Table Of ContentNeurons and
Interneuronal Connections of the
Central Visual System
Neurons and
Interneuronal Connections of the
Central Visual System
Ekaterina G. Shkol'nik-Yarros
Brain Institute
Academy of Medical Sciences of the USSR
Moscow, USSR
Translated from Russian by
Basil Haigh
Translation Editor
Robert W. Doty
Center for Brain Research
University of Rochester
Rochester, New York
<±>
PLENUM PRESS • NEW YORK-LONDON • 1971
The original Russian text, published by Meditsina Press in 1965
for the Academy of Medical Sciences of the USSR, has been corrected
by the author for the present edition. The English translation
is published under an agreement with Mezhdunarodnaya Kniga, the
Soviet book export agency.
E. r. WKonbH~K·flPPOC
HE~POHbl ~ MEH{HE~POHHbIE CBfl3~-3P~TEnbHbl~ AHAn~3ATOP
NEIRONY I MEZHNEIRONNYE SVYAZI-ZRITEL'NYI ANALIZATOR
Library of Congress Catalog Card Number 69·18115
ISBN-13: 978-1-4684-0717-4 e-ISBN-13: 978-1·4684-0715-0
001: 10.1007/978-1-4684-0715-0
© 1971 Plenum Press, New York
Softcover reprint of the hardcover 1s t edition 1971
A Division of Plenum Publishing Corporation
227 West 17th Street, New York, N.Y. 10011
United Kingdom edition published by Plenum Press, London
A Division of Plenum Publishing Company, Ltd.
Davis House (4th Floor), 8 Scrubs Lane, Harlesden, NW10 6SE, England
All rights reserved
No part of this pUblication !)lay be reproduced in any form
without written permission from the publisher
PREFACE
This century has witnessed the creation of new sciences extending the
frontiers of knowledge to an unprecedented degree. We have seen the birth
of cybernetics and bionics, bringing together such apparently distantly
related branches of science as neurohistology and automation, synaptology
and electronics. The electron microscope has resolved tissues almost down
to the molecular level, and histochemistry has led to the fine analysis of
brain structure.
However, before these and other new sciences can develop properly and
scientifically, a precise knowledge of the structure of the material with which
they are concerned is absolutely essential. That is why the need exists at the
present time for a detailed study of the larger units, i.e., the neurons, their
interrelationships and the pathways by which excitation is conducted.
Biologists, neurologists, physicists, and specialists in other technical disci
plines will find this study highly useful.
During recent years many advances have been made in knowledge of
the central visual system and its pathways. Above all, it has been found that
the visual system is very extensive. The optic tract is connected, not only
with the lateral geniculate body, but with the superior colliculus and the
pulvinar. Besides the discovery of these principal pathways, connections
have also been studied with the hypothalamus, the pretectal region, the
medial geniculate body, subthalamus, and other parts of the brain stem. The
visual system is thus connected with the reflex apparatus, the autonomic
nervous system, and the auditory and reticular systems. At the cortical level,
visual representation likewise has been shown not to be confined to the
typical visual center in Area 17. The discovery of these complex and
extensive connections at cortical and subcortical levels has considerably
broadened present concepts of analyzers in general and of the visual
analyzer in particular.
Refined electrophysiological investigations in recent years have revealed
remarkable facts concerning the convergence of excitation on visual cortical
neurons. The same neuron can apparently receive not only specific visual
impulses, but also impulses of a different character, such as vestibular,
vi Preface
auditory, etc. It has also been found that neurons reacting to onset and
cessation of light and to changes in the direction of movement exist not only
in the retina but also in the cortex (Jung et al.; Rubel and Wiesel), and that
many other types of neurons can be distinguished by their response to exci
tation of the visual receptor. Recent microelectrode studies of De Valois and
co-workers are developing in the same direction. They have shown that
neurons of the lateral geniculate body in primates do not respond equally
to colored stimuli.
What is revealed by these new data concerning the organization of
analyzers? Is it possible to correlate the anatomical and physiological facts?
With the gradual accumulation of facts concerning neurons of the central
visual system, problems have arisen which have been partially solved or
have given rise to other new problems: by comparison with other analyzers,
does the structure of the visual analyzer exhibit specificity? Are the attempts
to regard the retina as connected with the brain only by centripetal fibers
valid? Can a morphological basis for color vision be found in the structure
of the brain?
These and many other questions can be answered most satisfactorily
and completely by a systematic investigation of the neurons and inter
neuronal connections of the central visual system, and this was the main
purpose of the work described in this volume, most of which was done
between 1947 and 1960.
As a foundation for my research, carried on at the Brain Institute,
Academy of Medical Sciences of the U.S.S.R., I have been fortunate in hav
ing the experience of members of the Institute's staff, gained during many
years of investigating the phylogeny and ontogeny of the brain and its
neuronal structure. I particularly wish to express my sincere thanks to
Professor G.I. Polyakov, to T.A. Leontovich, and to G.P. Zhukova for
their unswerving and friendly support and for their helpful criticisms.
I am also grateful to A. A. Kudryashev and M. A. Vinogradova, of the
Photographic Laboratory of the Brain Institute and to laboratory artists
A. V. Chekurova, V. A. Nilova, and R. I. Minakova for preparing the
photographs and drawings for publication. The illustrations were made by
means of a drawing apparatus; the cortex and lateral geniculate body are
represented as composite drawings from series of sections impregnated
by Golgi's method.
I also wish to thank A. S. Novokhatskii, V. G. Skrebitskii, and I. M.
Feigenberg for their valuable comments during preparation of the manu
script for publication.
E.G. SHKOL'NIK-YARROS
CONTENTS
Chapter 1. Neurons of the Central Visual System........................... 1
The Cortex and Lateral Geniculate Body .................................. ..
Neuronal Structure of the Visual Cortex and Lateral Geniculate Body
in Some Mammals ... . .. ... ...... ... ...... . . . ... . .. .. .. .. ... . .. .. . ... . .. 13
Visual System of the Hedgehog (Insectivora) ........................... 13
Visual System of the Rabbit (Rodentia) ................................. 20
Visual System of the Dog (Carnivora) .................................... 37
Visual System of Monkeys (Primates) .................................... 57
Visual System of Man......................................................... 79
Size of the Neurons and Density of Their Arrangement ............ 100
Characteristics of the Layers of the Visual Cortex ..................... 105
Similarities and Differences Between Neurons of Monkey and
Man ........................................................................ 111
Distinctive Structural Features of Neurons in Areas 17, 18, and
19 of the Human Occipital Cortex ................................. 114
Chapter 2. Connections Between Neurons and Details of Their
Structure ........................................................................... 118
Endings and Branches of Axons ... .. .... .. .. .. .. .. .. .... .. ...... ......... ...... 118
Dendrites, Their Endings and Ramifications ................................. 124
Varieties of Connections Between Neurons in the Cortical and
Subcortical Parts of the Visual System .............................. 135
Axo-dendritic Contacts of Cortical Pyramidal Cells .................. 140
Axo-somatic Connections of Cortical Pyramidal Cells ............... 155
Axo-dendritic Contacts of Cortical Stellate Cells " ................ '" 160
Axo-somatic Contacts of Cortical Stellate Cells ..................... '" 161
Axo-axonal Connections in the Cortex .. ....... .. .. .. .. .. .. .. .......... 165
Axo-dendritic and Axo-somatic Contacts of Cells of the Lateral
Geniculate Body ... . .. ... ... .... .. ... . .. .. .. .. .. . ... .. .. .. .. . . ... .. .. . ... 166
Connections in the Retina ................................................... 173
Reality of the Systems of Spines on Dendrites; Their Origin and Role 175
vii
viii Contents
Structure of Interneuronal Connections in the Cortex 182
Chapter 3. Differences in Structure and Connections of the Visual
System at Cortical and Subcortical Levels .............................. 189
The Cortical Level .;................................................................ 189
Connections of Pyramidal Cells and Their Significance ........... . 189
Connections of the Long-Axon Star Cells of Cajal ................. . 193
Connections of Short-Axon Stellate Cells and Their Significance 195
The Subcortical Level .............................................................. . 199
Neurons of the Lateral Geniculate Body ................................. 199
The Main Differences Between Neurons of the Visual Cortex and
Lateral Geniculate Body................................................ 202
Chapter 4. Structure of the Central Visual System and Pathways ...... 210
Cortical Analyzer and Diffuse Elements ....................................... 210
Efferent Connections of the Visual Cortex ........................ ' ........... 221
Centrifugal Connections of the Retina.......................................... 239
A Scheme of the Structure of the Visual System ........................ '" 245
Chapter 5. Specificity of Structure of the Central Visual System ... '" 249
Structure of Neurons of the Visual System and Their Comparison
with Other Neurons............................................................ 249
Specificity of Structure in Relation to the Problem of Color Vision ... 258
New Data on the Structure and Function of the Lateral Geniculate
Body in Primates Relative to the Problem of Color Vision......... 268
Bibliography ........................................................................... 275
Index .................................................................................... 293
Chapter 1
NEURONS OF THE
CENTRAL VISUAL SYSTEM
THE CORTEX AND LATERAL GENICULATE BODY
Progressive development of the cerebral cortex in mammals in the course of
evolution takes place through many interdependent processes. The surface
area of the cortex is increased by the formation of fissures and gyri. The
fissures and gyri are formed as a result of an increase in the number of
neurons and of their long processes forming the white matter. The mass of
white matter is increased, particularly on account of association pathways,
and this in turn is connected with an increase in the number of pyramidal
cells in the cortex. Considerable differentiation takes place in the cortex,
with the appearance of new areas and subareas and their corresponding new
connections, for thousands of association, commissural, and projection fibers
arise from every point of the cortex. As the brain develops, and increases in
complexity in response to adaptation to the external environment, the num
ber of layers in the cortex changes. Changes in the architectonics of the brain
and in the structure of its layers are a manifestation of neuronal speciali
zation corresponding to the areas and lobes of the brain.
Within the limits of the visual system, differences are found in cortical
structure depending on the level of development of the nervous system and
the state of visual function.
It must also be emphasized that this process of progressive development
does not take place equally at all levels of the visual system. The extremely
fine specialization of the eyes of many fish (Detwiler, 1955) and the fine
differentiation of the retina in many birds are well known. The accurate
swoop of a predatory bird from a height while seeking food, and the precise
coordination of vision with movements and vestibular responses are charac
teristic of vision in birds. It is not surprising that in many vertebrates the
eye is larger than the brain (Fig. 1); at lower levels of evolution the peripheral
1
2
Chapter 1
h
to
bo
h--+-'. ...
Fig. 1. Relative size of the eye and brain in some vertebrates, mammals, and man.
A: 1, fish; 2, frog; 3, lizard (monitor); 4, bird (fowl); to, tectum opticum; bo, bulbus
oculi; t, telencephalon; h, hemisphere.
Neurons of the Central Visual System 3
Fig. 1. (Continued) B: 1, rabbit; 2, dog; 3, marmoset (lateral surface of hemisphere);
4, macaque; 5, man (sagittal section through skull and hemisphere). Remainder of legend
as in A. (Zvorykin and Shkol'nik-Yarros, 1953.)
