bluuebunny/crossref_metadata_2025_split huggingface dataset:
A comparative study of the extrinsic and intrinsic arterial blood supply to brains of submammalian vertebrates
Authors: Gillilan Lois A. 
Published: January 2005

AbstractThe brains of submammalian vertebrates are supplied only by the paired internal carotid arteries each of which divides into a caudal and a rostral division. In fishes,where the necessities of existence are taken care of largely by the respiratory and taste centers in the brainstem augmented by olfaction, the caudal division is the larger. As locomotion becomes more important and complex in reptiles and birds, the corpus striatum and the cerebellum become larger, necessitating a gradual shift of arterial blood into the rostral division. At the reptilian level the cerebral branches have evolved sufficiently to be recognized as having a mammalianlike pattern, and it is at this point that the mammalian terminology can be applied. Branches of the basilar artery, which is formed by the union of the two caudal rami, retain their basically segmental arrangement. The vertebral artery has not yet appeared.The intrinsic vascular patterns are in the form of a wide‐meshed plexus, at first uniformly distributed among cells and fibers, but later more ldense in the nuclear areas. The first evidence of specialization in the vascular arrangement is the formation of a perineuronal plexus within the optic lobes in amphibians and in the appearance of a definitive striate artery. The vascular patterns are correlated with the phylogenetic development and the general functional development of members of each of the classes described.
Patterns of fiber degeneration in the dorsal lateral geniculate nucleus of the cat following lesions in the visual cortex
Authors: Guillery R. W. 
Published: January 2005

AbstractGolgi preparations show a group of relatively fine axons ending in the dorsal lateral geniculate nucleus. These, the type I axons, are characterized by many short collateral terminal branches and form a well oriented plexus within the lateral geniculate nucleus. Individual axons distribute terminals to more than one geniculate lamina and some can be seen to come from the region of the internal capsule.Four or more days after damage to the visual cortex, the Nauta method shows relatively fine degenerating fibers that approach the lateral geniculate nucleus from a rostral direction. Some pass straight into lamina a, While others enter the three major laminae via the central interlaminar nucleus. The appearance of this degeneration suggests that the type I axons are cortico‐genciulate, as does the sequence of the diencephalic degenerative changes. Thus, relatively coarse corticofugal fibers to the lateral thalamus and tectum show heavy degeneration within three days. The fine axons in the lateral geniculate nucleus show slight, early degeneration after three days, extensive degeneration after four days. They are possibly collaterals of the coarser corticofugal fibers. A second group of coarse fibers which runs laterally from the lateral geniculate nucleus shows early degeneration after four days but does not show consistent and clear degeneration until five or more days. Since retrograde cell changes are already recognizable after four days the third group is regarded as geniculo‐cortical.
Electron microscopic studies of the dentate gyrus of the rat. II. Degeneration of commissural afferents
Authors: Laatsch R. H. , Cowan W. M. 
Published: January 2005

AbstractExperimental degeneration of the commissural afferents to the dentate gyrus of the rat has been studied using the electron microscope. Four and six days after unilater fimbrial section, unequivocal degeneration of axon terminals is found in the inner part of the molecular layer of the dentate gyrus of the opposite side. The affected endings are in synaptic contact both with the shafts of the granule cell dendrites and with the short dendritic spines which occur on the granule cell dendrites in this part of the molecular layer. These degenerating terminals show changes ranging from an increased axoplasmic density with aggregation of the synaptic vesicles, to a complete disappearance of the vesicles and mitochondria, and the engulfment of the endings by glycogen‐containing processes of glial cells. There is no proliferation of neurofilaments at any stage during this degeneration. Glial processes in the vicinity of degenerating axon terminals show reactive changes in the form of swelling and accumulation of glycogen, and probably proceed to phagocytosis of the degenerating nerve endings. On the side of the lesion the glial cells also show fibril proliferation, an even greater accumulation of glycogen, and a variety of ingested cellular debris.
Thalamic afferents from the dorsal column nuclei. An experimental anatomical study in the rat
Authors: Lund R. D. , Webster K. E. 
Published: January 2005

AbstractThe distribution of axons originating in the dorsal column nuclei has been studied using the Nauta technique on brains witth lesions restricted to small parts of the gracile and cuneate nuclei. The caudal area of each nucleus projects contralaterally to the ventrobasal complex in a topographical manner and in small amount to the pars medialis of the medial geniculate body. In addition, the rostral part of each nucleus sends axons to the contralateral zona incerta, anterior pretectal nucleus and posterolateral complex within the diencephalon as well as to the collicular plate and pontine protuberance of the brain stem. There is no clear evidence of a projection to the area comparable to the posterior thalamic complex of the cat.This work establishes the identity of some of the cytoarchitectonic divisions of the rat diencephalon, and indicates that the rostro‐caudal differences shown for the dorsal column nuclei are reflected in their ascending projections.
Formation and differentiation of the external granular layer of the chick cerebellum
Authors: Hanaway Joseph 
Published: January 2005

AbstractTo examine the formation and differentiation of the external granular layer, chick embryos ranging in age from two to 20 days were treated with tritiated thymidine and sacrificed after various time intervals. By studying the migration of the labeled cells at different stages of development, the following observations were made: (1) cells originating from the neuro‐epithelial layer along the ventricular surface of the cerebellar plate migrate through previously formed cell layers of neuroblasts to the surface; (2) the development of the lateral portion of the cerebellar plate is approximately 24 hours more advanced than that of the medial region, thus explaining the appearance of the external granular layer first laterally and then medially; (3) at no time during development can a proliferation center be found in the ventrolateral angle of the fourth ventricle. Based on theses results, it is concluded that the cells of the external granular layer originate from the neuroepithelium bordering the ventricular surface of the cerebellar plate and migrate from this position straight to the surface. No evidence for a surface migration from the ventrolateral angle in a dorsomedial direction can be found.Shortly after the formation of the external granular layer at day six, its cells begin to proliferate. During this period, which lasts until day 15, relatively few cells leave the external granular layer to migrate inwards. After this day a massive inward migration occurs, and the cells of the external granular layer differentiate into the granular cells and perhaps the glia cells. In the internal granular layer they intermingle with the Purkinje cells and Golgi II neurons, which originate in the neuro‐epithelial layer between days three and six of development. Shortly after hatching, when the external granular layer has fulfilled its function in cell production, it disappears.
Thalamic projection of the anterior ectosylvian gyrus (somatic area II) in the cat
Authors: DeVito June L. 
Published: January 2005

AbstractThalamic degeneration following discrete lesions of the portion of somatic area II lying within the anterior ectosylvian gyrus was observed in coronal and parasagittal sections. The sections had been treated by Nauta's silver impregnation method and stained alternately with cresyl violet or the Luxol fast preparation. The main site of degeneration lay in the posterior nuclear group, in a band of cells and fibers interposed between the ventrobasal complex and the medial geniculate body. Terminal degeneration was also present throughout the lateral region of the ventrobasal complex, being most dense caudolaterally. The dual thalamic connections reinforce electrical evidence of two populations of cells in somatic area II.
Pattern and field in cortical structure: The rabbit
Authors: Globus Albert , Scheibel Arnold B. 
Published: January 2005

AbstractPrevious attempts at classification of cortical neurons have been based on a number of anatomical characteristics, some of doubtful physiological significance. In seeking a functionally more relevant scheme, we have based our classification on three neural attributes; (a) size and shape of the dendritic domain, (b) presence or absence of dendritic spines, and (c) intra or extra‐cortical trajectory of the axon, as revealed in Golgi stained material. Our data indicate that neurons with extra‐cortically projecting axons (long axons) invariably possess spine‐rich dendrites forming domains with remarkably regular horizontal parameters (i.e. modular domains). Cells with axons limited to intra‐cortical paths (short axons) are characterized by spine‐poor or spine‐free dendrites forming domains which are highly variable in size and shape. These two categories appear dependant on structural characteristics related both to input and output functions of cortical neurons, and are called Class I and II, respectively. The significance of synaptic arrangements along horizontal and vertical components of Class I dendritic modules are compared with those for Class II cells, and possible relationships between dendritic structure and temporo‐spatial activity patterns are considered.
The non‐crossing of the pyramidal tract in procavia capensis (storr) and other instances of absence of the pyramidal crossing
Authors: Verhaart W. J. C. 
Published: January 2005

AbstractIn Procavia capensis the pyramidal tract descends uncrossed in the ventral funiculus of the cord, in which it can be followed throughout, the thoracic and lumbar segments. Termination of it fibers is almost entirely crossed similar to mammals with a substantial pyramidal corssing. Other instances of absence of a substantial pyramidal crossing are reported and it is concluded that the pyramidal crossing does not depend only on the termination of the pyramidal fibers in the medulla and the cord, and that the fibers can reach their contralateral endings without such a crossing.
Electrosensitivity of canal and free neuromast organs in a gymnotid electric fish
Authors: Suga Nobuo 
Published: January 2005

AbstractThe posterior lateral line nerve was studied by recording singel unit activity with glass miocropipette electrodes to examine the electrosensitivity of the canal and free neuromast organs. The fibers innervating these organs has no or irregular spontaneous discharges. For a 50 msec electric pulse applied through a pair of electrodes at the two ends of the fish, almost all fibers discharged impulses during the pulse, irrespective of its polarity. The electrosensitivity for a 50 msec electric pulse was 37 mV/cm on the average. When a 0.5–1.0 msec electric pulse was used, these fibers showed no responses to it, even if it was stronger than 40 mV/cm. Responses to organ discharges were not found at all. These organs do not seem to function as electroreceptors.The canal organ was excited by water ripple and by weak water currents allied to the trunk and can be considered a mechanoreceptor. The free neuromast of the trunk was mechanically excitable, but it did not respond to moderately strong water current, and its function remains unclear.
Helweg's triangular fasciculus in anencephalic fetuses
Authors: Mizuno Noboru , Yoshida Masami , Okamoto Michio 
Published: January 2005

AbstractHelweg's triangular fasciculi were identified in two human anencephalic fetuses, and the structures of their central nervous systems were compared with those of other anencephalic fetuses without the fasciculi.Since the inferior olivary nuclei and the brain regions above the level of the mesencephalon were not developed, these portions could be ruled out as the site of origin of Helweg's fasciculi.The spinal cords and the ascending fibers of these anencephalic fetuses were better preserved than the brain stem and descending fibers. In cases with existing Helweg's fasciculi the spinal gray matter was better developed than in cases without the fasciculus. Taking all these facts in account, it seems reasonable to assume that in the described cases Helweg's fasciculi consist, at least chiefly, of ascending fibers, especially spinoreticular fibers.
The efferent connections of the cerebellar nuclei in the pangolin,
Authors: Bautista Nestor S. , Foltz Floyd M. 
Published: January 2005

AbstractThe connections of the cerebellar nuclei were traced in a primitive and specialized eutherian mammal, the pangolin, by placing varied unilateral lesions in the basal cerebellar nuclei and staining the ensuing fiber degeneration with the selective staining techniques of Marchi and Nauta. The results showed a cerebellifugal system that is basically similar to the pattern described for other mammals. The brachium conjunctivum arises primarily from the interpositus and dentate nuclei and follows the typical mammalian course and termination in the red nucleus and thalamus. In addition, a rather extensive termination in the dorsal mesencephalic tegmentum is present. A variation was observed in the descending limb of the brachium conjunctivum which divides into two tracts, medial and lateral. The fastigial projections are directed mainly to caudal rather than rostral areas with extensive terminations in vestibular and reticular areas.The present study establishes further the constancy of the general organization of cerebellar efferents in mammals and the primitive position of the cerebellifugal system in phylogeny. An assumption is made that the efferent connections of the cerebellum are present in one form in all therian mammals.
Observations on the abdominal stretch receptor and the fine structure of associated axo‐dendritic synapses and neuromuscular junctions in homarus
Authors: Nadol Joseph B. , de Lorenzo A. J. Darin 
Published: January 2005

AbstractThe abdominal stretch receptor of lobster has been examined. Fine structural details of the receptor nerves are presented and neurophysiological correlations are suggested. Both axo‐dendritic synapses and neuromuscular junctions were examined. Axo‐dendritic synapses are of one type only, possessing elongated, or flattened, presynaptic vesicles approximately 200 Å in diameter and 400–600 Å long. In contrast two distinct types of neuromuscular junctions were observed. The first possesses spherical synaptic vesicles 500–900 Å in diameter. The second possesses synaptic vesicles of dimensions similar to those of axo‐dendritic synapses. It is suggested that synapses, both axo‐dendritic and neuromuscular, with elongated or flattened vesicles, are inhibitory, and that neuromuscular junctions with spherical vesicles are excitatory.
The neural structure of Clarke's nucleus of the spinal cord,
Authors: Boehme Cameron Catlin 
Published: January 2005

AbstractThe neural elements of Clarke's nucleus stained by the Golgi method have been studied in the cat. Three types of cells are found: (1) large bodied cells with many dendrites and (2) small bodied cells with few dendrites. The dendritic arborizations of both types extend mainly in a longitudinal direction, remaining within the nucleus and spreading as far as one millimeter. (3) Large bodied cells are found which have, in addition to a longitudinally directed arborization in the nucleus, branches extending ventrally into the intermediate nucleus. In the nucleus are found dendrites of cells which lie outside it at the base of the dorsal horn and in the intermediate nucleus.Three sources of afferents to Clarke's nucleus are confirmed: (1) dorsal column collaterals which terminate in the nucleus as longitudinally running knobbed fibrils, (2) lateral column collaterals terminating in small end‐feet and (3) heavy caliber endogenous fibers, some or all of which are axons of cells located in the base of the dorsal horn, and which terminate as fine fibrils in small end‐feet. Some dorsal column collaterals to Clarke's nucleus have terminal branches in the base of the dorsal horn as well. It is confirmed that small synaptic knobs such as those from lateral column collaterals and from heavy caliber endogenous fibers contact the bodies of cells in Clarke's nucleus. The large knobs from dorsal column collaterals are found contacting dendrites.
Avian nucleus isthmi and its relation to hippus
Authors: Showers Mary Jane C. , Lyons Patricia 
Published: January 2005

AbstractThe normal cytology and connections of the mesencephalic nucleus isthmi were examined in cell and fiber preparations of the brains of seven avian forms which included those of chicken, guinea hen, duck, ibis, turkey buzzard, pheasant and sparrow. In all these forms the isthmi complex consisted of three parts which appeared to be associated by position, connections and function. The magnocellular part begins at the region of junction of the diencephalon and the mesencephalon and lies ventral to the nucleus mesencephalicus lateralis pars dorsalis. The parvocellular portion of the nucleus isthmi is the largest subdivision of the complex. It appears and disappears within the rostrocaudal extent of the magnocellular portion of the nucleus. The third, most posterior, and most diminutive division of the nucleus isthmi is the nucleus semilunaris. The above description excludes the nucleus isthmo‐opticus as a representative of the nucleus isthmi. Connections of the isthmi complex, as assayed from normal and experimental methods, include the lateral lemniscus, the tectoisthmal, the isthmotectal, the isthmocerebellar, the isthmo‐oculomotor and the isthmostriatal pathways. Anatomicophysiologic investigation of the nucleus isthmi further supports its homology with scattered reticular cells along the lateral lemniscus in mammals rather than with the medial geniculate nucleus of mammals. The presence of the avian hippus might provide a useful investigative tool.
Studies on the developing cerebellums. Ultrastructure of the growth cones
Authors: Del Cerro Manuel P. , Snider Ray S. , Oster M. L. 
Published: January 2005

AbstractThe fine structure of the cerebellar cortex in rats was examined between the first and forty‐fifth post‐natal day. The formation and growth of axon and dendrites are reported here. As inferred from these observations, the process starts under the cell membrane as a local accumulation of vesicles without any visible content, about 1,100 Å in size. This is followed by an outward bulging of the membrane which then becomes filled with vesicles and is known as the primary growth cone. In axons the synaptic and growth cone vesicles coexist until the third week or longer. In dendrites secondary growth cones exist at the tip of the branching dendrites and spines. Variations in the shape of the growth cone vesicles related to the age of the animal are described, and the importance of attempting to isolate the growth cones and the vesicles is emphasized.
The basilar pontine gray of the opossum (Didelphis virginiana). II. Experimental determination of neocortical input
Authors: Martin George F. , King James S. 
Published: January 2005

AbstractThe pattern of neocortical input into the basilar pons of the opossum was determined by employing the Nauta‐Gygax technique ('54) on the brains of animals previously subjected to neocortical lesions. The results indicate that every neocortical area projects to some portion of the basilar pons in this form. Degenerating fibers resulting from more rostral cortical lesions (frontal and preorbital areas) terminated profusely within the medial and ventral nuclei and, to a lesser extent, in the smaller dorsal nucleus. Fascicles from more caudal areas (striate and peristriate cortices) ended abundantly in the lateral nuclear group, and in the lateral part of the ventral nucleus. Every neocortical region studied projected to some portion of the ventral pontine nucleus. Degenerating fibers terminated to some extent within each nucleus of the basilar pons as a result of lesions in midcortical regions (paramarginal, postorbital and parietal cortices). A few fibers of frontal, orbital and parietal origin terminated in the contralateral basilar pontine gray.
Projections from the orbital gyrus in the cat. I. To brain stem structures
Authors: Mizuno Noboru , Sauerland Eberhardt K. , Clemente Carmine D. 
Published: January 2005

AbstractDirect projections from the anterior part of the orbital gyrus and its immediate vicinity to the brain stem in the cat were investigated by means of the Nauta and Marchi methods. These experiments were carried out in an attempt to identify the anatomical substrates subserving orbital‐gyral inhibitory influences on somatic reflexes.The cortical layers of the anterior orbital gyrus and the immediately surrounding cortex were ablated unilaterally. Preterminal degeneration was found bilaterally in the spinal trigeminal nucleus. The most consoicuous degeneration occurred in the interpoler nuclei, caudal parts of the oral nuclei, and rostral portions of the caudal nuclei of the spinal trigeminal complex. Thus, degeneration was found in the trigeminal sensory nucleus from the level of the inferior olive rostrally to levels just caudal to the obex. Preterminal degeneration was also observed bilaterally in the mesencephalic reticular formation. Heavy preterminal degeneration was found in the reticular formation of the rostral midbrain and moderate degeneration was observed in the caudal mesencephalic reticular formation, the pontile reticular substance and medullary reticular nuclei.Based on these findings, the possible pathways involved in the mediation of orbital‐cortically induced inhibition on somatic reflexes were discussed.
Development of the sensory component of the respiratory mechanism of the toadfish (Opsanus tau)
Authors: Carroll Tracy Henry , Hogg Ira D. 
Published: January 2005

AbstractThis communication deals chiefly with the development of the sensory nerves that supply the portion of the head involved in respiration. It is a supplement to a previous paper (Tracy,′61) and describes in detail the origin of cells that form the sensory ganglia of four cranial nerves, V. VII, IX and X, together with their distribution, the branches that degenerate, motor distribution, and the time at which evidence of first motor movements controlled by them appears. It covers the details concerning the position of placodes which are the source of some of the cells from which the ganglia of these nerves are derived and the relative time at which they appear.In this article more emphasis is placed on the development of cranial nerves V and VII than on IX and X. Apparently the former two nerves are more involved in the mechanism of respiration than the latter two.Some incidental observations of importance are recorded that do not appear to bear particularly on the main thesis of the article. One of these concerns the paths of migration followed by the ectomesenchyme. Another statement is to the effect that the two kinds of mesenchyme do not mix but that a quite definite boundary region can usually be distinguished between them as if the process of differentiation has made them slightly incompatible.