15 Bioelectronics and Joseph D. Bronzino finity College/Biomedical Allience Instruments for Central Connecticut(BOACON) Edward J. Berbari Purdue University 115.1 The Electroencephalogram Philip L. Johnson Recording Techniques Frequency Analysis of the EEG University of Alabama at Nonlinear Analysis of the EEG. Topographic Mapping 115.2 The Electrocardiograph William M. smith Physiology. Instrumentation.Conclusions University of Alabama at 115.3 Pacemakers/Implantable Defibrillators Pacemakers. Implantable Cardioverter Defibrillators 115.1 The Electroencephalogram Joseph d. bronzino Electroencephalograms(EEGs)are recordings of the minute (generally less than 300 uV) electrical potential produced by the brain. Since 1924, when Hans Berger reported the measurements of rhythmic electrical activit the neuronal bases for specific behaviors and has offered great promise to reveal correlations between patha a on the human scalp, it has been suggested that these patterns of bioelectrical origin may provide clues regard logical processes and the electrical activity of specific regions of the brain. Over the years, EEG analyses have been conducted primarily in clinical settings, to detect gross organic pathologies and the epilepsies, and in research facilities to quantify the central effect of new pharmacological agents. As a result of these efforts, cortical EEG patterns have been shown to be modified by a wide variety of variables including biochemical, metabolic, circulatory, hormonal, neuroelectric, and behavioral factors. In the past, interpretation of the EEG was limited to visual inspection by a trained electroencephalographer capable of distinguishing normal activity from localized or generalized abnormalities of particular types from relatively long EEG records. This approach has left clinicians and researchers alike lost in a sea of EEG paper records. Computer technology has permitted the application of a host of methods to quantify EEG changes. With this mind, this section provides an introduction to some of the basic concepts underlying the generation of the EEG, a review of the basic approaches used in quantifying alterations in the EEG, and some insights regarding quantitative electrophysiology techniques The Language of the Brain The mass of brain tissue is composed of bundles of nerve cells(neurons) which constitute the fundamental uilding blocks of the nervous system. Figure 115. 1 is a schematic drawing of just such a cell. It consists of the cell body (or soma), the receptor zone(or dendrites), and the axon, which carries electrical signals from the soma to target sites such as muscles, glands, or other neurons. Numbering approx imately 20 billion in each human being, these tiny cells come in a variety of sizes and shapes. Although neurons are anatomically distinct units having no physical continuity between their processes, the axon ends on the as a spherical enlargement at the end of the axon to whis synapse. Under the microscope this often stands out soma and the dendrites of other cells in what is called a various names have been given, for example, boutons, c 2000 by CRC Press LLC© 2000 by CRC Press LLC 115 Bioelectronics and Instruments 115.1 The Electroencephalogram The Language of the Brain • Historical Perspective • EEG Recording Techniques • Frequency Analysis of the EEG • Nonlinear Analysis of the EEG • Topographic Mapping 115.2 The Electrocardiograph Physiology • Instrumentation • Conclusions 115.3 Pacemakers/Implantable Defibrillators Pacemakers • Implantable Cardioverter Defibrillators 115.1 The Electroencephalogram Joseph D. Bronzino Electroencephalograms (EEGs) are recordings of the minute (generally less than 300 µV) electrical potentials produced by the brain. Since 1924, when Hans Berger reported the measurements of rhythmic electrical activity on the human scalp, it has been suggested that these patterns of bioelectrical origin may provide clues regarding the neuronal bases for specific behaviors and has offered great promise to reveal correlations between patho￾logical processes and the electrical activity of specific regions of the brain. Over the years, EEG analyses have been conducted primarily in clinical settings, to detect gross organic pathologies and the epilepsies, and in research facilities to quantify the central effect of new pharmacological agents. As a result of these efforts, cortical EEG patterns have been shown to be modified by a wide variety of variables including biochemical, metabolic, circulatory, hormonal, neuroelectric, and behavioral factors. In the past, interpretation of the EEG was limited to visual inspection by a trained electroencephalographer capable of distinguishing normal activity from localized or generalized abnormalities of particular types from relatively long EEG records. This approach has left clinicians and researchers alike lost in a sea of EEG paper records. Computer technology has permitted the application of a host of methods to quantify EEG changes. With this in mind, this section provides an introduction to some of the basic concepts underlying the generation of the EEG, a review of the basic approaches used in quantifying alterations in the EEG, and some insights regarding quantitative electrophysiology techniques. The Language of the Brain The mass of brain tissue is composed of bundles of nerve cells (neurons) which constitute the fundamental building blocks of the nervous system. Figure 115.1 is a schematic drawing of just such a cell. It consists of three major components: the cell body (or soma), the receptor zone (or dendrites), and the axon, which carries electrical signals from the soma to target sites such as muscles, glands, or other neurons. Numbering approx￾imately 20 billion in each human being, these tiny cells come in a variety of sizes and shapes. Although neurons are anatomically distinct units having no physical continuity between their processes, the axon ends on the soma and the dendrites of other cells in what is called a synapse. Under the microscope this often stands out as a spherical enlargement at the end of the axon to which various names have been given, for example, boutons, Joseph D. Bronzino Trinity College/Biomedical Allience for Central Connecticut (BOACON) Edward J. Berbari Purdue University Philip L. Johnson University of Alabama at Birmingham William M. Smith University of Alabama at Birmingham