scholarly journals XIV. Electro-physiological researches.—Sixth series. Laws of the electric discharge of the torpedo and other electric fishes— theory of the production of electricity in these animals

1847 ◽  
Vol 137 ◽  
pp. 239-241 ◽  
Keyword(s):  
Electric Discharge ◽  
Electric Fish ◽  
The Body ◽  
Spinal Marrow ◽  
The Will ◽  
The Subject ◽  
Electric Fishes ◽  
The Brain

The present memoir is not a mere description of a certain number of facts lately discovered on the electricity of electric fishes; besides this, and more than this, it contains the laws and theory of these phenomena. Consequently the order of exposition of the facts in this memoir will be the same as that which a scientific arrangement of the subject would dictate. It is needless to remind the reader that the discharge of the electric fishes is subject to the will of the animal. On irritating any point of the body of an electric fish, it is easy to demonstrate by experiment that this irritation is transmitted by the nerves to the fourth lobe of the brain, and that then only the discharge takes place. If the spinal marrow be divided at any part of its length in a living torpedo, every kind of irritation below the point of section fails to produce any effect.

VI. Experiments made with a view to ascertain the principle on which the action of the heart depends, and the relation which subsists between that organ and the nervous system

1815 ◽  
Vol 105 ◽  
pp. 65-90 ◽  
Keyword(s):  
Nervous System ◽  
The Body ◽  
The Other ◽  
Modus Operandi ◽  
Spinal Marrow ◽  
Difference Of Opinion ◽  
The Subject ◽  
The Brain ◽  
General Opinion ◽  
Nervous Influence

The following experiments were begun with a view to as­ certain the manner in which certain poisons act in destroying life. I soon found that, in order to make any considerable progress in such an inquiry, it is necessary to ascertain how far the powers of the nervous and sanguiferous systems di­rectly depend on each other. There seems never to have been any difference of opinion respecting the direct depend­ence of the nervous on the sanguiferous system. When the powers of circulation are increased or diminished, the nervous system always suffers a corresponding change, nor can the latter, under any circumstances, continue to perform its functions after the former are destroyed. I speak of the warm blooded animals. In cold blooded animals the process of dying is so slow, that the functions of the nervous system abate very gradually, after the circulation has wholly ceased. The converse of the above proposition is by no means so generally admitted. It is evident that certain changes of the nervous, produce corresponding changes in the sanguiferous, system ; yet, while some assert, that the action of the heart depends as immediately on the brain, as that of the latter does on the heart, others maintain, that the nervous power may be wholly destroyed without impairing the vigour of this organ. This point it is necessary to determine, before we can trace with precision the modus operandi of poisons. The following inquiry therefore may be divided into two parts. In the first, I shall endeavour to ascertain how far the power of the heart is influenced by the state of the nervous system; in the other, by what steps certain poisons destroy the powers of both. This I shall reserve for another paper, and here confine my­self to the first part of the subject. Till the time of Haller, it seems to have been the general opinion, that the muscles derive their power from the nervous system. He taught, that the power of the muscles depends on their mechanism, that the nervous influence is merely a stimulus which calls it into action, and consequently that those muscles, the heart for example, which act only by the appli­cation of one peculiar stimulus, unconnected with the nervous system, are wholly independent of it. This opinion seemed confirmed by its being generally admitted, that the action of the heart continues after it is removed from the body, and that it cannot be influenced by stimulating the brain, or spinal marrow, or the nerves which terminate in it. Haller and his followers maintain, that there are two distinct vital powers, one of the nervous and another of the sanguiferous system.

Imaging and the Human Brain Project: A Review

2002 ◽  
Vol 41 (04) ◽  
pp. 245-260 ◽  
Author(s):  
C. Rosse ◽  
J. F. Brinkley
Keyword(s):  
Human Brain ◽  
Physical Structure ◽  
Imaging Informatics ◽  
The Body ◽  
Human Brain Project ◽  
The Us ◽  
Physical Organization ◽  
The Subject ◽  
The Individual ◽  
The Brain

Summary Objectives: Survey current work primarily funded by the US Human Brain Project (HBP) that involves substantial use of images. Organize this work around a framework based on the physical organization of the body. Methods: Pointers to individual research efforts were obtained through the HBP home page as well as personal contacts from HBP annual meetings. References from these sources were followed to find closely related work. The individual research efforts were then studied and characterized. Results: The subject of the review is the intersection of neuroinformatics (information about the brain), imaging informatics (information about images), and structural informatics (information about the physical structure of the body). Of the 30 funded projects currently listed on the HBP web site, at least 22 make heavy use of images. These projects are described in terms of broad categories of structural imaging, functional imaging, and image-based brain information systems. Conclusions: Understanding the most complex entity known (the brain) gives rise to many interesting and difficult problems in informatics and computer science. Although much progress has been made by HBP and other neuroinformatics researchers, a great many problems remain that will require substantial informatics research efforts. Thus, the HPB can and should be seen as an excellent driving application area for biomedical informatics research.

On the reflex function of the medulla oblongata and spinalis, or the principle of tone in the muscular system

1837 ◽  
Vol 3 ◽  
pp. 210-210
Keyword(s):  
Nervous System ◽  
Medulla Oblongata ◽  
Hydrocyanic Acid ◽  
Muscular System ◽  
Spinal Marrow ◽  
Reflex Action ◽  
The Will ◽  
The Brain ◽  
Morbid State

The author, after commenting on the opinions of Le Gallois and Cruveilhier relating to the functions of the spinal marrow, adverts to a property or function of the medulla oblongata and spinalis, which he considers as having escaped the notice of these and all other physiologists; namely, that by which an impression made upon the extremities of certain nerves is conveyed to these two portions of the nervous system, and reflected along other nerves to parts different from those which received the impression. He distinguishes muscular actions into three kinds: first, those directly consequent on volition; secondly, those which are involuntary, and dependent on simple irritability; and thirdly, those resulting from the reflex action above described, and which include those of the sphincter muscles, the tonic condition of the muscles in general, the acts of deglutition, of respiration, and many motions, which, under other circumstances, are under the guidance of the will. Volition ceases when the head or brain is removed; yet, as he shows by various experiments, movements may be then excited in the muscles of the limbs and trunk, by irritations applied to the extremities of the nerves which remain in communication with the spinal marrow: but these actions cease as soon as the spinal marrow is destroyed. Hence the author concludes that they are the effect of the reflex Action of the spinal marrow, which exists independently of the brain; and, indeed, exists in each part of the organ independently of every other part. He considers that this reflex function is capable of exaltation by certain agents, such as opium and strychnine, which in frogs produce a tetanic and highly excitable state of muscular irritability. Hence he is led to view the reflex function as the principle of tone in the muscular system. He considers that certain poisons, such as the hydrocyanic acid, act by destroying this particular function. The effects of dentition, of alvine irritation, and of hydrophobia, of sneezing, coughing, vomiting, tenesmus, &c. &c., are adduced as exemplifications of the operation of the same principle when in a morbid state of exaltation.

scholarly journals When Far Becomes Near: Remapping of Space by Tool Use

2000 ◽  
Vol 12 (3) ◽  
pp. 415-420 ◽  
Author(s):  
Anna Berti ◽  
Francesca Frassinetti
Keyword(s):  
Tool Use ◽  
Right Hemisphere ◽  
The Body ◽  
Line Bisection ◽  
Human Studies ◽  
Bisection Task ◽  
Near Space ◽  
The Subject ◽  
Line Bisection Task ◽  
The Brain

Far (extrapersonal) and near (peripersonal) spaces are behaviorally defined as the space outside the hand-reaching distance and the space within the hand-reaching distance. Animal and human studies have confirmed this distinction, showing that space is not homogeneously represented in the brain. In this paper we demonstrate that the coding of space as “far” and “near” is not only determined by the hand-reaching distance, but it is also dependent on how the brain represents the extension of the body space. We will show that when the cerebral representation of body space is extended to include objects or tools used by the subject, space previously mapped as far can be remapped as near. Patient P.P., after a right hemisphere stroke, showed a dissociation between near and far spaces in the manifestation of neglect. Indeed, in a line bisection task, neglect was apparent in near space, but not in far space when bisection in the far space was performed with a projection lightpen. However, when in the far space bisection was performed with a stick, used by the patient to reach the line, neglect appeared and was as severe as neglect in the near space. An artificial extension of the patient's body (the stick) caused a remapping of far space as near space.

scholarly journals On the nerves

1843 ◽  
Vol 4 ◽  
pp. 434-435
Keyword(s):  
Longitudinal Direction ◽  
The Body ◽  
Natural Temperature ◽  
The Will ◽  
Voluntary Motion ◽  
The Individual ◽  
Tubular Membranes ◽  
The Brain

The author gives the results of his examinations, both microscopical and chemical, of the structure and composition of the nerves; and concludes that they consist, in their whole extent, of a congeries of membranous tubes, cylindrical in their form, placed parallel to one another, and united into fasciculi of various sizes; but that neither these fasciculi nor the individual tubes are enveloped by any filamentous tissue; that these tubular membranes are composed of extremely minute filaments, placed in a strictly longitudinal direction, in exact parallelism with each other, and consisting of granules of the same kind as those which form the basis of all the solid structures of the body; and that the matter which fills the tubes is of an oily nature, differing in no essential respect from butter, or soft fat; and remaining of a fluid consistence during the life of the animal, or while it retains its natural temperature, but becoming granular or solid when the animal dies, or its temperature is much reduced. As oily substances are well known to be non-conductors of electricity, and as the nerves have been shown by the experiments of Bischoff to be among the worst possible conductors of this agent, the author contends that the nervous agency can be neither electricity, nor galvanism, nor any property related to those powers; and conceives that the phenomena are best explained on the hypothesis of undulations or vibrations propagated along the course of the tubes which compose the nerves, by the medium of the oily globules they contain. He traces the operation of the various causes which produce sensation, in giving rise to these undulations; and extends the same explanation to the phenomena of voluntary motion, as consisting in undulations, commencing in the brain, as determined by the will, and propagated to the muscles. He corroborates his views by ascribing the effects of cold in diminishing or destroying both sensibility and the power of voluntary motion, particularly as exemplified in the hybernation of animals, to its mechanical operation of diminishing the fluidity, or producing solidity, in the oily medium by which these powers are exercised.

scholarly journals On the decussation of fibres at the junction of the medulla spinalis with the medulla oblongata

1843 ◽  
Vol 4 ◽  
pp. 71-72
Keyword(s):  
Medulla Oblongata ◽  
Royal Society ◽  
The Body ◽  
Cerebral Lesion ◽  
Common Occurrence ◽  
Satisfactory Explanation ◽  
Actual Structure ◽  
Spinal Marrow ◽  
Motor Columns ◽  
The Brain

The author first alludes to what usually happens in affections of the brain, namely, that the loss of voluntary power and of sensation, manifest themselves in the opposite side of the body to that in which the cerebral lesion exists, a fact which has been attempted to be explained by the crossing of the fibres at the junction of the medulla oblongata with the anterior or motor columns of the medulla spinalis ; but such a structure, he observes, affords no explanation of the loss of sensation. The author then, referring to the communication of Sir Charles Bell to the Royal Society, in the year 1835, describing a decussation connected with the posterior columns, or columns of sensation, mentions that the accuracy of these dissections was doubted by Mr. Mayo and other eminent anatomists. The author proceeds to state that the symptoms of cerebral lesion do not always take place on the opposite side of the body to that in which the lesion of the brain exists, but that they occur sometimes on the same side; that the loss of power and of sensation, although confined to the same side, may exist in either the upper or the lower extremity; but that both are not necessarily implicated; and that, in fact, cases occur where there are marked deviations from what may be considered the more common occurrence. Having observed such cases, and not being aware of any satisfactory explanation, the author examined with care the continuation upwards of the anterior and posterior columns of the spinal marrow into the medulla oblongata and found that the decussation at the upper part of the spinal marrow belonged in part to the columns for motion, and in part to the columns for sensation; and farther, that the decussation is only partial with respect to either of these columns; thus elucidating hy the observation of the actual structure what before appeared very unsatisfactory in pathology, and anomalous in disease. The paper is illustrated by drawings made from the dissections of the author.

The Chemical Constitution of Cerebrine

1880 ◽  
Vol 26 (113) ◽  
pp. 32
Author(s):  
Edward G. Geoghegan
Keyword(s):  
The Body ◽  
Chemical Constitution ◽  
The Subject ◽  
The Brain

To judge from the sparse literature of the subject, cerebrine has not often been chemically studied. The first work of any importance was done by W. Müller.∗ Müller obtained the body, which he called “Cerebrine,” free from phosphorus by digesting the brain with baryta-water. He also analysed it, and proposed the formula, C34 H33 NO6.

scholarly journals On the nature of sleep

1837 ◽  
Vol 3 ◽  
pp. 179-180
Keyword(s):  
External World ◽  
Muscular Fibre ◽  
Natural Consequence ◽  
Vital Function ◽  
Spinal Marrow ◽  
The Subject ◽  
The Law ◽  
The Mind ◽  
The Brain ◽  
Do So

The author intends the present paper as a continuation of his in­quiries into the relations subsisting between the nervous and muscu­lar systems, which form the subject of his former papers, but which would be incomplete without the consideration of their condition during sleep. With this view he proposes to determine the particular organs, on the condition of which this peculiar state of the system depends; the laws by which it is governed ; and the influence it has upon other parts of the system. The necessity of intervals of repose applies only to those functions which are the medium of intercourse with the external world, and which are not directly concerned in the maintenance of life. The organs subservient to these two classes of functions may be viewed as in a great degree distinct from one an­ other. The brain and spinal marrow constitute alone the active por­tions of the nervous system. The law of excitement, which regulates the parts connected with the sensorial functions, including sensation, volition, and other intellectual operations, and the actions of the vo­luntary muscles, is uniform excitement, followed by a proportional exhaustion; which, when occurring in such a degree as to suspend their usual functions, constitutes sleep j all degrees of exhaustion which do not extend beyond the parts connected with the sensorial functions being consistent with health. On the other hand, the law of excitement of those parts of the brain and spinal marrow which are associated with the vital nerves, and are subservient to the vital func­tions, is also uniform excitement; but it is only when this excitement is excessive that it is followed by any exhaustion; and no degree of this exhaustion is consistent with health. The law of excitement of the muscular fibre, with which both the vital and sensitive parts of the brain and spinal marrow are associated, namely, the muscles of respi­ration, is interrupted excitement, which, like the excitement of the vital parts of these organs, is, only when excessive, followed by any degree of exhaustion. The author conceives that the nature of the muscular fibre is everywhere the same; the apparent differences in the nature of the muscles of voluntary and involuntary motion de­pending on the differences of their functions, and on the circumstances in which they are placed: and he concludes, that, during sleep, the vital, partaking in no degree of the exhaustion of the sensitive system, appears to do so simply in consequence of the influence of the latter on the function of respiration, the only vital function in which these systems co-operate. The author proceeds to make some observations on the cause of dreaming, the phenomena of which he conceives to be a natural consequence of the preceding proposition. In ordinary sleep, the sensitive parts of the brain, with which the powers of the mind are associated, are not in a state of such complete exhaustion as to preclude their being excited by slight causes of irritation, such as those which accompany the internal processes going on in the system. The sensorium is the more sensible to the impressions made by these internal causes, inasmuch as all the avenues to external impressions are closed, and the mind is deprived of the control it exercises, during its waking hours, over the train of its thoughts, by the help of the perceptions derived from the senses, and the employment of words for detaining its ideas, and rendering them objects of steady attention, and subjects of comparison.

scholarly journals XIV.—Of the Fourth and Sixth Nerves of the Brain;—being the concluding paper on the distinctions of the Nerves of the Encephalon and Spinal Marrow

1839 ◽  
Vol 14 (1) ◽  
pp. 237-241 ◽  
Author(s):  
Charles Bell
Keyword(s):  
Optic Nerve ◽  
Royal Society ◽  
Circular Muscle ◽  
Complex Nature ◽  
Spinal Marrow ◽  
The Subject ◽  
The Brain ◽  
Royal Society Of London

Interesting as theoptical properties of the eye have been to philosophers in every age, there are conditions of this organ which are no less curious, and which have not had their share of attention.In the year 1823, I introduced the subject to the Royal Society of London, nearly in the terms I am now using, but there is much more in the subject than I then conceived, although I see no reason to change the mode of contemplating it.The eight muscles of the eye, and the five nerves, exclusive of the optic nerve, which pass to them, imply the complex nature of the apparatus exterior to the globe, and I fear it is too plain that the subject has not been satisfactorily treated.It is chiefly with respect to the protecting motions of the eye that the difficulty occurs, for I hope the dependence of the proper organ of vision on the voluntary muscles of the eye, has been proved and acknowledged.Permit me to draw the attention of the Society to what appears a very simple piece of anatomy, the circular muscle which closes the eyelids, orbicularis palpebrarum.

scholarly journals A letter on a canal in the medulla spinalis of some quadrupeds. In a letter from Mr. William Sewell, to Everard Home, Esq. F. R. S

1832 ◽  
Vol 1 ◽  
pp. 325-325
Keyword(s):  
Fourth Ventricle ◽  
Human Subject ◽  
Transverse Section ◽  
The Other ◽  
Small Stream ◽  
Spinal Marrow ◽  
The Subject ◽  
Present Description ◽  
The Brain

The canal, which is the subject of this letter, appears to have been discovered by the author in the year 1803, although no account has been given of it till the present description was drawn up at the request of Mr. Home. From the extremity of the sixth ventricle of the brain in the horse, bullock, sheep, hog, and dog (which corresponds to the fourth ventricle in the human subject), a canal passes in a direct course to the centre of the spinal marrow, and may be discovered in its course by a transverse section of the spinal marrow in any part of its length, having a diameter sufficient to admit a large-sized pin; and it is proved to be a continued tube, from one extremity to the other, by the passage of quicksilver in a small stream in either direction through it.

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