The Amygdaloid Nuclear Complex: Anatomic Study of the Human Amygdala PDF
Preview The Amygdaloid Nuclear Complex: Anatomic Study of the Human Amygdala
Vincent Di Marino Yves Etienne Maurice Niddam The Amygdaloid Nuclear Complex Anatomic Study of the Human Amygdala 123 The Amygdaloid Nuclear Complex Vincent Di Marino Yves Etienne (cid:129) Maurice Niddam The Amygdaloid Nuclear Complex Anatomic Study of the Human Amygdala Vincent Di Marino Maurice Niddam Faculté de médecine Unité SAMU 13, Centre 15 Marseille Hôpital de la Timone France Marseille France Yves Etienne Unité de médecine légale Hôpital de la Timone Marseille France ISBN 978-3-319-23242-3 ISBN 978-3-319-23243-0 (eBook) DOI 10.1007/978-3-319-23243-0 Library of Congress Control Number: 2015953156 Springer Cham Heidelberg New York Dordrecht London © Springer International Publishing Switzerland 2016 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifi cally the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfi lms 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. T he use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specifi c statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made. Printed on acid-free paper Springer International Publishing AG Switzerland is part of Springer Science+Business Media (www.springer.com) To our beloved wives, our dear children and our adorable grandchildren To all the neuroscientists and neuroanatomists of the world Auth ors Vincent Di Marino is emeritus professor of anatomy at the Aix Marseille University (AMU), Faculty of Medicine; former director of the Kidney Transplantation Center of the Sainte- Marguerite Hospital; and former director of the Laboratory of Anatomy at the Faculty of Medicine, Marseille, France. Currently, his research topics are focused on the central nervous system and the pelvis. Faculté de Médecine de Marseille 27 Boulevard Jean Moulin 13385 Marseille Cedex 5 France ([email protected]). Yves Etienne is forensic scientist, doctor of medicine, former assistant of anatomy, former house physician in the hospitals of sanitary region and consulting practitioner in the Unit of Forensic Medicine in the Timone Hospital (Marseille, France). Unité de Médecine Légale Hôpital de la Timone 264 Rue Saint-Pierre 13385 Marseille Cedex 5 Maurice Niddam is forensic scientist, doctor of medicine, former assistant of anatomy, coordi- nating doctor of a medical center and regulating doctor of the Emergency Medical Service (SAMU 13, Center 15) in the Timone Hospital (Marseille, France). Unité SAMU 13, Centre 15 Hôpital de la Timone 264 Rue Saint Pierre 13385 Marseille Cedex 5 vii Foreword The amygdala is a small distinct brain structure, located in the anteromedial part of the tempo- ral lobe. Variably designated as a “corpus”, a “complex” or a “nucleus”, depending on the degree of importance its particular structure has inspired, this, admittedly small quantity of brain tissue, is made up of islets of gray matter and weighs 1 g. It is a basal brain nucleus that came to “glide” along the limbic cortex and appears to have perched on top of the hippocam- pus. In contrast to other structures comprising the limbic system, the functional identity of the amygdala is clear. It is the nodal point of our emotional life, it controls autonomic functions and their expression and plays a role in the processing of olfactory and auditory stimuli. T he physiology of the amygdala was initially studied in animals, mainly rats. Until the advent of functional imaging, there was no data available allowing to conclude that it had a similar function in humans, all the more since its size varies between species. The role that the amygdala plays in temporal epilepsy was discovered during the fi rst studies with intracerebral electrodes, performed by Talairach and Bancaud on patients with seizures, in the context of operative management. From the outset, the amygdala was proven to be very closely linked to the hippocampus, both during the interictal state, as well as at the outset of epileptic activity. The bidirectional character of these connections has also become a marker of epileptogenic foci in cases of medial temporal epilepsy (studies of Buser and Bancaud in 1983). The spec- trum of clinical signs related to the involvement of the amygdala was identifi ed later. The group of Talairach and Bancaud fi rst demonstrated the correlation with oro-alimentary autom- atisms, then Gloor (this particular neurophysiologist, working at the Neurologic Institute of Montreal, presented his thesis regarding the connections of the amygdala in 1957) demon- strated the association with experiences of “déjà vu” and paroxysmal memory recollections. Autonomic manifestations (heart rhythm acceleration, piloerection) and also emotional ones (anxiety, fear) have been clearly associated with paroxysmal discharges from the amygdala. Electrical stimulation of the amygdala results in reproduction of these same symptoms, espe- cially “déjà vu” experiences. This last fact illustrates its importance in the mechanisms of memory, in combination with the anterior hippocampus and the entorhinal cortex, especially with regard to emotional memory or the infl uence of emotions in memory encoding. Functional imaging has majestically demonstrated the role of the amygdala in encoding negative emotions and especially its specifi city in deciphering the emotional expression of the human face (Dolan). The team of Joseph Ledoux, having elucidated the functional circuitry of fear and its storage in memory (consolidation and extinction of fearful memories, studies by the Quirk team) in the rat, was also the one to demonstrate in humans, by means of functional MRI, the interactions between the median prefrontal cortex of the cingulate gyrus and the amygdala in regulating the response to a menace. All actual studies in the area of “affective” neurosciences report activation of the amygdala, which has become the cerebral “center of fear”. However, just as all sorts of amygdalar stimulations do not result in emotional modifi ca- tions, all patients with Urbach-Wiethe disease (a genetic disease characterized by calcifi ca- tions of the amygdala bilaterally) do not manifest with behavioral alterations, nor do they exhibit a much different judgement as regards emotionally charged facial expressions, com- pared to a control population (Siebert et al. 2003). These observations underline a certain ix
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