Lecture 5+6 AI generated

Question 1

Describe EEG and what it measures.

Answer 1

EEG stands for ElectroEncephaloGraphy and measures the electrical activity in the brain through voltage.

Question 2

How can EEG be used in nutritional or sensory research?

Answer 2

EEG can be used to study brain responses to nutritional or sensory stimuli, providing insights into cognitive processes related to taste, smell, or food perception.

Question 3

Define the differences between various EEG experimental design and analysis methods.

Answer 3

Different EEG experimental designs and analysis methods vary in terms of electrode placement, signal processing techniques, and experimental paradigms.

Question 4

Explain the pros and cons of EEG as a technique.

Answer 4

The pros of EEG include high temporal resolution, non-invasiveness, portability, and cost-effectiveness. However, cons may include the need for a reference, limited spatial resolution, and susceptibility to artifacts.

Question 5

Compare EEG to other imaging techniques like fMRI and MRI.

Answer 5

EEG provides high temporal resolution but lower spatial resolution compared to fMRI and MRI, which offer better spatial detail but are less suitable for capturing rapid brain activity.

Question 6

Describe the neural origin of EEG signals.

Answer 6

EEG signals originate from postsynaptic potentials in neurons, where neurotransmitters transmit electrical signals between presynaptic and postsynaptic neurons.

Question 7

How are electrodes placed on the head in EEG using the international 1020 system?

Answer 7

Electrodes are positioned based on measurements between specific head landmarks, ensuring consistent relative distances between electrodes for accurate brain activity recording.

Question 8

Describe the nasion and inion in relation to the skull.

Answer 8

The nasion is the point between the forehead and the nose, while the inion is the bump at the back of the skull.

Question 9

Define the locations labelled with letters in EEG.

Answer 9

Frontal, Temporal, Parietal, Occipital, and Central.

Question 10

How are electrodes used in EEG recordings?

Answer 10

Electrodes are conductive materials attached to a wire to record the potential between two points on the scalp.

Question 11

Do even numbers in EEG represent the right or left hemisphere?

Answer 11

Even numbers in EEG represent the right hemisphere, while odd numbers represent the left hemisphere.

Question 12

Describe the purpose of a reference electrode in EEG recordings.

Answer 12

The reference electrode influences the measurement by providing a baseline for comparison with the active electrode.

Question 13

What is the significance of Power spectrum analysis in EEG?

Answer 13

Power spectrum analysis helps quantify the raw EEG data by plotting different frequencies against their power, showing patterns of brain activity.

Question 14

How does Functional connectivity analysis differ from Power spectrum analysis in EEG?

Answer 14

Functional connectivity analysis in EEG focuses on correlations between oscillatory signals in different brain areas, looking at networks instead of individual electrodes.

Question 15

Define event-related potentials (ERPs) in EEG recordings.

Answer 15

Event-related potentials (ERPs) are brain reactions to stimuli that are synchronized and time-locked, occurring in response to multiple stimuli without adaptation or random noise.

Question 16

Describe the process of measuring ERPs.

Answer 16

Electrodes are attached to the scalp, connected to amplifiers, and a 10-20 system is used for consistency. The output is converted to numbers for measuring electrical potentials.

Question 17

What do early components of ERPs reflect?

Answer 17

They reflect physical characteristics of sensory stimuli.

Question 18

Define the Readiness Potential in ERPs.

Answer 18

It shows the preparation of a response, such as a movement, and can be measured with tasks like Go/NoGo.

Question 19

How are ERPs different from EEGs in terms of measurement?

Answer 19

ERPs are smaller in amplitude compared to EEGs, and background noise is removed before analysis.

Question 20

Describe the P3/P300 component in ERPs.

Answer 20

It is a late and large positive component, commonly seen in oddball paradigms, influenced by motivation and appearing more positive with lower probability events.

Question 21

What is the significance of using olfactory/gustatory ERPs in studying eating behavior?

Answer 21

They can provide insights into neural responses related to food stimuli, but are challenging due to stimulus delivery and adaptation issues.

Question 22

Describe the concept of the inverse problem in EEG analysis.

Answer 22

The inverse problem in EEG analysis refers to the challenge of determining the source of a signal measured from outside the brain, as opposed to directly measuring brain activity inside the brain.

Question 23

Define a dipole in the context of EEG analysis.

Answer 23

A dipole in EEG analysis refers to a source of electrical activity in the brain that generates a signal measurable outside the brain.

Question 24

How is the forward model used in EEG analysis?

Answer 24

The forward model in EEG analysis involves generating the signal that would be produced by a dipole and comparing it to the measured signal to determine the possible source of the signal.

Question 25

What are some examples of artifacts in EEG recordings?

Answer 25

Examples of artifacts in EEG recordings include eye movements, muscle activity, electrical noise, and sleepiness, which can distort the data.

Question 26

Describe the terminology used in fMRI/EEG data analysis for subjects, sessions, and runs.

Answer 26

Subjects are participants, sessions are measurements, and runs are the images obtained from the measurements in fMRI/EEG data analysis.

Question 27

Explain the difference in spatial resolution between fMRI and EEG imaging techniques.

Answer 27

fMRI has a higher spatial resolution (2-4 mm) due to voxels, while EEG has a lower spatial resolution (in cm) because it measures signals from electrodes on the scalp.

Question 28

What is the role of voxels in fMRI imaging?

Answer 28

Voxels in fMRI imaging represent the 3D pixels that make up the image of the brain, with each voxel containing information about the BOLD signal.

Question 29

How does the temporal resolution of EEG compare to fMRI?

Answer 29

EEG has a high temporal resolution (in milliseconds) compared to fMRI, which has a temporal resolution in seconds.

Question 30

Explain the concept of Iterative process in EEG analysis.

Answer 30

In EEG analysis, the Iterative process involves continuously refining the solution by trial-and-error until the source of the signal is accurately identified and the solution is no longer improving.

Question 31

Describe the preprocessing steps in fMRI analysis.

Answer 31

Preprocessing steps in fMRI analysis include slice-timing correction, motion correction, co-registration of anatomy-functional scans, normalization to a standard brain, and spatial smoothing.

Question 32

What is the purpose of registration in fMRI analysis?

Answer 32

Registration in fMRI analysis aligns images by correcting translations (x, y, z) and rotations (pitch, roll, yaw) to ensure proper alignment of brain images.

Question 33

How is the design matrix used in fMRI analysis?

Answer 33

The design matrix in fMRI analysis represents the task design graphically and is used in a linear model (Y = X*B + E) to estimate the relationship between predictors (X) and observations (Y).

Question 34

Define Statistical Parametric Map (SPM) in the context of fMRI analysis.

Answer 34

In fMRI analysis, a Statistical Parametric Map (SPM) is a map that shows the statistical significance of brain activity by representing contrasts in T-values, which are color-coded and overlaid on anatomical images.

Question 35

Differentiate between 1st level and 2nd level analysis in fMRI research.

Answer 35

1st level analysis in fMRI research involves analyzing data at the individual subject level, while 2nd level analysis focuses on group analysis to draw conclusions at a population level.

Question 36

Explain the purpose of thresholding in Statistical Parametric Maps (SPMs) in fMRI analysis.

Answer 36

Thresholding in SPMs is used to correct for multiple comparisons, ensuring that only statistically significant brain activity is considered in the analysis.

Question 37

Describe the process of reflecting the hemodynamic response function (HRF) in fMRI data analysis.

Answer 37

In fMRI data analysis, the HRF is convolved with the design matrix to estimate how well the model parameters explain the variance in the fMRI signal, leading to the creation of a Statistical Parametric Map (SPM).