Government of the Autonomous City of
Neuropsychiatric Hospital "José Tiburcio
Borda"
Laboratory of
Electroneurobiological Research
and Journal
Electroneurobiology
ISSN: 0328-0446
The
Comments on Professor Christfried Jakob's
Contributions
made in
The Cytoarchitectonics of the Adult Human
Cortex
by
Professor Constantin, Baron von Economo
in
Dr. Georg N. Koskinas
emeritus Assistant
of the Psychiatric and Neurological University Clinic in
Created at the
Psychiatric Clinic, Director Councillor J. Wagner v. Jauregg
Publisher: Julius Springer Verlag
1925
Translated into English by H. Lee Seldon (
who also offers the German text of the entire book
with its illustrations, as well as his English rendering (under completion), in
his website http://neptune.netcomp.monash.edu.au/staff/lseldon/LeePublications.html
Preliminary online version (not yet completely
revised). Notes in the present article are by Mariela Szirko
Electroneurobiología
2005; 13 (1), pp. 46 - 73; URL
<http://electroneubio.secyt.gov.ar/index2.htm>
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Professors von Economo and Koskinas made their
commentaries to refer (Literature,
page 803) to
JAKOB, CHR.: Vom Tierhirn zum Menschenhirn, München:
Lehmann, 1911
and
Das Menschenhirn, München: Lehmann.
Christfried Jakob (1866-1956) and
Constantin Freiherr von Economo (1876-1931)
--------
General part: General basis of the cytoarchitectonics
of the cerebral cortex
Chapter 1. Introductory remarks
A. Introduction
(Page 2)
Like
the sensory organs (for example, the eye bubbles from the mesencephalon), the
hemisphere pouchs of the cerebrum develop in pairs from the single telencephalon,
and one could understand them as a sensory organ whose view is on the inner
events in the central nervous system. The stimuli which enter this organ do not
come directly from the periphery, but are merely internal stimuli that come
from the entire remaining nervous system, to be received and processed as a
total. The cerebral cortex is also capable of accumulating these stimuli, so
that the surplus part of stimulus energy, which is not used in the simple
reflex arc, collects in the brain. By being able to change past energy into
present and future energy, it frees the organism from the brutal primitive law
of the reflex act and gives him individual freedom and personality (CHR.
JAKOB).
Prof. Jakob
sectioning a human brain on the sun-drenched veranda by the South entrance of
this Laboratory (right side of the photograph), at the time (1906-7) he was
composing his interference model of macro- and microcircuits for the
installments of "Localization of the soul and intelligence". Image
added for this article
B. Historical Notes
Original pagination (from the Table of
Contents):
CHRISTFRIED JAKOB Fundamental layers, 20
His “original gyri” and sector theory, 23
Page 17
Three
names must still be mentioned, that, although they are not directly connected
with cytoarchitectonics, will still greatly influence its study, namely CAJAL,
KAES and CHRISTFRIED JAKOB.
In 1886
GOLGI gave us, with his silver impregnation method for neurons, an unique means to recognize the form of a neuron together
with its dendrites and axon. Thus, we can derive basic knowledge about the
different cells types which appear in the nervous system. Soon therefrom CAJAL
began to systematically explore the human and animal cerebral cortex by means
of various silver methods, some also wonderfully developed by him. We owe the
knowledge that we have about it today to this highly-deserving Spanish scholar.
In the discussion of the individual cells forms in Chapter 2 (cf. p. 44 - 68),
furthermore with the discussion of the individual Areas and in many other
places we will still come back to individual results of his extensive
examinations. Knowledge of the entire cortical architectonics can help us
understand the processes in it only in conjunction with the knowledge of
CAJAL's explorations of the structure of individual cells and their precise
connections projections. With regret we must register the feeling that CAJAL's
great studies were ahead of their time, as he did them before the area division
of the cortex was postulated by MEYNERT and BETZ, a postulate which would
create the necessary coarse basis for CAJAL's detailed examinations. It is
often difficult today to utilize the important results that have been provided
by silver stains, because localization of these results to precise positions in
the cortex cannot be done. Therefore, CAJAL, with his untiring creativity, has
recently started with silver impregnation of the individual "Areae"
of the cortex, and we expect extraordinarily important results from these
studies, especially for a future fibrillo-architectonics.
In 1907
KAES published a text and atlas on the normal and pathological cortex, stained
by means of the myelin method. We want to summarize the most important results
here: The cortical thickness is greater in the newborn in the first months of
life than in adults; from the third month of life to the end of the first year,
it rapidly decreases; the decrease progresses slowly and further until the end
of the 20th year of life; around the 20th year it begins to increase again and
reaches its maximum in the 5th decade of life, in order to then decrease again.
Fig. 13, curve I, p. 21, shows this behavior in excerpts from KAES' original
pictures. The gyral cap, the gyral wall and the gyral valley behave rather
uniformly here. But not all parts of the cortex participate identically in
these alterations. KAES therefore divides the cortex into a so-called outer
main layer, including the outer three MEYNERT's layers up to the outer
Baillarger stripe, and the underlying inner main layer. KAES's curve II, Fig.
13, shows that the changes of the total cortical thickness are based
specifically on fluctuations of the outer main layer, that decreases up to the
20th year and then grows significantly again up to the 45th. Actually, the
inner main layer (curve III, Fig. 13) increases progressively but very slowly
from birth up to the fifth decade of life. If this observation should prove to
be a rule, it would be a fundamental fact of the development of the brain during
life, one whose importance is immediately clear to everyone. According to KAES,
individual brain regions adhere to this curve quite differently. It is
applicable to the entire forebrain; however, it does not apply to the visual
cortex - here the development curve shows a more continuous development. In
certain brain regions, the peak of the development curve shifts to other ages;
and so each brain area apparently has its own curve. In KAES's original work
the regional alterations are caused more through the outer main layer than the
one. KAES also determined the number of projection bundles per millimeter-wide
section of the cortex at different ages. We show parts of his curves in Fig.
14. The maximum is reached at approximately the 20th year; however, again both
the number of projection bundles as well as the year of the maximum vary
regionally; the cortex of the anterior central gyrus and the visual cortex
deviate the most from this average curve. KAES thinks furthermore that the
narrower cortex is the more developed and fiber-rich; in the adult this is
usually the left side. Because of the particular development pattern and the
delayed development peak of the outer main layer (in the 5th decade of life!),
KAES believes that it plays a special role in the development of individuality
and higher intellect. One objection to the measurements of KAES is that his
numbers are too large - he gives an average of 4.9 mm for the width of the
cortex at the gyral caps of the convex surface – it should be at most 3.5 mm! -
or too inaccurate. Certainly it would be very desirable to control whether the
rules formulated by KAES retain their validity after a correction of the
measurements. Then it is certain that these rules, particularly regarding the
behavior the outer and inner main layers, would be of fundamental importance.
With the Gudden method NISSL showed experimentally that only the cells of the
inner main layer are connected to the deep ganglia and projection tracks; this
discovery also points out a fundamental difference between outer and inner main
layers. We shall see how much these layers show regional differences in Chapter
4 (cf. p. 116 - 178).
Professor von Economo, early in his career as a scientist
Page 22
(even header): Introductory remarks.
In
CHRISTFRIED JAKOB's still unfinished works "Vom Tierhirn zum
Menschenhirn" and "The Human Brain" there are quite new results.
Although like the aforementioned ones, these are not directly connected with
cytoarchitectonics, they can still influence the latter. For the outer and the
inner main layers, which he considers the two fundamental layers of the fully
developed cortex, through phylogenetic studies and examinations of Gymnophions
(Coecilis lumbricoides) - an
especially suitable object, with a brain structure between amphibians and
reptiles [Note from Jakob's Laboratory, September,
2005: a few years later, Jakob discovered an error in systematics – the
supposed gymnophions were actually amphisbaenids! Prof. Jakob treated the error
humorously throughout his life and reported it in a series of books and
letters, none of which seem to have been known to Professors von Economo and
Koskinas by the time of writing their treatise, completed in September, 1924.
As the systematic position of his observations was duly corrected, the blunder
had no neurobiological consequences. MS] - he could demonstrate a
different origin for each layer. We borrow the following explanations and
illustrations from his book. With amphibians the cerebrum comprises only the
rhinencephalon and the Striatum, and the cerebral pouch that stretches itself
over it is still purely ependymal (Fig. 15). With Coecilia [Amphisbaena;
MS], where this blanket has already developed to a wider, nervous tissue, the
neurons of this formation (Archipallium), that will become Ammon's horn in
higher animals, correspond only to the inner fundamental layer. Those at the
lateral base of the Archipallium remain in continuous contact with the cells of
the Striatum c. st. (Fig. 16a, si). However, at the place (f.m.) where the
actual rhinencephalon (Rh) is bordered in the Fissura marginalis, a lateral
cells row originating from the cells of this rhinencephalon (se) pushes itself
over the cells of the Striatum and the inner fundamental layer (si) and forms
the basis of the outer fundamental layer (se). Together they form the ordinary
cortex, the neopallium. With embryological studies of the central nervous
system of opossums, CHR. JAKOB found places which seem to support this being a
general principle (Fig. 16b). (Compare Fig. 66 image VI of the three-month
human fetus.) He infers that the outer main or fundamental layer (II + III of
MEYNERT) derives originally from the rhinencephalon and is more sensory in
nature, whereas the inner fundamental layer (V + VI), which originates from the
Striatum, is motor in nature. In later life the two unify through layer IV,
whose granular cells form a system of short associations between the two
fundamental layers. The cortex of the Archipallium, which remains relatively
constant throughout animal phylogeny, forms Ammon's horn. The lateral pouch
with the two fundamental layers becomes the neopallium (the actual gray cortex)
through strong growth dorsally and medially and through increase in width. The
always peculiarly built Insula cortex (with the Claustrum) develops from the
area of the marginal fissure. Furthermore, at the base the
"rhinencephalon" has its own further development. The neopallium
develops immensely from outside to inside and folds itself in longitudinal
pleats, the origins of gyri. The most inner one is Ammon's horn, then the Gyrus
limbicus and towards the outside - still recognizable as primitive gyri in the
dog brain - Gyrus ectomarginalis, suprasylvicus, ectosylvicus and insulae. The
Operculum is created through swelling of the cortex edge at the Fissura
marginalis. Besides this ventro-dorsal development, a fan-like unfolding of the
cortex appears in the frontocaudal direction, with a rotation point in the
Insula area. This development causes, beside the above-mentioned segmentation
in primitive gyri, a sector-shaped construction along the longitudinal axis.
This is still very clear in the cortical structure of lissencephalic animals.
Fig. 17 (CHR. JAKOB) clearly shows this. Through further fan-shaped development
posteriorly the occipital lobe arises, and through further twisting of this
rear end downward and again forward the temporal lobe arises. This is described
by the sector diagram of primates (Fig. 18, from JAKOB). Each of these sectors
has its own physiological functions and own anatomical connections. A glance at
Fig. 18 and on our brain map (Figs. 19 and 20, which we show reduced for
comparison) shows a certain astounding similarity of both. The same holds for a
comparison of Fig. 17 with the brain map of lissencephalic animals (Fig. 104,
p. 243). The future will show whether these new and basic thoughts of CHR.
JAKOB on the fundamental layers and the sector development are right. We
mentioned them extensively here, because this description of the main layers is
closely related to our architectural studies and because it is possible that
the similarity of the sector-shaped development and the borders of the Areas
that appear on these illustrations, is based on more than a mere coincidence.
Fig. 15. Cross-section of the amphibian
cerebrum from CHR. JAKOB. The Corpus striatum C.str is well developed, while
the hemisphere cover (Pallium) appears only as a thin ependymal film mep over
the ventricle vl.
Historical Notes
(odd-page header): 23
Fig. 16 a. Cerebrum cross-section of
Coecilis lumbricoides (Gymnophion) from CHR. JAKOB. [Indeed
Amphisbaenidae; see note in text. The misattributed genus' nomen is Caecilia L. 1758, from Pliny the Elder;
occasional Coecilia appears from
1790's on] The Corpus striatum c. St is well developed. The Pallium
closes the ventricle vl dorsally; it is admittedly thin, but already neurons
are present in g (Archipallium). These cells originate from the lateral band of
the Corpus striatum and form the Stratum internum si, later to become the inner
fundamental layer. Rh rhinencephalon; fm Fissura marginalis is the base of the
rhinencephalon. From here a cells row se, the later outer fundamental layer,
grows from lateral and basal dorsally over the si. Therefore, se originally
comes from the rhinencephalon and later merges with the si, which comes from
the Striatum. sz Stratum zonal, sim Stratum intermedium, fh Fissura hippocampi.
- Fig. 16b shows similar relations in a cerebrum cross-section of an embryo of
the opossum (CHR. JAKOB).
Fig. 17. Lissencephalic brain on which,
according to CHR. JAKOB, the fan-shaped development of the sectors in
frontocaudal development is drawn. The Insula forms the rotation point of this
development. Also the segmental arrangement is drawn.
24 Introductory remarks.
Fig. 18 a and b. Primate brain (below) from
CHR. JAKOB also shows the sector development of a sophisticated gyrencephalic
brain. The temporal lobe is pushed downward and forwards through the fan-shaped
growth, and the occipital lobe is moved to the back. - For comparison a
lissencephalic brain is shown above in order to emphasize the movement of the
sectors.
All these
studies laid the foundations of normal cortex architectonics - for the various
purposes and goals discussed above. Major among these was to create the normal
basis necessary for recognition of pathological changes, although the study of
the latter has taken place simultaneously. BETZ and HAMMARBERG already studied
brains from idiots, and KAES included such from criminals. CAMPBELL and later
SCHRÖDER made cytoarchitectonic examinations with pyramidal tract lesions and
amyotrophic lateral sclerosis. KÖLPIN and LEWY with Huntington's chorea,
SPIELMEYER and BIELSCHOWSKY with paralyses without pyramidal tract lesions,
JOSEPH, A. JAKOB, BUSCAINO and KLARFELD, DOUTREBENTE and MARCHAND with Dementia
praecox (catatonia). ALZHEIMER, BRATZ, POLLACK and KOGERER showed changes in cells
and layers with epilepsy. C. and O. VOGT have tried to create bases for a
future patho-architectonics in a detailed treatise (Illnesses of the Cerebral
Cortex), which also includes numerous good pictures of normal cortex sections.
Several detailed publications have appeared from the Viennese neurological
Historical Notes. 25
Fig. 19 and 20. Our cytoarchitectonic brain map. Fig.
19 of the convex surface, Fig. 20 of the median surface of the human cerebrum
(cf. p. 206 and Figs. 92 - 95).
Cortical
measurements Page 41
3. Cortex volumes.
The
ratio of gray cortex to white matter volume decreases with higher ranks in the
animal phylogeny. We can see this for ourselves through a glance at a brain
slice of the rabbit (Fig. 31), in which the gray cortex is extremely broad, and
the white matter mass forms only a quite small inner section (cf. Fig. 25 of
the human). But even in a comparison of a brain cross-section of a lower
monkey, then an orangutan and a human, one is able to see this progressive
increase of white matter mass and relative decrease and thinning of the cortex.
According to CHR. JAKOB, in cross-sections from lower monkeys the gray matter
prevails over the white in the ratio of 5:1; with the Orangutan only by 3:1,
and with the human approximately 2:1.
Page
42 General remarks on the cortex and its neurons.
JAEGER has
measured the volumes of the gray cortex and white matter of the hemispheres. He
determined the volume for brain slices of a certain thickness by means of
ANTON's planimetric measurements. He calculated the volume of the cortex of
both hemispheres at 540 - 580 cm3, and that of the white matter at 400 - 490
cm3 (without the medulla). On average the ratio would be 560:445 or
approximately 1.2: 1. According to DANILEWSKI, the density of the gray matter
is 1038, that of the white matter 1043. Therefore, the total weight of cortex
substance of both hemispheres would be 581 g, that of the white matter
approximately 464 g, and the total of both hemispheres 1045 g (MEYNERT states
1032 g). This corresponds closely to an average total brain weight of 1330 g,
whereby approximately 145 g is due to the cerebellum, and approximately 140 g
to the brainstem. Of course, the absolute volume of cortex gray matter
increases in the animal phylogeny upwards, despite the decrease in the
proportion to the white matter. According to CHR. JAKOB, the ratios of cortex
gray volume of the lower monkeys to the Orangutan and the human are as 1: 5:
24, since the increase of the whole cerebrum is so great. (The brain of a
full-grown Orangutan weighs approximately 500 g, with brainstem and
cerebellum.) JAKOB could not find a conspicuously regular difference between
right and left hemisphere cortical volumes. The left to right ratio was in one
case 290:250 cm3, but many times the cortex gray volume of the right hemisphere
was greater than that of the left.
Page 44
General remarks on the cortex and its neurons.
In
HENNEBERG's table the beautiful surface development of the Hottentott and Javan
brains are very notable, often surpassing the European brains - a warning
against deriving rushed conclusions from such data. WAGNER found 54,000 mm2 for
the surface of the full-grown orangutan brain, 21,000 mm2 of it free surface
and 33,000 mm2 hidden. CHR. JAKOB gives the ratio of the total cortical surface
of the monkey to the Orangutang to the human as 1:5:17.