bluuebunny/crossref_metadata_2025_split huggingface dataset:
The development of the facial nerve in baboon embryos (Papio sp.)
Authors: Gasser Raymond F. , Hendrickx Andrew G. 
Published: January 2005

AbstractThe arrangement of the facial nerve was studied in 21 baboon embroys and fetuses, 2.6–36.0 mm crown‐rump length, (25–54 days fertilization age) and one adult. The head and neck regions of eight specimens were reconstructed graphically or with wax. The extramedullary part of the right nerve was traced microscopically and its configuration mapped.In early embryos (11–36 somites, 2.6–6.0 mm) the facial part of the facioacoustic primordium is either in close proximity or contacts the second arch epibrachial placode. It becomes a separate nerve (6.9–16.5 mm embryos) as the geniculate ganglion forms and the placode disappears. The first branches are the chorda tympani and greater petrosal. The pars intermedia and chorda tympani are large at 9 mm and the parent nerve terminates distally as a loose network of intermingling fibers. In 14.8–16.3 mm embryos connections are established with the deep petrosal and maxillary, and the tympanic, vagus and lingual nerves. Peripheral branches course into the occipital, cervical and mandibular regions. Between 18.3 and 36.0 mm the temporofacial and cervicofacial rami become evident and peripheral branches also extend into temporal, zygomatic and buccal regions. Communications are formed with branches of the auriculotemporal, zygomatic, infraorbital, buccal, mental, transverse cervical and great auricular nerves. Branches to the temporal and zygomatic areas lag in development.
The termination of ipsilaterral and contralateral optic fibers in the lateral geniculate body of Galago crassicaudatus
Authors: Campos‐Ortega J. A. , Gless P. 
Published: January 2005

AbstractThe lateral geniculate body of Galago crassicaudatushas five layers which have nbeen numbered in a ventrodorsal direction. The layers 1, 2, and 5 are composed of large cells and the layer 3 and 4of small ones. The ratio of crssed and uncrossed fiber is 1:1 Following enucleation of one eye, preterminal and terminal (synaptic)degeneration occurs in layers 2 and 4 ipsilaterally, whereas the contralateral fibers terminate in layers 1 and 5. The third layer recieves a small contribution of crossed and uncrossed fibers. As far as can be judged from lightmicroscopy, the type appears to be in the ration 3:1. Synaptic complexes composed of 2‐3 terminals in close approximation are frequently found.
The superior olivary complex and audition: A comparative study
Authors: Irving R. , Harrison J. M. 
Published: January 2005

AbstractThe sizes of the three major nuclei of the mammalian superior olivary complex were examined in a number of different species and variations in size were related to the relative prominence of haring and vision in each species. Size was measured by counting neurons in the several nuclei and by measuring the diameter of the eyes.The lateral superior olive was large inMicrochiroptera(3850–4340 cells), guinea pig (3780), cat (3360) and chinchilla (3220); of intermediate size in macaque (1830), rat (1430) and squirrel monkey (1300); and small in gerbil (1220), mouse (1190), hedgehog (1090), squirrel (1000) and hamster (980). These data suggest that this nucleus is necessary for complex auditory discriminations (echolocation inMicrochiroptera, for example) and that its size is not primarily determined by the taxonomic order of the animal.The medial nucleus of the trapezoid body was large in cat (5910), guinea pig (5840), hedgehog (4620) and chinchilla (4590); of intermediate size in rat (3870),Microchiroptera(3700) and macaque (3120); and small in squirrel monkey (2600), squirrel (2700), gerbil (2680), mouse (2270), and hamster (2130). The size of the nucleus was not related to sensory development or the size of the other olivary nuclei.The size of the medial superior olive was found to be highly correlated with the size of the VIth nucleus and eye diameter.
Architectonic studies of the telencephalon of Iguana iguana
Authors: Northcutt R. Glenn 
Published: January 2005

AbstractWith the atrophy of the aquatic olfactory organ and the increased complexity of locomotion, the amphibian telencephalon was reorganized from a structure dealing primarily with olfaction, to the reptilian structure functioning at four levels of organization. The primary olfactory centers are retained, and the posterolateral and medial basal regions become specialized as secondary olfactory centers.The anterolateral basal regions are reorganized as primary association centers of somatic information. A dorsal component develops due to the convergence of sensory modalities, and a ventral component develops which influences tectal centers.Three pallial elements are recognized which function as part of the primary and secondary association systems. The lateral pallial element (pyriform cortex) is functionally related to the secondary olfactory system. Part of the medial pallial element (dorsomedial hippocampal cortex) is functionally related to the secondary olfactory system while the other part (dorsal hippocampus) is related to the secondary association system.The secondary association system, which integrates all sensory modalites, has evolved along two lines in reptiles. The sauropsid line has lost the motor elements of the dorsolateral component of the dorsal pallium. The dorosomedial component of the dorsal pallium retained its motor elements and functions with the hippocampus as a transitional cortical structure.In the theropsid line, the motor elements of the dorsolateral component were retained in a system which bypasses the older tectal motor system.
Histogenesis of the dorsal and ventral cochlear nuclei in the mouse. An autoradiographic study
Authors: Pierce Elizabeth Taber 
Published: January 2005

AbstractThe time, site of origin and migration pathways of neuroblasts destined for the dorsal and ventral cochlear nuclei in the mouse have been determined autoradiographically. Neurons of the dorsal cochlear nucleus arise on gestation days 10 through 13, neurons of the ventral cochlear nucleus on days 10 through 14. Neurons of both nuclei arise within the primitive ependyma of the caudal extent of the primary rhombic lip at the level of the lateral recess; neurons of the dorsal cochlear nucleus arise caudal to neurons of the ventral cochlear nucleus. Granular cells arise on days 12 through 18 within the primitive ependyma of the secondary rhombic lip at the same levels.
Laminar structure of the dorsal lateral geniculate nucleus in the tree shrew (Tupaia glis)
Authors: Glickstein Mitchell 
Published: January 2005

AbstractThree tree shrews (Tupaia glis) were subjected to unilateral enucleation. Two of these were sacrificed seven months after surgery, and their brains were sectioned and stained for study of transneuronal atrophy within the dorsal lateral geniculate nucleus (LGN). The third animal was sacrificed ten days after enucleation; its brain was stained with a modified Nauta method for degenerating axons. Results of the two techniques are in good agreement. Ipsilateral and contralateral fibers were well segregated within the optic tracts. Transneuronal atrophy was found in layers 1 and 5 ipsilateral to the nucleated eye, and layers 2 and 4 contralaterally. Layer 3 did not appear to be differentially degenerated on the two sides, nor did a sixth layer, layer S, situated between layer 5 and the optic tract. Each superior colliculus receives fiber projections from both eyes, although those arising in the contralateral eye are far greater in number.
Organization of the posterior dorsal thalamus of the hedgehog
Authors: Erickson R. P. , Hall W. C. , Jane J. A. , Snyder M. , Diamond I. T. 
Published: January 2005

AbstractA study of the responsiveness of single neurons in the hedgehog thalamus to sensory stimulation was undertaken with the hypothesis that modality specific relay nuclei characteristic of the mammalian thalamus differentiate out of a pool of multisensory neurons. Support for this hypothesis was obtained in earlier investigations of the opossum thalamus. In some ways the hedgehog may be an even better representative of a primitive stage of thalamic development. For example, there is very little structural difference between the ventroposterior nucleus and the medial geniculate body. The results of the present microelectrode investigation showed that neither the ventroposterior nucleus nor the medial geniculate body was modality specific. Further, many neurons in the ventroposterior nucleus showed wide receptive fields characteristic of the posterior group of nuclei in cats. This finding of convergence of sensory input upon single neurons of the dorsal thalamus in a generalized mammalian type suggests that the specificity characteristic of higher mammals is a product of an evolutionary trend. Thus comparative neurology provides additional evidence that precise receptive fields must play an important role in behavioral adaptation.
The spinal roots in the sloth (Choloepus hoffmanni peters)
Authors: Goffart M. , Gerebtzoff M. A. , Duchesne P. Y. 
Published: January 2005

AbstractIn the lower half of the thoracic region in Choloepus hoffmanni, a didactyl sloth, which possesses 23 dorsal vertebrae, the spinal roots assume a rostralward direction. This situation raises difficult problems in early embryological development as it already prevails — although slightly altered — in the 100 gm foetus. The myelinated nerve fiber diameters in the ventral roots are smaller than in the cat. This conforms to the general rule that “red” and slow muscle fibers are supplied by thinner motor fibers than the “white” fast muscles, because in the sloth the whole of the musculature is of the former type. The γ efferent system is well developed. The sympathetic preganglionic fibers are thought to be mostly unmyelinated. From the fiber spectrum in the dorsal roots it appears that the muscle spindle afferents are also of smaller diameter than in the cat. The cuscle spindles, the sympathetic chain and the aortic origin of the intercostal arteries are described.
Observations on the fine structure and distribution of presumptive baroreceptor nerves at the carotid sinus
Authors: Rees P. M. 
Published: January 2005

AbstractComparative nerve fiber counts show that the areas of the carotid bifurcation receiving a rich innervation correspond in extent to areas of the vascular wall with a thinned and elastic tunica media. Presumptive baroreceptor nerves within the carotid sinus wall were examined by electron microscopy in normal rabbits and also after superior cervical ganglionectomy and/or Hering's nerve transection. The glossopharyngeal (baroreceptor) nerve terminals are either denuded of a cellular covering or are thinly clothed in Schwann cell cytoplasm, and are intimately related over wide areas to at least three sinus wall components: to elastin at the medio‐adventitial border, to collagen in the inner one‐half of the adventitia, and to the surfaces of isolated adventitial smooth muscle cells. These muscle cells also receive a terminal innervation from the superior cervical ganglion. There is no nervous penetration of the sinus tunica media. The spatial arrangement of the adventitial muscle cells and their associated sensory and motor nerves simulates a smooth muscle spindle, possibly constituting a morphological basis for an efferent control of baroreceptor output.The baroreceptor nerve terminals contain large accumulations of mitochondria, and also myelin figures and small dense bodies resembling glycogen granules. Evidence is presented that baroreceptor impulses may be conveyed from the sinus wall in both myelinated and nonmyelinated nerve fibers.
Self‐stimulation in the rabbit: An anatomical map of stimulation effects
Authors: Bruner Alfred 
Published: January 2005

AbstractAn anatomical map of brain stimulation effects in rabbits, based on lever pressing and observational data, revealed close correspondence to the findings from other species, particularly rats. Strongest self‐stimulation was obtained from the posterolateral hypothalamus, fornix, and rostral tegmentum. Rhinencephalic placements occasionally yeilded mild self‐stimulation, but more frequently gave negative or ambiguous effects. Negative effects were obtained in the medial hypothalamus and reticular formation, while caudate nucleus stimulation appeared emotionally neutral. Also in agreement with earlier findings, EEG seizures did not accompany self‐stimulation of the posterolateral hypothalamic area, but did often accompany self‐stimulation of rhinencephalic structures. As in cats, hippocampal θ synchronization was observed to accompany approach behavior, while desynchronization accompanied withdrawal and freezing.
Ascending projections of the substantia nigra in the rat,
Authors: Faull Richard L. M. , Carman John B. 
Published: January 2005

AbstractThe Nauta method was used to study the fiber degeneration resulting from electrolytic lesions in the midbrain of 34 albino rats. Lesions were placed in the substantia nigra alone (pars compacta, 3; pars reticularis, 8; both parts, 3); in the substantia nigra and surrounding structures (6); immediately caudal (3), dorsocaudal (3), dorsal (4) and ventral (1) to the substantia nigra; and in the hemisphere and lateral midbrain along the track of the electrode (3). All the degeneration resulting from damage by the electrode to the cerebrum and lateral midbrain was accounted for in terms of known fiber pathways. Lesions involving the substantia nigra (pars reticularis and/or pars compacta) with or without damage to surrounding structures produced fine fiber degeneration which passed rostrally in the pars compacta and the dorsal capsule of the subthalamic nucleus, turned dorsomedially and entered the ventrolateral border of nucleus ventralis medialis thalami (VM) where it terminated. This nigrothalamic pathway did not degenerate when the nigra was not involved. Lesions involving the superior cerebellar peduncle, red nucleus or prerubral radiation also produced terminal degeneration in VM. However, the fibers of this cerebellorubrothalamic pathway, which were not interrupted by lesions confined to the substantia nigra, entered the caudal pole of VM. There was no evidence of a direct nigrostriatal pathway. The demonstration of projections from the cerebellum and substantia nigra to VM establishes this nucleus as the homologue in the rat of nuclei ventralis anterior and ventralis lateralis thalami in primates.
Projections of thalamic and cortical gustatory areas in the rat,
Authors: Wolf George 
Published: January 2005

AbstractThe method of Nauta was used to stain axons which degenerated after lesions of the thalamic projection nucleus and cortical zone subserving gustation in the rat. Lesions of the medial subnucleus of the thalamic ventral nuclear complex resulted principally in degeneration which passed rostrolaterally through the thalamus, internal capsule, globus pallidus, and striatum to terminate in insular and inferior parietal cortex around the region of the middle cerebral artery. Lesions of this cortical projection zone resulted in degeneration which passed caudomedially through the same striatal and pallidal areas traversed by the thalamocortical fibers. One component of these fibers continued into the thalamus to terminate just dorsal to the medial subnucleus. A second component turned caudally into the cerebral peduncle to terminate in the substantia nigra. There was evidence of terminal degeneration in the striatum but not in the pallidum after both thalamic and cortical lesions. There was no evidence of degeneration in any structures primarily associated with olfactory or alimentary functions.
The ultrastructure of the conus medullaris and filum terminale
Authors: Miller Carol 
Published: January 2005

AbstractElectron microscopy of the conus medullaris and intradural filum terminale in the adult cat and monkey show a preponderance of ependymal cells, many of which are oriented around either a central canal or narrow clefts. Some rest directly on connective tissue. Randomly dispersed degenerating neural processes and fibrous astrocytic gliosis are prominent. Some ependymal cytoplasmic abnormalities also are present. The pathogenesis of these changes is unknown.
An electron microscopic study on the innervation of the trout heart
Authors: Yamauchi Akio , Burnstock Geoffrey 
Published: January 2005

AbstractThe neuromuscular inter‐relationship was investigated in three regions of the trout heart: the sinoauricular junction, the auricle and the ventricle. The innervation of the sinoauricular tissue was unusually dense; in one plane of section, the number of axons less than 200Å apart from cardiac muscle cells was approximately equal to the total number of muscle cells. Some muscle cells had up to eight close axon contacts. It is suggested that every muscle cell in this region of the fish heart has at least one and probably many more individual neuromuscular contacts. Many ganglion cells, some with presynaptic terminal were observed in the sinoauricular region. Multivesicular bodies were commonly seen in the cytoplasm. The innervation of the ventricle near the apex was very sparse and that of the auricle appeared to be intermediate between the two extremes.The ventricular muscle cells were somewhat larger and contained a higher area of myofibrils than those in the auricle and the sinoauricular tissue. M‐lines in the myofibrils were demonstrated in the cardiac muscle of the trout. Intraaxonal vesicles were mostly agranular. However, in about 9.5% of the 1472 axon profiles examined, a number of small (500–700Å) and large (∼800Å) granular vesicles were also present, which suggests that, in contrast to the general view, there are some nerves containing catecholamines supplying the fish heart.It is likely that the sinoauricular region in the fish heart is homologous to the smus node in avian and mammalian hearts.
Cell origin of the ventral spinocerebellar tract
Authors: Ha Hongchien , Liu Chan‐Nao 
Published: January 2005

AbstractThe cells of origin of the ventral spinocerebellar tract have never been determined conclusively. We attempted to determine the cell origin of this tract by applying anatomical methods. Retrograde changes were observed in the lumbosacral segments following hemicerebellectomy, severance of cerebellar peduncle or hemisection of spinal cord at various levels. The chromatolytic motor‐type neurons were plotted, most occupying the dorso‐lateral portion of the ventral gray, with fewer cells in the medial, lateral and central part of ventral horn. Ablation of these neurons in different animals resulted in axonal degeneration which could be traced to the cerebellum via chiefly contralateral lateral funiculus and from the ventral spinocerebellar tract. The morphology of the ventral spinocerebellar tract neurons was studied by the Golgi method. Incidental findings of axonal degeneration bilaterally in the dorsal spinocerebellar tracts, with ipsilateral domination, following ablation of the ventral spinocerebellar tract neurons were discussed.
The development of the nucleus of origin of centrifugal fibers to the retina in the chick
Authors: Cowan William Maxwell , Wenger Eleanor 
Published: January 2005

AbstractThe development of the isthmo‐optic nucleus – the site of origin of centrifugal fibers to the avian retina – has been studied in normal chick embryos and after early complete or partial removal of the optic vesicle. The nucleus arises from the junctional region between the caudal midbrain tegmentum and roof plate at about the sixth or seventh day of incubation and soon forms a compact, oval cell mass midway between the trochlear nucleus and the medial edge of the tectum. Within three or four days it is invaded by afferent fibers from the optic tectum, through the tecto‐isthmal tract, and becomes transformed into a convoluted, but essentially two‐dimensional sheet, by a large scale degeneration of cells, especially in its central part.Extirpation of the optic vesicle has no effect upon the initial proliferation, differentiation or migration of the cells, but the ensuing cellular degeneration is considerably exaggerated, so that after complete removal of the vesicle, the nucleus shows a total cell loss by the nineteenth day of incubation. The tecto‐isthmal fibers disappear at, or just before, the period of maximal cell death; the centrifugal fibers from the nucleus (the isthmo‐optic tract) degenerate at a slightly later stage. Large, but incomplete, lesions of the vesicle before Stage 13 result in considerable cell losss throughout the nucleus; smaller lesions at these stages result in only a slight cellular hypoplasia. Incomplete lesions at Stage 13, or later, usually result in a complete cell loss in one or other topographical portion of the nucleus, the remaining parts being unaffected.
Ascending projections of the primary cochlear nuclei and nucleus laminaris in the pigeon
Authors: Boord Robert L. 
Published: January 2005

AbstractAuditory projections were studied, by the Nauta method, from medullary to mesencephalic levels following lesions in nuclei magnocellularis, angularis and laminaris and transection of the dorsal cochlear decussation and trapezoid body in the midline of the medulla.Fragmented axons project bilaterally to nucleus laminaris from the medial part of nucleus magnocellularis. Degenerated fibers from the lateral part of nucleus magnocellularis, medial part of nucleus angularis. and nucleus laminaris projects to the homolateral superior olivary nucleus. cross the raphé in the trapezoid body, ascend in the contralateral lateral lemniscus, distribute to the ventral and lateroventral nuclei of the lateral lemniscus and, at least third order axons from nucleus laminaris. terminate in nucleus mesencephali lateralis pars dorsalis. No ascending auditory neurons project, even following midventral section of the trapezoid body, to nucleus isthmi, nucleus semilunaris nor. with certainty, to the dorsal nucleus of the lateral lemniscus.This study supports the homology of the avian nucleus mesencephali lateralis pars dorsalis and nucleus laminaris with the mammalian central nucleus of the inferior colliculus and medial superior olivary nucleus respectively. Furthermore, on the basis of fiber projections and cellular organization. nucleus magnocellularis of the pigeon appears to correspond to the anterior ventral cochlear of higher mammals and the medial parts of nucleus angularis to the posterior ventral cochlear nucleus.
Morphological characteristics of mouse stellate and basket cells and their neuroglial envelope: An electron microscopic study
Authors: Lemkey‐Johnston N. , Larramendi L. M. H. 
Published: January 2005

AbstractSampling of stellate cells from the molecular layer of cerebellar cortex at two distinct levels within yielded two populations of cells referred to as stellate and basket cells respectively. The appearance of the soma, the several kinds of dendrites and their accompanying spines can be characterized on the electron microscopic level for each type of cell and correlate well with Golgi impregnation studies.Analytical studies were made to determine the proportion of neural and glial elements in direct apposition to stellate and basket soma and their respective dendrites. On the average the glial covering of a basket or stellate cell was 12–14% of the cell profile, reaching 18.6% for the distal portions of dendrites.A quantitative analysis of the amount of soma and dendritic perimeter in contact with synaptic boutons revealed the percentage of perimeter surface covered by terminal boutons was 15.2% for basket soma, 4.5% for the stellate soma, 21% for basket dendrites and 10.3% for stellate dendrites.An interesting group of cells located in the Purkinje cell layer had the morphological characteristics of basket cells but an unusual synaptic input and an unusually high proportion of glial envelope due to their unique position.This report is an introduction to a comparative analysis of the distribution, and densities of different types of synapses upon basket and stellate cells.