Neurobiological Bases of Abnormal Aggression and Violent Behaviour

Neurobiological Bases of Abnormal Aggression and Violent Behaviour

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József Haller Neurobiological Bases of Abnormal Aggression and Violent Behaviour

József Haller Department of Behavioral Neurobiology Institute of Experimental Medicine Budapest, Hungary ISBN 978-3-7091-1267-0 ISBN 978-3-7091-1268-7 (ebook) DOI 10.1007/978-3-7091-1268-7 Springer Wien Heidelberg New York Dordrecht London Library of Congress Control Number: 2014934422 Springer-Verlag Wien 2014 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. Exempted from this legal reservation are brief excerpts in connection with reviews or scholarly analysis or material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. Duplication of this publication or parts thereof is permitted only under the provisions of the Copyright Law of the Publisher s location, in its current version, and permission for use must always be obtained from Springer. Permissions for use may be obtained through RightsLink at the Copyright Clearance Center. Violations are liable to prosecution under the respective Copyright Law. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. While the advice and information in this book are believed to be true and accurate at the date of publication, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein. Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com)

Preface Understanding the brain control of aggression was greatly enhanced over the last decade. Out of the multitude of new developments, this book will primarily focus on two: the emergence of abnormal aggression models in animals and the introduction and expansion of brain imaging techniques in humans. Although apparently unrelated, these developments bridged an important gap between animal and human aggression research. In sharp contrast with human research where aggression-related psychopathologies are of major interest, animal research was for long dominated by laboratory models of natural aggressiveness. Newly developed models detached from this classical approach by mimicking etiological factors of aggression-related psychopathologies and by identifying deviant forms of aggression that arise as a consequence of these treatments. Thus, animal research gradually shifted from studying aggression as a natural phenomenon to studying models of abnormal aggression. Recently developed models made clear that laboratory equivalents of etiological factors induce profound changes in brain function and alter qualitatively the neural circuits that are activated by social conflict and that regulate aggressive behavior under these circumstances. Before the advent of brain imaging techniques, human research lacked adequate tools to study brain function. This is in sharp contrast with animal research where a wide range of advanced technologies were developed over the last decades. In lack of appropriate research tools, assumptions on human brain mechanisms were based on animal studies that were occasionally cross-checked by studies involving people with accidental brain lesions and by brain stimulation techniques that were rather infrequently employed. Brain imaging techniques provide powerful tools of investigation, which showed spectacular advancements over the last decade. New technologies not only allow the study of structural features but also reveal brain connectivity, neurotransmitter receptor profiles, and other important aspects of brain function. In brief, models of abnormal aggression made animal studies more relevant for human research, while brain imaging techniques made human research more relevant for understanding brain mechanisms. These newly acquired features of v

vi Preface the two main sides of aggression research have the potential to make them closer partners and to start a process of integration that is beneficial for both sides and for aggression research in general. The main aim of this book is to create a platform for interactive thinking. We strongly believe that the control of aggression in general and of abnormal aggressiveness in particular cannot be understood without integrating animal findings of translational value and human findings. Close interactions between the two sides offer human research the chance to take advantage of the depth of analysis allowed by the advanced neuroanatomical and neurofunctional methodologies currently used in animal research, while research on animal aggression will greatly benefit from incorporating information on the phenomenon it models. The two developments discussed here opened new channels of information exchange and created the possibility of jointly addressing the triple linkage of etiological factors, brain changes, and behavior and to unravel novel treatment opportunities that take into account all three. This book intends to be the first step towards the integration of concepts and findings that makes this possible. Budapest, Hungary József Haller

Contents 1 Normal and Abnormal Aggressions: Definitions and Operational Approaches... 1 1.1 Demarcating and Characterizing Aggression: Theoretical Definitions........................................ 2 1.1.1 Basic Definitions... 2 1.1.2 Definitions for Subtypes...... 4 1.1.3 Normal and Abnormal Aggressions: Basic Principles.... 5 1.1.4 A Theoretical Classification of Aggressive Behaviors... 7 1.2 Quantifying Aggression: Operational Approaches...... 9 1.2.1 Models of Normal Aggression in Animals... 9 1.2.2 Models of Abnormal Aggression in Animals... 13 1.2.3 Classification of Abnormal Aggression Models... 19 1.2.4 Normal and Abnormal Aggressions in Humans... 20 1.2.5 Classifications of Operational Approaches in Humans... 27 1.3 Definitions, Approaches, and the Validity of Conclusions... 29 2 Hormonal Determinants... 33 2.1 Hormones and Brain Function.......................... 33 2.2 Testosterone... 35 2.2.1 Mechanisms of Action..... 36 2.2.2 Developmental Effects on Aggression in Animals and Humans... 37 2.2.3 Postpubertal Effects in Animals: Normal and Abnormal Aggressions...... 41 2.2.4 Does Testosterone Affect Aggression in Humans?...... 46 2.2.5 Testosterone and Abnormal Aggression in Humans... 50 2.2.6 Overview... 51 2.3 Glucocorticoids... 53 2.3.1 Mechanisms of Action..... 53 2.3.2 Normal Aggression in Animals... 55 2.3.3 Abnormal Aggression in Animals... 58 vii

viii Contents 2.3.4 Healthy Human Controls... 59 2.3.5 Abnormal Aggression in Humans.................. 61 2.3.6 Overview... 66 2.4 Overall Evaluation of Hormonal Determinants..... 68 3 Neural Circuits Subserving Aggression: General Models... 69 3.1 Animals.......................................... 69 3.1.1 Cats............ 69 3.1.2 Rats............ 71 3.2 Humans......... 73 3.3 Outlook... 76 4 Focal Points of Aggression Control... 79 4.1 The Hypothalamus... 79 4.1.1 Hypothalamically Controlled Behaviors.... 79 4.1.2 Hypothalamic Control of Aggression in Animals and Humans... 82 4.1.3 Hypothalamic Mechanisms of Abnormal Aggression in Animals... 88 4.1.4 The Human Case.............................. 94 4.1.5 Overview: Etiological Factor-Dependent Alterations in the Hypothalamus.... 95 4.2 The Prefrontal Cortex.... 96 4.2.1 Prefrontal Anatomy of Violence: A Prelude... 96 4.2.2 An Overall Summary of the General View........... 97 4.2.3 Problems with the General View...... 99 4.2.4 The Psychological Landscape Hypothesis... 112 4.2.5 The Neural Network Hypothesis................. 117 4.3 The Amygdala...... 120 4.3.1 Structure and General Roles in Behavior............. 121 4.3.2 Normal Aggression in Animals... 124 4.3.3 Abnormal Aggression in Animals... 127 4.3.4 Normal and Abnormal Aggressions in Humans... 129 4.3.5 Overview... 134 4.4 The Periaqueductal Gray... 135 4.4.1 The Role of the Periaqueductal Gray (PAG) in Behavioral Control... 135 4.4.2 The Role of the PAG in Animal Aggression... 138 4.4.3 The Role of the PAG in Human Aggression... 143 4.4.4 Overview... 144 5 The Role of Emerging Techniques in Understanding Aggression... 145 5.1 Optogenetics... 145 5.2 Epigenetics... 146 5.3 Functional Pharmacology... 148 5.4 Genetics and Pharmacogenetics... 149 5.5 Overview......................................... 150

Contents ix 6 Summary and Synthesis... 151 6.1 Who s Flying the Plane and What Kind of Plane?... 151 6.2 Behavior and Brain Function in Animal Aggression.......... 152 6.2.1 Normal Aggression... 152 6.2.2 Abnormal Aggression..... 154 6.2.3 The Role of the Prefrontal Cortex.................. 157 6.3 Behavior and Brain Function in Human Aggression...... 158 6.3.1 The Dual Theory of Aggression................... 159 6.3.2 Types of Aggression and Brain Function... 162 6.4 Hormones... 164 Postscript... 165 References... 167 Index... 215