Does Magnetic Resonance Imaging (MRI) have radioactivity or no radioactivity?
No radioactivity
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What is the quote by Nancy Kanwisher, MIT?
"It is as if until these brain scanners arrived, psychologists were trying to work out how a car works by just driving it around. Now somebody says 'Hey let's open the hood and look inside!".
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What is example 1 of an fMRI study?
Focusing Attention on the Health Aspects of Foods Changes Value Signals in vmPFC and Improves Dietary Choice
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What is example 2 of an fMRI study?
functional MRI predictors of responsiveness to cognitive behaviour therapy for psychosis - Pre-therapy brain activity and responsiveness to CBT
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What is example 3 of an fMRI study?
Voluntary out-of-body experience
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What is learning objective 1?
To understand how blood oxygenation changes following neural activation
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What is learning objective 2?
To understand how these blood oxygen changes allow us to do fMRI
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BOLD fMRI - B
Blood
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BOLD fMRI - O
Oxygen
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BOLD fMRI - L
Level
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BOLD fMRI - D
Dependent
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What do red blood cells contain?
Hemoglobin
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What are two forms of hemoglobin?
Beta and Alpha
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What is HbO2?
Oxy hemoglobin
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What is Hbr?
De-oxy hemoglobin
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What do you get when you add HbO2 and Hbr together?
Total Hemoglobin (Hbt) (or Cerebral Blood Volume (CBV))
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Blood oxygen level dependence (BOLD) fMRI works because...
blood is 'magnetic'
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Is deoxy-haemoglobin paramagnetic or diamagnetic?
Paramagnetic
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Is oxy-haemoglobin paramagnetic or diamagnetic?
Diamagnetic
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Deoxy-haemoglobin - Decrease/increase MR signal - a lot/a bit?
Decreases MR signal a lot
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Oxy-haemoglobin - Decrease/increase MR signal - a lot/a bit?
Increases MR signal a bit
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What is it meant by MR signal?
The brightness of the image
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The BOLD fMRI 'signal' is related to the...
Oxygenation of blood
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Deoxyhemoglobin 'appears' as...
The brain extracts oxygen for metabolism
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If the brain becomes active, oxygen consumption should.... Therefore the amount of deoxyhemoglobin should...
Increase; increase
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But why doesn't deoxyhemoglobin go down?
Because flow has increased so much
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Quote from Buxton
'An unexpected physiological phenomenon'
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The washing away of deoxyhemoglobin produces an ... in the BOLD fMRI signal
Increase
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What is the most commonly used 'mapping signal'?
The positive BOLD signal
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What is the positive BOLD signal?
The washing away of deoxyhemoglobin produces an increase in the BOLD fMRI signal
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The early increase in deoxyhemoglobin produces a ...in the BOLD fMRI signal ('a dip').
Decrease
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What did people become very interested in?
The early increase in deoxyhemoglobin produces a decrease in the BOLD fMRI signal ('a dip')
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Why care about the 'dip'?
Increased spatial resolution
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Increase or decrease? Cerebral blood flow increases and amount of deoxyhemoglobin?
Decreases
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Increase or decrease? Cerebral blood flow increase and BOLD fMRI signal?
Increases
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Increase or decrease? Oxygen consumption increases and amount of deoxyhemoglobin?
Increases
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Increase or decrease? Oxygen consumption increases and BOLD fMRI signal?
Decreases
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But CBF overcompensates for oxygen consumption so the BOLD signal...
Increases
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Summary of Myles Jones - Lecture 2 - fMRI
BOLD fMRI; The Hemodynamic (Blood) response; Changes in the BOLD fMRI signal
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Other cards in this set
Card 2
Front
Does Magnetic Resonance Imaging (MRI) have radioactivity or no radioactivity?
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