bluuebunny/crossref_metadata_2025_split huggingface dataset:
Peripheral synaptogenesis in nerve parabiosis
Authors: Estable Clemente , Reissenweber Nelson J. , Benedetti Washington L. 
Published: December 2004

AbstractOne hundred and ninety‐two rats were parabiotically coupled to test regeneration of the sciatic nerve of the “donor” rat in the denervated gastrocnemius of the “host.”.Proliferation of the implanted nerve was clearly demonstrated after 30 days. Histological and histochemical study revealed the formation of motor end‐plates of increasing complexity and after survival of 300 days mature motor end‐plates were observed. The electrophysiological study demonstrated that the muscle responded to stimulation of the nerve with normal stimulus. The immunological interaction did not interfere with the formation of “functional” motor end‐plates and central nerve centers of the “donor” rat are capable of eliciting motor activity of the limb of the “host.”.
The development of sensory innervation in the mouth and pharynx of the albino norway rat (mus norvegicus albinus)
Authors: Hogg Ira D. , Bryant James W. 
Published: December 2004

AbstractIn 7 mm rat embryos some sensory fibers from the four cranial nerves that innervate the mouth, pharynx and larynx have grown almost into contact with the basement membrane of the epithelium. Such fibers become more numerous but stay below it until the fetus has reached the twentieth day of gestation. At 25 mm C. R., or on the twentieth day, some fibers grow into the epithelium. Some are branched and some terminate in a Merkel's disc. By that time all types of lingual papillae can be recognized, but taste buds have not formed.Nerve endings begin to appear at about the same time in the tongue, oral surface of the palate, and oral mucosa of the cheeks and lips. Taste buds are said to appear at about the time of birth. No functional bud was found at 36 mm C. R.Intraepithelial nerve terminals have been found in the mouth at about the eighteenth day (20 mm). Other investigators have shown that rat embryos of 15.5 days can respond to the stroke of a hair across the snout by a lateral movement of the head and at 19 days can protrude the tongue independently of other movements. No record has been found concerning the age at which swallowing first occurs in the rat. It seems evident that some fibers can be stimulated at about the time they touch the basement membrane and before any recognized receptor has formed.
A quantitative analysis of the normal neuron population of the hypothalamic magnocellular nuclei in man and of their projections to the neurohypophysis
Authors: Morton Allan 
Published: December 2004

AbstractThe supraoptic nucleus in man extends throughout the greater length of the hypothalamus and most of it is retrochiasmatic in location. It contains an average of 75,500 neurons, of which about two‐thirds are in its dorsolateral portion (SON‐dl) and one‐third in its combined dorsomedial and ventromedial portions. The average density of neurons in SON‐dl is 15,300 per mm3 and, unlike neuron frequency, is remarkably constant from specimen to specimen. The paraventricular nucleus has an average of 55,500 magnocellular neurons.In patients surviving one year or longer after hypophysectomy, there is retrograde loss of over 80% of neurons in both the supraoptic and paraventricular nuclei. Neuron loss occurs uniformly thrughout the length of each nucleus. Density decrease in SON‐dl is almost exactly proportional to decrease in neuron frequency.It is concluded from these observations that most of the neurons throughout the entire extent of both the supraoptic and paraventricular nuclei in man project to the posterior lobe of the neurohypophysis and that there are over 200,000 fibers in the hypophysial stalk.
The development of the trigeminal nerve in baboon embryos (Papio sp.)
Authors: Gasser Raymond F. , Hendrickx Andrew G. 
Published: December 2004

AbstractThe arrangement of the trigeminal nerve or its primordium was studied in 27 baboon embryos and fetuses 2.5–63.0 mm (crown‐rump length), 24–64 days insemination age. The head region of seven representative specimens was reconstructed graphically or with wax. The entire extramedullary part of the nerve, including the related parasympathetic ganglia, was traced microscopically in serial sections stained with either hematoxylin and eosin or protargol‐S and eosin.The crest is first apparent in five somite embryos (24 days) and becomes more prominent and extends farther ventrally by eight somites (25 days). Lateral and ventral to the crest the ectoderm shows a slight, gradual thickening but not as a distinct placode. At 11–19 somites (25–27 days) the primordium is a column of cells that becomes loosely arranged as it terminates in the first arch. By 21–22 somites (28 days) the enlarged primordium has the three divisions with the mandibular being most prominent and closely applied to ectoderm near the first groove. Between 26 and 36 somites (29–30 days) the trigemial ganglion and motor root become apparent. The distal part of each division is eosinophilic and fibrous. Branches from each division begin to form as sprays of fibers by 6.9–9.0 mm (32–33 days) and the primordia of the four related parasympathetic ganglia become evident. Many of the definitive branches and their communications with other nerves are present at 11.6–16.5 mm (36–40 days). Most of the branches and many communications with the facial nerve are established by 18.3–36.0 mm (45–54 days). All of the named branches, including the meningeal branches, are present at 63 mm (64 days).
Quantitative studies on the postnatal growth of the spinal cord and the vertebral column of the albino mouse
Authors: Sakla Francois B. 
Published: December 2004

AbstractThe rate of growth of the various regions of the spinal cord and the vertebral column of the albino mouse aged, 1, 10, 20, 30 and 120 days was studied. It was found that:

There is more rapid growth in the length of the vertebral column than that of the spinal cord. The lower regions of the vertebral column grow more rapidly than the upper regions but the reverse was found in the spinal cord resulting in regression of the spinal cord. The cord ends at one day opposite the fifth sacral vertebra and then receded to the fifth lumbar vertebra till 120 days.
The white matter has a more rapid rate of growth in volume than the gray matter. So the process of myelination and the growth of the fibers in diameter exceed the rate of growth of the neurons and their dendrites.
The packing density of the neurons is nearly the same in all regions of the cord with the exception of the cervical region which showed less packing density due to more branching of their dendrites.
The total number of neurons at each region is fixed from birth till maturity. The thoracic region contains the highest number of neurons followed by the cervical then the lumbar and the least number is in the sacral region.
Observations on the organization of the dendritic processes and receptor terminations in the abdominal muscle receptor organ of homarus
Authors: Nadol Joseph B. , Darin de Lorenzo A. J. 
Published: December 2004

AbstractThe dendritic processes and terminals of the abdominal muscle receptor organ of the lobster have been studied with the electron microscope. In both the “fast” and “slow” adapting components of the muscle receptor organ, dendritic processes ramify within the body of the stretch muscle in a zone of “relative muscle exclusion,” where the continuity of the muscle bundle is interrupted by a zone of connective tissue. The cell bodies and larger dendritic processes are ensheathed in alternate layers of connective tissue and Schwann cells, but the smallest dendritic twigs are entirely divested of their Schwann cell envelope. The membrane of the dendritic terminations is intimately applied to either connective tissue of the zone of relative muscle exclusion or to the sarcolemma of the stretch muscle. This apposition is interpreted as morphological specialization for transduction or mechanoelectric conversion. It is suggested that these two types of dendritic terminals may represent two distinct sites for transduction and may also mediate different modalities of input.The distribution of dendritic processes and terminals differs in the fast and slow systems. In the fast system the dendrites quickly ramify into a glomerular burst of processes near the junction of stretch muscle and connective tissue. In the slow system, the dendrites ramify more gradually and lie more nearly parallel to the long axis of the stretch muscle.In both the fast and slow systems, but especially in the dendritic terminals of the fast neuron, collections of vesicles 400–2000 Å in diameter have been observed. These vesicles are clearly different in fine structure from those found in the neuromuscular junction or axo‐dendritic synapses.An effort is made to relate neurophysiological characteristics of this system with the fine structural observations, with particular attention to the mechanism of transduction, or mechanoelectric conversion.
Embryogenesis of the inferior olivary nucleus in the rat: A radioautographic study and a re‐evaluation of the rhombic lip
Authors: Ellenberger Carl , Hanaway Joseph , Netsky Martin G. 
Published: December 2004

AbstractInterkinetic nuclear migrations studied by redioautography in the medullar neuroepithelium of the 14‐day rat embryo are similar to those in other areas of the neuraxis in other species. The cell cycle lasts approximately 12 hours. Olivary neurons are produced along the length of the alar plate on embryonic days 14 and 15, mostly on day 14. Between 36 and 48 hours after injection of thymidine‐ H3, labeled cells migrate into the mantle layer and are more concentrated in the alar lamina than in the basal lamina. The olivary primordium appears in the ventromedial medulla on day 17 and is almost mature by day 21. Labeled neurons in the alar lamina migrate to the primordium in two bands, the marginal and the submarginal migration strands. From these strands, labeled cells move into the ventrolateral and ventromedial portions of the olivary complex, Newly arrived neurons push the existing cells dorsally. By embryonic day 21, as proliferation of cells in the neuroepithelium ceases, the migration strands disappear, and the olive in fully formed.In the series injected on day 14, heavily labeled neurons become located dorsally in the medial accessory, dorsal accessory and principal nucleus; lightly labeled cells are found in the ventral half of the complex. In the series injected on day 15, labeled cells are found only in the ventral portions of the olive, in the medial accessory nucleus.His described 2 rhombic lips. The first may be an artifact. The second is not seen in the medulla of the rat. If the term is used for any species, it is best viewed as the lateral part of the alar plate.
The projection of the acoustic nerve to the ventral cochlear nucleus of the rat. A Golgi study
Authors: Feldman Martin L. , Harrison J. M. 
Published: December 2004

AbstractAcoustic nerve fibers, stained by the rapid Golgi method, were observed to bifurcate, after entering the ventral cochlear nucleus, into an ascending and a descending branch. Each branch was composed of fibers running parallel to each other with very little overlap. Prior to bifurcating, the acoustic nerve fibers gave rise to collaterals which ramified in the region of the bifurcations. Ascending branch fibers terminated in bulbs of Held and bore from zero to five additional collateral endings, including bulbs of Held. Descending, branch fibers gave rise within the posterior ventral cochlear nucleus to from zero to five collateral endings. These included large endings identified as bulbs of Held. Ascending and descending branch collaterals did not extend beyond 40–50 μ from their paret axons. Descending branch fibers projected into the dorsal cochlear nucleus. The area of the ventral cochlear nucleus dorsal to the region of bifurcations was innervated in a unique manner. This innervation occurred via long dorsally running collaterals arising from the most dorsal fibers of the ascending and descending branch projections.The data suggest morphological correlates of certain neurophysiological and behavioral findings in the areas of auditory localization and discrimination.
Fine structural studies of the main sensory trigeminal nucleus in the cat and rat
Authors: Gobel Stephen , Dubner Ronald 
Published: December 2004

AbstractThis study describes some of the fine structural features of the neurons and synaptic connections in the main sensory trigeminal nucleus at the level of the motor trigeminal nucleus. The dendritic spread of some neurons spans more than half with width of the nucleus. Primary dendrites arise either from main stem dendrites or directly from the cell body and divide at acute or right angles ito long secondary dendrites. The primary trigeminal afferent fibers form numerous large boutons en passant. These large central boutons are often surrounded by large spines, the shafts of secondary dendrites and small peripheral boutons. Such groupings of axonal and dendritic processes make up the trigeminal glomeruli. Within these glomeruli axo axonic synapses occur (1) between adjacent outer surfaces of central and peripheral boutons, (2) on evaginations of central boutons which project into peripheral boutons, and (3) on evaginations of peripheral boutons which project into central boutons. The trigeminal central boutons also synapse on primary dendrites, main stem dendrites and on cell bodies.
Efferent projections of the superior colliculus in the opossum
Authors: Rafols Jose A. , Matzke Howard A. 
Published: December 2004

AbstractThe Fink and Heimer technique was used to study the ascending and descending fiber degenerations resulting from unilateral electrolytic lesions in the superior colliculus of sixteen adult opossums. The ascending fiber degeneration left the colliculus by way of a small parabrachial bundle or with the brachium of the superior colliculus. The former bundle contributed degenerating terminals to the suprageniculate, parabrachial, and magnocellular medial geniculate nuclei and appeared to terminate in the lateral terminal nucleus of Hayhow (Hayhow, '66). The latter bundle contributed fibers to the pretectal and posterolateral nuclei as well as discrete projections to the ventral lateral geniculate nucleus and ventral thalamus.Descending degenerating fibers in the brainstem were destributed along three tracts: (1) a medial predorsal bundle, (2) an intermediate tectoreticular, and (3) a lateral tectopontine. These tracts were seen to terminate mainly in tegmental and reticular centers as well as in the lateral basilar nucleus of the pons. Degenerating fibers of the predorsal bundle were followed to lower medullary levels but could not be traced to spinal levels.The present findings are descussed in relation to data reported for more developed mammalian species.
Subcortical projection of the magnocellular medial geniculate body of monkey
Authors: Locke Simeon 
Published: December 2004

AbstractSubcortical projection of the magnocellular medial geniculate body to the lateral segment of the globus pallidus is suggested on the basis of anatomical observations in six Macaca mulatta. In two, extensive decortication failed to produce complete degeneration of the magnocellular division of the nucleus, suggesting the existence of a subcortical projection as well. In four other monkeys, lesions in the globus pallidus produced varying degrees of nerve cell loss with associated gliosis in the magnocellular medial geniculate nucleus. The suggestion is offered that this nucleus is an area of thalamic representation of vestibular function which projects to globus pallidus and vestibular cortex.
Neocortical projections to the pons and medulla of the nine‐banded armadillo (Dasypus novemcinctus)
Authors: Harting John K. , Martin George F. 
Published: December 2004

AbstractThe pattern of neocortical projections to the pons and medulla was determined by employing the Nauta‐Gygax technique ('54) on the brains of armadillos subjected to neocortical ablations. The results of this study indicate that the pretrigeminal basilar pontine gray receives input from a considerable portion of the neocortex. Degenerating fibers resulting from a lesion of the frontal tip of the neocortex terminated within the dorsal medial, the medial and the ventral medial areas of the rostral basilar pontine gray. Corticopontine fibers from the mid‐presupraorbital neocortex ended throughout the rostral to caudal extent of the basilar pontine gray, and terminated within the dorsal medial, the medial and the ventral medial areas; whereas degenerating fibers resulting from a lesion of the neocortex immediately rostral to the supraorbital sulcus terminated within the medial, the ventral and the ventral lateral areas of the basilar pontine gray. The neocortex immediately caudal to the supraorbital sulcus distributed corticopontine fibers to the ventral, the ventral lateral, the dorsal lateral and to the dorsal areas of the basilar pontine gray, while degenerating fibers resulting from lesions of the caudal one‐third and most caudal tip of the neocortex projected to the ventral and lateral portions of the basilar pontine gray.Neocortical projections to the pontine and medullary reticular formation originated mainly from cortical areas rostral and immediately caudal to the supraorbital sulcus. The neocortex rostral to the supraorbital sulcus distributed to the rostral and medial portions of the pontine reticular formation, whereas corticoreticular fibers from the neocortex immediately caudal to the suprarbital sulcus, also distributed degenerating fascicles to the spinal trigeminal nucleus, the nucleus of the solitary tract and to the nucleus cuneatus. No degenerating fibers were seen to terminate within motor nuclei of cranial nerves located within either the pons or medulla.
Quantitative delineation of the efferent anatomy of the medial mammillary nucleus of the cat
Authors: Fry William J. 
Published: December 2004

AbstractA quantitative description based on fractional parts of the total neuron population discovered for the projecting neuron subpopulations of the medial mammillary nucleus in the cat is presented. Five neuron subpopulations send projections through the principal mammillary tract to the thalamic, subthalamic and tegmental structures and one intrinsic subpopulation has been identified. These subpopulations describe in detail the structural organization of the projecting neurons. Although the methodology and supportive research leading to these results is quite extensive the material presented in this paper is concerned with 15 cats in which appropriate lesions have been placed. These animals provide the data upon which the quantative description rests.
The dendritic tree of spinal neurons
Authors: Gelfan Samuel , Kao Grace , Ruchkin Daniel S. 
Published: December 2004

AbstractThe size of the dendritic tree was determined from the number, length and diameter of primary dendrites and number and length of their branches in 360 unselected neurons from all areas of the spinal gray of L7 segment in Golgi‐Kopsch preparations (dog). A direct proportionality was demonstrated between the size of the dendritic tree of a neuron and the number of its primary dendrites; a basic dependence of the entire dendritic complex upon the number of initial dendrite extensions from cell body. The existence of two dendrite parameter levels, and consequently two size levels of the whole dendritic tree, was also established; one for the large neurons and one for the small ones. The parameter and tree size differences between the two classes of neurons, the latter distinguished by different cell body‐size ranges, were all statistically highly significant. Very little of the variability of the parameters or of the whole tree could be accounted for by the variability of the specific cell body‐size within each of the two groups of neurons or within the entire sample. The morphological distinction is between two classes of neurons. The mean dendrite surface area for the entire population sample of large neurons was some five times greater than the mean for the small ones. With commensurate cell body‐size differences, and thus total receptive surface area, this implies a 5‐fold difference in mean number of synaptic contacts/neuron. The evidence, in addition, strongly pointed to motoneurons as having larger dendritic trees, on the average, than interneurons with comparably‐sized cell bodies. It was previously estimated that only 2% of interneurons in L7 segment, which outnumber motoneurons 30:1, are large cells.
The differential effects of unilateral lid closure upon the monocular and binocular segments of the dorsal lateral geniculate nucleus in the cat
Authors: Guillery R. W. , Stelzner D. J. 
Published: December 2004

AbstractOne eyelid has been sutured in each of three seven‐day old kittens. Three months later the brains were fixed and stained by the Nissl method. In the contralateral lateral geniculate nucleus the cells of the deprived lamina A were smaller, more closely packed and paler staining than those in the normally innervated, ipsilateral lamina A. However, these changes were seen in the medial parts of the contralateral lamina A only. The lateral parts, which extend beyond the border of lamina A1 and which project to the monocular parts of the visual cortex showed no change. These results show that some geniculate cells are not affected by deprivation. The observations are consistent with the view that during normal development geniculate cell axons from adjacent laminae compete with each other for synaptic surfaces upon binocular cortical neurons: that unilateral lid suture upsets the balance of this competition and that the reduced perikaryal growth in the lateral geniculate nucleus is secondary to the unbalanced axonal development, which occurs in the binocular portions of the geniculocortical projection but which cannot occur in the monocular portions, where there is no competition.
The effects of Wulst ablations on color, brightness and pattern discrimination in pigeons (Columba livia)
Authors: Pritz Michael B. , Mead William R. , Northcutt R. Glenn 
Published: December 2004

AbstractPigeons were trained to peck at a transparent response key on which was projected either a color, brightness or pattern discrimination problem. Each subject was trained on only one of these problems. Training was continued until the subjects had reached asymptote. After reaching asymptote, subjects received brain ablations (by subpial suction) according to the following design: hyperstriate group, tissue removed from the Wulst; ablated controls, tissue removed from the neostriatum and corticoid areas; operated controls, no neural tissue intentionally removed. After a two week recovery period, each subject was re‐tested on the same discrimination task that it had learned pre‐operatively. Those birds with ablations of the Wulst showed deficits in performance on the brightness and pattern problems, but not on the color problem. Ablated and control subjects showed no post‐operative deficits. These findings indicate that the Wulst functions in brightness and pattern discrimination, but may not be essential for color discrimination.