Hoofdstuk 4 Flashcards

1
Q

Structural imaging

A

Measures of the spatial configuration of different types of tissue in the brain (CT and MRI)

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2
Q

Functional imaging

A

Measures temporary changes in brain physiology associated with cognitive processing; the most common method is fMRI and is based on a hemodynamic measure

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3
Q

Wat zijn computerized tomography (CT) scans?

A

Gemaakt aan de hand van hoeveel X-ray straling wordt opgenomen door verschillende weefsels, het kan grijs en wit matter niet uit elkaar halen, kan niet gebruikt worden voor functional imaging

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4
Q

Wat zijn de voordelen van MRI tegenover CT?

A

-het is veilig, geen ioniserende straling
-beter spatial resolution
-je kan het verschil tussen gray en white matter beter zien
-kan zo aangepast worden dat je veranderingen in zuurstof in het bloed ziet (fMRI)

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5
Q

Hoe werkt MRI?

A

-Eerst wordt een groot magnetisch veld geplaatst om een deel van het lichaam dat gescand wordt
-H-atomen in water hebben een zwak magnetisch veld
-Deze H-atomen liggen alle kanten op, maar door een sterk magnetisch veld gaan ze de kant opstaan van dit veld
-een kleine radiofrequentie wordt toegepast wat de richting van de protonen 90 graden draait
-Als de protonen deze draai maken produceren ze een aan te tonen magnetisch veld, dit is wat de basis vormt van het MRI signaal
-dit wordt herhaalt

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6
Q

Wat is het verschil tussen MRI en fMRI?

A

-MRI meet alleen de permanente karakteristieken van het brein
-fMRI meet de moment-tot-moment veranderende karakteristieken van het brein die worden geassocieerd met veranderingen van cognitieve processen

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7
Q

Wat is PET voor een methode?

A

Meet het verschil in blood flow in een directe regio, hiervoor is een radioactieve tracer nodig

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8
Q

Waar is fMRI gevoelig voor?

A

De concentratie van zuurstof in het bloed

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9
Q

Voxel-based morphometry (VBM)

A

A technique for segregating and measuring differences in white matter and gray matter concentration

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10
Q

Difussion tensor imaging (DTI)

A

Uses MRI to measure white matter connectivity between brain regions

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11
Q

Voxels

A

A volume-based unit; in imaging research the brain is divided into many of thousands of these

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12
Q

Fractional anisotropy (FA)

A

A measure of the extent to which diffusion takes place in some directions more than others

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13
Q

BOLD (blood oxygen-level-dependent contrast)

A

The signal measured in fMRI that relates to the concentration of deoxyhemoglobin in the blood

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14
Q

hemodynamic response function (HRF)

A

Changes in the BOLD signal over time
-initial dip, neuron observes oxygen, there is a small rise in deoxyhemoglobin
-overcompensation, the blood flow to the region increases, BOLD signal increases
-undershoot, blood flow returns to normal level, increase in deoxyhemoglobin

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15
Q

Wat houdt fNIRS in?

A

-Meet ook BOLD signaal, maar doet dit door ‘licht’ van een bepaalde golflengte te zenden naar het brein, de mate waarin het signaal verbroken wordt door oxygen en deoxyhemoglobin wordt gebruikt om het BOLD te meten
-nieuwe methode, kost minder, maar kan alleen gebruikt worden bij metingen dichtbij de scalp

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16
Q

Cognitive substraction

A

A type of experimental design in functional imaging in which activity in a central task is subtracted from activity in an experimental task

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17
Q

Pure insertion (or pure deletion)

A

The assumption that adding a different component to a task does not change the operation of other components

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18
Q

Interactions

A

The effects of one variable upon another

19
Q

What is required for the method of cognitive conjunctions?

A

One is able to identify a set of tasks that have a particular component in common

20
Q

Efference copy

A

A motor signal used to predict sensory consequences of an action

21
Q

What is the difference between a parametric design and a categorical design?

A

In a parametric design the variable of interest is treated as a continuous dimension rather than a categorical distinction

22
Q

Functional integration

A

The way in which different regions communicate with each other

23
Q

Resting state paradigms

A

A technique for measuring functional connectivity in which correlations between several regions (networks) are assessed while the participant is not performing any tasks

24
Q

Default mode network

A

A set of brain regions that is more hemodynamically active during rest than during tasks

25
Q

What is een van de grootste problemen binnen fMRI?

A

Ieder brein ziet er anders uit; verschillende lengtes gyri, locaties van de sulci

26
Q

Stereotactic normalization

A

The mapping of individual differences in brain anatomy onto a standard template

27
Q

Smoothing

A

Redistributing brain activity from neighboring voxels to enhance the signal-to-noise regio

28
Q

Wat is de volgorde van activiteiten die er gebeuren om van de hypothesis naar de data interpretatie te gaan bij fMRI?

A

-Data acquisition
-Correct for head movement
-Stereotactic normalization
-Smoothing
-Divide data according to design
-Perform statistical comparison

29
Q

Hoe worden hoofdbewegingen geprobeerd tegen te gaan bij fMRI?

A

Het hoofd wordt vastgezet en de participant wordt geïnstrueerd zo stil mogelijk te blijven liggen

30
Q

Talairach coordinates

A

Locations in the brain defined relative to the atlas of Talairach and Tournoux

31
Q

Family Wise Error (FWE)

A

An approach for correcting for many statistical comparisons based on the number of tests being conducted

32
Q

False discovery rate (FDR)

A

An approach for correcting for many statistical comparisons based on the number of positive results obtained

33
Q

Inhibition

A

A reduction/suppression of the activity of a brain region (or a cognitive process), triggered by activity in another region/process

34
Q

Inhibitory interactions

A

When the presynaptic neurons are active, the postsynaptic neuron is switched off

35
Q

Excitation

A

An increase of the activity of a brain region (or a cognitive process), triggered by activity in another region/process, when the presynaptic neurons are active, the postsynaptic neuron is switched on, most connections are like this

36
Q

Activation

A

An increase in physiological processing in one condition relative to some other conditions

37
Q

Deactivation

A

A decrease in physiological processing in one condition relative to some other conditions

38
Q

What are the two most common disagreements between fMRI data and lesion data?

A

-Imaging data imply that a brain region is used in a given task, but lesion data suggest that this region is not essential to the task
-Imaging data imply that a brain region is not used in a given task, but lesion data suggest that this region is critical to the task

39
Q

Semantic dementia

A

A progressive loss of information from semantic memory

40
Q

Semantic memory

A

Conceptually based knowledge about the world, including knowledge of people, places, the meaning of objects and words

41
Q

Multi-voxel pattern analysis (MVPA)

A

An fMRI analysis method in which distributed patterns of activity are linked to cognitive processes

42
Q

Can fMRI be used as a lie detector?

A

although fMRI might have some use in lie detection, it is unlikely to offer a simple solution to this complex and important reaction-world problem

43
Q

Vegetative state

A

A disorder or consciousness in which patients with severe brain damage are in a state of partial arousal