Q.1 Which imaging modality measures changes in blood oxygenation to infer neural activity?
Electroencephalography (EEG)
Functional Magnetic Resonance Imaging (fMRI)
Positron Emission Tomography (PET)
Magnetoencephalography (MEG)
Explanation - fMRI detects the BOLD (Blood‑Oxygen‑Level‑Dependent) signal, which reflects changes in deoxy‑hemoglobin concentration linked to neural activation.
Correct answer is: Functional Magnetic Resonance Imaging (fMRI)
Q.2 What is the primary advantage of diffusion tensor imaging (DTI) over conventional MRI?
Higher temporal resolution
Direct measurement of electrical activity
Visualization of white‑matter tract orientation
Detection of neurotransmitter levels
Explanation - DTI exploits anisotropic diffusion of water molecules to map the directionality of white‑matter fibers, which conventional MRI cannot resolve.
Correct answer is: Visualization of white‑matter tract orientation
Q.3 Which of the following is a non‑invasive technique that records magnetic fields produced by neuronal currents?
Electrocorticography (ECoG)
Magnetoencephalography (MEG)
Intracortical microstimulation
Transcranial magnetic stimulation (TMS)
Explanation - MEG measures the tiny magnetic fields generated by synchronized postsynaptic currents without penetrating the skull.
Correct answer is: Magnetoencephalography (MEG)
Q.4 In the context of neuroimaging, what does the term "spatial resolution" refer to?
The speed at which images are acquired
The smallest distinguishable detail in the image
The number of subjects that can be scanned simultaneously
The intensity of the magnetic field
Explanation - Spatial resolution indicates how finely an imaging system can differentiate two separate points in space.
Correct answer is: The smallest distinguishable detail in the image
Q.5 Which tracer is commonly used in PET scans to assess glucose metabolism in the brain?
Fluorodeoxyglucose (FDG)
Oxygen‑15 water
Carbon‑11 raclopride
Technetium‑99m sestamibi
Explanation - FDG is an analogue of glucose; its uptake reflects regional cerebral metabolic rate for glucose, making it ideal for functional PET studies.
Correct answer is: Fluorodeoxyglucose (FDG)
Q.6 What does the acronym "EEG" stand for?
Electrical Excitation Graph
Electroencephalography
Electromagnetic Emission Gradient
Encephalic Energy Gauge
Explanation - EEG records the electrical potentials generated by neuronal ensembles via electrodes placed on the scalp.
Correct answer is: Electroencephalography
Q.7 Which of the following preprocessing steps is essential before source localization in EEG?
Band‑pass filtering
Spatial smoothing
Temporal down‑sampling
All of the above
Explanation - Band‑pass filtering removes unwanted frequencies, spatial smoothing reduces noise across electrodes, and down‑sampling eases computational load, all improving source estimates.
Correct answer is: All of the above
Q.8 The term "BOLD" in fMRI stands for:
Blood‑Oxygen‑Level‑Dependent
Brain‑Oscillation‑Linked Dynamics
Baseline‑Optimized Lateral Diffusion
Biochemical‑Osmotic‑Light Detection
Explanation - BOLD contrast arises from changes in the magnetic properties of hemoglobin depending on its oxygenation state.
Correct answer is: Blood‑Oxygen‑Level‑Dependent
Q.9 Which mathematical technique is frequently employed to separate overlapping neural sources in MEG data?
Fourier Transform
Independent Component Analysis (ICA)
Linear Discriminant Analysis
K‑means clustering
Explanation - ICA assumes statistical independence of sources and can decompose mixed MEG signals into constituent components.
Correct answer is: Independent Component Analysis (ICA)
Q.10 In functional connectivity analysis, what does the term "seed‑based correlation" refer to?
Correlation of a predefined brain region with the rest of the brain
Correlation between subjects' behavioral scores
Correlation of neuronal spikes with heart rate
Correlation of scanner noise across runs
Explanation - A seed region's time‑course is correlated with all other voxels to identify networks that co‑activate with the seed.
Correct answer is: Correlation of a predefined brain region with the rest of the brain
Q.11 Which of the following is a limitation of using PET for functional brain mapping?
Low temporal resolution
Inability to measure metabolic activity
Requirement of invasive electrodes
Poor spatial resolution
Explanation - PET scans integrate tracer uptake over minutes, making it unsuitable for tracking rapid neural dynamics.
Correct answer is: Low temporal resolution
Q.12 What is the main physical principle behind functional Near‑Infrared Spectroscopy (fNIRS)?
Emission of X‑rays from the scalp
Absorption of near‑infrared light by oxy‑ and deoxy‑hemoglobin
Magnetic resonance of water protons
Electrical conductivity changes in the skull
Explanation - fNIRS quantifies changes in hemoglobin concentrations by measuring how near‑infrared light is attenuated as it passes through cortical tissue.
Correct answer is: Absorption of near‑infrared light by oxy‑ and deoxy‑hemoglobin
Q.13 Which brain imaging technique provides the highest temporal resolution?
fMRI
PET
EEG
DTI
Explanation - EEG can sample neural activity on the order of milliseconds, far surpassing the seconds‑scale temporal resolution of fMRI and PET.
Correct answer is: EEG
Q.14 In the context of neuroimaging, what is a "voxel"?
A voltage measurement unit
A three‑dimensional pixel representing a volume element
A type of electrode
A software algorithm for denoising
Explanation - Voxels are the smallest distinguishable 3‑D units in volumetric imaging data such as MRI or PET.
Correct answer is: A three‑dimensional pixel representing a volume element
Q.15 Which artifact is most commonly associated with EEG recordings during eye movements?
Cardiac artifact
Muscle (EMG) artifact
Electrode drift
Electrooculogram (EOG) artifact
Explanation - Eye blinks and movements generate large potentials that appear in EEG channels, recorded as EOG artifacts.
Correct answer is: Electrooculogram (EOG) artifact
Q.16 What does the term "connectome" refer to in neuroimaging?
A map of neuronal firing rates
A comprehensive map of neural connections in the brain
A list of all neurotransmitters
A database of brain lesion locations
Explanation - The connectome represents the complete set of structural and functional connections among brain regions.
Correct answer is: A comprehensive map of neural connections in the brain
Q.17 Which of the following is a common method for correcting multiple comparisons in whole‑brain fMRI analysis?
Bonferroni correction
Fourier transformation
Principal Component Analysis
Linear regression
Explanation - Bonferroni (or other false‑discovery‑rate) corrections adjust the statistical threshold to account for the large number of voxel‑wise tests.
Correct answer is: Bonferroni correction
Q.18 In DTI, what does the metric "fractional anisotropy (FA)" quantify?
The overall water diffusion rate
The degree of directionality of water diffusion
The magnetic susceptibility of tissue
The electrical conductivity of white matter
Explanation - FA values range from 0 (isotropic diffusion) to 1 (completely anisotropic), reflecting fiber integrity and organization.
Correct answer is: The degree of directionality of water diffusion
Q.19 Which neuroimaging modality is most suitable for tracking fast oscillatory activity (e.g., gamma band) in the cortex?
fMRI
MEG
PET
DTI
Explanation - MEG can capture neural magnetic fields with millisecond precision, allowing analysis of high‑frequency oscillations.
Correct answer is: MEG
Q.20 What is the primary source of the EEG signal recorded at the scalp?
Action potentials of individual neurons
Summed postsynaptic potentials of pyramidal cells
Blood flow changes in the cortex
Magnetic fields generated by glial cells
Explanation - EEG mainly reflects the synchronous intracellular currents of large, aligned pyramidal neuron populations.
Correct answer is: Summed postsynaptic potentials of pyramidal cells
Q.21 Which preprocessing technique is used to reduce head‑motion induced artifacts in fMRI data?
Spatial smoothing
Slice‑time correction
Realignment (motion correction)
Temporal filtering
Explanation - Realignment estimates and corrects for head displacement across volumes, mitigating motion‑related signal changes.
Correct answer is: Realignment (motion correction)
Q.22 In the context of neural network mapping, what does "graph theory" provide?
A way to simulate neuronal firing
A set of equations for magnetic field calculation
Tools to quantify network topology (e.g., degree, clustering)
Methods for improving scanner hardware
Explanation - Graph theory treats brain regions as nodes and connections as edges, enabling metrics like degree centrality, modularity, and path length.
Correct answer is: Tools to quantify network topology (e.g., degree, clustering)
Q.23 Which of the following is a typical frequency band examined in EEG analysis?
Alpha (8‑13 Hz)
Beta (30‑100 Hz)
Delta (0.5‑4 Hz)
All of the above
Explanation - EEG studies commonly analyze delta, theta, alpha, beta, and gamma bands to characterize brain states.
Correct answer is: All of the above
Q.24 What does the term "inverse problem" refer to in MEG/EEG source localization?
Predicting future brain activity from past data
Estimating the distribution of neural sources that produced the measured fields
Reversing the polarity of recorded signals
Converting magnetic fields into electrical currents
Explanation - The inverse problem is ill‑posed; multiple source configurations can generate the same external measurements, requiring constraints for a solution.
Correct answer is: Estimating the distribution of neural sources that produced the measured fields
Q.25 Which of the following best describes a 'task‑based' fMRI experiment?
Scanning subjects at rest without any stimulation
Presenting a specific cognitive or motor task while acquiring images
Measuring structural brain anatomy only
Recording simultaneous EEG and MRI
Explanation - Task‑based fMRI contrasts brain activity during a designed experimental condition against a baseline.
Correct answer is: Presenting a specific cognitive or motor task while acquiring images
Q.26 What is the main reason for using a high‑field MRI scanner (e.g., 7 T) for neuroimaging?
To reduce the cost of scanning
To increase signal‑to‑noise ratio and spatial resolution
To make the scanner portable
To eliminate the need for contrast agents
Explanation - Higher magnetic field strengths boost SNR, enabling finer spatial detail and more precise functional mapping.
Correct answer is: To increase signal‑to‑noise ratio and spatial resolution
Q.27 In functional connectivity, what does a high correlation coefficient between two brain regions imply?
They have identical anatomical structures
They are likely to be functionally linked or co‑activated
One region controls the blood flow of the other
They are physically adjacent
Explanation - Correlation measures the similarity of temporal activity patterns; high values suggest synchronized functional engagement.
Correct answer is: They are likely to be functionally linked or co‑activated
Q.28 Which of these techniques can directly measure neurotransmitter receptor binding in vivo?
fMRI
PET
EEG
DTI
Explanation - PET radioligands can be designed to bind specific receptors, allowing quantification of receptor density and occupancy.
Correct answer is: PET
Q.29 What is the purpose of 'spatial smoothing' during fMRI preprocessing?
To increase temporal resolution
To reduce high‑frequency noise and improve signal detection across neighboring voxels
To align the brain to a standard template
To correct for head motion
Explanation - Smoothing applies a Gaussian kernel, averaging signals across nearby voxels, which enhances statistical power at the cost of spatial specificity.
Correct answer is: To reduce high‑frequency noise and improve signal detection across neighboring voxels
Q.30 Which of the following best describes the term "temporal resolution" in neuroimaging?
The smallest physical distance that can be resolved
The shortest time interval that can be distinguished between two events
The number of subjects scanned per hour
The contrast between gray and white matter
Explanation - Temporal resolution reflects how quickly a technique can detect changes in neural activity over time.
Correct answer is: The shortest time interval that can be distinguished between two events
Q.31 Which of the following is NOT a typical source of physiological noise in fMRI data?
Respiration
Cardiac pulsation
Neuronal spiking
Subject motion
Explanation - Neuronal activity is the signal of interest; respiration, cardiac pulsation, and motion generate unwanted fluctuations.
Correct answer is: Neuronal spiking
Q.32 In the context of neuroimaging data sharing, what does the acronym "BIDS" stand for?
Brain Imaging Data Structure
Biomedical Imaging Data Standard
Basic Integrated Data System
Brain Information Distribution Service
Explanation - BIDS provides a standardized folder and file naming convention to facilitate reproducible neuroimaging research.
Correct answer is: Brain Imaging Data Structure
Q.33 Which imaging method uses radioactive tracers that emit positrons, which then annihilate to produce detectable gamma photons?
SPECT
fMRI
PET
MEG
Explanation - Positron Emission Tomography relies on positron‑emitting isotopes; the resulting annihilation photons are captured by detectors surrounding the head.
Correct answer is: PET
Q.34 What is the primary clinical use of functional MRI (fMRI) in neurosurgery?
Mapping eloquent cortex to avoid critical areas during tumor resection
Measuring intracranial pressure
Assessing bone density
Detecting scalp infections
Explanation - Pre‑operative fMRI helps surgeons locate language, motor, and sensory regions to minimize postoperative deficits.
Correct answer is: Mapping eloquent cortex to avoid critical areas during tumor resection
Q.35 Which of the following best describes a 'resting‑state' fMRI scan?
Subjects perform a memory task while being scanned
Subjects are instructed to stay still with eyes closed or fixated, and spontaneous brain activity is recorded
Subjects are given a contrast agent to enhance blood flow
Subjects receive electrical stimulation during scanning
Explanation - Resting‑state fMRI captures intrinsic functional connectivity without external task demands.
Correct answer is: Subjects are instructed to stay still with eyes closed or fixated, and spontaneous brain activity is recorded
Q.36 Which parameter in DTI is most sensitive to changes in myelination?
Mean diffusivity (MD)
Fractional anisotropy (FA)
T2 relaxation time
Echo time (TE)
Explanation - FA increases with greater axonal packing and myelin integrity; reductions often indicate demyelination.
Correct answer is: Fractional anisotropy (FA)
Q.37 Which of the following is a major advantage of simultaneous EEG‑fMRI acquisition?
Higher spatial resolution than fMRI alone
Ability to directly measure neuronal magnetic fields
Combining high temporal (EEG) and high spatial (fMRI) information
Elimination of all physiological noise
Explanation - Simultaneous recording leverages the complementary strengths of each modality for richer neurophysiological insight.
Correct answer is: Combining high temporal (EEG) and high spatial (fMRI) information
Q.38 In EEG source reconstruction, what does the term "forward model" refer to?
Predicting scalp potentials from a given set of cortical sources
Estimating the location of sources from recorded potentials
Filtering the raw EEG signal
Adjusting for head movement
Explanation - The forward model computes the lead‑field matrix, linking neural source activity to measured electrode potentials.
Correct answer is: Predicting scalp potentials from a given set of cortical sources
Q.39 Which imaging technique uses magnetically labeled blood cells to map cerebral blood flow?
Arterial Spin Labeling (ASL) MRI
Diffusion Weighted Imaging (DWI)
Magnetization Transfer Imaging (MTI)
Susceptibility Weighted Imaging (SWI)
Explanation - ASL magnetically tags inflowing arterial blood water as an endogenous tracer, enabling quantitative perfusion maps.
Correct answer is: Arterial Spin Labeling (ASL) MRI
Q.40 What does the acronym "MEG" stand for?
Magnetic Excitatory Gradient
Magnetoencephalography
Micro‑electrode Graphing
Motor Evoked Gamma
Explanation - MEG records magnetic fields produced by synchronized neuronal currents.
Correct answer is: Magnetoencephalography
Q.41 Which of the following is a common metric for assessing the reliability of functional connectivity measurements across sessions?
Intraclass Correlation Coefficient (ICC)
Root Mean Square Error (RMSE)
Signal‑to‑Noise Ratio (SNR)
Peak‑to‑Peak Amplitude
Explanation - ICC quantifies the consistency of measurements (e.g., connectivity strengths) across repeated scans.
Correct answer is: Intraclass Correlation Coefficient (ICC)
Q.42 In the context of neuroimaging, what is a "parcellation"?
Division of the brain into discrete regions or parcels for analysis
A technique for increasing magnetic field strength
A type of electrode implantation
A method for enhancing image contrast
Explanation - Parcellation schemes define ROIs (regions of interest) used in structural or functional analyses.
Correct answer is: Division of the brain into discrete regions or parcels for analysis
Q.43 Which of the following physiological signals is most often recorded simultaneously with EEG to assist in artifact removal?
Electrocardiogram (ECG)
Respiration belt signal
Electrooculogram (EOG)
Skin conductance
Explanation - EOG tracks eye movements and blinks, allowing targeted removal of ocular artifacts from EEG data.
Correct answer is: Electrooculogram (EOG)
Q.44 What is the main challenge of using high‑density EEG (e.g., 256 channels) for source localization?
Insufficient temporal resolution
Increased computational load and need for accurate head models
Inability to detect low‑frequency activity
Requirement for invasive surgery
Explanation - More electrodes improve spatial sampling but demand precise forward models and greater processing power to solve the inverse problem.
Correct answer is: Increased computational load and need for accurate head models
Q.45 Which brain‑mapping technique relies on the detection of changes in magnetic susceptibility of deoxygenated hemoglobin?
Functional MRI (BOLD)
Near‑Infrared Spectroscopy (NIRS)
Positron Emission Tomography (PET)
Electroencephalography (EEG)
Explanation - The BOLD signal originates from magnetic susceptibility differences between oxy‑ and deoxy‑hemoglobin.
Correct answer is: Functional MRI (BOLD)
Q.46 Which of the following is a standard atlas used for cortical parcellation in fMRI studies?
MNI (Montreal Neurological Institute) atlas
Cohen’s d atlas
Hounsfield unit atlas
Kepler atlas
Explanation - The MNI template provides a standardized coordinate system and anatomical labels for group analyses.
Correct answer is: MNI (Montreal Neurological Institute) atlas
Q.47 What does the term "neurovascular coupling" describe?
The relationship between neuronal firing and local blood flow changes
The binding of neurotransmitters to vascular receptors
The electrical conduction in peripheral nerves
The diffusion of water molecules in white matter
Explanation - Neurovascular coupling underlies the BOLD response; active neurons trigger metabolic demand that increases cerebral blood flow.
Correct answer is: The relationship between neuronal firing and local blood flow changes
Q.48 Which statistical method is commonly used to identify brain regions that show significant activation across subjects in fMRI group analysis?
t‑test (random‑effects model)
K‑means clustering
Linear regression without correction
Fourier analysis
Explanation - Random‑effects t‑tests assess whether the mean activation across participants differs significantly from zero, accounting for inter‑subject variability.
Correct answer is: t‑test (random‑effects model)
Q.49 In PET imaging, what is the purpose of using a "radioligand"?
To enhance magnetic field strength
To bind selectively to a target molecule (e.g., receptor) for visualization
To cool the scanner during operation
To improve electrode conductivity
Explanation - Radioligands are radioactive compounds that target specific biological processes, enabling quantitative PET imaging.
Correct answer is: To bind selectively to a target molecule (e.g., receptor) for visualization
Q.50 Which of the following is NOT a typical step in the preprocessing pipeline for diffusion MRI?
Eddy‑current correction
Brain extraction
Temporal filtering
Tensor fitting
Explanation - Diffusion MRI preprocessing focuses on spatial distortions and signal modeling; temporal filtering is irrelevant as diffusion data are not time‑series in the same way as fMRI.
Correct answer is: Temporal filtering
Q.51 What does the abbreviation "GLM" stand for in fMRI data analysis?
General Linear Model
Global Light Modulation
Gradient Lattice Mapping
Gated Lateral Motion
Explanation - The GLM models the observed BOLD signal as a linear combination of predictors (e.g., task regressors) plus error.
Correct answer is: General Linear Model
Q.52 Which of the following best describes the purpose of a "canonical hemodynamic response function (HRF)" in fMRI analysis?
To model the shape of the BOLD response to a brief neural event
To correct for head motion
To increase spatial resolution
To measure electrical conductivity
Explanation - The canonical HRF approximates the typical time‑course of the BOLD signal following a neural impulse, used in GLM design matrices.
Correct answer is: To model the shape of the BOLD response to a brief neural event
Q.53 In the context of neural network mapping, what does "hub node" refer to?
A region with a high degree of connections to many other nodes
A node that only connects to one other node
A node located in the brain stem
A node that represents the visual cortex only
Explanation - Hub nodes have high centrality and are thought to integrate information across the brain network.
Correct answer is: A region with a high degree of connections to many other nodes
Q.54 Which imaging technique can provide information about both structural connectivity and myelination simultaneously?
Diffusion Tensor Imaging (DTI)
Functional MRI (fMRI)
Magnetoencephalography (MEG)
Positron Emission Tomography (PET)
Explanation - DTI derives metrics like FA that reflect fiber orientation and microstructural integrity, including myelination.
Correct answer is: Diffusion Tensor Imaging (DTI)
Q.55 Which of the following is a key limitation of using scalp EEG for localizing deep brain sources?
High spatial resolution
Low signal attenuation
Signal smearing due to volume conduction
Direct measurement of synaptic currents
Explanation - Electrical potentials generated by deep sources are attenuated and mixed by surrounding tissues, reducing localization accuracy.
Correct answer is: Signal smearing due to volume conduction
Q.56 In a typical fMRI experiment, what does the term "TR" refer to?
Temporal resolution
Repetition time – the interval between successive pulse sequences
Transmission ratio
Tissue relaxation time
Explanation - TR determines how often a full brain volume is acquired and influences temporal resolution.
Correct answer is: Repetition time – the interval between successive pulse sequences
Q.57 Which of the following best describes the purpose of "independent component analysis (ICA)" in fMRI preprocessing?
To increase the magnetic field strength
To separate noise components (e.g., motion, physiological) from neural signal
To compute the BOLD response function
To transform data into the frequency domain
Explanation - ICA decomposes the data into spatially independent components, allowing removal of artifacts while preserving neural networks.
Correct answer is: To separate noise components (e.g., motion, physiological) from neural signal
Q.58 What is the typical spatial resolution (voxel size) of a standard 3 T fMRI scan?
1 mm³
2–3 mm³
5–10 mm³
10–15 mm³
Explanation - Standard 3 T fMRI protocols acquire voxels around 2–3 mm isotropic, balancing coverage and signal‑to‑noise ratio.
Correct answer is: 2–3 mm³
Q.59 Which neuroimaging modality can directly record neuronal action potentials from a small number of neurons?
Single‑unit electrophysiology (intracortical electrodes)
fMRI
PET
MEG
Explanation - Intracortical microelectrodes detect the voltage spikes of individual neurons, offering the highest temporal and spatial specificity.
Correct answer is: Single‑unit electrophysiology (intracortical electrodes)
Q.60 In the context of brain mapping, what does the term "atlas-based segmentation" refer to?
Dividing the brain into regions using a pre‑defined anatomical template
Segmenting the MRI signal based on frequency bands
Separating blood from tissue in PET images
Creating a 3‑D printed model of the brain
Explanation - Atlas‑based segmentation assigns each voxel to an anatomical label derived from a standardized brain atlas.
Correct answer is: Dividing the brain into regions using a pre‑defined anatomical template
Q.61 Which of the following is a common measure of functional segregation in brain networks?
Global efficiency
Modularity
Betweenness centrality
Clustering coefficient
Explanation - Modularity quantifies the degree to which a network can be divided into relatively independent modules (clusters).
Correct answer is: Modularity
Q.62 What does the term "echo planar imaging (EPI)" describe?
A rapid MRI sequence used for acquiring BOLD fMRI data
A method for visualizing electrical activity
A technique for measuring diffusion anisotropy
A way to record auditory evoked potentials
Explanation - EPI acquires an entire image plane after a single RF excitation, enabling fast temporal sampling required for fMRI.
Correct answer is: A rapid MRI sequence used for acquiring BOLD fMRI data
Q.63 Which of the following best explains why higher magnetic field strengths increase the BOLD contrast in fMRI?
They lengthen the T1 relaxation time
They amplify the magnetic susceptibility differences between oxy‑ and deoxy‑hemoglobin
They reduce the need for contrast agents
They increase the speed of data acquisition
Explanation - At higher fields, the susceptibility effect of deoxy‑hemoglobin is stronger, leading to larger signal changes.
Correct answer is: They amplify the magnetic susceptibility differences between oxy‑ and deoxy‑hemoglobin
Q.64 In neuroimaging, what is the purpose of "coregistration"?
Aligning functional data to a structural image of the same subject
Increasing the field of view of the scanner
Correcting for magnetic field inhomogeneities
Segmenting gray matter from white matter
Explanation - Coregistration spatially aligns datasets (e.g., fMRI to T1‑weighted MRI) so that functional results can be interpreted anatomically.
Correct answer is: Aligning functional data to a structural image of the same subject
Q.65 Which technique uses the principle of nuclear magnetic resonance to generate images of brain anatomy?
Computed Tomography (CT)
Magnetic Resonance Imaging (MRI)
Positron Emission Tomography (PET)
Electroencephalography (EEG)
Explanation - MRI exploits the alignment and relaxation of hydrogen nuclei in a magnetic field to produce high‑resolution anatomical images.
Correct answer is: Magnetic Resonance Imaging (MRI)
Q.66 What does the term "signal‑to‑noise ratio (SNR)" describe in the context of neuroimaging?
The proportion of brain tissue to cerebrospinal fluid
The relative strength of the desired signal compared to random fluctuations
The ratio of magnetic field strength to gradient strength
The number of electrodes used
Explanation - Higher SNR indicates clearer images or recordings, improving detection of true neural activity.
Correct answer is: The relative strength of the desired signal compared to random fluctuations
Q.67 Which of the following is a major benefit of using multi‑band (simultaneous multi‑slice) acquisition in fMRI?
Allows scanning multiple participants at once
Reduces the number of required electrodes
Increases temporal resolution by acquiring several slices simultaneously
Eliminates the need for head fixation
Explanation - Multi‑band techniques excite multiple slices at once, shortening TR and enabling faster whole‑brain coverage.
Correct answer is: Increases temporal resolution by acquiring several slices simultaneously
Q.68 In the context of PET, what does the term "half‑life" of a radiotracer refer to?
The time it takes for the tracer to reach the brain
The period during which the tracer emits half of its total radiation
The duration of the scanner's magnetic field
The time needed to reconstruct an image
Explanation - Half‑life determines how long a radiotracer remains active; it influences dosing, imaging windows, and safety.
Correct answer is: The period during which the tracer emits half of its total radiation
Q.69 Which of the following best describes the concept of "effective connectivity"?
Statistical correlation between brain region time series
Causal influence of one neural system over another
Physical white‑matter pathways linking regions
Similarity of BOLD signal amplitudes
Explanation - Effective connectivity models directed interactions, often using methods like Dynamic Causal Modeling (DCM).
Correct answer is: Causal influence of one neural system over another
Q.70 What is the main purpose of applying a "high‑pass filter" during EEG preprocessing?
To remove slow drifts and baseline wander
To eliminate high‑frequency muscle artifacts
To increase the amplitude of alpha waves
To correct for head motion
Explanation - High‑pass filters attenuate frequencies below a set cutoff (e.g., 0.5 Hz), reducing low‑frequency noise.
Correct answer is: To remove slow drifts and baseline wander
Q.71 Which imaging technique can be used to map iron deposition in the brain?
Susceptibility Weighted Imaging (SWI)
Diffusion Weighted Imaging (DWI)
Functional MRI (fMRI)
Positron Emission Tomography (PET)
Explanation - SWI is sensitive to magnetic susceptibility differences, making it suitable for detecting iron-rich regions.
Correct answer is: Susceptibility Weighted Imaging (SWI)
Q.72 In graph theory applied to brain networks, what does a "short path length" indicate about the network?
High segregation
Efficient global integration of information
Reduced connectivity
Large number of isolated nodes
Explanation - Short average path lengths mean signals can travel across the network with few intermediate steps, supporting rapid integration.
Correct answer is: Efficient global integration of information
Q.73 Which of the following is a typical application of functional Near‑Infrared Spectroscopy (fNIRS) in neuroscience?
Studying cortical activation during naturalistic tasks in infants
Mapping deep subcortical nuclei
Measuring electrical conduction velocity
Assessing bone density
Explanation - fNIRS is portable, tolerant to movement, and suitable for populations (e.g., infants) where MRI is challenging.
Correct answer is: Studying cortical activation during naturalistic tasks in infants
Q.74 What does the term "resting‑state network" (RSN) refer to?
A set of brain regions showing correlated spontaneous activity when no explicit task is performed
A collection of muscles that are at rest
A network of blood vessels supplying the brain
A set of electrodes used in EEG
Explanation - RSNs, such as the default mode network, are identified via functional connectivity analyses of resting‑state data.
Correct answer is: A set of brain regions showing correlated spontaneous activity when no explicit task is performed
Q.75 Which of the following best describes the purpose of "slice‑timing correction" in fMRI preprocessing?
Aligning slices to a common temporal reference to account for inter‑slice acquisition delays
Correcting head motion between volumes
Increasing spatial resolution of the images
Removing physiological noise
Explanation - Since slices are acquired sequentially, slice‑timing correction interpolates the data to a common time point, improving temporal accuracy.
Correct answer is: Aligning slices to a common temporal reference to account for inter‑slice acquisition delays
Q.76 What is a primary advantage of using a "surface‑based" analysis over a "volume‑based" analysis in cortical fMRI studies?
Better alignment of cortical folding patterns across subjects
Higher temporal resolution
Reduced need for motion correction
Ability to image deep brain structures
Explanation - Surface‑based methods respect the 2‑D geometry of the cortex, improving inter‑subject correspondence of gyri and sulci.
Correct answer is: Better alignment of cortical folding patterns across subjects
Q.77 In the context of neural mapping, what does the term "multimodal integration" refer to?
Combining data from different imaging modalities (e.g., EEG and fMRI) to gain complementary information
Using multiple scanners simultaneously on the same subject
Applying several filters to a single signal
Increasing the magnetic field strength
Explanation - Multimodal integration exploits the strengths of each technique (e.g., EEG temporal, fMRI spatial) to build richer brain models.
Correct answer is: Combining data from different imaging modalities (e.g., EEG and fMRI) to gain complementary information
Q.78 Which of the following is a common approach to visualize the results of a functional connectivity analysis?
Heat‑map of correlation matrix
Bar graph of electrode impedance
Histogram of voxel intensities
3‑D rendering of skull morphology
Explanation - Correlation matrices are often displayed as color‑coded heat‑maps to illustrate strength of connections between regions.
Correct answer is: Heat‑map of correlation matrix
Q.79 What does the "B0" field denote in MRI terminology?
The static main magnetic field strength
The gradient field used for slice selection
The RF excitation pulse frequency
The noise level of the scanner
Explanation - B0 is the uniform magnetic field generated by the main magnet; its magnitude (e.g., 3 T) defines the scanner's field strength.
Correct answer is: The static main magnetic field strength
Q.80 Which of the following best describes a "voxel‑wise" statistical analysis?
Testing each voxel individually for significant effects across the brain
Aggregating signals across all voxels into a single value
Analyzing only surface voxels
Performing a regional average before statistical testing
Explanation - Voxel‑wise analysis evaluates statistical hypotheses at every voxel, requiring correction for multiple comparisons.
Correct answer is: Testing each voxel individually for significant effects across the brain
Q.81 What is the main reason that EEG signals are typically referenced to a common electrode?
To eliminate the need for amplification
To provide a stable voltage baseline for differential measurement
To increase the magnetic field strength
To reduce the number of channels needed
Explanation - Referencing defines a zero‑potential point, allowing each electrode to record the potential difference relative to that reference.
Correct answer is: To provide a stable voltage baseline for differential measurement
Q.82 Which of the following is an example of a non‑linear dimensionality reduction technique used in neuroimaging data analysis?
Principal Component Analysis (PCA)
t‑Distributed Stochastic Neighbor Embedding (t‑SNE)
Fast Fourier Transform (FFT)
Linear regression
Explanation - t‑SNE preserves local structure in high‑dimensional data when projecting to low dimensions, useful for visualizing complex neuroimaging patterns.
Correct answer is: t‑Distributed Stochastic Neighbor Embedding (t‑SNE)
Q.83 In the context of MRI, what does the term "T2*" refer to?
The time constant describing spin‑spin relaxation including magnetic field inhomogeneities
The time needed to acquire a full brain volume
The echo time for diffusion weighting
The temperature of the scanner bore
Explanation - T2* incorporates both intrinsic T2 decay and additional dephasing due to field inhomogeneities, critical for BOLD contrast.
Correct answer is: The time constant describing spin‑spin relaxation including magnetic field inhomogeneities
Q.84 Which of the following best explains why MEG is less sensitive to scalp conductivity variations compared to EEG?
Magnetic fields are not attenuated by the skull and scalp
MEG uses higher voltage electrodes
MEG recordings are performed inside the MRI scanner
MEG signals are generated by glial cells
Explanation - Magnetic fields pass through biological tissues with minimal distortion, whereas electric potentials are filtered by conductivity differences.
Correct answer is: Magnetic fields are not attenuated by the skull and scalp
Q.85 What is the primary objective of "bias field correction" in structural MRI preprocessing?
To correct for intensity inhomogeneities caused by coil sensitivity variations
To remove motion artifacts
To increase temporal resolution
To segment gray and white matter
Explanation - Bias field correction normalizes voxel intensities across the image, improving subsequent segmentation and analysis.
Correct answer is: To correct for intensity inhomogeneities caused by coil sensitivity variations
Q.86 Which of the following is a widely used software package for processing EEG and MEG data?
SPM
FSL
EEGLAB
AFNI
Explanation - EEGLAB is an open‑source MATLAB toolbox dedicated to EEG/MEG data analysis, including preprocessing, ICA, and time‑frequency analysis.
Correct answer is: EEGLAB
Q.87 In functional connectivity, what does the term "seed‑to‑voxel" analysis produce?
A single time series for the whole brain
A map showing correlation strength between a seed region and every other voxel
A list of electrode impedances
A structural connectivity matrix
Explanation - Seed‑to‑voxel analysis computes the correlation of the seed's time course with each voxel, yielding a whole‑brain connectivity map.
Correct answer is: A map showing correlation strength between a seed region and every other voxel
Q.88 Which of the following is a common physiological noise source that can be regressed out of fMRI data using a "RETROICOR" approach?
Scanner gradient heating
Cardiac pulsation and respiration
Subject head shape
Electrode impedance
Explanation - RETROICOR (RETROspective Image CORrection) models and removes periodic physiological fluctuations related to heartbeats and breathing.
Correct answer is: Cardiac pulsation and respiration
Q.89 What does the term "temporal autocorrelation" refer to in fMRI time series analysis?
Correlation of a voxel's signal with neighboring voxels
Correlation of a voxel's signal with itself at different time points
Correlation between two separate subjects
Correlation between MRI scanner temperature and signal intensity
Explanation - Temporal autocorrelation describes the dependence of a signal on its own past values, which must be accounted for in statistical modeling.
Correct answer is: Correlation of a voxel's signal with itself at different time points
Q.90 Which of the following best characterizes a "small‑world" network architecture in brain connectivity?
High clustering and short path lengths, balancing segregation and integration
Random connections with no clustering
Only long‑range connections
A fully disconnected network
Explanation - Small‑world networks combine local specialization (clustering) with efficient global communication (short paths), a hallmark of brain organization.
Correct answer is: High clustering and short path lengths, balancing segregation and integration
Q.91 In the context of neuroimaging, what does the acronym "TR" and "TE" together define?
The spatial resolution of the scan
The temporal resolution and echo time, influencing image contrast
The type of head coil used
The amount of radiation dose delivered
Explanation - TR (repetition time) determines how often images are acquired; TE (echo time) influences T2/T2* weighting, together shaping contrast and timing.
Correct answer is: The temporal resolution and echo time, influencing image contrast
Q.92 Which of the following methods can be used to increase the effective signal‑to‑noise ratio (SNR) of EEG recordings?
Averaging multiple epochs of the same event-related potential
Increasing the magnetic field strength
Using a higher flip angle in MRI
Applying a low‑pass filter only
Explanation - Averaging reduces random noise while preserving phase‑locked neural signals, thereby enhancing SNR for evoked potentials.
Correct answer is: Averaging multiple epochs of the same event-related potential
Q.93 What is the purpose of "field map acquisition" in fMRI preprocessing?
To correct for spatial distortions caused by magnetic field inhomogeneities
To measure blood oxygenation levels
To estimate head motion
To acquire structural images
Explanation - Field maps quantify B0 variations, enabling correction of geometric distortions especially in EPI images.
Correct answer is: To correct for spatial distortions caused by magnetic field inhomogeneities
Q.94 Which of the following best describes the concept of "brain‑computer interface" (BCI) in neuroengineering?
A system that translates brain signals into commands for external devices
A type of MRI coil
A method for enhancing synaptic plasticity with drugs
A surgical procedure to implant electrodes
Explanation - BCIs decode neural activity (e.g., EEG, ECoG) in real time to control computers, prostheses, or communication devices.
Correct answer is: A system that translates brain signals into commands for external devices
Q.95 Which of the following is a commonly used metric for assessing the strength of a functional connection between two brain regions?
Pearson correlation coefficient
Voxel size
Magnetic field strength
TR (repetition time)
Explanation - Pearson's r quantifies the linear relationship between two time series, serving as a basic functional connectivity measure.
Correct answer is: Pearson correlation coefficient
Q.96 In diffusion MRI, what does the term "b‑value" control?
The strength and timing of diffusion‑sensitizing gradients, influencing diffusion weighting
The magnetic field strength of the scanner
The size of the voxel
The number of slices acquired
Explanation - Higher b‑values increase sensitivity to diffusion but reduce SNR; they are set by gradient amplitude and duration.
Correct answer is: The strength and timing of diffusion‑sensitizing gradients, influencing diffusion weighting
Q.97 Which of the following best defines "neuroplasticity" as investigated with neuroimaging techniques?
The brain's ability to change its structure or function in response to experience or injury
The fixed anatomical layout of the brain
The magnetic resonance of iron deposits
The constant blood flow regardless of activity
Explanation - Neuroimaging can capture structural remodeling (e.g., cortical thickness) or functional reorganization linked to learning or recovery.
Correct answer is: The brain's ability to change its structure or function in response to experience or injury
Q.98 Which of the following is a common approach for visualizing structural connectivity derived from diffusion MRI?
Fiber tractography
Heat‑map of BOLD signal
Power spectral density plot
Time‑frequency decomposition
Explanation - Tractography reconstructs probable white‑matter pathways by following the principal diffusion directions voxel‑by‑voxel.
Correct answer is: Fiber tractography
Q.99 What is the primary purpose of using a "high‑density" EEG cap (e.g., 256 channels) compared to a standard 32‑channel cap?
To improve spatial sampling of scalp potentials and enhance source localization
To increase the magnetic field strength
To reduce the amount of data generated
To measure blood flow directly
Explanation - More electrodes provide finer coverage, allowing better reconstruction of underlying cortical sources.
Correct answer is: To improve spatial sampling of scalp potentials and enhance source localization
Q.100 Which of the following techniques can directly assess the metabolic activity of neuronal tissue via oxygen consumption?
Functional MRI (BOLD)
Positron Emission Tomography (PET) with ^15O‑water
Diffusion Tensor Imaging (DTI)
Magnetoencephalography (MEG)
Explanation - ^15O‑water PET measures cerebral blood flow, which is tightly coupled to oxygen metabolism, providing a quantitative metabolic map.
Correct answer is: Positron Emission Tomography (PET) with ^15O‑water
Q.101 In the analysis of EEG data, what does the term "event‑related potential" (ERP) refer to?
A time‑locked average of EEG activity following a specific stimulus or event
The baseline noise level of the recording
The magnetic field generated by the brain
A measure of blood oxygenation
Explanation - ERPs reveal consistent neural responses by averaging across many repetitions of the same event, enhancing signal relative to noise.
Correct answer is: A time‑locked average of EEG activity following a specific stimulus or event
Q.102 Which of the following best explains why the BOLD signal is considered an indirect measure of neural activity?
It reflects hemodynamic changes that follow neuronal activation rather than the electrical activity itself
It directly records action potentials
It measures the concentration of neurotransmitters
It is based on magnetic field recordings
Explanation - The BOLD response arises from vascular responses to metabolic demands, providing an indirect proxy for underlying neural firing.
Correct answer is: It reflects hemodynamic changes that follow neuronal activation rather than the electrical activity itself
Q.103 Which of the following is an example of a "task‑free" fMRI acquisition paradigm?
Resting‑state scan with eyes closed
Finger tapping task
Visual stimulus presentation
Auditory oddball task
Explanation - Task‑free (resting‑state) scans do not involve explicit cognitive or motor tasks, allowing assessment of intrinsic connectivity.
Correct answer is: Resting‑state scan with eyes closed
Q.104 What does the term "magnetization transfer contrast" (MTC) refer to in MRI?
A technique that highlights macromolecular bound water by applying off‑resonance saturation pulses
A method for measuring blood flow
A way to increase temporal resolution
A type of diffusion weighting
Explanation - MTC suppresses signals from free water, enhancing contrast from tissues with high macromolecular content (e.g., myelin).
Correct answer is: A technique that highlights macromolecular bound water by applying off‑resonance saturation pulses
Q.105 Which of the following is a primary advantage of using simultaneous EEG‑MEG recordings?
Combined sensitivity to both radial (EEG) and tangential (MEG) source orientations
Elimination of all physiological artifacts
Reduced need for head fixation
Higher magnetic field strength
Explanation - EEG is more sensitive to radial currents, MEG to tangential; together they provide a more complete view of source geometry.
Correct answer is: Combined sensitivity to both radial (EEG) and tangential (MEG) source orientations
Q.106 In the context of neuroimaging data sharing, what is a "Data Use Agreement" (DUA) primarily for?
Specifying the legal and ethical terms under which shared data may be accessed and used
Improving the spatial resolution of images
Increasing the magnetic field strength of scanners
Standardizing the format of MRI pulse sequences
Explanation - DUAs protect participant privacy and define permissible analyses for shared datasets.
Correct answer is: Specifying the legal and ethical terms under which shared data may be accessed and used
Q.107 Which of the following is a common method for correcting for head motion in resting‑state fMRI data?
Scrubbing (removing high‑motion volumes)
Increasing the flip angle
Applying a band‑stop filter at 60 Hz
Using a larger voxel size
Explanation - Scrubbing identifies and excludes volumes exceeding motion thresholds, reducing motion‑related artifacts in connectivity analyses.
Correct answer is: Scrubbing (removing high‑motion volumes)