i To be published by MIT Press (Some additional revisions are possible before publication) An Introduction to the Event-Related Potential Technique Steven J. Luck The University of Iowa ii Table of Contents Preface............................................................................................................................................................................................................v Acknowledgments ..................................................................................................................................................................................... viii Chapter 1- An Introduction to Event-Related Potentials and Their Neural Origins...................................................................................1 Overview...................................................................................................................................................................................................1 Goals and Perspective...............................................................................................................................................................................1 A Bit of History ........................................................................................................................................................................................1 A Simple Example Experiment................................................................................................................................................................3 A Real Experiment ...................................................................................................................................................................................4 Reliability of ERP Waveforms.................................................................................................................................................................5 Advantages and Disadvantages of the ERP Technique ..........................................................................................................................6 Comparison with Behavioral Measures..............................................................................................................................................6 Comparison with Other Physiological Measures ...............................................................................................................................7 Choosing the Right Questions.............................................................................................................................................................8 The Neural Origins of ERPs.....................................................................................................................................................................8 Basic Electrical Concepts....................................................................................................................................................................8 Electrical Activity in Neurons.............................................................................................................................................................8 Summation of Postsynaptic Potentials................................................................................................................................................8 Volume Conduction.............................................................................................................................................................................9 Magnetic Fields....................................................................................................................................................................................9 ERP Localization...............................................................................................................................................................................10 A Summary of Major ERP Components ...............................................................................................................................................10 Visual Sensory Responses.................................................................................................................................................................10 Auditory Sensory Responses.............................................................................................................................................................11 Somatosensory, Olfactory, and Gustatory Responses......................................................................................................................12 The N2 Family...................................................................................................................................................................................12 The P3 Family....................................................................................................................................................................................12 Language-Related ERP Components................................................................................................................................................13 Error Detection ..................................................................................................................................................................................14 Response-Related ERP Components ................................................................................................................................................14 Suggestions for Further Reading............................................................................................................................................................15 Text Boxes ..............................................................................................................................................................................................15 Text Box 1.1: Which Way is Up?.....................................................................................................................................................15 Text Box 1.2: Component Naming Conventions .............................................................................................................................16 Chapter 2- The Design and Interpretation of ERP Experiments................................................................................................................22 Overview.................................................................................................................................................................................................22 Waveform Peaks Versus Latent ERP Components...............................................................................................................................22 Voltage Peaks are not Special ...........................................................................................................................................................22 Peak Shapes are not the Same as Component Shapes......................................................................................................................22 Distortions Caused by Averaging .....................................................................................................................................................23 What is an ERP Component?.................................................................................................................................................................23 Avoiding Ambiguities in Interpreting ERP Components .....................................................................................................................25 Avoiding Confounds and Misinterpretations.........................................................................................................................................26 Examples from the Literature.................................................................................................................................................................29 Example 1: Auditory Selective Attention.........................................................................................................................................29 Example 2: Partial Information Transmission..................................................................................................................................30 Example 3: Dual-Task Performance.................................................................................................................................................32 Suggestions for Further Reading............................................................................................................................................................34 Summary of Rules, Principles, and Strategies.......................................................................................................................................35 Text Boxes ..............................................................................................................................................................................................35 Text Box 2.1: Examples of Subtle Confounds .................................................................................................................................35 Text Box 2.2: My Favorite ERP Component ...................................................................................................................................36