Contents
0 1 I 2 3 4 5 6 II 7 8 9 10 III 11 12 IV 13 14 V 15 16 17 18 19 20 VI 21 22 VII 23 24 VIII 25 26 27 IX 28 APP A B N S
_________________________________ INFO UPDATING ERRATA EXERCISES _________________________________ TITLE PAGE DEDICATION PREFACE CONTENTS SYMBOLS AND UNITS ABBREVIATIONS PHYSICAL CONSTANTS 1 INTRODUCTION 1.1 THE CONCEPT OF BIOELECTROMAGNETISM 1.2 SUBDIVISIONS OF BIOELECTROMAGNETISM 1.2.1 Division on a theoretical basis 1.2.2 Division on an anatomical basis 1.2.3 Organization of this textbook 1.3 IMPORTANCE OF BIOELECTROMAGNETISM 1.4 SHORT HISTORY OF BIOELECTROMAGNETISM 1.4.1 The first written documents and first experiments in bioelectromagnetism 1.4.2 Electric and magnetic stimulation 1.4.3 Detection of bioelectric activity 1.4.4 Modern electrophysiological studies of neural cells 1.4.5 Bioelectromagnetism 1.4.6 Theoretical contributions to bioelectromagnetism 1.4.7 Summary of the history of bioelectromagnetism 1.5 NOBEL PRIZES IN BIOELECTROMAGNETISM PART I ANATOMICAL AND PHYSIOLOGICAL BASIS OF BIOELECTROMAGNETISM 2 ANATOMY AND PHYSIOLOGY OF NERVE AND MUSCLE CELLS 2.1 INTRODUCTION 2.2 NERVE CELL 2.2.1 The main parts of the nerve cell 2.2.2 The cell membrane 2.2.3 The synapse 2.3 MUSCLE CELL 2.4 BIOELECTRIC FUNCTION OF THE NERVE CELL 2.5 EXCITABILITY OF NERVE CELL 2.6 THE GENERATION OF THE ACTIVATION 2.7 CONCEPTS ASSOCIATED WITH THE ACTIVATION PROCESS 2.8 CONDUCTION OF THE NERVE IMPULSE IN AN AXON 3 SUBTHRESHOLD MEMBRANE PHENOMENA 3.1 INTRODUCTION 3.2 NERNST EQUATION 3.2.1 Electric potential and electric field 3.2.2 Diffusion 3.2.3 Nernst-Planck equation 3.2.4 Nernst potential 3.3 ORIGIN OF THE RESTING VOLTAGE 3.4 MEMBRANE WITH MULTI-ION PERMEABILITY 3.4.1 Donnan equilibrium 3.4.2 The value of the resting-voltage Goldman-Hodgkin-Katz equation 3.4.3 The reversal voltage 3.5 ION FLOW THROUGH THE MEMBRANE 3.5.1 Factors affecting ion transport through the membrane 3.5.2 Membrane ion flow in a cat motoneuron 3.5.3 Na-K pump 3.5.4 Graphical illustration of the membrane ion flow 3.6 CABLE EQUATION OF THE AXON 3.6.1 Cable model of the axon 3.6.2 The steady-state response 3.6.3 Stimulation with a step-current impulse 3.7 STRENGTH-DURATION RELATION 4 ACTIVE BEHAVIOR OF THE MEMBRANE 4.1 INTRODUCTION 4.2 VOLTAGE-CLAMP METHOD 4.2.1 Goal of the voltage-clamp measurement 4.2.2 Space clamp 4.2.3 Voltage clamp 4.3 EXAMPLES OF RESULTS OBTAINED WITH THE VOLTAGE-CLAMP METHOD 4.3.1 Voltage clamp to sodium Nernst voltage 4.3.2 Altering the ion concentrations 4.3.3 Blocking of ionic channels with pharmaceuticals 4.4 HODGKIN-HUXLEY MEMBRANE MODEL 4.4.1 Introduction 4.4.2 Total membrane current and its components 4.4.3 Potassium conductance 4.4.4 Sodium conductance 4.4.5 Hodgkin-Huxley equations 4.4.6 Propagating nerve impulse 4.4.7 Properties of the Hodgkin-Huxley model 4.4.8 The quality of the Hodgkin-Huxley model 4.5 PATCH-CLAMP METHOD 4.5.1 Introduction 4.5.2 Patch clamp measurement techniques 4.5.3 Applications of the patch-clamp method 4.6 MODERN UNDERSTANDING OF THE IONIC CHANNELS 4.6.1 Introduction 4.6.2 Single-channel behavior 4.6.3 The ionic channel 4.6.4 Channel structure: biophysical studies 4.6.5 Channel structure: studies in molecular genetics 4.6.6 Channel structure: imaging methods 4.6.7 Ionic conductance based on single-channel conductance 5 SYNAPSE, RECEPTOR CELLS, AND BRAIN 5.1 INTRODUCTION 5.2 SYNAPSES 5.2.1 Structure and function of the synapse 5.2.2 Excitatory and inhibitory synapses 5.2.3 Reflex arc 5.2.4 Electric model of the synapse 5.3 RECEPTOR CELLS 5.3.1 Introduction 5.3.2 Various types of receptor cells 5.3.3 The Pacinian corpuscle 5.4 ANATOMY AND PHYSIOLOGY OF THE BRAIN 5.4.1 Introduction 5.4.2 Brain anatomy 5.4.3 Brain function 5.5 CRANIAL NERVES 6 THE HEART 6.1 ANATOMY AND PHYSIOLOGY OF THE HEART 6.1.1 Location of the heart 6.1.2 The anatomy of the heart 6.2 ELECTRIC ACTIVATION OF THE HEART 6.2.1 Cardiac muscle cell 6.2.2 The conduction system of the heart 6.3 THE GENESIS OF THE ELECTROCARDIOGRAM 6.3.1 Activation currents in cardiac tissue 6.3.2 Depolarization wave 6.3.3 Repolarization wave PART II BIOELECTRIC SOURCES AND CONDUCTORS AND THEIR MODELING 7 VOLUME SOURCE AND VOLUME CONDUCTOR 7.1 THE CONCEPTS OF VOLUME SOURCE AND VOLUME CONDUCTOR 7.2 BIOELECTRIC SOURCE AND ITS ELECTRIC FIELD 7.2.1 Definition of the preconditions 7.2.2 Volume source in a homogeneous volume conductor 7.2.3 Volume source in an inhomogeneous volume conductor 7.2.4 Quasistatic conditions 7.3 THE CONCEPT OF MODELING 7.3.1 The purpose of modeling 7.3.2 Basic models of the volume source 7.3.3 Basic models of the volume conductor 7.4 THE HUMAN BODY AS A VOLUME CONDUCTOR 7.4.1 Tissue resistivities 7.4.2 Modeling the head 7.4.3 Modeling the thorax 7.5 FORWARD AND INVERSE PROBLEM 7.5.1 Forward problem 7.5.2 Inverse problem 7.5.3 Solvability of the inverse problem 7.5.4 Possible approaches to the solution of the inverse problem 7.5.5 Summary 8 SOURCE-FIELD MODELS 8.1 INTRODUCTION 8.2 SOURCE MODELS 8.2.1 Monopole 8.2.2 Dipole 8.2.3 Single isolated fiber: transmembrane current source 8.2.4 Discussion of transmembrane current source 8.3 EQUIVALENT VOLUME SOURCE DENSITY 8.3.1 Equivalent monopole density 8.3.2 Equivalent dipole density 8.3.3 Lumped equivalent sources: Tripole model 8.3.4 Mathematical basis for double-layer source (uniform bundle) 8.4 RIGOROUS FORMULATION 8.4.1 Field of a single cell of arbitrary shape 8.4.2 Field of an isolated cylindrical fiber 8.5 MATHEMATICAL BASIS FOR MACROSCOPIC VOLUME SOURCE DENSITY (FLOW SOURCE DENSITY) AND IMPRESSED CURRENT DENSITY 8.6 SUMMARY OF THE SOURCE-FIELD MODELS 9 BIDOMAIN MODEL OF MULTICELLULAR VOLUME CONDUCTORS 9.1 INTRODUCTION 9.2 CARDIAC MUSCLE CONSIDERED AS A CONTINUUM 9.3 MATHEMATICAL DESCRIPTION OF THE BIDOMAIN AND ANISOTROPY 9.4 ONE-DIMENSIONAL CABLE: A ONE-DIMENSIONAL BIDOMAIN 9.5 SOLUTION FOR POINT-CURRENT SOURCE IN A THREE-DIMENSIONAL, ISOTROPIC BIDOMAIN 9.6 FOUR-ELECTRODE IMPEDANCE METHOD APPLIED TO AN ISOTROPIC BIDOMAIN 10 ELECTRONIC NEURON MODELS 10.1 INTRODUCTION 10.1.1 Electronic modeling of excitable tissue 10.1.2 Neurocomputers 10.2 CLASSIFICATION OF NEURON MODELS 10.3 MODELS DESCRIBING THE FUNCTION OF THE MEMBRANE 10.3.1 The Lewis membrane model 10.3.2 The Roy membrane model 10.4 MODELS DESCRIBING THE CELL AS AN INDEPENDENT UNIT 10.4.1 The Lewis neuron model 10.4.2 The Harmon neuron model 10.5 A MODEL DESCRIBING THE PROPAGATION OF ACTION PULSE IN AXON 10.6 INTEGRATED CIRCUIT REALIZATIONS PART III THEORETICAL METHODS IN BIOELECTROMAGNETISM 11 THEORETICAL METHODS FOR ANALYZING VOLUME SOURCES AND VOLUME CONDUCTORS 11.1 INTRODUCTION 11.2 SOLID-ANGLE THEOREM 11.2.1 Inhomogeneous double layer 11.2.2 Uniform double layer 11.3 MILLER-GESELOWITZ MODEL 11.4 LEAD VECTOR 11.4.1 Definition of the lead vector 11.4.2 Extending the concept of lead vector 11.4.3 Example of lead vector applications: Einthoven, Frank, and Burger triangles 11.5 IMAGE SURFACE 11.5.1 The definition of the image surface 11.5.2 Points located inside the volume conductor 11.5.3 Points located inside the image surface 11.5.4 Application of the image surface to the synthesis of leads 11.5.5 Image surface of homogeneous human torso 11.5.6 Recent image-surface studies 11.6 LEAD FIELD 11.6.1 Concepts used in connection with lead fields 11.6.2 Definition of the lead field 11.6.3 Reciprocity theorem: the historical approach 11.6.4 Lead field theory: the historical approach 11.6.5 Field-theoretic proof of the reciprocity theorem 11.6.6 Summary of the lead field theory equations 11.6.7 Ideal lead field of a lead detecting the equivalent electric dipole of a volume source 11.6.8 Application of lead field theory to the Einthoven limb leads 11.6.9 Synthesization of the ideal lead field for the detection of the electric dipole moment of a volume source 11.6.10 Special properties of electric lead fields 11.6.11 Relationship between the image surface and the lead field 11.7 GABOR-NELSON THEOREM 11.7.1 Determination of the dipole moment 11.7.2 The location of the equivalent dipole 11.8 SUMMARY OF THE THEORETICAL METHODS FOR ANALYZING VOLUME SOURCES AND VOLUME CONDUCTORS 12 THEORY OF BIOMAGNETIC MEASUREMENTS 12.1 BIOMAGNETIC FIELD 12.2 NATURE OF THE BIOMAGNETIC SOURCES 12.3 RECIPROCITY THEOREM FOR MAGNETIC FIELDS 12.3.1 The form of the magnetic lead field 12.3.2 The source of the magnetic field 12.3.3 Summary of the lead field theoretical equations for electric and magnetic measurements 12.4 THE MAGNETIC DIPOLE MOMENT OF A VOLUME SOURCE 12.5 IDEAL LEAD FIELD OF A LEAD DETECTING THE EQUIVALENT MAGNETIC DIPOLE OF A VOLUME SOURCE 12.6 SYNTHESIZATION OF THE IDEAL LEAD FIELD FOR THE DETECTION OF THE MAGNETIC DIPOLE MOMENT OF A VOLUME SOURCE 12.7 COMPARISON OF THE LEAD FIELDS OF IDEAL LEADS FOR DETECTING THE ELECTRIC AND THE MAGNETIC DIPOLE MOMENTS OF A VOLUME SOURCE 12.7.1 The bipolar lead system for detecting the electric dipole moment 12.7.2 The bipolar lead system for detecting the magnetic dipole moment 12.8 THE RADIAL AND TANGENTIAL SENSITIVITIES OF THE LEAD SYSTEMS DETECTING THE ELECTRIC AND MAGNETIC DIPOLE MOMENTS OF A VOLUME SOURCE 12.8.1 Sensitivity of the electric lead 12.8.2 Sensitivity of the magnetic lead 12.9 SPECIAL PROPERTIES OF THE MAGNETIC LEAD FIELDS 12.10 THE INDEPENDENCE OF BIOELECTRIC AND BIOMAGNETIC FIELDS AND MEASUREMENTS 12.10.1 Independence of flow and vortex sources 12.10.2 Lead field theoretic explanation of the independence of bioelectric and biomagnetic fields and measurements 12.11 SENSITIVITY DISTRIBUTION OF BASIC MAGNETIC LEADS 12.11.1 The equations for calculating the sensitivity distribution of basic magnetic leads 12.11.2 Lead field current density of a unipolar lead of a single-coil magnetometer 12.11.3 The effect of the distal coil 12.11.4 Lead field current density of a bipolar lead PART IV ELECTRIC AND MAGNETIC MEASUREMENT OF THE ELECTRIC ACTIVITY OF NEURAL TISSUE 13 ELECTROENCEPHALOGRAPY 13.1 INTRODUCTION 13.2 THE BRAIN AS A BIOELECTRIC GENERATOR 13.3 EEG LEAD SYSTEMS 13.4 SENSITIVITY DISTRIBUTION OF EEG ELECTRODES 13.5 THE BEHAVIOR OF THE EEG SIGNAL 13.6 THE BASIC PRINCIPLES OF EEG DIAGNOSIS 14 MAGNETOENCEPHALOGRAPHY 14.1 THE BRAIN AS A BIOMAGNETIC GENERATOR 14.2 SENSITIVITY DISTRIBUTION OF MEG-LEADS 14.2.1 Sensitivity calculation method 14.2.2 Single-coil magnetometer 14.2.3 Planar gradiometer 14.3 COMPARISON OF THE EEG AND MEG HALF-SENSITIVITY VOLUMES 14.4 SUMMARY PART V ELECTRIC AND MAGNETIC MEASUREMENT OF THE ELECTRIC ACTIVITY OF THE HEART 15 TWELVE-LEAD ECG SYSTEM 15.1 LIMB LEADS 15.2 ECG SIGNAL 15.2.1 The signal produced by the activation front 15.2.2 Formation of the ECG signal 15.3 WILSON CENTRAL TERMINAL 15.4 GOLDBERGER AUGMENTED LEADS 15.5 PRECORDIAL LEADS 15.6 MODIFICATIONS OF THE 12-LEAD SYSTEM 15.7 THE INFORMATION CONTENT OF THE 12-LEAD SYSTEM 16 VECTORCARDIOGRAPHIC LEAD SYSTEMS 16.1 INTRODUCTION 16.2 UNCORRECTED VECTORCARDIOGRAPHIC LEAD SYSTEMS 16.2.1 Monocardiogram by Mann 16.2.2 Lead systems based on rectangular body axes 16.2.3 Akulinichev VCG lead systems 16.3 CORRECTED VECTORCARDIOGRAPHIC LEAD SYSTEMS 16.3.1 Frank lead system 16.3.2 McFee-Parungao lead system 16.3.3 SVEC III lead system 16.3.4 Fischmann-Barber-Weiss lead system 16.3.5 Nelson lead system 16.4 DISCUSSION ON VECTORCARDIOGRAPHIC LEADS 16.4.1 The interchangeability of vectorcardiographic systems 16.4.2 Properties of various vectorcardiographic lead systems 17 OTHER ECG LEAD SYSTEMS 17.1 MOVING DIPOLE 17.2 MULTIPLE DIPOLES 17.3 MULTIPOLE 17.4 SUMMARY OF THE ECG LEAD SYSTEMS 18 DISTORTION FACTORS IN THE ECG 18.1 INTRODUCTION 18.2 EFFECT OF THE INHOMOGENEITY OF THE THORAX 18.3 BRODY EFFECT 18.3.1 Description of the Brody effect 18.3.2 Effect of the ventricular volume 18.3.3 Effect of the blood resistivity 18.3.4 Integrated effects (model studies) 18.4 EFFECT OF RESPIRATION 18.5 EFFECT OF ELECTRODE LOCATION 19 THE BASIS OF ECG DIAGNOSIS 19.1 PRINCIPLE OF THE ECG DIAGNOSIS 19.1.1 On the possible solutions to the cardiac inverse problem 19.1.2 Bioelectric principles in ECG diagnosis 19.2 APPLICATIONS OF ECG DIAGNOSIS 19.3 DETERMINATION OF THE ELECTRIC AXIS OF THE HEART 19.4 CARDIAC RHYTHM DIAGNOSIS 19.4.1 Differentiating the P, QRS. and T waves 19.4.2 Supraventricular rhythms 19.4.3 Ventricular arrhythmias 19.5 DISORDERS IN THE ACTIVATION SEQUENCE 19.5.1 Atrioventricular conduction variations 19.5.2 Bundle-branch block 19.5.3 Wolff-Parkinson-White syndrome 19.6 INCREASE IN WALL THICKNESS OR SIZE OF ATRIA AND VENTRICLES 19.6.1 Definition 19.6.2 Atrial hypertrophy 19.6.3 Ventricular hypertrophy 19.7 MYOCARDIAL ISCHEMIA AND INFARCTION 20 MAGNETOCARDIOGRAPHY 20.1 INTRODUCTION 20.2 BASIC METHODS IN MAGNETOCARDIOGRAPHY 20.2.1 Measurement of the equivalent magnetic dipole 20.2.2 The magnetic field-mapping method 20.2.3 Other methods of magnetocardiography 20.3 METHODS FOR DETECTING THE MAGNETIC HEART VECTOR 20.3.1 The source and conductor models and the basic form of the lead system for measuring the magnetic dipole 20.3.2 Baule-McFee lead system 20.3.3 XYZ lead system 20.3.4 ABC lead system 20.3.5 Unipositional lead system 20.4 SENSITIVITY DISTRIBUTION OF BASIC MCG LEADS 20.4.1 Heart- and thorax models and the magnetometer 20.4.2 Unipolar measurement 20.4.3 Bipolar measurement 20.5 GENERATION OF THE MCG SIGNAL FROM THE ELECTRIC ACTIVATION OF THE HEART 20.6 ECG-MCG RELATIONSHIP 20.7 CLINICAL APPLICATION OF MAGNETOCARDIOGRAPHY 20.7.1 Advantages of magnetocardiography 20.7.2 Disadvantages of magnetocardiography 20.7.3 Clinical application 20.7.4 Basis for the increase in diagnostic performance by biomagnetic measurement 20.7.5 General conclusions on magnetocardiography PART VI ELECTRIC AND MAGNETIC STIMULATION OF NEURAL TISSUE 21 FUNCTIONAL ELECTRIC STIMULATION 21.1 INTRODUCTION 21.2 SIMULATION OF EXCITATION OF A MYELINATED FIBER 21.3 STIMULATION OF AN UNMYELINATED AXON 21.4 MUSCLE RECRUITMENT 21.5 ELECTRODE-TISSUE INTERFACE 21.6 ELECTRODE MATERIALS AND SHAPES 22 MAGNETIC STIMULATION OF NEURAL TISSUE 22.1 INTRODUCTION 22.2 THE DESIGN OF STIMULATOR COILS 22.3 CURRENT DISTRIBUTION IN MAGNETIC STIMULATION 22.4 STIMULUS PULSE 22.5 ACTIVATION OF EXCITABLE TISSUE BY TIME-VARYING MAGNETIC FIELDS 22.6 APPLICATION AREAS OF MAGNETIC STIMULATION OF NEURAL TISSUE PART VII ELECTRIC AND MAGNETIC STIMULATION OF THE HEART 23 CARDIAC PACING 23.1 STIMULATION OF CARDIAC MUSCLE 23.2 INDICATIONS FOR CARDIAC PACING 23.3 CARDIAC PACEMAKER 23.3.1 Pacemaker principles 23.3.2 Control of impulses 23.3.3 Dual chamber multiprogrammable 23.3.4 Rate modulation 23.3.5 Anti-tachycardia/fibrillation 23.4 SITE OF STIMULATION 23.5 EXCITATION PARAMETERS AND CONFIGURATION 23.6 IMPLANTABLE ENERGY SOURCES 23.7 ELECTRODES 23.8 MAGNETIC STIMULATION OF CARDIAC MUSCLE 24 CARDIAC DEFIBRILLATION 24.1 INTRODUCTION 24.2 MECHANISMS OF FIBRILLATION 24.2.1 Reentry 24.2.2 Reentry with and without anatomic obstacles 24.3 THEORIES OF DEFIBRILLATION 24.3.1 Introduction 24.3.2 Critical mass hypothesis 24.3.3 One-dimensional activation/defibrillation model 24.4 DEFIBRILLATOR DEVICES PART VIII MEASUREMENT OF THE INTRINSIC ELECTRIC PROPERTIES OF BIOLOGICAL TISSUES 25 IMPEDANCE PLETHYSMOGRAPHY 25.1 INTRODUCTION 25.2 BIOELECTRIC BASIS OF IMPEDANCE PLETHYSMOGRAPHY 25.2.1 Relationship between the principles of impedance measurement and bioelectric signal measurement 25.2.2 Tissue impedance 25.3 IMPEDANCE CARDIOGRAPHY 25.3.1 Measurement of the impedance of the thorax 25.3.2 Simplified model of the impedance of the thorax 25.3.3 Determining changes in blood volume in the thorax 25.3.4 Determining the stroke volume 25.3.5 Discussion of the stroke volume calculation method 25.4 THE ORIGIN OF IMPEDANCE SIGNAL IN IMPEDANCE CARDIOGRAPHY 25.4.1 Model studies 25.4.2 Animal and human studies 25.4.3 Determining the systolic time intervals from the impedance 25.4.4 The effect of the electrodes 25.4.5 Accuracy of the impedance cardiography 25.5 OTHER APPLICATIONS OF IMPEDANCE PLETHYSMOGRAPHY 25.5.1 Peripheral blood flow 25.5.2 Cerebral blood flow 25.5.3 Intrathoracic fluid volume 25.5.4 Determination of body composition 25.5.5 Other applications 25.6 DISCUSSION 26 IMPEDANCE TOMOGRAPHY 26.1 INTRODUCTION 26.2 IMPEDANCE MEASUREMENT METHODS 26.2.1 Electric measurement of the impedance 26.2.2 Electromagnetic measurement of the electric impedance 26.3 IMAGE RECONSTRUCTION 27 THE ELECTRODERMAL RESPONSE 27.1 INTRODUCTION 27.2 PHYSIOLOGY OF THE SKIN 27.3 ELECTRODERMAL MEASURES 27.4 MEASUREMENT SITES AND CHARACTERISTIC SIGNALS 27.5 THEORY OF EDR 27.6 APPLICATIONS PART IX OTHER BIOELECTROMAGNETIC PHENOMENA 28 THE ELECTRIC SIGNALS ORIGINATING IN THE EYE 28.1 INTRODUCTION 28.2 THE ANATOMY AND PHYSIOLOGY OF THE EYE AND ITS NEURAL PATHWAYS 28.2.1 The major components of the eye 28.2.2 The retina 28.3 ELECTRO-OCULOGRAM 28.3.1 Introduction 28.3.2 Saccadic response 28.3.3 Nystagmography 28.4 ELECTRORETINOGRAM 28.4.1 Introduction 28.4.2 The volume conductor influence on the ERG 28.4.3 Ragnar Granit contribution APPENDIXES APPENDIX A CONSISTENT SYSTEM OF RECTANGULAR AND SPHERICAL COORDINATES FOR ELECTROCARDIOLOGY AND MAGNETOCARDIOLOGY A.1 INTRODUCTION A.2 REQUIREMENTS FOR A CONSISTENT SYSTEM OF COORDINATES A.3 ALIGNMENT OF THE COORDINATE SYSTEM WITH THE BODY A.4 CONSISTENT SPHERICAL COORDINATE SYSTEMS A.5 COMPARISON OF THE CONSISTENT COORDINATE SYSTEM AND THE AHA-SYSTEM A.6 RECTANGULAR ABC-COORDINATES APPENDIX B THE APPLICATION OF MAXWELL'S EQUATIONS IN BIOELECTROMAGNETISM B.1 INTRODUCTION B.2 MAXWELL'S EQUATIONS UNDER FREE SPACE CONDITIONS B.3 MAXWELL'S EQUATIONS FOR FINITE CONDUCTING MEDIA B.4 SIMPLIFICATION OF MAXWELL'S EQUATIONS IN PHYSIOLOGICAL PREPARATIONS B.5 MAGNETIC VECTOR POTENTIAL AND ELECTRIC SCALAR POTENTIAL IN THE REGION OUTSIDE THE SOURCES B.6 STIMULATION WITH ELECTRIC AND MAGNETIC FIELDS B.6.1 Stimulation with electric field B.6.2 Stimulation with magnetic field B.7 SIMPLIFIED MAXWELL'S EQUATIONS IN PHYSIOLOGICAL PREPARATIONS IN THE REGION OUTSIDE THE SOURCES NAME INDEX SUBJECT INDEX