How can MRIs be resolved?
Within cortical maps
What does being resolved within cortical maps create?
Finer resolutions that EEGs or ERPs
What is the temporal resolution of Structural and Functional MRIs?
Structural- Hours/days
Functional- Seconds
What are the 4 aspects of structural MRIs?
-Study anatomy
-Identify abnormalities
-Follow development
-Show plasticity
What do imaging methods rely on?
Contrast between tissue types
How did the study on learning to juggle indicate changes in gray matter, shown in a MRI?
When tested after 3 months. there were statistically significant expansion of gray matter corresponding with areas linked to visual motion.
Even after 8mnths, there was a decrease in density, but still above baseline
Why are there abundant protons in rotary motion in our body?
High water content of soft tissue
What happens once the ppt is in the scanner?
They are within the strong magnetic field generated so their individual protons (and their rotation axes which are randomly orientated) become aligned to the magnetic field
What happens in an MR scanner initially?
The net magnetization vector is parallel to the external magnetic field in the scanner bore, so 100% of net magnetization is in the direction of the external magnetic field
What happens when the radio frequency coil emits a radio frequency pulse?
The net magnetization vector is turned into an orientation perpendicular to the external magnetic field, so at this moment 0% of net magnetization is in the direction of the external magnetic field.
What happens after the radio frequency pulse?
The vector of net magnetisation returns to the direction of the external magnetic field, or net magnetisation recovers to 100 % of pre-RF value.
During this phase of recovery, an MR signal is measured
Why can this process be done with multiple repeats?
The net magnetisation returns to the value before radio frequency pulse
What happens if the MR signal is measured during spin-lacttice relaxation?
Structural contrast can be established between tissue and cerebrospinal fluid
What is the goal of fMRIs?
Identify brain areas that support sensory and cognitive processes and derive models of brain function
What does fMRI measure?
Blood flow
What is required for an fMRI?
A contrast that separates non-activated from activated tissue
What does the T2* contrast depend on?
The balance of deoxygenated to oxygenated haemoglobin within blood in a voxel
How does the T1 signal increase?
After a radio frequency pulse
How does the T2 and T2* signal decrease/decay?
After the radio frequency pulse
What happens in an inhomogeneous field?
T2* decay is faster
Where is there an increased MR signal intensity?
With an increased concentration of oxy-hemoglobin as makes T2* decay slower
What is diamagnetic?
Does not affect the local magnetic field
Is oxy-hemoglobin or deoxy-hemoglobin diamagnetic?
Oxy-hemoglobin
What is the BOLD signal?
Indirect measure of neural activity form different signal intensities forming the basis of a contrast
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1) Emotion 120
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2) Emotion 217
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Emotion MCQs24
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3) Sex differences 129
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4) Sex differences 220
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Sex Differences MCQs27
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5) Methods 1 (TMS)24
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6) Methods 2 (EEG + ERPs)40
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Methods MCQs30
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7) Structural and functional MRI32
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8) Neuropsychology with lesion studies30
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fMRI and lesion study MCQs23
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9/10) Alzheimer’s37
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Alzheimer's MCQs19
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11) Neurodegeneration 124
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12) Neurodegeneration 236
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Neurodegeneration MCQs38
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13) SZ 138
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13) SZ 226
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SZ MCQs39
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14) Neurobiology of Decision Making 125
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14) Neurobiology of Decision Making 221
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Neurobiology of Decision Making MCQs34
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15) Anxiety36
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Anxiety MCQs16
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16) Intro to learning24
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16) Classical conditioning24
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Learning 1 MCQs21
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17) Instrumental conditioning26
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17) Numbers and Counting26
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Instrumental condiitoning MCQs15
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Numbers and Counting MCQs20
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18) Associative Learning34
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Associative learning MCQs21
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18) Time33
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Time MCQs21
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19) Classical/instrumental interactions24
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Classical/instrumental MCQs15
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19) Categorisation31
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Categorisation MCQs19
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20) Rescorla-Wagner Model 121
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21) Rescorla-Wagner Model 218
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Rescorla-Wagner MCQs22
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22) Learning and Attention 115
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23) Learning and Attention 212
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Learning and Attention MCQs15
