Part 3

And in another place he says: ›If the cerebrum is either inflamed or obstructed, or flaccid, or injured otherwise, the intellectual faculty is unsettled; as in paralysis, melancholy, in cases of delirium, in atrophy, apoplexy, in fevers, and other diseases; nay, the determination of the will also is similarly affected. For each single cortical substance contributes its share to this intellectory, that is, to this organ of the understanding, etc.› (›The Brain›, No. 104, r).

All these observations concerning the consequences of injury to the cerebral cortex—and the above-mentioned discoveries regarding the structure of the cerebral substance and the hypotheses concerning the relation of the cerebral cortex and cortical elements to the ›spiritus animalis› and the perceptions,—these _clinical_ and _anatomical experiences taken together_ seem to have led SWEDENBORG to the conviction that the activity of the soul and not least that just now in question, the sensory, had its seat in the cortex of the cerebrum.

He now enters into a detailed analysis of the course of the sensory nerves as far as they are able to be demonstrated (›in ipsius oculi luce›), and he thus follows the optic nerves to the optic thalami, and thence their radiation towards the cerebral cortex, the olfactory nerves to the corpora striata or the medulla of the centrum ovale and from there out towards its cortical surroundings, the auditory nerves to the medulla oblongata and thence up toward the cortex of the cerebrum, (›versus supremum corticem›), and in the same manner he follows the nerves of taste and touch. (See Œc. R. A. II., No. 192; and III., No. 66). He cannot now follow further the particular fibres through the medulla all the way to the cortex, of whose importance for consciousness and sensibility he became convinced through the clinical experiences, but here he must _suppose_ a connection, and he says: ›these effects (conscious perceptions) could never be produced ... unless in every quarter there were _a mutual connection and perpetual communication of the cortical substance with the medullary_, as regards the fibrils ...›, (as well as a special arrangement of the cortical elements and special qualifications in them, of which more will be said later).[66]

From all this it is clear, that it was probably through _a combination of clinical and anatomical experiences_ that SWEDENBORG secured the premises for his conclusions that the centre of the soul’s sensory activity is in the cortex of the cerebrum.

ON THE CENTRES OF THE MOTOR FUNCTIONS.

SWEDENBORG also placed the centres of the soul’s motor activity in the cerebral cortex (See Œc. R. A., No. 127, etc.).

I have not been able to find anything of this kind even hinted at in the antecedent literature. We are reminded of how preceding authors, who made an attempt at some kind of localization of the origin of motion, in most cases placed this in the medulla of the brain, as for example the BARTHOLINS;[67] and also BOERHAAVE.[68] And as we have just heard, HALLER still held the same view.[69] Nevertheless SWEDENBORG expresses his conception without the slightest hesitation, and this he did because he regarded it as resting on a sure foundation. His strongest grounds and proofs were here also derived from the _clinical and pathological observations_ in certain cerebral diseases which had caused changes in the cortex, and in patients, who had been injured in the cerebral cortex. It was these clinical cases at which I hinted just now. And now some of these may be brought forward, for the most part as SWEDENBORG himself has related them—with some few abbreviations:

A female seventy years of age, who after exhibiting the premonitory symptoms of apoplexy for some months suddenly _lost the power of speech_, and on being conveyed to bed, lost all sensation and motion. On a post mortem examination a large cavity was found in the cortical substance of her brain (›in ejus Cerebri substantia corticali ampla cavitas reperta fuerit›, see Œc. R. A. II., No. 154). The case was taken from J. J. WEPFER’s ›_Historiae Apoplecticorum_› (Amsterdam, 1681, pp. 5-11).

Another case taken from WEPFER was the following: A man 50 years of age had for some weeks before his death suffered from excruciating headache, the pain of which sometimes drove him mad, so that he was not seldom unconscious of what he said and did. On examining his head after death, the whole surface of the cerebrum and cerebellum, including both the convolutions and the furrows between them, seemed to be clogged all over with a gelatinous substance, from which, when it was pricked with a lancet, genuine serum oozed out. And also the very substance of the cerebrum and cerebellum had imbibed a large quantity of serum. (Œc. R. A., loco cit. and J. J. WEPFER: Op. cit., p. 15-19).

A case from A. PACCHIONI was as follows: A young man had died under symptoms of fever, severe headache and _spasms_, or _cramp_. On opening his cranium, it appeared that the firm fibrous membrane of the brain, the dura mater, was loosened from the bone on the top of the head; and here, according to the description, it had exercised a strong pressure upon the underlying portion of the brain and was tightly adherent to it. (Œc. R. A., loc. cit.)——Consequently, in the last two cases: inflammation of the membranes of the brain, or meningitis with accompanying influence upon the superficial layer of the brain, the cerebral cortex.

And still another case from PACCHIONI, which was still more convincing: A youth was brought into the hospital in an almost unconscious condition, spoke incoherently, cast himself about in all directions, etc.; and furthermore——his _lips were somewhat drawn over to the left side_ (›_labris ad sinistrum paululum detractis_›), thus a right-sided _facial paralysis_! On examination after death no injuries could be found upon the integuments of the head, nor upon the outer or inner sides of the cranium, but on the left side of the brain _a depression of the cortex_ was discovered, occasioned by the formation of a tumor or ›bladder› on that part of the surrounding dura mater lying just over the place of depression: ›_ibi depressus et durioris consistentiae cortex cerebri cavernam ostendebat vesicae congruentem_.›[70]

SWEDENBORG brought forward still more cases, so incomplete, however, that it is not worth while to repeat them here. But he had at hand a very large number of cases, as he says: ›phalanges observationum idem testificantium› (Œc. R. A. No. 154), or, as he says in another place, so many that a bare enumeration of them would fill two whole pages (Œc. R. A. II., 154).

SWEDENBORG had made a specially careful study of a great many _cases of apoplexy_ and _hemiplegy_, which naturally, in so far as they affected the cortex, gave him direct guidance in judging of its function. And he also understood very well how to judge at the same time with regard to the importance of bleedings in the soft membrane of the brain, the pia mater, on and between the convolutions of the brain, the ›gyri›, and the pressure that these exercise upon the cortex, and the results of prevented circulation in cases of apoplexy. For in all these cases, he says, the transmission of blood to the cortex is checked, and by this the cortex was disturbed in its function, and this was the cause of the loss of sensation and of the paralysis. (Œc. R. A., III., No. 411 and III., No. 413; see also ›The Brain›, No. 89).

But SWEDENBORG had also directed his attention to that method of investigation which, to the brain physiologists of the present day, is the best aid for the examination of the motor functions of the cerebral cortex, namely, _experiments on animals_. He quotes such experiments, in which _incisions_ had been made into the cortex ›just to the marrow›, as it is expressed, (›usque ad substantiam medullarem› [RIDLEY], Œc. R. A., I., No. 505); or when the brain (in dogs) had been _pierced_, (Œc. R. A., II., No. 154), and how these injuries had occasioned spasms or contractions of the trunk or extremities (RIDLEY). He also describes such cases in which fine needles had been pierced through the dura mater and corrosive liquors introduced through the holes, with the result that severe disturbances occurred in both motility and sensibility, and also how through such injuries muscular contractions had been provoked, by which it was sometimes observed that with certain stimuli the contractions first occurred in certain groups of muscles (for example, in the head or neck) and afterwards spread to the other parts of the body. (BAGLIVI ›The Brain›, No. 20).

As will be seen, these experiments were no ›precision-investigations›; and the same may be said of the clinical and pathological ones. And this may be the more easily understood, when we consider that in those times so much interest was not attached to such special observations of pathological changes in the cerebral cortex; for this was then regarded only as a gland, a secreting organ or reservoir for the ›spiritus animalis›. These observations were therefore made more as it were in passing. The same is also true of the experimental investigations on animals, quoted above. These were in reality made not in order to investigate any function of the cortex, but for other purposes, namely, in order to search out the causes of the pulsations of the brain, or the qualities and functions of the dura mater, etc.

Yet, as we shall see later on, some of the cases, in the original descriptions, really contain statements somewhat more exact and of greater interest even for the theory of cortical localizations, than those which SWEDENBORG quoted; but he seems to have here adduced no more than what had reference to the _cortex regarded as a whole_, and which showed what great changes in both the power of sensation and motion injuries in the cortex could produce. If we take this into consideration, and if we synthesize all these experiences, and add to this the increased knowledge concerning the minute structure of the brain, which had been produced especially by MALPIGHI’s discoveries, we must admit that SWEDENBORG had good reasons for his view that the soul’s activity had its seat in the cortex of the cerebrum.

THE DOCTRINE OF LOCALIZATIONS.

But SWEDENBORG, as is well known, did not stop here. The cerebral cortex certainly constituted a whole which transformed the sensations into thoughts and determinations, but all the regions of the cortex were not of the same degree: some ruled the higher, others the lower functions, thus also containing subdivisions, in some of which the sense-impressions were received, in others from which the motor impulses proceeded. (See ›The Brain›, Nos. 66, 68, 71, 88, 98, 100, 102, etc.).

This conception of the brain appears at first glance as very modern. But upon searching the literature before SWEDENBORG’s time one finds that the thought was not so entirely original. New was the thought of attributing the psychical functions to the cortex, new also was the attempt to accurately determine upon the place where the different functions originate; but the _idea of localization_ itself is found again in the literature which SWEDENBORG already had at his disposal.

BOERHAAVE, for instance, says, in his ›Institutiones medicæ›, when speaking of the sensations, that they give rise to _different perceptions_, partly owing to the differing species and nature of the outer objects, and partly to the different natures of the sense-organ and the affected nerve, but partly also _to the different regions in the cerebral medulla from which the nerve proceeds_. Thus we have here a kind of localization to a special region of the brain, although in its _medulla_.[71] And still more clearly does BOERHAAVE express the same idea in his ›Prælectiones academicae,› where he says: ›In the ’Sensorium commune’ there are _regions locally distinguished for the different senses, just as every sense has its own special sense-organ_.›[72]

And before BOERHAAVE the philosopher DESCARTES had expressed an idea concerning a certain form of localization of the various elements of psychic activity. For he supposed that the images of sensation and the images of the memory, etc., which the soul perceives, arise on those places on the walls of the brain’s central ventricle, where, according to his opinion, the various nerves originate. In a similar way he also imagined the origin of motility localized. (R. DESCARTES: ›De homine›, publ. by F. SCHUYL, Ludg. Bat., 1662).

We here reproduce some illustrations from the work of DESCARTES just mentioned, which are designed to show how he thought that the images of sensation arise. — — See the figures 1, 2, 3.

We thus see that the idea of localization itself was not altogether new. But how did SWEDENBORG ultimate and develope it?

With regard to function SWEDENBORG divided the hemispheres of the cerebrum into two parts: one anterior region and one posterior, conceiving the fissure of Sylvius as the dividing boundary between them. (›The Brain›, Nos. 16, 88, 91).

To the anterior region he attributed the actual operation of the soul, while he supposed that the posterior region was chiefly engaged in the animation of the blood. He adds, however, ›it cannot be denied that sensations reach even the posterior region of the brain, yet our mind does not become conscious of them to the same degree as it does in the anterior region› (›The Brain›, No. 71).

In this _anterior region of the cerebrum_ he distinguished _three lobes_, or so called ›curiae›, the first one highest up, ›in the crown›, a middle one below it, and a third one lowest down, _i. e._, nearest to the fissure of Sylvius.[73] In these three lobes the actual psychic life is developed, and that so much the more clearly and perfectly, the higher up in the region these intricate processes occur. It is here that perceptions, thoughts, judgments, conclusions, come into being; it is from here that ultimately will and determination issue. (See ›The Brain›, Nos. 12, 66, 71, 88, 98, 100, 102).

As regards the sensory part of the psychic activity, SWEDENBORG does not make any attempt at a detailed localization; but as regards the motor functions he arranges their centres within the above-mentioned regions as follows: ›_The muscles and actions_ which are _in the ultimates of the body_ or in the soles of the feet seem to depend more immediately _upon the highest parts_ (_of the brain_), upon _the middle lobe_ the muscles which belong to _the abdomen and thorax_, and upon the _third lobe_ those which belong to _the face and head_;› and he adds, ›for they seem to correspond to one another in an inverse ratio› (›The Brain›, No. 68).

Whence did SWEDENBORG get all this? Whence the whole of this doctrine of localizations? In his first great anatomical work, ›Œconomia Regni Animalis›, nothing is said about it; first in his last anatomical work, ›De Cerebro›, is it advanced, and then — — — quite finished! One is at first glance tempted to think that he had succeeded in finding some new clinical experiences, upon which he could found this doctrine. For he had not even finished the account of the function of the brain’s anterior region, before interjecting: ›Therefore, if this portion (the anterior region) of the cerebrum is wounded, then the internal senses—imagination, memory, thought—suffer; the very will is weakened, and the power of its determination blunted. This is not the case if the injury is in the back part of the cerebrum› (›The Brain›, No. 88). But afterwards he does not bring forward (in ›De Cerebro›) any observations which could serve as proof with regard to this. And if one examines the cases he has referred to in his preceding works, one cannot possibly arrive at the localization of the psychic functions which he has here (in ›De Cerebro›) sketched; for the evidence concerning the _position_ of the injuries in the cortex are entirely too scanty and incomplete. But if we consult the _original descriptions_, we find there many other and more particular data than those quoted by SWEDENBORG when he was only concerned in explaining the function of the cortex as a whole. WEPFER, for instance, reports in his ›Historiæ apoplecticorum› concerning the woman seventy years of age, who suddenly _lost the power of speech_, that the cavity, filled with blood, which was found in the cortex at the autopsy, was located in the right hemisphere, _just behind the forehead_ (›ad frontem fere antrorsum›), and that it extended rather far both backwards and upwards; even measurements were given (length 8, breadth 4, depth about 2 uncias). It was also stated that the blood-vessels whose bursting caused bleeding belonged to the antero-lateral branches of the carotid artery in the brain. It is also mentioned that no changes were found in the left hemisphere of the brain; and from the clinical account it appears that even after the stroke the woman was able to move the extremities of the right side.[74] — — — All this indicates quite evidently that the lesion of the cortex was situated in the anterior region of the brain!

And PACCHIONI reports concerning the youth, who was afflicted with the right-sided _facial paralysis_, that even the extremities of the right side were somewhat paralysed, and that the cyst, which at the post mortem examination was found on the left hemisphere, extended _from the crown to the region of the temple_ (›a capitis vertice in temporalem regionem›).[75] Thus this case also furnishes an unmistakable indication that the cortical lesion was situated in the anterior region of the brain.

It seems strange that SWEDENBORG did not here supply an account of these interesting and convincing cases, which he nevertheless, as we have seen, was well acquainted with. For his habit is to furnish the chapters of his works with an introduction in which he reports, often in very detailed form, the statements of the authors upon which he bases his conclusions. Since in the present case such an account is lacking, this may depend: either upon the fact that this last anatomical work of SWEDENBORG, ›De Cerebro›, was not quite completed and finally edited for the press, or thereon that Dr. RUDOLF TAFEL, who edited the translation which is now accessible in print, excluded it. For Dr. TAFEL says in a note that the introduction to the chapter in question would be introduced into Part II., chapters 1 and 2, but—Part II. was never printed! Since, however, the Royal Swedish Academy of Sciences will publish ›De Cerebro› in its edition of SWEDENBORG’s Scientific works, this question will no doubt be cleared up. But this much is quite clear from what has already been adduced, that the cases of paralysis which SWEDENBORG previously quoted in a brief form are in the original descriptions reported so completely and in such detail that one can without the least doubt localize the cortical lesions reported in those cases in the anterior (superior) region of the cerebrum.

We now pass to an examination of the _anatomical_ literature to which SWEDENBORG had access. And, as we shall find, we can here see whence SWEDENBORG derived _material for his detailed doctrine_ concerning the function of the brain’s anterior region. This becomes evident on comparing SWEDENBORG’s mode of thinking of the brain’s psychical activity with the descriptions of preceding authors in anatomy.

The group of nuclei, ›_corpus striatum_›, in the cerebrum had been an object of special interest for preceding authors.

The Englishman, THOMAS WILLIS, had for example in his ›Cerebri anatome› (published in 1667) portrayed them as a kind of junction, ›internodes›, by which the cerebrum coheres with the medulla oblongata; and he pays special attention to it on account of its peculiar structure (›The Brain›, No. 476); and he is said even to have attributed to them the ›Sens commun›.[76]

And the professor in Montpellier, RAIMOND VIEUSSENS, had given in his ›Neurographia universalis› (published in 1685) a very exact description of the ›corpus striatum›, (not only of its ›superior nuclei›: ›Corp. striat. sup. ant.› = Nucleus caudatus and ›Corp. striat. sup. post.› = ›Thalamus opticus›, but also of its lower lateral nucleus = ›Nucleus lentiformis›) as also of the mighty medullary tract of nerve fibres, i. e., ›capsula interna›, which passes through the same, and which on the one hand is distributed to the brain, especially to its anterior (superior) region, and on the other hand by means of the nerves radiates into the various parts of the body.

(In order to facilitate orientation we may refer to C. TOLDT: ›Anatomischer Atlas›, 1899, 8 Lieferung, Fig. 92: ›Querschnitt des verlängerten Markes und der Gehirnstiele. Verlauf der Pyramidenbahn von der Pyramidenkreuzung an durch die Pyramide, die Brücke und die Basis des Grosshirnstiels in die innere Kapsel, woselbst sie in den Stiel des Stabkranzes, Pedunculus coronæ radiatæ, eingeht.›)

SWEDENBORG, who had studied and often quoted both WILLIS and VIEUSSENS, likewise attributed a very great significance to the corpus striatum. All the sensory impressions pass through it to the brain, and all the voluntary impulses to motion pass out by the same path. (›The Brain›, No. 67). ›It is›, says he in his figurative way, ›in a certain sense, the Mercury of the Olympus; it announces to the soul what is happening to the body, and it bears the mandates of the soul to the body› (›The Brain›, No. 67).

And as the corpus striatum lay most immediately under the anterior (superior) region of the brain, and was in close connection with it, so the sensory impressions would for the most part pass to this region, and the voluntary impulses to motion would likewise proceed from it (›The Brain›, Nos. 66, 67).

The same VIEUSSENS had furnished a very detailed description of the passage of the nerve tracts in question, which pass through the corpus striatum and capsula interna, and had followed them both upwards towards the hemispheres of the brain and downwards towards the spinal cord. When he followed them upwards, he found that they formed _three regions_ in the ›centrum ovale›: the _regio superna_, highest up nearest the crown, the _regio media_, in the middle, and the _regio infima_, lowest down, and consequently nearest the fissure of Sylvius. (R. VIEUSSENS: ›Neurographia univ.›, pp. 115 and 117).