bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abducens internuclear neurons and their role in conjugate horizontal gaze
Authors: Carpenter Malcolm B. , Batton Robert R. 
Published: January 2005

AbstractExperimental evidence suggests that brain stem lesions producing paralysis of lateral gaze and dissociation of conjugate horizontal eye movements have certain common features. Both of these disturbances involve abducens internuclear neurons (Abd IN) or their projections. Attempts were made to determine the course and terminal distribution of Abd IN in the monkey by autoradiographic techniques. Tritiated amino acids injected in the abducens nucleus (Abd N) labeled: (1) root fibers ipsilaterally, and (2) fibers that ascended in medial parts of the contralateral medial longitudinal fasciculus (MLF). In the opposite oculomotor complex (OMC) silver grains were profuse over the ventral nucleus (VN, medial rectus muscle) and patchy over caudal parts of the dorsal nucleus (DN, inferior rectus muscle). Labeling of cells in the reticular formation ventral to Abd N resulted in transport ipsilaterally, outside the MLF, to the rostral interstitial nucleus of the MLF (RiMLF), a cell group considered to be concerned with vertical eye movements.Bilateral labeling of Abd N and cells of the nucleus prepositus (NPP) resulted in bilateral: (1) transport of isotope via root fibers and the MLF, and (2) selective distribution of silver grains in the OMC. Bilateral silver grain distribution in the OMC suggested profuse terminations in VN, patchy terminations in DN and vertical, linear terminations in caudal parts of the medial nucleus (MN, superior rectus muscle). Comparisons with more discrete unilateral labeling of cells in Abd N suggested that cells of the NPP project selectively to terminations in MN, and may be related to upward eye movements.Two conclusions were drawn: (1) The paresis of ocular adduction which occurs in both anterior internuclear ophthalmophlegia and in paralysis of lateral gaze results from involvement of Abd IN or their ascending projections, and (2) the NPP appears to project selectively to parts of MN of the OMC, a cell group said to provide crossed innervation for the superior rectus muscle.
A quantitative comparison between the ganglion cell populations and axonal outflows of the visual streak and periphery of the rabbit retina
Authors: Vaney David I. 
Published: January 2005

AbstractA vertical density profile of the ganglion cells 2 mm temporal of the optic nerve head in the rabbit retina has been produced by counting somata in the cresyl‐violet‐stained, ganglion cell layer of a flat‐mounted retina. Somata classified as ganglion cells were characterized by obvious Nissl staining in an extensive cytoplasm and typically had diameters greater than 9 μm. The accuracy of the profile, and thus of the classification criteria, has been substantiated by electron micrographic determination of the numbers of ganglion cell axons arising within local regions of known area on the same retinaThis study indicates that Vaney and Hughes' estimate ('76) of 547,100 presumed ganglion cells in the rabbit retina should be changed to 373,500 ganglion cells. The latter value is within the statistical error of their optic nerve count of 394,000 fibersThe mean diameter of ganglion cells 6 mm from the visual streak in the inferior periphery (density: 550 cells/mm2) was 28% greater than that of cells on the peak of the streak (density: 5,400 cells/mm2), although the form of the ganglion cell diameter distribution did not change markedly with eccentricity. The increase in the mean size of ganglion cells in the periphery appeared to be approximately matched by an increase in the size of their axons. Larger axons became myelinated farther from the edge of the myelinated band than did smaller axonsWithin the ganglion cell layer there was another population of cells which were quite distinct from the obvious neuroglia: Their nuclei were similar to those of the larger ganglion cells and many appeared to have Nissl granules within their limited cytoplasm. About half of this heterogeneous population was classified as “coronate cells,” which were characterized by the partial nuclear encapsulation of their eccentric cytoplasm.
Somatic sensory cortex (SmI) of the prosimian primate Galago crassicaudatus: Organization of mechanoreceptive input from the hand in relation to cytoarchitecture
Authors: Carlson Mary , Welt Carol 
Published: January 2005

AbstractMechanoreceptive input from the hand to the somatic sensory cortex (SmI) of the prosimian primate Galago crassicaudatus was examined with microelectrode mapping methods. In anesthetized animals, low threshold cutaneous input from the hand projects to SmI cortex in a single, complete, somatotopically organized pattern. Within this single pattern, cells with receptive fields on the glabrous skin of the palm, digits and digit tips are located in the rostral half, and cells with RFs on the hairy skin of the dorsal hand and digits are located in the caudal half of the hand area. The cutaneous hand area is coextensive with the densely granular architectonic region of SmI.Studies of single cells in this region of awake galagos reveal the same pattern of cutaneous input and, in addition, demonstrate the presence of cells responding to joint movement not detected in anesthetized animals. Cells responsive to joint movement are arranged in vertically oriented columns located adjacent to cutaneous columns with receptive fields on the same part of the hand.In anesthetized animals, cells rostral to the granular region, in an area typified by increasing numbers of pyramidal cells in layer V and decreasing numbers of granular cells in upper layers, respond to high threshold stimulation of large areas of the hand. The few cells isolated in this area in awake animals respond to either active or passive hand movements. In such animals, cells caudal to the granular region, in an area characterized as agranular and alaminar cortex, respond to either passive stimulation of single or multiple joints or to active hand movements.These results, together with similar findings in a related prosimian, Nycticebus coucang, emphasize the generality of a single cutaneous hand area in SmI of prosimian species. The demonstration of multiple hand areas corresponding to multiple cytoarchitectonic subdivisions in SmI of Old and New World simians illustrates the increased degree of SmI differentiation from the prosimian to the simian grade of organization. The present results further suggest that determination of the homologues of multiple areas or subdivisions within and surrounding SmI in primates will require comparisons of somatotopy, submodality, sulcal patterns, cytoarchitecture, and connectivity in representative members of prosimian and simian families.
Rohon‐beard cells and other large neurons in Xenopus embryos originate during gastrulation
Authors: Lamborghini Janet E. 
Published: January 2005

AbstractThe time of origin (birthday) of Rohon‐Beard cells in Xenopus laevis was studied by 3H‐thymidine autoradiography. Rohon‐Beard cells were selected because they are a morphologically identifiable population of neurons in which the development of chemical and electrical excitability has been studied. A single injection of a radioactive DNA precursor was given to animals in successive stages of development from blastula to late tail bud (Nieuwkoop and Faber stages 8–33/34). The label was available throughout the stage of injection and longer. The labeling pattern was examined when animals had reached stage 42, when Rohon‐Beard cells are easily recognized. All neurons including Rohon‐Beard cells were labeled in animals injected with 3H‐thymidine before stage 10 1/2 (early gastrula). Unlabeled Rohon‐Beard cells were observed in animals injected with 3H‐thymidine in and after stage 10 1/2. The percentage of unlabeled Rohon‐Beard cells increased as development progressed. About 80% were born by the completion of gastrulation (stage 13). The other ∼20% were born during neurulation and early tail bud stages. By stage 27, no Rohon‐Beard neuron incorporated 3H‐thymidine. In addition to Rohon‐Beard neurons, five other neuronal populations begin generation during gastrulation: Mauthner neurons (Vargas‐Lizardi and Lyser, '74), trigeminal ganglion cells, large basal plate cells of the medulla, extramedullary neurons, and primary motor neurons. The first birthdays in any of the six populations are temporally close to but appear to be independent of the others.
Development of the dorsal lateral geniculate nucleus in normal and visually deprived cats
Authors: Hickey T. L. 
Published: January 2005

AbstractAlthough much is known about the cell size changes that take place in the cat dorsal lateral geniculate nucleus as a result of visual deprivation, very little is known about the time course of either of these changes or the changes that occur during normal development. In addition, all previous studies of lateral geniculate nucleus cell size have been confined to the dorsal laminae A and A1 since the more ventral “C” laminae are impossible to identify in normal Nissl stained material. However, it is possible to extend the cell measurement data to laminae C, C1, and C2 by using autoradiographic techniques.Cross‐sectional area measurements of dorsal lateral geniculate nucleus cells were made in 47 normally reared kittens and 45 monocularly deprived kittens. All of the normal kittens and 39 of the 45 deprived kittens were studied during the first 70 days of postnatal life. Six deprived cats used to study the deprivatin induced changes in cell size in the “C” laminae were allowed to survive for longer periods.In normal kittens, lateral geniculate nucleus cells grow rapidly during the first four weeks of life. Cells in the deprived layers also grow rapidly during this time, however, at the end of the first month their growth stops and a slow shrinkage takes place over the next several weeks. In the ‘C’ laminae of deprived cats significant changes in cell size are confined to layer C.Although many of the deprived cats show greater deprivation induced changes in cell size in the binocular segment of the lateral geniculate nucleus than in the monocular segment, other cats show approximately equal changes in cell size in the two regions. In addition, some cats exhibit little, if any, deprivation induced change in lamina A cell size but do show quite severe cell shrinkage in lamina A1.
Subcortical afferents to the hippocampal formation in the monkey
Authors: Amaral David G. , Cowan W. Maxwell 
Published: January 2005

AbstractThe distribution of neurons in the basal telencephalon, the diencephalon, and the brainstem that project to the hippocampal formation has been analyzed in mature cynomolgus monkeys (Macaca fascicularis) by the injection of horseradish peroxidase into different rostro‐caudal levels of the hippocampal formation. After injections which involve Ammon's horn, the dentate gyrus, and the subicular complex, retrogradely labeled neurons are found in the following regions: in the amygdala (specifically in the anterior amygdaloid area, the basolateral nucleus, and the periamygdaloid cortex); in the medial septal nucleus and the nucleus of the diagonal band; in the ventral part of the claustrum; in the substantia innominata and the basal nucleus of Meynert; in the rostral thalamus (specifically in the anterior nuclear complex, the laterodorsal nucleus, the paraventricular and parataenial nuclei, the nucleus reuniens, and the nucleus centralis medialis); in the lateral preoptic and lateral hypothalamic areas, and especially in the supramammillary and retromammillary regions; in the ventral tegmental area, the tegmental reticular fields, the raphé nuclei (specifically in nucleus centralis superior and the dorsal raphé nucleus), in the nucleus reticularis tegmenti pontis, the central gray, the dorsal tegmental nucleus, and in the locus coeruleus.
Immunocytochemical localization of enkephalin in the neostriatum of rat brain: A light and electron microscopic study
Authors: Pickel Virginia M. , Sumal Khushdev K. , Beckley Susan C. , Miller Richard J. , Reis Donald J. 
Published: January 2005

AbstractThe peroxidase‐antiperoxidase (PAP) immunocytochemical technique was used to determine the light and electron microscopic localization of antisera directed against either methionine [Met5]‐ or leucine [Leu5]‐enkephalin in the neostriatum of brains from untreated rats. By light microscopy, neuronal perikarya and processes showing enkephalin‐like immunoreactivity (ELI) were unevently distributed throughout the neostriatum. The greatest accumulation of neuronal structures showing ELI was in the ventro‐ and caudo‐ lateral portions of the nucleus. The labeled perikarya measured 10–15 μm in diameter and constituted about 15–20% of the total neurons in the enostriatum. By electron microscopy, examination of three areas from horizontal and coronal sections revealed no regional differences in types of neurons showing ELI or in their synaptic organization. All labeled neurons showed a relatively low intensity reaction product which was diffusely distributed throughout the perikarya and dendrites. The cytoplasm contained relatively few organelles, which included mitochondria, endoplasmic reticulum and numerous “alveolate” vesicles. The dendrites had many spiny processes which formed asymmetric synapses with unlabeled axon terminals containing all small clear vesicles. In contrast to the perikarya and dendrites a dense accumulation of reaction product was present in a few myelinated and numerous unmyelinated axons and axonal varicosties. Approximately 75% of the labeled varicosities did not form a specialized synaptic junction in a single plane of section. The remaining 25% of the labeled terminals formed asymmetric junctions primarily with unlabeled dendrites and rerely with unlabeled perikarya or axons. The morphology and synaptic relations of the neurons showing ELI suggest that they may belong to the general group of medium‐sized spiny cells characterized in Golgi studies by Kemp and Powell ('71a). At least some of the peptide‐containing neurons may also have a myelinated efferent axon.
Development of the hippocampal region in the rat II. Morphogenesis during embryonic and early postnatal life
Authors: Bayer Shirley A. 
Published: January 2005

AbstractMorphogenesis of the entire hippocampal region was examined in normal rats from embryonic (E) day E10 to E22 and on postnatal (P) days P1, P7, and P21, and was correlated with autoradiographic datings (Bayer, '79c). This region is postulated to form from two connected primordia in the telencephalon, easily recognizable on E16. One lies in the dorsomedial wall and generates a portion of the subiculum, Ammon's horn and the dentate gyrus. The other lies in the dorsoposterior wall and generates the entorhinal cortex and part of the parasubiculum and presubiculum. A cortical plate appears in the presumptive entorhinal region on E17; a cell‐sparse fibrous zone appears in the middle of the cortical plate on E19. Lamination in the entorhinal cortex proceeds from lateral to medial and from deep to superficial, with the thickening of layer III being the last to appear on E22. Lamination in the subiculum starts on E18, but the distinction between superficial laminae in the para‐ and presubiculum cannot be made until E22. The stratum pyramidale is small on E20 in presumptive Ammon's horn, then greatly lengthens between E21‐P1. In early dentate gyrus development, cells migrate from the neuroepithelium near the outgrowth of the fimbria and adjacent to the choroid plexus toward a subpial location. The ectal limb of the granular layer appears at the two extremes of the dentate gyrus on E20; the endal limb apears perinatally and develops rapidly to become morphologically similar to the ectal limb by P7.A volumetric analysis of growth in Ammon's horn (including a portion of the subiculum), dentate gyrus, fimbria, and fornix was made from E15 to P21. The neuroepithelium increases to a peak volume on E18 and disappears by P1. The subependymal zone becomes distinct on E18, reaches a peak volume on E20 and disappears by P7. Rapid rates of growth in the stratum oriens and strata radiatum, lacunosum‐moleculare occur between E16‐E17 and between E22‐P1. The pyramidal layer grows rapidly between E18‐E19 (presumptive subicular pyramids) and between E22‐P1 (presumptive Ammon's horn pyramids). Growth rates of the dentate hilus are rapid prenatally and decline postnatally, while dentate granular and molecular layers maintain high postnatal growth rates. The fimbria and fornix have early (E18‐E19) and late (E21‐E22) spurts of growth.To accurately locate regions of primitive migratory and mitotic cells within each lamina of Ammon's horn and the dentate gyrus, the number of cells surviving a single exposure to 200 R X‐rays in embryonic brains (E15‐E22) were compared with controls. The neuroepithelium increases its radioresistance from E15‐E21 and reaches control levels by E22; the subependymal zone is highly radiosensitive throughout development. In contrast, radioresistance in the stratum oriens and dentate hilus declines and reaches a low point on E20. Over 70% of the cells in the strata pyramidale, radiatum, lacunosum‐moleculare, and dentate granular layer are radioresistant throughout development.
Ultrastructure of HRP‐identified sympathetic preganglionic neurons in cats
Authors: Chung Kyungsoon , La Velle F. W. , Wurster R. D. 
Published: January 2005

AbstractElectron microscopic studies were conducted on cat sympathetic preganglionic neurons which were labeled using retrograde transport of horseradish peroxidase from the injection site in the stellate ganglion to somas in the thoracic spinal cord. Based on size, the identified somas were divided into two groups: large multipolar somas (25–35 μm), usually having three dendrites with a mean diameter of 8 μm, and small fusiform somas (12–24 μm), with two primary dendrites with a mean diameter of about 4 μm. The ultrastructures of the perikarya and dendrites were similar to other spinal neurons. Three types of terminals were identified: 1) round asymmetric terminals, 2) pleomorphic symmetric terminals, and 3) round symmetric terminals. On the soma, pleomorphic terminals were more numerous than round asymmetric terminals. On the dendrites, the density of round asymmetric terminals was similar to plemorphic symmetric terminals. Round symmetric terminals represent only a small percent on either the soma or dendrites. Because of the greater total density of terminals on the dendrites than soma, pleomorphic symmetric and round asymmetric terminals are primarily located on the dendrites. Very few dense‐core vesicles characteristic of monoamine terminals were observed, perhaps due to the fixative used.
Efferent projections of the deep mesencephalic nucleus (pars lateralis) in the rat
Authors: Veazey R. B. , Severin C. M. 
Published: January 2005

AbstractThe projections of the lateral part of the deep mesencephalic nucleus (DMN) were traced by autoradiography and retrograde horseradish peroxidase (HRP) techniques. At the level of the DMN, projections from its lateral part crossed the midline and terminated in the medial and lateral part of the contralateral DMN. Furthermore, two labeled tracts passed rostrally from the lateral part of the DMN. One tract coursed dorsolaterally from the lateral DMN to terminate in the ipsilateral lateral thalamic nucleus. The second tract coursed ventrally and rostrally over the substantia nigra toward the ipsilateral zona incerta. At the caudal part of the zona incerta these fibers divided into two bundles. One bundle coursed superiorly to terminate bilaterally in the mediodorsal nucleus of the thalamus. The second bundle of fibers passed anteriorly to enter the ipsilateral zona incerta. Some of these fibers terminated upon neurons of the zona incerta and the ventromedial part of the subthalamic nucleus. The remaining fibers within the zona incerta coursed anteriorly to enter the internal capsule. These fibers terminated in the entopeduncular nucleus and medial part of the globus pallidus. These findings indicate that the lateral part of the DMN is likely to be involved in the ascending activating system of the reticular formation by connections with thalamic nuclei. Furthermore, the lateral part of the DMN may play a part in suprasegmental motor control via connections with rostral brain stem motor centers.
Strain‐specific variations in the folial pattern of the mouse cerebellum
Authors: Inouye Minoru , Oda Sen‐Ichi 
Published: January 2005

AbstractThe folial pattern of the mouse cerebellum was compared in 13 inbred strains and a closed colony. The morphological variation of the cerebellum among individual animals was slight within each inbred strain, whereas it was marked in the closed colony. There was no sex‐related difference in the cerebellar folial pattern. The cerebellum of mice from each inbred strain presented a characteristic folial pattern in which some similarties were recognized among animals from genetically related strains. These findings revealed that the morphological variation in the folial pattern of the cerebellum was strain‐specific in mice and had an intimate connection with the genetic control.
Central origins of cranial nerve parasympathetic neurons in the rat
Authors: Contreras Robert J. , Gomez Maximo M. , Norgren Ralph 
Published: January 2005

AbstractThe location of central neurons that contribute preganglionic parasympathetic axons to cranial nerves VII, IX, and X in rats has been identified using horseradish peroxidase (HRP) tracting methods. Collectively, these neurons form an uniterrupted dorsal column that extends over the entire length of the medulla. The cephalic end of this column turns ventrally with neurons scattered in the parvicellular reticular formation between the rotral pole of the nucleus of the solitary tract (NST) and the facial motor nucleus. Applying HRP crystals to the cut cervical vagus labels neurons in the classically defined dorsal motor nucleus. Rostrally, this distribution continues along the medial edge of NST, ending just caudal to neurons exiting in the lingual‐tonsilar branch of IX. At the rostral pole of the NST and ventral to it, neurons occur that serve the lingual‐tonsilar and tympanic branches of IX, as well as the chorda tympani and greater superficial petrosal (GSP) branches of VII. Central neurons of the chorda tympani and tympanic nerves spread ventrally from NST into a sparse but largely coextensive distribution in the reticular formation lateral to the ascending radiations of the facial motor nucleus. Immediately ventral to this distribution, a dense accumulation of GSP efferent neurons appears rostrolateral to the facial motor nucleus. Although they vary considerably in number and packing density, the neurons of the dorsal efferent column and those extending from it into the reticular formation have similar morphological characteristics. The somata are medium‐sized, fusiform, or multipolar, but with usually no more than five or six major processes.