Part I Background 1. 1 Principles of Multimodal Functional Imaging and Data Integration. 3 Amo Villringer, Christoph Mulert, and Louis Lemieux

Transcription

1 Part I Background 1 1 Principles of Multimodal Functional Imaging and Data Integration. 3 Amo Villringer, Christoph Mulert, and Louis Lemieux 1 Introduction 3 2 Modes of Data Integration 4 3 Multimodal Data Acquisition Strategies'. Degree of Synchrony 7 4 Multimodal Data Integration Strategies Spatial Coregistration Asymmetric Integration Symmetrical Data Fusion 10 5 Summary 12 2 EEG: Origin and Measurement 19 Femando Lopes da Silva 1 Introduction to the Electrophysiology of the Brain 19 2 Origin of EEG and MEG 1: Cellular Sources 20 3 Main Types of Rhythmical EEG/MEG Activities: Phenomenology and Functional Significance Sleep EEG Phenomena Alpha Rhythms of Neocortex and Thalamus Beta/Gamma Activity of the Neocortex DC 30 4 Origin of the EEG/MEG II: Generators, Volume Conduction and Source Estimation 30 5 Localisation Methods Applied to Spontaneous Oscillatory Activities EEG-Correlated fmri 34 6 Conclusions. 34 Bibliografische Informationen digitalisiert durch

2 x Contents 3 The Basics of Functional Magnetic Resonance Imaging 39 Ralf Deichmann, Ulrike Nöth, and Nikolaus Weiskopf 1 The Basics of MR Imaging Spins in an External Magnetic Field The Magnetic Resonance Effect Spatial Encoding in MR Imaging Relaxation Times Tl andt Gradient Echoes and the Relaxation Time T2* k-space Echo Planar Imaging (EPI) Spin Echoes The Specific Absorption Rate (SAR) 49 2 The Cerebral Blood Flow (CBF) Definition, Order of Magnitude, Measurement Arterial Spin Labelling Measurements Labelling Methods Quantification Problems in ASL 53 3 The Cerebral Blood Volume (CBV) Definition, Order of Magnitude, Measurement Contrast Agent-Based Methods Contrast Agent-Free Method: Vascular Space Occupancy Measurement 56 4 The BOLD Effect and Functional MRI 57 4 Locally Measured Neuronal Correlates of Functional MRI Signals 63 Amir Shmuel 1 Blood Oxygénation Level Dependent Functional MRI Signals 63 2 Synaptic Activity and Local Field Potentials; Spiking and Multiunit Activity 64 3 Neurophysiological Activity and fmri Signals: Time and Space 65 4 Neurophysiological Activity and fmri Signals: Amplitude and Reliability 66 5 The Driving Force of the Haemodynamic Response: Synaptic or Spiking Activity? 68 6 Neuronal Correlates of Negative Bold Responses 73 7 Neuronal Correlates of Spontaneous Fluctuations in fmri Signals 74 8 Neurovascular Coupling 75 9 Summary 78 5 What Can fmri Add to the ERP Story? 83 Christoph Mulert 1 Introduction 83 2 ERP Generator Localisation 85 3 The Inverse Problem of EEG 85

3 Contents xiü 4 Does fmri Help to Solve the Inverse Problem? 88 5 Further Aspects Serial Processing vs. Parallel and Reciprocal Network Activity Subcortical Processing 90 6 Conclusions 91 6 The Added Value of EEG-fMRI in Imaging Neuroscience 97 Rainer Goebel and Fabrizio Esposito 1 Introduction 97 2 The EEG-fMRI Integrated Source Space 98 3 Integration Strategies for EEG-fMRI Studies Illustration of the Integration of fmri and EEG in the Temporal Domain Illustration of the Integration of fmri and EEG in the Spatial Domain Discussion 108 Part II Technical and Methodological Aspects of Combined EEG-fMRI Experiments EEG Instrumentation and Safety 115 Philip J. Allen Abbreviations Introduction EEG Instrumentation Electrodes EEG Recording System RF Emissions Miscellaneous Factors Summary Safety Safety Limits Static Field Gradient Fields Eddy Currents RF Fields Implanted Electrodes Summary EEG Quality: Origin and Reduction of the EEG Cardiac-Related Artefact 135 Stefan Debener, Cornelia Kranczioch, and Ingmar Gutberiet 1 Introduction Characteristics of the Pulse Artefact Origin of the Pulse Artefact, Simulations and Modelling Reducing the Pulse Artefact Using Waveform Removal Approaches 142

4 xiv Contents 5 Removing the Pulse Artefact Using Spatial Pattern Removal Approaches Evaluation of Pulse Artefact Removal Approaches Conclusions EEG Quality: The Image Acquisition Artefact 153 Petra Ritter, Robert Becker, Frank Freyer, and Arno Villringer Abbreviations Origin of the Image Acquisition Artefact Characteristics of the Image Acquisition Artefact Avoiding Image Acquisition Artefacts: Interleaved EEG-fMRI Protocols Reduction of Image Acquisition Artefacts Reduction at the Source Synchronisation of EEG and fmri Data Acquisitions Correction of the Image Acquisition Artefact Using EEG Post-Processing Artefact Template Subtraction Computing and Correcting Timing Errors Temporal Principal Component Analysis Independent Component Analysis Filtering in the Frequency Domain Evaluation of Correction Methods Image Quality Issues 173 David Carmichael 1 fmri Pulse Sequences GE-EPI Image Blurring Geometric Distortion Signal Dropout Image Ghosting RF Interference Other Sources of Image Artefact in fmri Bulk Head Motion Physiological Noise The Impact of EEG Recording on MR Image Quality Main Static Magnetic Field (B o ) Effects Transverse Rotational Magnetic Field (B,) Effects Impact on SNR fmri Quality Assurance (QA) Quantification of SNR and Temporal SNR The Weisskoff Test Coherent Noise Testing Summary and Conclusions 194

5 Contents xv 11 Specific Issues Related to EEG-fMRI at ß 0 > 3 T 201 Giorgio Bonmassar and Karen J. Mullinger 1 Introduction Safety Considerations Physical Principles and Relevant Safety Guidelines Safety Studies at High Fields EEG Recording and Quality Pulse-Related Artifact Other Noise Sources at High Field Image Quality Example of an Application of EEG-fMRI at 7 T: Auditory Steady State Response (ASSR) Conclusions 211 Appendix 1 : The Multidimensional Kalman Adaptive Filtering Method 212 Appendix 2: The Open Hardware and Software Project. The High-Field One System for Real-Time EEG-fMRI 214 Main Design Features Experimental Design and Data Analysis Strategies 221 Christian-G. Bénar, Andrew P. Bagshaw, and Louis Lemieux 1 Introduction Data Acquisition and Experimental Design Interleaved EEG and fmri Acquisitions: Triggered and Sparse Scanning Simultaneous EEG and fmri Acquisitions: Continuous Scanning Experimental Protocol Analysis of Simultaneously Acquired EEG-fMRI Data Model-Based Analysis of fmri Time-Series Data EEG-Derived GLM: Use of Event Onsets and Illustration in Epilepsy EEG-Derived GLM: Parametric Design and Single Trial EEG-Derived GLM: EEG Spectrum Multivariate Analysis EEG and fmri Localisation: Modes of Integration Comparison of Independently Derived Results fmri as a Spatial Constraint for EEG Source Reconstruction Towards Symmetrical Models of EEG and fmri Fusion Unresolved Problems and Caveats Relationship Between Neuronal Activity, EEG and fmri Signals Specific Issues Related to Spontaneous Brain Activity The Impact of Data Acquisition and Processing Artefacts on fmri Data Analysis Summary and Outlook 247

6 xvi Contents Part III Applications of EEG-fMRI 259 Resting State Brain Rhythms 263 Helmut Laufs 1 Considerations for the Study of Rest Why Study the Resting State? A Multimodal Approach to the Resting State From Unimodal to Multimodal Studies of Rest Endogenous Brain Oscillations in Healthy Subjects Similar Electrical Oscillations, Different fmri Networks Similar fmri Networks, Different Electrical Oscillations Brain Oscillations and Networks During Sleep Endogenous Brain Oscillations in Patients with Epilepsy Linking Neuronal Oscillations to Haemodynamic Changes Conclusion Sleep 279 Michael Czisch and Renate Wehrle Abbreviations FMRI in Sleep Research Sleep Imaging Sleep EEG and fmri in Sleep Research fmri During Sleep: Technical Challenges General Issues with Sleep fmri More Specific Issues with Sleep fmri Possible Solutions FMRI in Sleep: Results Spontaneous Sleep Sensory Processing During Sleep Animal Data Summary and Outlook 301 Epilepsy EEG-fMRI in Adults with Focal Epilepsy 309 Matthew C. Walker, Umair J. Chaudhary, and Louis Lemieux 1 Introduction Interictal EEG-fMRI What Is an Interjetai Spike? Interictal Epileptiform Activity in Presurgical Assessment Methodology 313

7 Contents xvü 2.4 Relevance of the Observed BOLD Changes Clinical Utility The Influence of Lesions letal EEG-fMRI Limitations of letal EEG-fMRI Detection of letal Activity General Linear Model Building Application of letal EEG-fMRI Conclusions EEG-fMRI in Idiopathic Generalised Epilepsy (Adults) 333 Patrick Carney and Graeme Jackson 1 Idiopathic Generalised Epilepsy Definition and Classification The EEG in Idiopathic Generalised Epilepsy Mechanisms of Generalised Spike and Wave in Idiopathic Generalised Epilepsy EEG-fMRI in Human IGE Early EEG-fMRI Studies Overview of EEG-fMRI Data Structures and Networks: Future Directions for EEG-fMRI in IGE Conclusion EEG-fMRI in Children with Epilepsy 349 Michael Siniatchkin and Francois Dubeau Abbreviations EEG-fMRI in Children with Epilepsy Methodological Issues Specific to Paediatric EEG-fMRI Studies Patient Selection and Scanning Modelling IED-Related BOLD Changes in Children: Variability and Developmental Changes Results of EEG-fMRI Studies in Paediatric Epilepsy Idiopathic Focal Epilepsies Symptomatic and Cryptogenic Focal Epilepsies Epileptic Encephalopathies Idiopathic Generalised Epilepsies 358 Activation Studies Combining EEG and fmri in Pain Research 365 G.D. Iannetti and A. Mouraux 1 Introduction Combining EEG and fmri in Pain Research: General Issues Combining EEG and fmri in Pain Research: Practical Issues 370

8 xviji Contents 3.1 Selectivity of the Nociceptive Input in EEG-fMRI Studies Delivery of Nociceptive Stimuli in the EEG-fMRI Environment Experimental Design Studies Combining EEG and fmri in Pain Research Future Directions: EEG-Driven Analysis of fmri BOLD Responses to Nociceptive Stimulation Single-Trial Estimation of the Magnitude of Stimulus-Evoked EEG Responses Correlation Between EEG and fmri Responses at Single-Trial Level Simultaneous EEG and fmri of the Human Auditory System 385 Christoph S. Herrmann, Andre Brechmann, and Henning Scheich 1 Introduction Specifics of Auditory Recordings Interference of the Static Magnetic Field Interference of Transient Magnetic Fields BOLD Response to Scanner Noise Sparse Sampling Silent fmri Acquisition Adjusting Auditory Stimulus Frequencies Simultaneous EEG and fmri in Auditory Experiments Low-Noise fmri Sequences for Simultaneous Experiments Conclusions Visual System 401 Robert Becker, Petra Ritter, and Arno Villringer 1 Simultaneous EEG-fMRI of the Visual System: Signal Quality fmri-informed EEG of the Visual System Localising Visual Evoked Potentials Visual Attention and Other Cognitive Processes EEG-Informed fmri of the Visual System Spontaneous EEG Oscillations Task-Related EEG Activity Uninformed EEG-fMRI and Other Approaches Event-Related Oscillations Visual Attention and Other Cognitive Processes Investigating Neurovascular Coupling in the Visual System by EEG-fMRI Outlook 413

9 Contents xix 21 Cognition 419 Susanne Karch and Christoph Mulert 1 Advantages and Disadvantages of Simultaneous EEG-fMRI Recordings of Cognitive Functions Cognitive Functions Attention Executive Functions Memory Limitations and Outlook 439 Special Topics Neuronal Models for EEG-fMRI Integration 453 James M. Kilner and Karl J. Friston 1 EEG and fmri Integration Neuronal Model of EEG-fMRI Integration Dimensional Analysis Modelling Activations Effect of Neuronal Activation on BOLD Effect of Neuronal Activation on EEG Empirical Evidence for the Model Summary BOLD Response and EEG Gamma Oscillations 465 Gregor Leicht, Christoph S. Herrmann, and Christoph Mulert 1 Introduction Methodical Issues Gamma Activity and BOLD Response Co-variation of High-Frequency Oscillations and the BOLD Signal Gamma Activity and BOLD Response: Variation Across Subjects Gamma Activity and BOLD Response: Further Reports Outlook: Single-Trial Coupling of Gamma Activity and BOLD Response Conclusions EEG-fMRI in Animal Models 485 Damien J. Ellens and Hal Blumenfeld 1 Introduction 485

10 хх Contents 2 Advantages of EEG-fMRI in Animal Models Limitations and Technical Challenges of EEG-fMRI in Animal Models Anaesthesia Movement: Curarisation and Habituation Physiology MR-Compatible Electrodes EEG Artefacts and Artefact Removal Data Analysis Applications of Simultaneous EEG-fMRI in Animals Epilepsy Absence Seizure Models Generalised Tonic-Clonic Seizure Models Partial Seizure Models Sleep Sensorimotor Stimulation Models The Electrophysiological Substrates of the BOLD Effect: Simultaneous Microelectrode EEG Recordings and fmri Future Directions Conclusions EEG-fMRI Information Fusion: Biophysics and Data Analysis 511 Jean Daunizeau, Helmut Laufs, and Karl J. Friston 1 Introduction EEG-fMRI Information Fusion: Limitations Neurovascular Coupling and Decoupling Experimental Limitations EEG-fMRI Information Fusion: Solutions Information Fusion: Definition Asymmetrical vs. Symmetrical Approaches EEG to fmri Approaches fmri to EEG Approaches Towards Symmetrical EEG-fMRI Approaches Conclusion 522 Outlook 527 Index 529