Hoofdstuk 4

Question 1

Structural imaging

Answer 1

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

Question 2

Functional imaging

Answer 2

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

Question 3

Wat zijn computerized tomography (CT) scans?

Answer 3

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

Question 4

Wat zijn de voordelen van MRI tegenover CT?

Answer 4

-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)

Question 5

Hoe werkt MRI?

Answer 5

-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

Question 6

Wat is het verschil tussen MRI en fMRI?

Answer 6

-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

Question 7

Wat is PET voor een methode?

Answer 7

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

Question 8

Waar is fMRI gevoelig voor?

Answer 8

De concentratie van zuurstof in het bloed

Question 9

Voxel-based morphometry (VBM)

Answer 9

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

Question 10

Difussion tensor imaging (DTI)

Answer 10

Uses MRI to measure white matter connectivity between brain regions

Question 11

Voxels

Answer 11

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

Question 12

Fractional anisotropy (FA)

Answer 12

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

Question 13

BOLD (blood oxygen-level-dependent contrast)

Answer 13

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

Question 14

hemodynamic response function (HRF)

Answer 14

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

Question 15

Wat houdt fNIRS in?

Answer 15

-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

Question 16

Cognitive substraction

Answer 16

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

Question 17

Pure insertion (or pure deletion)

Answer 17

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

Question 18

Interactions

Answer 18

The effects of one variable upon another

Question 19

What is required for the method of cognitive conjunctions?

Answer 19

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

Question 20

Efference copy

Answer 20

A motor signal used to predict sensory consequences of an action

Question 21

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

Answer 21

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

Question 22

Functional integration

Answer 22

The way in which different regions communicate with each other

Question 23

Resting state paradigms

Answer 23

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

Question 24

Default mode network

Answer 24

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

Question 25

What is een van de grootste problemen binnen fMRI?

Answer 25

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

Question 26

Stereotactic normalization

Answer 26

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

Question 27

Smoothing

Answer 27

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

Question 28

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

Answer 28

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

Question 29

Hoe worden hoofdbewegingen geprobeerd tegen te gaan bij fMRI?

Answer 29

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

Question 30

Talairach coordinates

Answer 30

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

Question 31

Family Wise Error (FWE)

Answer 31

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

Question 32

False discovery rate (FDR)

Answer 32

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

Question 33

Inhibition

Answer 33

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

Question 34

Inhibitory interactions

Answer 34

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

Question 35

Excitation

Answer 35

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

Question 36

Activation

Answer 36

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

Question 37

Deactivation

Answer 37

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

Question 38

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

Answer 38

-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

Question 39

Semantic dementia

Answer 39

A progressive loss of information from semantic memory

Question 40

Semantic memory

Answer 40

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

Question 41

Multi-voxel pattern analysis (MVPA)

Answer 41

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

Question 42

Can fMRI be used as a lie detector?

Answer 42

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

Question 43

Vegetative state

Answer 43

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