Podcast
Questions and Answers
What type of magnetic material is strongly attracted to magnetic fields and can pose safety risks in MRI?
What type of magnetic material is strongly attracted to magnetic fields and can pose safety risks in MRI?
Which property describes a material that is slightly repelled by magnetic fields?
Which property describes a material that is slightly repelled by magnetic fields?
What happens to hemoglobin when it binds oxygen?
What happens to hemoglobin when it binds oxygen?
Which of the following substances act as contrast agents in MRI due to their paramagnetic properties?
Which of the following substances act as contrast agents in MRI due to their paramagnetic properties?
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What is the primary safety concern regarding ferromagnetic materials in MRI?
What is the primary safety concern regarding ferromagnetic materials in MRI?
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Which material is known to exhibit both paramagnetic and diamagnetic properties depending on its oxygen saturation?
Which material is known to exhibit both paramagnetic and diamagnetic properties depending on its oxygen saturation?
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Why are MRI systems designed to minimize ferromagnetic materials?
Why are MRI systems designed to minimize ferromagnetic materials?
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What occurs when biological tissues are subjected to magnetic fields?
What occurs when biological tissues are subjected to magnetic fields?
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What property do paramagnetic substances exhibit that makes them attracted to magnetic fields?
What property do paramagnetic substances exhibit that makes them attracted to magnetic fields?
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Which of the following materials is considered a diamagnetic substance?
Which of the following materials is considered a diamagnetic substance?
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How does hemoglobin's binding of oxygen affect its magnetic properties?
How does hemoglobin's binding of oxygen affect its magnetic properties?
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What enhances MRI images when using gadolinium as a contrast agent?
What enhances MRI images when using gadolinium as a contrast agent?
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Which safety feature is NOT associated with MR-compatible EEG cap systems?
Which safety feature is NOT associated with MR-compatible EEG cap systems?
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What is a common characteristic of most biological tissues in relation to magnetism?
What is a common characteristic of most biological tissues in relation to magnetism?
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Which component is essential for the MR compatibility of EEG caps?
Which component is essential for the MR compatibility of EEG caps?
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What happens to deoxyhemoglobin's magnetic properties when it is fully oxygenated?
What happens to deoxyhemoglobin's magnetic properties when it is fully oxygenated?
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What component is NOT part of a commonly used MR-compatible EEG cap system?
What component is NOT part of a commonly used MR-compatible EEG cap system?
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Which property of materials is relevant for ensuring patient safety during MRI?
Which property of materials is relevant for ensuring patient safety during MRI?
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What is the primary safety feature of the MR-compatible EEG cap?
What is the primary safety feature of the MR-compatible EEG cap?
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What is the main purpose of RF shielding resistors in EEG caps?
What is the main purpose of RF shielding resistors in EEG caps?
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Which of the following statements about paramagnetic materials is true?
Which of the following statements about paramagnetic materials is true?
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What type of magnetic field is primarily generated by gradient switching in MRI?
What type of magnetic field is primarily generated by gradient switching in MRI?
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Which material is considered weakly diamagnetic in the context of MRI?
Which material is considered weakly diamagnetic in the context of MRI?
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What is the primary purpose of correcting gradient and cardioballistic artifacts?
What is the primary purpose of correcting gradient and cardioballistic artifacts?
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Which method involves creating an estimate of the gradient artifact to remove it from noisy data?
Which method involves creating an estimate of the gradient artifact to remove it from noisy data?
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What frequency range is primarily associated with the alpha rhythm identified in EEG recordings?
What frequency range is primarily associated with the alpha rhythm identified in EEG recordings?
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When does the alpha rhythm exhibit the highest amplitude?
When does the alpha rhythm exhibit the highest amplitude?
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Which of the following techniques is NOT listed as a main method for correcting gradient artifacts?
Which of the following techniques is NOT listed as a main method for correcting gradient artifacts?
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What is the essential characteristic of the neuronal EEG signal in relation to the gradient artifact?
What is the essential characteristic of the neuronal EEG signal in relation to the gradient artifact?
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What physiological activity is the alpha rhythm potentially an index of?
What physiological activity is the alpha rhythm potentially an index of?
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What is the primary cause of an action potential in a neuron?
What is the primary cause of an action potential in a neuron?
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Which of the following is a marker of N2 light sleep in EEG readings?
Which of the following is a marker of N2 light sleep in EEG readings?
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How do postsynaptic potentials (PSPs) differ from action potentials?
How do postsynaptic potentials (PSPs) differ from action potentials?
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Which of the following accurately describes a postsynaptic potential?
Which of the following accurately describes a postsynaptic potential?
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What is a significant factor for ensuring compatibility in simultaneous EEG-fMRI procedures?
What is a significant factor for ensuring compatibility in simultaneous EEG-fMRI procedures?
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What is the primary nature of an action potential compared to a postsynaptic potential?
What is the primary nature of an action potential compared to a postsynaptic potential?
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Which of the following best describes the duration of a postsynaptic potential?
Which of the following best describes the duration of a postsynaptic potential?
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What is a consequence of neurotransmitter binding at synapses?
What is a consequence of neurotransmitter binding at synapses?
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Which statement is true regarding the changes in membrane potential during an action potential?
Which statement is true regarding the changes in membrane potential during an action potential?
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What does an increased P300 amplitude generally indicate?
What does an increased P300 amplitude generally indicate?
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What do shorter P300 latencies typically suggest about mental performance?
What do shorter P300 latencies typically suggest about mental performance?
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Which disorder is associated with a decrease in P300 amplitude?
Which disorder is associated with a decrease in P300 amplitude?
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What effect does caffeine have on P300 amplitude and processing?
What effect does caffeine have on P300 amplitude and processing?
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Which of the following is NOT a characteristic of the P300 wave in individuals with schizophrenia?
Which of the following is NOT a characteristic of the P300 wave in individuals with schizophrenia?
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What does the latency prolongation of P300 suggest about cognitive processes?
What does the latency prolongation of P300 suggest about cognitive processes?
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Which of the following psychiatric disorders has been noted for P300 amplitude reduction during manic psychosis?
Which of the following psychiatric disorders has been noted for P300 amplitude reduction during manic psychosis?
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In terms of P300, what does an increase in the cognitive resources demand imply?
In terms of P300, what does an increase in the cognitive resources demand imply?
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Study Notes
BM402: Engineering in Medicine
- Course name: BM402: Engineering in Medicine
- Date: 24th October 2024
- Location: M 2170 - South Campus
MRI
- Functional MRI
- Applications of MRI and fMRI
- EEG
- Applications of EEG
- Multimodal Imaging
EEG Basics
- Electro-encephalo-gram (EEG): Measurement of electrical patterns on the scalp reflecting cortical activity (brainwaves).
- Electrical: EEG measures electrical potentials from the brain.
- Electrode: Electrodes are placed on the scalp to measure the electrical potentials.
- EEG cap: A cap containing electrodes to measure electrical signals from the brain.
- Amplifier: An amplifier boosts the weak electrical signals from the electrodes.
- Processing: Processing the amplified signals to understand patterns and activity.
- Picture/Record: Visual display and recording of the measured brainwaves.
- Brainwave types:
- Delta (1.0-4.0 Hz): Sleep, dreaming
- Theta (4.0-8.0 Hz): Drowsiness
- Alpha (8.0-12.0 Hz): Reflective, restful
- Beta (12.0-25.0 Hz): Busy, active mind
- Gamma (>35 Hz): Problem-solving, concentration
International 10-20 System
- System for electrode placement on the head for EEG recordings.
- Standardized placement locations on the scalp.
- Numerical percentages for defining locations, e.g., 10%, 20%
Electrocorticography (ECOG)
- ECOG, IEEG
- Intracortical microelectrode: An electrode that is inserted directly into the brain.
- Grid and stick electrodes: Used in intracortical recordings.
- Dr. Kareem Zaghloul: Researcher associated with neural signatures of memory and information in the human brain.
EEG History
- Detailed history of EEG, including significant developments and key researchers like Hans Berger.
- Timeline of Technological Advancements:
- Equipment recordings
- Evoked potentials
- Event-related potentials
- Topographic analyses
- Computer-aided signal processing
- Brain-computer interfaces
- Brain-controlled therapies
- Personalized medicine
- Key areas: technology, findings, and applications (1929-1938, 1950, 1960,...1980,.., 1990, 2000, 2010, 2020)
EEG - Brain Rhythms & Frequency Bands
- Different brainwave frequencies correlate with different mental states, categorized:
- Gamma: Problem solving, concentration (Frequency>35Hz)
- Beta: Busy, active mind (frequency 12-35Hz)
- Alpha: Reflective, restful (frequency 8-12Hz)
- Theta: Drowsiness (Frequency 4–8Hz)
- Delta: Sleep, dreaming (Frequency 0.5–4Hz)
EEG Recordings During Sleep
- EEG stages during sleep: Wake, Stage 1, Stage 2, Stage 3, REM, and their characteristic frequency bands
Recording the Electrical Activity of the Brain
- Definition of action potential
- Local field potential
- Electroencephalogram
Postsynaptic Potentials (PSPs)
- Definition of Postsynaptic potentials
- Relation to chemical transmission at the synapse
- Duration of PSPs
Simultaneous EEG-fMRI
- Advantages and disadvantages of simultaneous EEG and fMRI.
- Compatibility issues (magnetic fields, RF emissions, materials).
- Techniques and components for compatibility: electrode cap, connector box, resistors, battery pack, EEG amplifier/digitizer.
- Main artifacts: gradient, ballistocardiogram (BCG)
- Artefact correction methods: template, blind source separation, filtering
Magnetic Properties Relevant to MRI
- Ferromagnetism: Strongly attracted to magnetic fields (iron).
- Paramagnetism: Slightly attracted to magnetic fields (gadolinium, deoxyhemoglobin).
- Diamagnetism: Slightly repelled by magnetic fields (biological tissues).
- Importance of these properties for device design and interpreting results
Event-Related Potentials (ERPs)
- Definition: neural response associated with a specific sensory, cognitive or motor event.
- Recording: Average change in voltage over time, starting at stimulus onset, multiple trials
- Identification of ERP components (e.g., P100, N100, P200, P300) related to sensory properties, selective attention, and endogenous cognitive activity
- Latency and amplitude as indicators of mental performance and neurobiological vulnerability.
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