E-Book, Englisch, 256 Seiten
Neff Contributions to Sensory Physiology
1. Auflage 2013
ISBN: 978-1-4831-9160-7
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: 6 - ePub Watermark
Volume 7
E-Book, Englisch, 256 Seiten
ISBN: 978-1-4831-9160-7
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: 6 - ePub Watermark
Contributions to Sensory Physiology, Volume 7, was published with two principal objectives in mind: (1) to bring together reports of current research on all of the sensory systems; and (2) to provide an opportunity for the scientist studying a sensory system to give a detailed account of a series of experiments or to present, at some length, a theory about the physiological basis of sensation. The book contains six chapters and opens with a summary of neuroanatomical studies which show that the cochlear nucleus is the origin of several distinct fiber pathways which have differing fiber diameters, routes, and terminations in more central nuclei of the auditory system. Subsequent chapters deal with the optic chiasm of the vertebrate brain; the morphological basis of orientation selectivity; visual control of movement; visual functions in monkeys following removal of visual cerebral cortex; and subdivisions in sensory systems. It is the hope of the editor and publisher that this serial publication will provide better communication among those who study sensory systems and that it will also be a valuable source of information for scientists from other fields who occasionally seek a representative sample of research that is being done in this important area of physiology rather than just a summary.
Autoren/Hrsg.
Weitere Infos & Material
1;Front Cover;1
2;Contributions to Sensory Physiology;4
3;Copyright Page;5
4;Table of Contents;6
5;Contributors;8
6;Preface;10
7;Contents of Previous Volumes;12
8;Chapter 1. Parallel Ascending Pathways from the Cochlear Nucleus: Neuroanatomical Evidence of Functional Specialization;16
8.1;I. INTRODUCTION;16
8.2;II. ANATOMY OF THE COCHLEAR NUCLEUS;17
8.3;III. PROJECTIONS OF THE VENTRAL COCHLEAR NUCLEUS;24
8.4;IV. DISCUSSION;44
8.5;REFERENCES;50
9;Chapter 2.
The Optic Chiasm of the Vertebrate Brain;54
9.1;I. INTRODUCTION;54
9.2;II. THE ''CLASSICAL'' VIEW OF THE OPTIC CHIASM;55
9.3;III. POSTCLASSICAL DEVELOPMENTS;60
9.4;IV. GENERAL CONCLUSIONS;82
9.5;ACKNOWLEDGMENTS;83
9.6;REFERENCES;83
10;Chapter 3.
Studies on the Morphological Basis of Orientation Selectivity;90
10.1;I. INTRODUCTION;90
10.2;II. 2-[14C]DEOXYGLUCOSE METABOLIC MAPPING;94
10.3;III. SPATIAL DISTRIBUTION OF DENDRITES;97
10.4;IV. CONCLUSION;111
10.5;ACKNOWLEDGMENTS;112
10.6;REFERENCES;112
11;Chapter 4.
Visual Control of Movement: The Circuits Which Link Visual to Motor Areas of the Brain with Special Reference to the Visual Input to the Pons and Cerebellum;118
11.1;I. VISUAL CONTROL OF MOVEMENT;118
11.2;II. VISUAL INPUT TO THE PONS AND CEREBELLUM;129
11.3;III. THE ROLE OF THE CEREBELLUM IN VISUALLY GUIDED BEHAVIOR;149
11.4;ACKNOWLEDGMENTS;155
11.5;REFERENCES;155
12;Chapter 5. Visual Functions in Monkeys after Total Removal of Visual Cerebral Cortex;162
12.1;I. INTRODUCTION;162
12.2;II. MATERIAL AND METHODS;164
12.3;III. RESULTS;179
12.4;IV. DISCUSSION;204
12.5;V. SUMMARY;211
12.6;ACKNOWLEDGMENTS;212
12.7;REFERENCES;212
13;Chapter 6.
The Segregation of Function in the Nervous System: Why Do Sensory Systems Have So Many Subdivisions?;216
13.1;I. INTRODUCTION;216
13.2;II. HOW ARE SUBDIVISIONS DEFINED?;217
13.3;III. METHODS OF DETERMINING SUBDIVISIONS;229
13.4;IV. SPECIES VARY IN NUMBERS OF SUBDIVISIONS; SIMILAR SUBDIVISIONS HAVE BEEN INDEPENDENTLY ACQUIRED;237
13.5;V. THE EVOLUTION OF SUBDIVISIONS;238
13.6;VI. WHAT IS THE FUNCTIONAL SIGNIFICANCE OF SUBDIVIDING?;245
13.7;VII. HOW SENSORY SYSTEMS WORK;246
13.8;VIII. SUMMARY AND CONCLUSIONS;247
13.9;ACKNOWLEDGMENTS;248
13.10;REFERENCES;248
14;Index;256
Parallel Ascending Pathways from the Cochlear Nucleus
Neuroanatomical Evidence of Functional Specialization
W. Bruce Warr, The Boys Town Institute for Communication Disorders in Children, Omaha, Nebraska
Publisher Summary
This chapter provides an overview of the neuroanataomical studies, which demonstrate that the cochlear nucleus is the origin of several distinct fiber pathways that have differing fiber diameters, routes, and terminations in the central nuclei of the auditory system. The chapter analyzes the projections of histologically defined subdivisions of the ventral cochlear nucleus (VCN) and projections from the dorsal cochlear nucleus (DCN). The projections of the cochlear nucleus present a comprehensibly small number of specialized ascending pathways, and the differences in neuronal composition in each part of the cochlear nucleus are associated with differences in the course and connections of its efferent fibers. A major similarity in neuronal composition between parts, namely, the nearly ubiquitous multipolar cell, is also reflected in similarities in projections from different subdivisions of the VCN. In the chapter, these findings are related to other pertinent anatomical data and, to a lesser extent, to electrophysiological findings.
I Introduction
In recent years, evidence from neuroanatomical and single-unit electrophysiological studies has accumulated to support the view that the cochlear nucleus contains an orderly array of morphologically and functionally distinct populations of neurons. One component of this evidence derives from studies of the ascending fiber projections which arise from the various parts of the cochlear nucleus. It is my purpose here to present a documented summary of neuroanatomical studies which show that the cochlear nucleus is the origin of several distinct fiber pathways which have differing fiber diameters, routes, and terminations in more central nuclei of the auditory system. Because of the relevance of projection studies to the task of arriving at a coherent and functionally significant parcellation of the ventral cochlear nucleus (VCN), this account consists primarily of an analysis of the projections of histologically defined subdivisions of this region. Projections from the dorsal cochlear nucleus (DCN) will be dealt with only in discussion at the end of the article.
The work described here was carried out in the domestic cat. Although this animal is particularly advantageous because so much auditory research has been and continues to be done in this species, comparative studies provide ample evidence that both the anatomy of the auditory system and hearing ability in mammals exhibit sufficient species differences so as to make interspecies generalizations quite difficult. However, comparative research has furnished important insights into the physical, evolutionary, and neurobiological factors which may account for at least some of this diversity (Harrison and Irving, 1966b; Masterton and Diamond, 1967; Masterton , 1969; Harrison and Feldman, 1970; Masterton and Glendenning, 1978; Harrison, 1978; Heffner and Heffner, 1980).
II Anatomy of the Cochlear Nucleus
The central auditory system of the cat is well developed and its main nuclear groups are large enough to permit reasonably discrete experimental manipula-tion. As is shown in Fig. 1, the cochlear nerve enters the VCN at its ventrolateral margin. Owing to the sequential bifurcation and rostrocaudal dispersion of its branches, the cochlear nerve forms a tapered root which divides the VCN into anterior and posterior parts (Fig. 2A). Cochlear nerve fibers from the apical (low-frequency) end of the cochlea bifurcate most ventrolaterally, followed in a dorsomedial sequence by those from progressively more basal portions of the cochlea (Sando, 1965). Thus, an orderly remapping of the selective frequency response characteristics of cochlear nerve fibers is established within each part of cochlear nucleus, although some irregularities have been noted in the vicinity of the nerve root itself (Bourk , 1981), and tuning is not uniformly sharp (Godfrey , 1975).
Fig. 1 Photograph illustrating major surface structures of the cat’s auditory brain stem. The cerebral cortex, cerebellum, and cerebellar peduncles have been partially removed. The inset and close-up photographs were taken from similar angles. The cochlear nerve is cut at its point of entry into the ventral cochlear nucleus. The anteroventral cochlear nucleus is visible as a rounded feature immediately dorsal to the vestibular nerve. Most of the posteroventral cochlear nucleus is covered by the dorsal cochlear nucleus. The ridge (tenia choroidea) on the surface of the cochlear nucleus (arrow) marks the ventral margin of the lateral recess of the fourth ventricle. Key to abbreviations in this and all subsequent figures: AV, Anteroventral cochlear nucleus; CNIC, central nucleus of the inferior colliculus; D, dorsal component of the trapezoid body; DAS, dorsal acoustic striae; DCN, dorsal cochlear nucleus; Gl, globular and multipolar cell area; Gl & MCA, globular and multipolar cell area; IC, inferior colliculus; ICP, inferior cerebellar peduncle; IH, interstitial nucleus of the stria of Held; LGB, lateral geniculate body; LL, lateral lemniscus; LNTB, lateral nucleus of the trapezoid body; LSO, lateral superior olivary nucleus; MCA, multipolar cell area; MCP, middle cerebellar peduncle; MGB, medial geniculate body; ML, medial lemniscus; MNTB, medial nucleus of the trapezoid body; MSO, medial superior olivary nucleus; NLL, nucleus of the lateral lemniscus; NLLd, dorsal nucleus of the lateral lemniscus; NLLdm, dorsomedial part of the ventral nucleus of the lateral lemniscus; NLLi, intermediate part of the ventral nucleus of the lateral lemniscus; NLLpm, posteromedial part of the ventral nucleus of the lateral lemniscus; NLLV, ventral nucleus of the lateral lemniscus; OCA, octopus cell area; P, pyramidal tract; PN, Pontine nucleus; POal, anterolateral periolivary nucleus; POdl, dorsolateral periolivary nucleus; POdm, dorsomedial periolivary nucleus; POp, posterior periolivary nucleus; POpv, posteroventral periolivary nucleus; POvm, ventromedial periolivary nucleus; PV, posteroventral cochlear nucleus; Pyr. Tr., pyramidal tract; SCP, superior cerebellar peduncle; SH, stria of Held; Sph. CA, spherical cell area; ST. V, spinal tract of the trigeminal nerve; TB, trapezoid body; V, ventral component of the trapezoid body; Vest. N., vestibular nerve; VNLL, ventral nucleus of the lateral lemniscus; VNTB, ventral nucleus of the trapezoid body; V Mot. Nuc, motor nucleus of the trigeminal nerve; V Root, root of the trigeminal nerve; V Sen. Nuc, main sensory nucleus of the trigeminal nerve;VI Nuc, abducens nucleus; VII genu, genu of the facial nerve; VII Nuc, motor nucleus of the facial nerve; VII Root, facial nerve root.
Fig. 2 Key to percentile levels of the photographic atlas (Fig. 3) shown projected schematically onto quasi-sagittal (A) and horizontal (B) sections. The inset diagrams show the plane and level of sections A and B with respect to the transverse plane. See legend to Fig. 1 for key to abbreviations.
A Subdivisions of the Cochlear Nucleus
In order to compare the projections of different parts of the VCN, I have found it essential to have a means of describing lesions or injection sites in different animals in terms of a standard reference or coordinate system. The block model of the cochlear nucleus in the cat (Kiang , 1975), based largely on the cytoarchitectonic criteria of Osen (1969), provides such a means, but I prefer the directness and inherent morphological fidelity of a photographic atlas. The atlas I use was prepared as follows. Histological sections were prepared from a normal 4-kg adult male cat employing methods of tissue fixation, blocking, and staining identical to those used for the specimen upon which the Kiang block model was based (including the preparation of an alternative series of...
