Ch4: The imaged brain Flashcards
Measures of the spatial configuration of different types of tissue in the brain (principally CT and MRI)
Structural imaging
Measures temporary changes in brain physiology associated with cognitive processing; the most common method is fMRI and is based on a hemodynamic measure
Functional imaging
A technique for segregating and measuring differences in white matter and gray matter concentration
Voxel-based morphometry (VBM)
A technique that uses MRI to measure white matter connectivity between brain regions
Diffusion tensor imaging (DTI)
A measure of the extent to which diffusion takes place in some directions more than others
Fractional anisotropy (FA)
Blood oxygen-level dependent contrast; the signal measured in fMRI that relates to the concentration of deoxyhemoglobin in the blood
BOLD
Changes in the BOLD signal over time
Hemodynamic response function (HRF)
A type of experimental design in functional imaging in which activity in a control task is subtracted from activity in an experimental task
Cognitive subtraction
The assumption that adding a different component to a task does not change the operation of other components
Pure insertion (also pure deletion)
The effect of one variable upon another
Interactions
A motor signal used to predict sensory consequences of an action
Efference copy
The way in which different regions communicate with each other
Functional integration
A technique for measuring functional connectivity in which correlations between several regions (networks) are assessed while the participant is not performing any tasks
Resting-state paradigm
A set of brain regions that is more hemodynamically active during rest than during tasks
Default mode network
The mapping of individual differences in brain anatomy onto a standard template
Stereotactic normalization
Redistributing brain activity from neighbouring voxels to enhance the signal-to-noise ratio
Smoothing
A volume-based unit (cf. pixels, which are 2D); in imaging research, the brain is divided into many thousands of these
Voxel
Locations in the brain defined relative to the atlas of Talairach and Tournoux
Talairach coordinates
An approach for correcting for many statistical comparisons based on the number of tests being conducted
Family Wise Error (FWE)
An approach for correcting for many statistical comparisons based on the number of positive results obtained
False Discovery Rate (FDR)
A reduction/suppression of the activity of a brain region (or a cognitive process), triggered by activity in another region/process
Inhibition
An increase of the activity of a brain region (or a cognitive process), triggered by activity in another region/process
Excitation
An increase in physiological processing in one condition relative to some other condition(s)
Activation
A decrease in physiological processing in one condition relative to some other condition(s)
Deactivation
A progressive loss of information from semantic memory
Semantic dementia
Conceptually based knowledge about the world, including knowledge of people, places, the meaning of objects and words
Semantic memory
An fMRI analysis method in which distributed patterns of activity are linked to cognitive processes
Multi-voxel pattern analysis (MVPA)
A disorder of consciousness in which patients with severe brain damage are in a state of partial arousal
Vegetative state
Which type of scan is typically used only in clinical settings? A) CT B) fMRI C) ERP D) MEG
A) CT
Which imaging method measures the white matter connectivity between regions? A) DTI B) TMS C) VBM D) MEG
A) DTI
Which of the following is a T2-weighted image of the brain?
A) First from the left
B) Second from the left
C) Third from the left
D) None of the above
C) Third from the left
Protons from which type of molecule found in the human body form the main basis for the MRI signal?
A) CH4
B) H20
C) Amino Acids
D) Fats
B) H20
The strength of the magnetic field in MRI is measured in which units?
A) Newtons
B) Microvolts
C) BOLD
D) Tesla
D) Tesla
The primary images of interest formed in a functional MRI experiment are called:
A) T2*
B) T1
C) T2
D) T1*
A) T2*
Which of the following techniques measures changes in blood flow directly?
A) MRI
B) fMRI
C) MEG
D) PET
D) PET
The image below depicts which of the following?
A) Grey matter density
B) Undershoots
C) White matter tracts
D) Flagellum
C) White matter tracts
An fMRI scan taken when a participant is given no stimuli or task instructions is called:
A) Multi-variate pattern analysis
B) Default mode
C) Resting-state
D) VBN
C) Resting-state
Which stage of processing is omitted in multivariate pattern analysis (MVPA)?
A) Correction for head movement
B) Smoothing
C) Statistical inference
D) Masking
B) Smoothing
The correct temporal ordering of the phases of the hemodynamic response function (HRF) is:
A) Vascularization; under-compensation; plateau
B) Overcompensation; undershoot; plateau
C) Initial dip; overcompensation; undershoot
D) Flooding; undershoot; latent peak
C) Initial dip; overcompensation; undershoot
The principle of cognitive subtraction holds that it is possible to infer functionally specialized brain regions by:
A) Using TMS to temporarily ‘lesion’ areas of the healthy brain
B) Parametrically increasing cognitive load
C) Identifying regions activated by an experimental, but not baseline, task
D) Comparing behavior of brain-damaged participants with healthy controls
C) Identifying regions activated by an experimental, but not baseline, task
Functional integration is most closely associated with which of the following?
A) Localization
B) Effective connectivity
C) Pure insertion
D) Functional specialization
B) Effective connectivity
Which of the following statements about fNIRS (functional near-infrared spectroscopy) is TRUE?
A) It is less portable than fMRI
B) It measures a BOLD response
C) It has a temporal resolution similar to EEG
D) It involves the use of radioactive isotopes
B) It measures a BOLD response
Talairach coordinates define locations in the brain according to x, y, and z values, with the origin lying at a region called the:
A) Anterior commissure
B) Parahippocampal gyrus
C) Sylvian fissure
D) Basal ganglia
A) Anterior commissure
The process of smoothing spreads the raw activation of a given voxel to neighboring voxels according to which function?
A) Gaussian distribution
B) Band pass
C) Exponential
D) Logarithmic
A) Gaussian distribution
By choosing a more conservative significance level (P value) in neuroimaging analysis, one runs the risk of failing to detect true regions of activation, an error known as:
A) Type II
B) Bonferroni
C) Type I
D) Random field
C) Type I
When the presynaptic neuron is active, causing the postsynaptic neuron to switch off, this particular neuronal interaction is best described as:
A) Inhibitory
B) Transitory
C) Excitatory
D) Sensory
A) Inhibitory
According to Farah et al. (2014) how good is fMRI at separating truthful versus deceitful answers?
A) Between 90% and 100%
B) Between 50% and 69%
C) At chance
D) Between 69% and 100%
D) Between 69% and 100%
The study by Miyawaki et al. (2008) measured the pattern of activity over which brain region to determine what letters participants were viewing?
A) Frontal lobe
B) Fusiform gyrus
C) Amygdala
D) V1
D) V1
