Texture of the Nervous System of Man and the Vertebrates: Volume I An annotated and edited translation of the original Spanish text with the additions of the French version by Pedro Pasik and Tauba Pasik

660 Pages·1999·22.08 MB·English

by  Santiago Ramón y Cajal (auth.)

Santiago Ramön y Cajal
Texture of the
Nervous System of Man and the Vertebrates
Volume I
An annotated and edited translation of the original Spanish text
with the additions of the French version by
Pedro Pasik and Tauba Pasik
Springer-Verlag Wien GmbH
Prof. em. Dr. Pedro Pasik
Prof. em. Dr. Tauba Pasik
Department of Neurology
Mount Sinai School of Medicine
New York, NY, USA
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© 1999 Springer-Verlag Wien
Originally published by Springer-Verlag Wien New York in 1999
Softcover reprint of the hardcover 1st edition 1999
Typesetting: Thomson Press (India) Ltd., New Dehli
Cover design: B. Kollmann
Printed on acid-free and chlorine-free bleached paper
SPIN: 10637744
With 270 (partly coloured) Figures
ISBN 978-3-7091-7323-7 ISBN 978-3-7091-6435-8 (eBook)
DOI 10.1007/978-3-7091-6435-8
TO THE MEMORY OF
JANOS (JOHN) SZENTAGOTHAI
1912-1994
FOREWORD
Most scientists agree that the 21st century will be the "Century of Biology".
The revolution that started a few decades ago with the extraordinary develop
ment of molecular biology, has provided the basis for the understanding of the
mechanisms that govern life through the regulation of cell function and cell-to
cell interactions.
Neuroscience will surely be one of the biological disciplines that will profit
the most from this revolution. Neuroscience comprises the study of the brain,
and the more difficult relationship of brain and behavior. It is indeed a very
broad field of investigation that, from molecular biology and genetics, passing
through systems physiology, functional mapping of the brain, and even human
behavior, has as the ultimate goal the understanding of how the brain works.
The importance of this aim is immense, since it is the only scientific approach
to understanding ourselves.
Today, owing to the great progress made in neuroscientific research, there is
a real hope that highly complex processes such as sensory perception, ICTlg
term memory, learning and others will soon be comprehended in their entirety.
This progress is timely to help in finding solutions to social and health
problems emerging in our society from the growth of urban population density
and its cohorts of stress and tensions, the increase in drug-addiction, the
prolongation of longevity, etc. It is obvious that a better understanding of brain
function, and therefore of ourselves, will improve the quality6f our life. In a
sense, neuroscience can be viewed as ushering in a new humanism, ready to
challenge the nature of human beings and their responsibilities. From Neuro
science shall emerge a new vision of the world and of mankind within the
world.
The present revolution in Neuroscience has its roots in the work of Santiago
Ramon y Cajal, who during almost half a century (1887-1934) of patient work
was able to show that the nervous system is made up of billions of indepen
dent, richly and precisely interconnected nerve cells. His studies on the
architectural organization of the brain, and his prophetical predictions of its
functions became the basis of neuroanatomy, neurophysiology, neuropathol
ogy, and what he named as "rational psychology". This monumental work
justifies his well deserved title of founder of modem Neuroscience.
Of course, despite the outstanding accomplishments of Cajal, and his genius
in unraveling the complexity of brain structure, the postulation and subsequent
demonstration of the neuron doctrine, was not solely the result of his own
viii Foreword
investigation. As it always happens in Science, the contemporary knowledge in
the field and the introduction of novel analytical and experimental methods
greatly contributed to Cajal's achievements. During the second half of the 19th
century, most investigators considered the nervous system as a huge syncitium,
within which protoplasmic processes emerging from cell bodies, after breaking
up into thinner branches, dissolved into a tight network that terminated by
reconstituting the nerve fibers of the white matter. Investigators such as
Wilhelm His in Germany and August Forel in Switzerland were the first to
fight successfully the network, or reticularist, theory. W. His (1886), analyzing
the early stage of nervous system development, was able to determine that
embryonicaxons are a continuation of the first process emerging from
postmitotic nerve cells, and that they grow from the free distal end of this
process. Forel (1887) based his conclusions of Gudden's type of experiments
by showing that, after axonal avulsion of motor cranial nerve roots, only those
cells at the origin of the avulsed axons become atrophic. These observations
gave indirect proof of the reciprocal trophic dependency between axons and
their cell bodies. There is no doubt, however, and despite some recent
unfounded attacks, that Cajal was crucial in solving the controversy about the
way nerve cells communicate, and their processes terminate. Cajal's technical
skills in modifying Camillo Golgi's silver stain (reazione nera), and in
developing new metallic impregnation methods, as well as the successful use
of the embryonic and degeneration approaches of his predecessors, provided
the necessary tools for his discoveries.
It is interest to recall that neuromorphologists are currently passing through
a somewhat similar innovative period to that experienced by Cajal after Golgi's
technical breakthrough in 1873. Thus, the longed-for wish to correlate the
chemical constituents of the neuron with their structural counterparts, as a
valuable approach to better appraise neuronal function and organization, is
now a reality. In the last quarter of this century, great technological advances
emerging from physics, chemistry and molecular biology, have revolutionized
the field and breathed new life into the morphological approach. The main
advances in histochemistry, which have made neuromorphology one of the
most rapidly expanding fields in Neuroscience, can be summarized as follows:
Histofiuorescent methods for studying monoaminergic systems, which
opened up the new field of analysis of neuronal systems with identified
neurotransmitters.
Autoradiography and the diversity of its application, from tracing
connections (axoplasmic transport), identifying neurotransmitters in neu
rons (specific reuptake mechanisms), quantitative analysis of receptor
binding and metabolic activity of neuronal networks, to in situ hybridization
for the detection of messenger RNAs in order to study gene expression and
regulation.
Foreword ix
- Immunocytochemistry with its many uses, such as antibodies to study the
morphological distribution of small (i.e. amino acid haptens) and large
molecules. Among many important discoveries, it is noteworthy that this
method was the basis for the concept of the co-localization of multiple
neurotransmitters in the same neuron and axon terminal.
Finally, advances in physical science and informatics have been extremely
useful in generating new tools to study the organization, chemical composition
and dynamics of the neuron. Hence, the development of computer-assisted
image-analysis has greatly promoted quantitative studies that were impossible
only a few years ago. For instance, the quantification of receptors distribution,
and of metabolic activity of neurons in autoradiograms; three-dimensional
morphometry of neuronal bodies and their dendrites in Golgi-stained or, better
yet, in intracellularly injected neurons; analysis of somatodendritic gradients
of neurotransmitter receptor-protein distribution, or synaptic density in
immunofluorescent preparations analyzed with confocal microscopy, etc. In
addition, new tools (video-enhanced contrast microscopy, and optical recording
of neuronal activity, positron emission tomography (PET), and the newly
generated functional magnetic resonance imaging (MRI) techniques have
added a new temporal dimension to the morphological approach. Indeed, these
non-invasive imaging techniques allow the investigator to examined the same
neuronal populations over extended periods of time, and even to repeat the
observations weeks, months or years later.
In my view, although research and technical advances contemporary with
Cajal were instrumental in carrying out his work, it was his analytical power
and brilliant interpretations the sole responsible for his discoveries. We are in
his debt for opening up this new era in the history of Neuroscience. The best
evidence for my enthusiastic assertion is the validity of Cajal's opus magnum,
the "Textura del Sistema Nervioso del Hombre y de los Vertebrados". This
book, published in Madrid between 1899 and 1904, and its French translation
by L. Azoulay in 1909 and 1911, has kept the attention of most neuroscientists
for almost a century. It is still widely cited today, not much because of its
historical value but for the accuracy of its descriptions of brain organization,
and the present interest in the interpretations advanced therein. Just as an
example, in 1892 Cajal published his first ideas on the "chemotactic
hypothesis" in the article "La retine des vertebres" (La Cellule 9: 121-152;
1892). His main concern was to explain how developing or regenerating axons
find their way toward their specific targets. This concept, renamed in the book
"neurotropic hypothesis", was further elaborated for over 20 years of
continuous work. Cajal assumed that the targets produced diffusible
chemoattractant factors, to guide the arriving axons at a distance. However,
since no evidence was found for the occurrence of such attracting substances,
the hypothesis was abandoned in favor of Paul Weiss' "contact guidance"
x Foreword
theory (J Exp Zool 68: 393-448, 1934). Studies carried out during the last
10 years, however, have provided not only direct evidence for a chemotropic
guidance of developing axons, but also of chemorepulse influences.
Furthermore, a family of chemoattractant molecules, the netrins, was
identified, and their genes have been cloned already. In this respect, the work
of Marc Tessier-Lavigne and Thomas Jessell was essential for the molecular
understanding of how developing commissural spinal axons are attracted to
and cross the anterior commissure of the embryonic spinal cord. Modem
cellular and molecular studies have revived the neurotropism of Cajal, and his
figure 7 of the development of commissural spinal neurons (Anatomischer
Anzeiger 5: 85-95, 1890) has been reproduced profusely.
One major problem with Cajal's opus magnum is that it was published in
Spanish. Although beautifully written, it was poorly understood by most
scientists. Cajal himself was aware that Spanish was not the most favorable
vehicle for scientific communication. His work, although universal, was
addressed to the few scientists who could understand and discuss his inno
vative ideas. For historical (the Spanish-American war) and cultural reasons,
Cajal chose French as his scientific language. Since 1905, three years after
starting his journal (Trabajos del Laboratorio de Investigaciones Biologicas de
la Universidad de Madrid), most of his articles appeared in French. Moreover,
Cajal had the good fortune that L. Azoulay, professor of Histology at the
University of Paris and an excellent writer, volunteered to translate the Texutra.
The only serious disadvantage was that Azoulay, probably due to a lack of
familiarity with some of the subtleties of the Spanish language, introduced a
number of errors, despite the fact that Cajal reviewed and updated this French
translation.
As stated above, the rapid and important current advances in Neuroscience
producing great expectations for the forthcoming millennium, and the un
relenting interest in Cajal's work mark the urgent need for the first English
version of the "Textura del Sistema Nervioso del Hombre y de los Verte
brados". This necessity is now fulfilled through the efforts of Pedro and Tauba
Pasik, and their excellent version of Cajal's book. This remiition, avoiding the
errors present in the French translation, reveals for the first time the entirety of
Cajal's original ideas in the present universal language of Science. Pedro and
Tauba Pasik meet all the requirements for this mammoth job. They are brilliant
neuroscientists, and their work on the primate thalamus and basal ganglia,
particularly that with the Golgi silver impregnation and derivatives, deserves to
be considered as a continuation of Cajal's own "spirit". Moreover, Spanish is
their mother tongue, they studied Anatomy from French textbooks, and
English is their scientific language. This trilingual training offers the best
guarantees for the optimal translation of Cajal's book. Moreover, their
extensive knowledge of Neuroanatomy vouches for the scholarly treatment of
some obscured points in their annotations. Finally, their strenuous efforts in
Foreword xi
providing an accurate list of references will be greatly appreciated by serious
researchers interested in tracking original sources.
We are indebted to Pedro and Tauba Pasik for making the original Textura, a
treasure only accessible to a few of us, available to all neuroscientists. What an
excellent homage to celebrate the first centennial of this book!
Paris, Spring 1997 Constantino Sotelo
PRESENT A nON
On behalf of the Instituto Cajal and myself I have the pleasure to present this, I
hope definitive, English version of Santiago Ramon y Cajal's opus magnum
"Textura del Sistema N ervioso del Hombre y de los Vertebrados" . The "Textura"
was originally published in two volumes by Nicolas Moya of Madrid in 1899
(Ist volume) and 1904 (2nd volume, in two parts) collating a number of
monographs in which Cajal had published his results obtained in just fifteen
years of intense and passionate work using the, at that time novel, Golgi
method and silver impregnation techniques. The "Textura" became widely
appreciated owing to Cajal's international reputation amongst leading authori
ties of the day. Just a few years later, a French translation under the title "Histol
ogie du Systeme Nerveux de I'Homme et des Vertebres" was prepared by Leon
Azoulay, a brilliant man and a good friend in Cajal's own words. This trans
lation was reviewed and updated by Cajal himself with new additions of text
and drawings pertaining to his most recent findings. It was published by A.
Maloine of Paris in 1909 (1st volume) and 1911 (second volume). Today, there
is general acceptance that this was the starting point of modem neuroscience.
The French "Histologie" of 1909-1911, which is considered the standard
reference edition, was reprinted by the Instituto Cajal on the occasion of the
centennial of its founder in 1952-1955. This edition appeared most timely as
electron microscopy was able to show, for the first time, the existence of the
synaptic gap; the most brilliant confirmation of the theory of the independence
of neurons postulated many years back by Cajal. This edition was soon out of
print, and a second reprinting was published in 1972. A facsimile of the "Textura"
appeared recently, beautifully reproduced by colleagues at the University of
Alicante. There is also an English translation by Neely and Larry Swanson
from the French "Histologie" published by Oxford University Press in 1995.
The present edition by Professors Tauba and Pedro Pasik is a translation
from Spanish into English of "Textura" with additions from "Histologie",
preserving Cajal's most direct literary style, which had been lost in the French
edition. The present version also corrects a number of errors in the French
edition that have persisted in subsequent re-impressions, most of which were
apparently due to the lack of familiarity of the French translator with the
subtleties of the Spanish language. The task of translating is certainly critical,
and must be performed adhering to the spirit of the original. I remember a
fellow, back in the early sixties, when I was at Harvard, trying to read a
passage in Spanish of one of Cajal's descriptive techniques. He was trying to