Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Psych 301 > Neuroimaging > Flashcards

Neuroimaging Flashcards

You may prefer our related Brainscape-certified flashcards:
Psychology 101 flashcards GRE® Psychology flashcards
1
Q

history of brain imaging techniques

A
  • X-ray (2d visualization)
  • Cerebral angiography: used iodine as a contrast agent to increase contrast between vasculature (bloodflow) and tissue to see arteries travelling into brain (helpful for looking for effects of strokes; hemorrhages)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

3 methods of structural (anatomical) brain imaging

A
  • CT (previously CAT)
  • MRI
  • DTI (within MRI)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Computed Topography (CT)

A
  • type of structural imaging
  • Used for strokes, hemorrhages, tumors
  • Form of x-ray that rotates around the head (3d visualization)
  • Limitation: radiation exposure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Magnetic Resonance Imaging (MRI)

A
  • type of structural imaging
  • Put head in strong magnetic field (3T), hydrogen atoms line up along the poles of magnetic field
  • Big magnetic fields not always better (largest is ~24T)
  • Can do overlay plot and Diffusion Tensor Imaging
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

overlay plot

A
  • can be done through MRI
  • Different patients with different lesions -> what’s responsible?
  • Overlaying various images indicates common damage amongst individuals responsible for behavioural changes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Diffusion Tensor Imaging

A
  • type of MRI
  • Just looking at white matter in the brain
  • Indicates lesions (missing parts of white matter); differences in white matter tracts between different populations (ie. Those with psychopathy); tumours
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How does an MRI machine work?

A
  • 1: align all protons with large magnetic field
  • 2: momentarily perturb that alignment with a second varying magnetic field (send a pulse through; will knock protons out of alignment)
  • 3: measure radiofrequency (RF) signal producing during realignment with the large magnetic field (“relaxation”/going back to normal)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

3 kids of functional (activity-based) brain imaging

A
  • EEG
  • PET
  • fMRI
  • These are all non-invasive, indirect measures
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Electroencephalography (EEG)

A
  • Cap covered in electrodes, gel used to get better signal
  • Shows waves/changes in voltage; looking for overall changes in activity (action potentials)
    • Amplitude (height of waves; volts) & frequency (length between waves; cycles per second/Hz)
    • Waves: Gamma (high Hz) -> beta -> alpha -> mu -> theta -> delta (low Hz); high brain activity (ie. Doing math problems) means higher Hz
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Positron Emission Tomography (PET)

A
  • Give injection of radioactive substance (ie. Radioactive glucose), watch where it goes
  • Diaschisis: ability to detect functional problems at would be hidden in structural scans
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Functional Magnetic Resonance Imaging (fMRI)

A
  • Looks for changes in bloodflow
  • Ogawa: recognized difference in magnetic qualities between oxygenated and deoxygenated blood
  • Hemodynamic response: area that was active 6 seconds ago gets lots of oxygenated blood
  • Blood-Oxygen Level Dependent (BOLD) Response: area “lights up” with lots of blood; indication that it’s active
  • Functional hyperemia: sends more blood there, strongly driven by glutamate release, causes dilation of blood vessels
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what can functional brian imaging measure?

A
  • Changes in bloodflow
  • Glucose consumption
  • Oxygen
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

paired image subtraction

A
  • Functional imaging technique
  • Subtracting experimental condition from control condition when looking at brain activity (displayed as clusters of “voxels”)
  • Assumptions: basic processes that all come together (constituent cognitive processes)
  • Quality of results depends on control condition
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

mean difference images

A
  • Functional imaging technique
  • Average activity across all individuals
  • Potential problem: doesn’t look like any 1 person’s activity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

PET scans and comas

A
  • PET scans revealed brain activity of people in comas in response to voices/image
  • however, initial tests showed this was automatic and not indicative of higher-level processing/awareness
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

fMRI scans and comas

A
  • used to see if people in comas have awareness/higher-level processing
  • Came up with technique: asking people to mentally tour your home or play imaginary tennis (lights up different brain areas in fMRI)
  • Used this to get vegetative patients to answer yes or no questions (play tennis for yes, tour home for no)
17
Q

degrees of conciousness

A

locked-in syndrome -> minimally conscious -> vegetative -> coma -> brain death

18
Q

neuroimaging and strokes

A
  • Neuroimaging rehabilitation may translate to better outcomes after stroke
  • includes structural imaging, functional imaging, and combined measures
19
Q

neuroimaging and strokes: structural imaging

A
  • Structural imaging (ex. CT, MRI, diffusion tensor imaging) allows for lesion identification and location
  • Limitation: provides no info about function
  • PLORAS system predicts ability to re-gain speech by comparing brain scans of patient to brain scans of similar patients
20
Q

neuroimaging and strokes: functional imaging

A
  • Functional imaging measured BOLD signals from brain which may indicate neural activity
  • BOLD levels post-stroke indicate impairment
21
Q

neuroimaging and strokes: combined measures

A
  • May be best to combine neuroimaging with clinical or neurophysiological measures to predict response to therapy
  • Meausres of structure & function may be useful in predicting which patients are more likely to benefit from intervention
  • Limitation: studies re: this have only been conducted with patients at chronic stage of stroke recovery
  • PREP: algorithm combining clinical, neurophysiological, and neuroimaging measures to predict recovery of upper limb function
22
Q

problems with fMRI studies

A
  • spatial averaging
  • spatial resolution
  • temporal resolution
  • “not necessarily necessity”
  • focus on increase in activity
  • regional hemodynamics (in diff. regions of brain)
  • confound: anxiety (scanner causes it)
  • drugs (ex. having coffee before scan)
  • reliability
  • statistics
23
Q

problems with fMRI studies: spatial averaging

A

averaging doesn’t really work; doesn’t give you true location

24
Q

problems with fMRI studies: spatial resolution

A

spatial resolution not good for talking about specific brain regions

25
Q

problems with fMRI studies: temporal resolution

A

activity can be measured across seconds whereas activity happens using miliseconds

26
Q

problems with fMRI studies: “not necessarily necessity”

A

although brain activity correlates with behaviour, it doesn’t mean that the activity of that part of the brain causes the behaviour

27
Q

problems with fMRI studies: focuses on increases in activity

A

sometimes inhibition of activity can be just as important as increase in activity

28
Q

problems with fMRI studies: anticipatory hemodynamics

A

brain predicts activity and preps for it by shunting oxygen there before you start the task

29
Q

problems with fMRI studies: statistics

A

dead salmon showing brain activity shows problem of false positives; if you don’t correct/control your data you could have a huge amount of false positives

30
Q

Default Mode Network

A
  • The brain’s activity at resting state (seen with fMRI)
  • Shows that even at passive state, brain is quite active
  • Includes medial prefrontal cortex, posterior cingulate, and lateral parietal cortex
31
Q

voxel

A

3d equivalent of a pixel

Psych 301 (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions