Biomedical Imaging 2

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Biomedical Imaging 2

• Class 9 Electric and Magnetic Field Imaging
  Electroencephalography (EEG), Magnetoencephalograp
  hy (MEG). Part 1 Theory
• 04/02/08

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Biological Contrast Mechanisms
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Microscopic Ion Concentrations
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Simplified Membrane, Ion Channel Depiction
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Microscopic Ion Currents
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Propagation of Ion Currents
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Propagation of Ion Currents
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Typical Voltage vs. Time Transients
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Interaction of Nerve and Muscle
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Electromyography (EMG)
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Examples of EMG Recordings
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Electrocardiography (ECG, EKG)
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Electrocardiography (ECG, EKG)
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Magnetocardiography (MCG)
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Magnetocardiography (MCG)
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Electric Transmission of Biological Information
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Electric Transmission of Biological Information
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Invasive Recording of Electric Activity
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Properties of Electrically Active Tissues
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Typical Central Nervous System (CNS) Neuron
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Microscopic/Internal ? Macroscopic/External
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EEG and MEG Have Different Surface Effects
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EEG and MEG Have Different Surface Effects
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EEG and MEG Have Different Surface Effects
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EEG and MEG Have Different Surface Effects
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Typical Event-Related Potential (ERP) Measurement
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Averaging Across Repeats (Time-Series Analysis!)
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ERP Components
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But Can We Do ERP Imaging?
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Theoretical Advantages of MEG
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Spatial Resolution of MEG
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Spatial Resolution of MEG
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Comparison of Properties of Functional Brain
Imaging Methods
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Measurement Apparatus
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Scale of Biomagnetic Fields
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MEG Helmet
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MEG Raw Data and Image
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Placement of EEG Electrodes
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Placement of EEG Electrodes
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Dependence of Amplitude on Position
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Spatial Sensitivity of an EEG Electrode Pair
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EEG WaveformsFrequency Bands
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Power Spectrum of Typical EEG
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Behavioral Correlates of EEG Waveforms
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Locating Source of EEG Signal (e.g., Epileptic
Focus)
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Locating Source of EEG Signal (e.g., Epileptic
Focus)
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Locating Source of EEG Signal (e.g., Epileptic
Focus)