Structural imaging is static in time, a "snapshot"
-CAT(CT), MRI, DTI
Q: functional brain imaging, 🗹🗹: Visualize dynamic active processes in the brain
directly (i.e. local field potentials) or indirectly (i.e. fMRI BOLD signal)
-Live subjects
-PET,fMRI,EEG,ERP
Q: spacial resolution, 🗹🗹: Refers to the amount of spatial detail you can see in the
image (i.e. cubic centimeters, millimeters? single-cells vs. cell populations)
-Relevance to structural imaging:Amount of neuroanatomical detail you can see
-Relavance to functional imaging: Precision with which you can localize activation to
specific brain regions
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Q: temporal resolution, 🗹🗹: -Only relevant for functional imaging
-Refers to the precision/accuracy with which you can capture dynamic neural events in
time
-Poor temporal resolution - the activity in visual cortex occurred sometime within 1
minute after the visual stimulus was presented
-Good temporal resolution - the activity in visual cortex occurred sometime within the
250 milliseconds after the visual stimulus was presented
Q: DTI, 🗹🗹: -diffusion tensor imaging
-White matter tracts
-Direction of water flow
-Especially helpful in understanding connectivity between regions
-Used extensively in tumour mapping
Q: C(A)T, 🗹🗹: -computed axial tomography
-essentially an "x-ray absorption map"
-Different tissues absorb different amounts of x-ray radiation → look different on the
image
-poor spatial resolution [MRI's is so much better]
-High density material absorbs more x-ray radiation [appears bright on a CT, ex: bone]
-Lower density material absorbs little x-ray radiation [appears dark on a CT, ex: soft
tissues/blood]
Q: tomography, 🗹🗹: imaging by sections
Q: MRI, 🗹🗹: -magnetic resonance imaging
-basically a map of local proton magnetic properties
-MR frequencies are tuned to pick up water protons
-structural MRI applies a strong magnetic field, causing protons in H2O molecules to
align with the field and flip their spins, when field is turned off/down, protons are
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"released" and gradually return to normal spin; this causes emission of radio signals
that can be measured and turned into an image
-thus, tissues with different proton densities have different magnetic properties→
appear different on an MRI image so there is contrast due to proton density AND decay
properties of the tissue
-magnet strength is 3000x stronger than the field strength of earth
Q: MRI safety issue and issues, 🗹🗹: -No metal on/in
body:Jewelry,Pacemakers,Surgical clips or implants, Metal fragments
-Individuals with tattoos: certain inks have trace amounts of metals and thus can be
adversely affected during scan which can lead to burns
-loose metal objects could be attracted to the magnet
-motion artifacts (MRI requires subject to be still)
-physiological artifacts: heart rate, breathing, etc
Q: C(A)T dangers, 🗹🗹: safety issues due to X-ray radiation [leads to small
percentage of cancers]
Q: spacial resolution: CT vs MRI, 🗹🗹: MRI has better resolution [more detailed
picture of brain]
psych 345 quiz 3 Questions and Answers
(Expert Solutions)
Q: structural brain imaging, 🗹🗹: -Visualizes static anatomical structure of the brain
-Does not require a live subject
-Structural brain imaging allows us to assess damage and/or structural abnormalities in
neural architecture
-Structural imaging is static in time, a "snapshot"
-CAT(CT), MRI, DTI
Q: functional brain imaging, 🗹🗹: Visualize dynamic active processes in the brain
directly (i.e. local field potentials) or indirectly (i.e. fMRI BOLD signal)
-Live subjects
-PET,fMRI,EEG,ERP
Q: spacial resolution, 🗹🗹: Refers to the amount of spatial detail you can see in the
image (i.e. cubic centimeters, millimeters? single-cells vs. cell populations)
-Relevance to structural imaging:Amount of neuroanatomical detail you can see
-Relavance to functional imaging: Precision with which you can localize activation to
specific brain regions
, Page | 2
Q: temporal resolution, 🗹🗹: -Only relevant for functional imaging
-Refers to the precision/accuracy with which you can capture dynamic neural events in
time
-Poor temporal resolution - the activity in visual cortex occurred sometime within 1
minute after the visual stimulus was presented
-Good temporal resolution - the activity in visual cortex occurred sometime within the
250 milliseconds after the visual stimulus was presented
Q: DTI, 🗹🗹: -diffusion tensor imaging
-White matter tracts
-Direction of water flow
-Especially helpful in understanding connectivity between regions
-Used extensively in tumour mapping
Q: C(A)T, 🗹🗹: -computed axial tomography
-essentially an "x-ray absorption map"
-Different tissues absorb different amounts of x-ray radiation → look different on the
image
-poor spatial resolution [MRI's is so much better]
-High density material absorbs more x-ray radiation [appears bright on a CT, ex: bone]
-Lower density material absorbs little x-ray radiation [appears dark on a CT, ex: soft
tissues/blood]
Q: tomography, 🗹🗹: imaging by sections
Q: MRI, 🗹🗹: -magnetic resonance imaging
-basically a map of local proton magnetic properties
-MR frequencies are tuned to pick up water protons
-structural MRI applies a strong magnetic field, causing protons in H2O molecules to
align with the field and flip their spins, when field is turned off/down, protons are
, Page | 3
"released" and gradually return to normal spin; this causes emission of radio signals
that can be measured and turned into an image
-thus, tissues with different proton densities have different magnetic properties→
appear different on an MRI image so there is contrast due to proton density AND decay
properties of the tissue
-magnet strength is 3000x stronger than the field strength of earth
Q: MRI safety issue and issues, 🗹🗹: -No metal on/in
body:Jewelry,Pacemakers,Surgical clips or implants, Metal fragments
-Individuals with tattoos: certain inks have trace amounts of metals and thus can be
adversely affected during scan which can lead to burns
-loose metal objects could be attracted to the magnet
-motion artifacts (MRI requires subject to be still)
-physiological artifacts: heart rate, breathing, etc
Q: C(A)T dangers, 🗹🗹: safety issues due to X-ray radiation [leads to small
percentage of cancers]
Q: spacial resolution: CT vs MRI, 🗹🗹: MRI has better resolution [more detailed
picture of brain]
