THE DOMINANT FOCUS Electrophysiologicallnvestigations

Transcription

1 THE DOMINANT FOCUS Electrophysiologicallnvestigations

2 Neuropsychology A Series of Special Research Reports Under the Editorship of A. R. Luria 1972 THE BRAIN AND HEARING: Hearing Disturbances Associated with Local Brain Lesions A. v. Baru and T. A. Karaseva 1973 THE DOMINANT FOCUS: Electrophysiological Investigations V. S. Rusinov

3 THE DOMINANT FOCUS Electrophysiological Investigations v. s. Rusinov Institute tor Higher Nervous Activity and Neurophysiology Academy of Sciences of the USSR Moscow, USSR Translated from Russian by Basil Haigh Translation Editor Robert W. Doty Center tor Brain Research Medical Center, University of Rochester Rochester, New York Springer Science+Business Media, LLC 1973

4 The original Russian text published in Moscow in 1969 by Meditsina Press, has been corrected and revised by the author for this edition. The translation is published under an agreement with Mezhdunarodnaya Kniga, the Soviet book export agency. DOMINANTA: ELEKTROFIZIOLOGICHESKIE ISSLEDOVANIYA Vladimir Sergeevich Rusinov ~OMlIHAHTA 3HeKTpo~H3BOHOrBqeCKBe HccHeAoBaHuR BAaouMup CepzeeBu't PYCUHOB ISBN DOI / ISBN (ebook) Library of Congress Catalog Card Number ISBN Springer Science+Business Media New York Originally published by Consultants Bureau, New York in 1973 Softcover reprint of the hardcover 1 st edition 1973 AII rights reserved No part of this publication may be reproduced in any form without written permission from the publisher

5 Preface This book describes an electrophysiological investigation of foci of excitation in the central nervous system of animals and man, foci which become dominant in character. The dominant focus, or dominant as it is usually called by Russian physiologists, is one of the fundamental processes underlying the activity of the central nervous system. The discovery of the mechanisms of formation of dominant foci is important for a deeper understanding of the activity of the human and animal brain and for identifying the pathophysiological mechanisms in lesions of the nervous system. The book summarizes the results of many years of investigation, both experimental and clinical, into the nature and properties of foci of excitation arising at different levels of the central nervous system. A brief survey of the literature on Ukhtomskii's theory of the dominant is given in Chapter I and the present state of this theory is reviewed. The other chapters of the book deal with the results of research in the field of dominant foci undertaken in the author's laboratory. The experimental data relating to changes in the level of the steady cortical potential during the formation of the dominant focus and conditioned reflex are examined. The results obtained by polarization of the cortex with a weak direct current in order to form a dominant focus, and also by polarization of the reticular system of the brain stem and specific and nonspecific nuclei of the thalamus and hypothalamus are given. Electrophysiological studies of the character of excitation in dominant foci, and the relationships between cortical foci of excitation and foci of excitation induced experimentally in various subcortical structures are dev

6 vi PREFACE scribed. The author submits a working hypothesis on mechanisms of dominant formation based on electrophysiological findings and on conversion of the dominant focus into a "temporary connection" as seen in conditioned reflexes. Much attention is paid to experimental data on excitation traces associated with the dominant focus and their possible significance for mnemonic mechanisms. The results of electrophysiological investigations of foci of excitation in healthy subjects and in patients with organic brain lesions are examined, with particular reference to the dynamics of changes in evoked responses in man. Results obtained by auto- and cross-correlation analysis of the electrical activity of the human and animal brain in the presence of foci of excitation are also examined. The book is intended for medical scientists, biologists, physiologists, biophysicists, and workers in other specialties interested in neural processes. It could also serve as additional reading for advanced students of medicine and biology.

7 Contents Chapter I. Foci of Excitation and Conditions for Their Conversion into Dominant Foci 1. A brief historical survey The summation reflex and the dominant The swallowing dominant. Two foci of excitation with rhythmic action in the central nervous system Disinhibition of the dominant The swallowing dominant and conditioned reflex Impgrtance of the time factor Wenckebach periods in the rhythmic activity of the focus of excitation Interaction between a cortical focus of excitation and the swallowing center Foci of excitation induced by strychnine in subcortical structures A focus of excitation in the visual cortex Corticofugal influences from foci of excitation Chapter II. The Problem of Stationary Excitation and Changes in the Cortical Steady Potential during the Formation of Dominant Foci and Temporary Connections 1. Two approaches to the theory of excitation Slow long-lasting potentials in the cortex Interaction of slow potentials with evoked responses and dendritic potentials Hypotheses on the genesis of slow electrical potentials vii

8 viii CONTENTS 5. Infraslow rhythmic potentials The problem of stationary excitation Slow potentials in the cortex during defensive conditioning Long-lasting depolarization of the single neuron.. 56 Chapter ill. A Model of the Cortical Dominant Focus Produced by Weak, Steady Current 1. Polarization of the rabbit motor cortex by steady current Conversion of the dominant into inhibition; the double strength optimum of the direct current Trace phenomena associated with the dominant focus and memory Foci of excitation in the central nervous system evoked by a pulsating current. Pavlygina's experiments ' Chapter IV. Diffuse Effects in the Central Nervous System. The Reticular Formation and the Dominant Focus 1. The data of classical physiology on diffuse effects in the central nervous system The reticular formation of the brain stem and "arousal reactions" Similarity between EEG of the motor and visual cortex in the presence of a motor dominant reinforced by photic stimulation Electrical activity of the lateral geniculate body and caudate nucleus in the presence of a cortical dominant focus The cortical dominant focus in long-term experiments Electrical activity of the medial geniculate body and caudate nucleus in the presence of a motor dominant reinforced by acoustic stimulation Chapter V. Cortical-Subcortical Relationships, Thalamo Cortical Connections, and Dominant Foci in the Hypothalamus 1. Polarization of thalamic areas Polarization of the medial nuclei of the thalamus

9 CONTENTS ix 3. Polarization of the hypothalamus Polarization of individual layers of the cortex The recruiting response Functional connections of the nonspecific thalamocortical system with cortical neurons Chapter VI. Relations between Specific and Nonspecific Thalamo-Cortical Systems. Correlation Analysis of EEG Rhythms 1. Relations between the specific and nonspecific thalamo-cortical systems in man based on the study of evoked potentials Correlation analysis of the EEG of the motor and visual cortex during polarization of the motor cortex Foci of increased excitability evoked in the cortex by repetitive stimulation Generators of rhythmic electrical activity in the human cortex, particularly the motor cortex, as revealed by correlation analysis Correlation analysis of rhythmic driving of the human EEG by flashes The rhythmic driving by flashes when a pathological focus is present in the brain Chapter VIT. Convergence of Impulses on Neurons of the Motor Cortex, and the Motor Dominant 1. Functional convergence and polysensory neurons of the motor cortex Changes in ultrastructure of the motor cortex following polarization by weak direct current General scheme of processes in the central nervous system during anodal polarization of the motor cortex Conclusion Bibliography