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Mind, Brain and Education > Theme 5B > Flashcards

Theme 5B Flashcards

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1
Q

True or false: Everyone has brain waves that can be measured using EEG

A

true

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2
Q

True or false: The fMRI-scanner uses magnetic resonance to make pictures of brain cells that light up

A

not true

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3
Q

True or false: EEG sends weak electrical pulses through the brain

A

not true

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4
Q

True or false: In scientific research using fMRI and EEG, data are being analysed via standardized protocols

A

not true

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5
Q

True or false: fMRI measures changes in the oxygen levels in the brain’s blood vessels

A

True

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6
Q

True or false: In scientific research using fMRI and EEG, data are being analysed via standardized protocols

A

Not true

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7
Q

True or false When using EEG, one is never certain about where in the brain the signal comes from

A

true

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8
Q

Techniques complement each other: Temporal and spatial resolution

A

Temporal resolution
•Precision of a measurement with respect to time

Spatial resolution
•Precision of a measurement with respect to space

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9
Q

When to use which technique?

  • EEG/MEG:
  • fMRI/EEG/MEG:
  • MRI:
  • TMS/TES (“brain stimulation”):
A

•EEG/MEG: temporal resolution

  • fMRI/EEG/MEG:
  • functional measures
  • correlational relations brain-behavior
  • MRI: anatomical measures
  • TMS/TES (“brain stimulation”): causal relations brain-behavior
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10
Q

What can we do with an MRI scanner?

A
  • MRI (magnetic resonance imaging) – a picture of your brain’s anatomy
  • fMRI (functional MRI) – a “movie” of your brain’s activity
  • DTI (diffusion tensor imaging) – pictures of the pathways of communication
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11
Q

MRI versus fMR

A

MRI, fMRI and DTI scans are made using the same machine, with different settings.

MRI: high resolution
•Shows structure/ anatomy in high detail
•Tissue contrast

fMRI: low resolution
• Time series of 3D picture (movie), fewer details
•E.g.: every 2 sec during 5 minutes
•Functional contrast: hemodynamics (blood oxygen level)

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12
Q

Functional MRI: 4 steps

A
  1. Person in scanner performs a task that activates a certain process, like inhibition, calculating, reading, etc… •Difficult to isolate complex processes
  2. Activated process > activated neurons > changed oxygen level in surrounding blood vessels
  3. Scans during the experimental condition are compared to scans during a control condition •Brain activity is always relative: shows a difference! •Choice of control condition influences results
  4. Colored “blobs”: areas in which the statistical value of
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13
Q

Origin of fMRI signal (4)

A
  1. Researcher provides stimuli / task (e.g. Stop task – lecture 5A)
  2. Stimuli/task activates neurons in certain brain areas
  3. Brain areas with activated neurons need oxygen
  4. Fresh blood (= oxygen rich) will be supplied (seconds later!)
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14
Q

Blood influences MRI signal

A
  • Oxygenated vs. deoxygenated blood (Hb) have different magnetic properties
  • BOLD signal: Blood Oxygen Level Dependent
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15
Q

Summary (f)MRI

A
  • The colored “blobs” are in fact a (thresholded) statistical map
  • The task probably activates the intended cognitive process
  • Or actually: the intended cognitive process probably stronger than the control task
  • “Activates” means in fact that the blood composition changed, probably as a result of increased activity of the neurons at the same location•In sum, probably, the colored brain parts in an fMRI picture reflect the neural activity specific to the investigated process.
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16
Q

EEG: electro-encephalogram
vs.
MEG: magneto-encephalogram

A

BOTH methods: uncertain localization due to volume conduction

•MEG slightly less sensitive to volume conduction

17
Q

ERP components

A

ERP = Event Related Potential

  • Well described components like N400
  • Some have OK localization due to a lot of research
  • Shape + timing informative for normal + impaired processing & brain development
18
Q

Interpreting neuro-imaging results

1.Correlation vs. causation

A

fMRI/EEG/MEG: correlation methods

  • Brain activity in area X correlates with performance on task A (vs control task B)
  • We can’t conclude that area X is necessary for (causally related to) performance on task A
19
Q

Interpreting neuro-imaging results

2.Reverse inference

A

Forward inference (= justified): what brain activity/region is associated with a given experimental condition/contrast?

  1. ‘if cognitive process X is engaged, then brain area Z is active’ Reverse inference (= unjustified): going backwards from the presence of brain activation to the engagement of a particular cognitive function: 1.In the present study, when task/contrast A was presented, brain area Z was active.
  2. In other studies, when cognitive process X was putatively engaged, brain area Z was active.
  3. Thus, the activity of area Z in the present study demonstrates engagement of cognitive process X by task comparison A.
20
Q

Interpreting neuro-imaging results

3.Individual differences

A
  • Neuro-imaging findings of different brain function in a disorder: “group” results
  • Average of group 1 different from average of group 2

•Brain anatomy and fMRI/EEG signals known to differ across subjects, as well as task-related activity (strategies)
•Individual diagnoses not possible!
>More sophisticated analysis-techniques: classifier algorithms
>Never 100% accurate!

21
Q

Neuroscience advantage

A
  • Neuro-imaging enables studying the living human brain in action •Understanding brain-behavior relations
  • Techniques complement each other
  • Longitudinal studies
  • Imaging development: e.g. adolescent brain
  • Typical and atypical development
  • Shedding light on mechanisms:
  • Adding a level in understanding influences on educational outcomes (week 1)
22
Q

Neuroscience limitations

A
  • fMRI signal is indirect (measures blood, not neurons) and slow
  • EEG/ERP will never tell you where the activity originates
  • fMRI maps/ERP’s are relative to a control condition  importance of a good experimental design
  • Complex behavior is hard to study with neuro-imaging experiments: task design, scanner/lab environment, etc
  • Interpretation caveats
  • Correlation vs. causation
  • Reverse inference
  • Individual differences

Mind, Brain and Education (13 decks)

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