In an animal from which the cerebellum has been removed, the functions of life do not appear to be destroyed, but all power of either walking or flying straight is lost.
Disease or injury of the cerebellum usually produces blindness, giddiness, a tendency to move backwards, a staggering, irregular gait, and a feeling of insecurity in maintaining various positions.
The cerebellum is connected with other parts of the nervous system by strands of white matter on each side, radiating from the center and divided into numerous branches.
The functions of the cerebellum are not certainly known.
The cerebellum not being stunted, seemed, by the side of the greatly shrunken cerebrum, surprisingly large.
In the higher Mammalia the lateral parts forming the hemispheres of the cerebellum become formed as swellings at the sides at a considerably later period, and are hardly developed in the Monotremata and Marsupialia.
In Birds the cerebellum attains a very considerable development (fig.
The middle lobe becomes the optic lobes (corpora bigemina or corpora quadrigemina in Mammalia) and the crura cerebri; while the posterior lobe becomes converted into the cerebellum and medulla oblongata.
Anteriorly the cerebellum is connected with the roof of the mid-brain by a delicate membrane, the velum medullae anterius, or valve of Vieussens (fig.
Near their junction with the cerebellumthey form prominent bodies, which are regarded by Miklucho-Maclay as representing the true cerebellum of Elasmobranchii.
Throughout the Vertebrata an anterior lobe of the hind-brain becomes very early marked off, so that the primitive hind-brain becomes divided into two regions which may be conveniently spoken of as the cerebellum (figs.
This distinction, which becomes much more evident later on by a thickening of the walls and roof of the front portion, separates the hind-brain into the cerebellum and the medulla oblongata (fig.
The cerebellumis composed of gray and white matter, the former being darker than that of the cerebrum.
It has been supposed by some that the cerebellum is the seat of sexual instinct.
The arrangement of the white and gray matter of the medulla oblongata is similar to that of the spinal cord; that is to say, the white matter is external and the gray internal; whereas in the cerebellum and cerebrum this order is reversed.
Their peculiar influence upon the cerebellum causes the subject to reel and stagger, as though a portion of that organ were removed; the group of energetic faculties is stupefied, and mental as well as corporeal lethargy is the result.
This fact may be proved by removing the cerebellumof a bird and observing the results, which are an uncertainty in all its movements, and difficulty in standing, walking, or flying, the bird being unable to direct its course.
In the animal kingdom we find an apparent correspondence between the size of the cerebellum and the variety and extent of the movements of the animal.
Some physiologists suppose that the cerebellum is the source of that harmony or associative power which co-ordinates all voluntary movements, and effects that delicate adjustment of cause to effect, displayed in muscular action.
The anterior gives form to the forehead, the middle rests in the cavity at the base of the skull, and the posterior lobe is supported by the tentorium, by which it is separated from the cerebellum beneath.
The fact appears that an ample development of the posterior base of the cerebrum and the cerebellum indicates nutritive activity, which is certainly a condition most favorable to the display of amativeness.
If the cerebellum and cerebrum of a dove be removed, the bird will make no effort to procure food, but if a crumb of bread be placed in its bill, it is swallowed naturally and without any special effort.
Panse and Kishi, on the other hand, contend that the ear gives no structural signs of such peculiarities as the dancing and deafness suggest; they therefore look to the cerebellum for the seat of the disturbance.
One may be said never to have thoroughly acquired a set of muscular movements such as we have mentioned, until the cerebellum has taken over the task and relieved the cerebrum of the conscious effort.
One's technique is never perfected until the cerebellum assumes control and direction of the necessary movements and the impulses are sent forth from below the plane of ordinary consciousness.
The skilled skater, bicyclist, typist, or machinist depends upon the cerebellum for the ease and certainty with which he performs his movements "without thinking of them.
A cast of the brain-case shows that the cerebral hemispheres were smooth and small, the cerebellum of course completely uncovered and nearly as large as the cerebrum.
The brain has much convoluted cerebral hemispheres, but the cerebellum is completely uncovered by them.
In the brain the cerebellum is completely exposed; the hemispheres are furrowed, but the corpus callosum is rudimentary.
In accordance with its age the cerebral convolutions of this Dog are much simpler than in existing Dogs, and the hemispheres do not cover the cerebellum so much.
The brain differs from that of the Anthropoidea in that the cerebellum is, as in the lower Mammalia, exposed.
The most notable anomaly of thecerebellum is the hypertrophy of the vermis, which represents the middle lobe found in the lower mammals.
This vermis was so enlarged in the case of Vilella, that it almost formed a small, intermediatecerebellum like that found in the lower types of apes, rodents, and birds.
It is probable that the anterior horns of the cerebellum are equivalent to the prolongations of the cerebellum into the central cavity of the optic lobes of Teleostei, which are continuous with the so-called fornix of Goettsche.
The cerebellum is in most Ganoids relatively smaller, and this is even the case with Amia; but the cerebellum of Lepidosteus is hardly less bulky than that of most Teleostei.
The most essential feature of the cerebellum in Teleostei is its prolongation forwards into the ventricles of the optic vesicles as the valvula cerebelli.
The cerebellum contains a large unpaired prolongation of the fourth ventricle.
Footnote 513: In Wilder's figure the walls of the cerebellumare represented as much too thin.
The cerebellum is much larger than in the majority of Ganoids, and resembles in all essential features the cerebellum of Teleostei.
The bilobed appearance both of the mid-brain and cerebellum should be noticed.
There may be some doubt whether the function called amativeness is located in the cerebellum at all; at least, it is perfectly certain that amativeness is not the exclusive function of the cerebellum.
Says Carpenter, the learned physiologist, "The seat of the sexual sensation is no longer supposed to be in the cerebellum generally; but probably in its central portion, or some part of the medulla oblongata.
The cerebellum is intimately connected with the principal vital organs; hence, if it is largely developed, the individual will possess a well-developed physical organism and a good degree of constitutional vigor.
In such an animal as the lamprey, where the cerebellum is only commencing, this constriction does not occur in the embryo.
Subsequently the first cerebral vesicle becomes divided into two to form the prosencephalon and thalamencephalon, while the third cerebral vesicle is also divided into two to form the region of the cerebellum and medulla oblongata.
The difficulty lies rather in the position of the cerebellum and corpora quadrigemina, and the solution is as simple as it is conclusive.
The other division in the hind-brain region, which separates the region of the cerebellum from the medulla oblongata, is due to the growth of the cerebellum, and indicates its posterior limit.
In the last chapter it has been suggested that the presence of the trochlear or fourth cranial nerve has given rise to the formation of the cerebellum by a similar spreading.
The cerebellum is very large, and the surface of the medulla oblongata is more or less modified or specialized.
In front of thecerebellum lies the largest pair of lobes, each of them hollow, the optic nerves being attached to the lower surface.
It is thought that the cerebellum is wanting in these fishes, or represented by a narrow commissure (corpus restiforme) across the front of the medulla.
Under the cerebellum is the medulla, below which the spinal cord begins.
This is the cerebellum and it has charge of certain powers of motion.
In the Dipnoans the cerebral hemispheres are united, while the optic lobe and cerebellum are very small.
Action on motor-centres ofCerebellum and Basal Ganglia.
The hind portion of thecerebellum is large, which points to intellectual inferiority in the True Lemurs as compared with the Apes.
In the brain the whole of the cerebellum and the olfactory lobes are covered by the cerebrum.
In very young individuals the cerebellum is more covered by the cerebrum than it is in the adult.
In the brain the cerebrum exhibits the more important grooves characterising the brain of the higher Apes (Simiidae) well developed; the cerebellum (or hind brain) is also well developed.
The main brain (or cerebrum) covers the cerebellum in all the members of the Cercopithecidae; and in them the principal convolutions and fissures found in the human brain are more or less developed.
The cerebellumoccurs in its simplest form in lampreys and Dipnoans (fig.
A valvula cerebelli occurs also in ganoids, while in the Crossopterygians a similar extension of the cerebellum projects backwards into the IV.
Gall maintained that as a result of castration the development of the cerebellum was hindered, and that this failure of development could be detected by external examination of the occipital region.
The phrenologists taught that the cerebellum was the center for the sexual instinct, but there is no evidence in favor of this guess.
The Cerebellum Regarding the cerebellum, there is much knowledge at hand, but it is difficult to give the gist of it in a few words.
On the one hand, the cerebellum receives a vast number of axons from the lower sensory centers; while, on the other hand, it certainly has nothing to do with conscious sensation or perception.
While the spinal cord and brain stem vary according to the size of the body, and the cerebellum with the motility of the species of animal, the size of the cerebrum varies more or less closely with the intelligence of the species.
In the ape's brain as thus depicted, the portion of the cerebellum left uncovered is greater than in the lemurs, the lowest type of Primates, and almost as large as in the rodentia, or some of the lowest grades of the mammalia.
In many of these creatures, such as the Saimiri (Chrysothrix), the cerebral lobes overlap and extend much farther behind the cerebellum in proportion than they do in Man.
The extension of the displaced cerebellum beyond the cerebrum at d.
Backward extension of the cerebrum, beyond the cerebellum at e.
With animals that run immediately upon birth, the cerebellumis much more powerfully developed than with animals that are born blind, are helpless, and that learn to walk with difficulty.
The absolute and relative excess in the weight of the cerebellum of woman has an enormous significance.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "cerebellum" in a variety of sentences. We hope that you will now be able to make sentences using this word.