bluuebunny/crossref_metadata_2025_split huggingface dataset:
Retinofugal projections of nonecholocating (Pteropus giganteus) and echolocating (Myotis lucifugus) bats
Authors: Cotter John R. , Pierson Pentney Roberta J. 
Published: January 2005

AbstractThe projections and terminations of retinofugal pathways were studied in nonecholocating (Pteropus giganteus) and echolocating (Myotis lucifugus) bats by two methods, that of anterograde axonal degeneration following unilateral enucleation and anterograde axoplasmic transport of isotope following unilateral intraocular injection of tritiated proline.In Pteropus giganteus crossed and uncorssed projections terminated in several brainstem areas and the nuclei of the accessory optic system. Bilateral projections to the hypothalamus ended in the suprachiasmatic nuclei (SCN). In the ventral thalamus the projection terminated bilaterally in internal (VLGi) and external (VLGe) divisions of the ventral lateral geniculate (VLG) nuclei, although the projection to VLGi was greater than that to the other subdivision of VLG. Three lateral laminae of the dorsal lateral geniculate (DLG) nucleus and a medial division were each involved in contralateral and ipsilateral projections of the retina to the dorsal thalamus. Partially segregated and partially overlapping patterns from the two eyes and concealed lamination were identified in the lateral three laminae at some levels. In addition, the projection to the dorsal thalamus involved the contralateral lateral posterior nucleus. In the pretectum the projection terminated bilaterally in the nuclei of the optic tract (NOT), pretectal olivary nuclei (PON), anterior pretectal nuclei (APN) and posterior pretectal nuclei (PPN). The pattern of termination in the superior colliculus was such that contralateral and ipsilateral projections ended in different tiers in the superficial gray (SG) layer, those on the contralateral side being largely confined to the upper and lower tiers and those of the ipsilateral side being confined to a middle tier. Projections to contralateral medial, lateral, and dorsal accessory optic nuclei traversed the accessory optic tract.In Myotis lucifugus crossed projections terminated in the SCN, VLG, DLG, pretectum and superior colliculus. The projection to the VLGe was greater than that to VLGi. In the DLG, retinal fibers terminated in two major subdivisions. The stratification of retinal terminals observed in Pteropus was not present in Myotis> Pretectal terminations were confined to two restricted areas which were tentatively identified as the NOT and the PON. In the contralateral superior colliculus the projection terminated in two tiers in the SG. A small uncrossed component of the projection was limited in its termination to the ipsilateral SCN, DLG and VLG. The accessory optic system did not appear to be present in Myotis.These results indicate that there are basic differences in the overall projection of the retina upon the brainstem of echolocating and nonecholocating bats.
Primary afferent fibers in the tract of Lissauer in the rat
Authors: Chung Kyungsoon , Langford Lauren A. , Applebaum Arnold E. , Coggeshall Richard E. 
Published: January 2005

AbstractMore than two‐thirds of the axons in the tract of Lissauer at mid‐thoracic and lumbosacral levels of the rat spinal cord are primary afferent fibers. The proportions of primary afferents in the tract are approximately the same at the two spinal levels. A slightly higher percentage of the unmyelinated, as opposed to the myelinated, fibers are primary afferents. There is a somewhat greater percentage of primary afferent axons in medial parts of the tract in mid‐thoracic levels, but all areas of the tract that were examined contain a majority of primary afferent fibers. The primary afferent axons appear to travel less than a segment in the tract at mid‐thoracic levels but for several segments in the tract at lumbo‐sacral levels. These data indicate that the tract of Lissauer is predominately a primary afferent fiber system in these segments of the rat.
Electron microscopic studies of serially sectioned cat spinal α‐motoneurons. II. A method for the description of architecture and synaptology of the cell body and proximal dendritic segments
Authors: Conradi S. , Kellerth J‐O. , Berthold C‐H. 
Published: January 2005

AbstractThe paper presents a method for ultrastructural analysis and description of neuronal architecture and synaptology of cat spinal α‐motoneurons from complete series of consecutive ultrathin sections through the cell body and proximal parts of the dendrites. The method implies that sections are selected for analysis only at certain constant intervals in the series. The occurrence of boutons of different morphological types on the neuronal surface was expressed by their percentage covering of the neuronal membrane. The neuronal surface was divided into a number of compartments and the synaptic covering was calculated separately for each compartment. An interval of 6 μm between the sections was used for these calculations, and the obtained values for synaptic covering were found not to differ significantly from those obtained in controls at 3 μm intervals. The number and location of individual large boutons (C‐ and M‐types) were studied at 3 μm section intervals, and the escape of boutons connected to this procedure was estimated from control observations at 1 μm intervals. It is concluded that detailed information on neuronal synaptology can be obtained with this method, which will be used in three subsequent studies on functionally identified and intracellularly stained cat α‐motoneurons.
An autoradiographic study of the subcortical projections of the rabbit striate cortex in the adult and during postnatal development
Authors: Holländer H. , Tietze J. , Distel H. 
Published: January 2005

AbstractThe subcortical projections of the rabbit striate cortex were studied by autoradiography. Small injections of 3H‐leucine were placed into the striate cortex of 15 rabbit pups aged between one day and one month and six adult rabbits (strain Chbb:Ch). Terminal fields of projection occurred only ipsilateral to the injection, and these were found in the caudate nucleus (CN), the claustrum (Cla), the thalamic reticular nucleus (TRN), the dorsal (LGNd) and the ventral (LGNv) lateral geniculate nuclei, the pulvinar (Pul), the ventrolateral (Vl) the posterior (Po) thalamic nuclei, the anterior (APN) and posterior (PPN) pretectal nuclei, the nucleus of the optic tract (NOT), the superior colliculus (SC) and the basal pontine nuclei (PN). Cla was innervated via the superficial corticocortical and CN via the corticocaudate pathways. The remaining projections were innervated via the subcortical pathway which comprised three bundles: The deep bundle (to TRN, LGNd, Pul and Po), the superficial bundle (to LGNv, APN, PPN, NOT, and SC), and the peduncular bundle (to PN). The projection to SC showed remarkable changes of its terminal pattern during the first and second postnatal weeks. These changes were characterized by a strong reduction of the horizontal extension of the terminal labelling and an increasing concentration on the stratum griseum superficiale. Similar changes were not observed in the other projections.
Aging in the rat olfactory bulb: Quantitative changes in mitral cell organelles and somato‐dendritic synapses
Authors: Hinds James W. , McNelly Nancy A. 
Published: January 2005

AbstractQuantitative measurements of the major organelles in the mitral cell perikaryon as well as numbers of mitral somato‐dendritic synapses, have been made on electron micrographs from rats aged 3 to 30 months. The volume fraction of the cisternae of rough endoplasmic reticulum (RER) is constant throughout the period studied. Hence the amount of RER per cell reflects changes in perikaryal size. Thus there is a 3‐fold increase of volume of cisternae of RER per mitral cell from 3 to 27 months and a halving from 27 to 30 months. A similar pattern is seen for the volume of mitochondria per cell. The volumes of dense bodies and cisternae of the Golgi complex per cell show a different pattern, that of a linear increase throughout the period, with no suggestion of a decrease from 27 to 30 months. An interesting finding is that the volume fraction of ground substance (perikaryal cytoplasm exclusive of the measured organelles) shows a remarkably constant value from 3 to 27 months and then a highly significant decrease from 27 to 30 months. This decrease, restricted to the period from 27 to 30 months, suggests a fundamental breakdown in cellular homeostasis in the oldest animals.Numbers of somato‐dendritic, mitral‐to‐granule synaptic junctions per mitral cell and per olfactory bulb show a significant increase from 3 to 24 and 27 months, respectively, and then a suggestive decrease from 24 and 27 to 30 months. This finding indicates that new synapse formation is possible in normal adult rats, perhaps even in quite old rats.
The cochlear nuclei of some turtles
Authors: Miller Malcolm R. , Kasahara Michiko 
Published: January 2005

AbstractHistological sections of the brains of eight species of turtles representing six different families were studied in order to delineate the cochlear nuclei. In addition, the posterior eighth cranial nerve root and its ganglion were sectioned in 15 specimens of Kinosternon leucostomum, and the distribution of the degenerated nerve fibers and terminals was determined. Two primary and one probably secondary nuclei were demonstrated by the terminal degeneration pattern of the cochlear fibers.A spherical nucleus angularis and an elongated nucleus magnocellularis together form a column of primary cochlear nuclei in the dorsal alar lamina of the medulla. Heavy terminal degeneration is seen associated with these cells following transection of the posterior eighth nerve and ganglion. Nucleus magnocellularis is probably homologous with the nucleus magnocellularis medialis of lizards and crocodiles, and has been described in turtles as nucleus dorsalis magnocellularis by previous authors.A probably secondary cochlear nucleus, nucleus laminaris, lies just ventral to the nucleus magnocellularis. It is associated with the nucleus magnocellularis throughout its length but is shorter. Nucleus laminaris remains free of terminal degeneration after destruction of the posterior eighth nerve and ganglion.The cochlear nuclei of other turtle species were very similar to those of Kinosternon leucostomum.
Distribution of primary afferent fibers within the sacrococcygeal dorsal horn: An autoradiographic study
Authors: Réthelyi M. , Trevino D. L. , Perl E. R. 
Published: January 2005

AbstractThe spinal segmental distribution and intersegmental course of primary afferent fibers were studied by injecting (by pressure or iontophoresis) tritiated amino acids (L‐proline or L‐leucine) into spinal ganglia of coccygeal and sacral segments and autoradiographically analyzing histological sections of the spinal cord, particularly those regions lying dorsal to the central canal. The results from eight cats and three monkeys are described.A heavy projection of primary afferent fibers to the marginal zone (lamina I), the substantia gelatinosa Rolandi (lamina II), and throughout the nucleus proprius (laminae III‐IV) was demonstrated. The projections to these three areas appeared to be substantially independent. Primary afferent fibers were found to course rostrally and caudally within the marginal zone, in the midline dorsal to the central canal, in Lissauer's tract, and in the dorsal columns. A crossed projection passed by way of the dorsal commissure to the contralateral marginal zone and to a region ventrolateral to the contralateral nucleus proprius.There was a distinct medial‐to‐lateral shift in the termination of primary afferent fibers in the substantia gelatinosa and in the dorsal protion of the nucleus proprius. The most medial distribution occurred immediately caudal to the entry zone of the primary afferent fibers, and the most lateral at the cephalad end of the segment immediately rostral to the entry level. Small (iontophoretic) injections revealed circumscribed fields of termination, approximately 40 μm 70 μm (dorsoventrally) by 400 μm or more (rostrocaudally) in the substantia gelatinosa.
Thalamic relay nuclei for cerebellar and certain related fiber systems in the cat
Authors: Hendry S. H. C. , Jones E. G. , Graham J. 
Published: January 2005

AbstractAnterograde labeling techniques were used to define the terminal distributions in the thalamus of afferents arising in the deep cerebellar nuclei, entopeduncular nucleus and substantia nigra. Anterograde and retrograde labeling methods were then used to determine the extent of the cortical projections of the cerebellar relay nuclei. The cerebellar projection to the contralateral ventral nuclei of the thalamus terminates in a zone which is separate from that receiving pallido‐ and nigrothalamic fibers. None of the zones of termination of these fiber systems corresponds to commonly recognized cytoarchitectonic divisions. Instead, they include parts of the ventroanterior (VA), ventrolateral (VL) and principal ventromedial (VMp) nuclei.Some cells within the zone of termination of cerebellar afferents project to parietal cortex (areas 5 and 7). A further, distinct group of cells in this zone projects to motor cortex (area 4). But projections to area 4 also arise from small groups of cells: (a) in the zone receiving nigro‐ and pallidothalamic fibers; (b) in the part of VL, distinct from the cerebellar terminal zone, in which spinothalamic fibers terminate.Cerebellar, nigral, and entopeduncular fibers also terminate in the intralaminar nuclei. These projections are far greater in extent than those arising in the spinal cord. Some parts of the intralaminar nuclei are dominated by a particular afferent system, while others show substantial overlap of the terminal zone of several afferent systems.
An HRP and autoradiographic study of the projection from the cerebellar cortex to the nucleus interpositus anterior and nucleus interpositus posterior of the cat
Authors: Bishop G. A. , McCrea R. A. , Lighthall J. W. , Kitai S. T. 
Published: January 2005

AbstractThe recently developed anatomical techniques of retrograde transport of the enzyme horseradish peroxidase (HRP), anterograde transport of tritiated amino acid, and intracellular injections of HRP were used to study the organization of the corticonuclear projection to the nucleus interpositus anterior (NIA) and the nucleus interpositus posterior (NIP) of the cat.Injections of HRP into the NIA and the NIP revealed that the major areas of the cortex which provided afferents to these two nuclei were the intermediate cortex of the anterior lobe (IAL) and the paramedian lobule (PML). There were, however, significant differences in the distribution of Purkinje (Pk) cells which projected to each nucleus. The NIA received afferents from all areas of the IAL while the NIP projection area was restricted to a band located at the medialmost aspect of the lobe. All areas of the PML, in particular the intermediate folia, projected to the NIP, while the Pk cells which sent axons to the NIA were restricted to the rostral and caudal folia of this lobule. The projection from each area was somatotopically organized.The axons of intracellularly stained Pk cells were followed to their termination in the NIA and NIP confirming the results obtained with the two extracellular techniques. An attempt was made to examine the organization of the corticonuclear projection at the single cell level in the PML. Pk cells located in the same sagittal plane appeared to terminate in the same area of the same nucleus while Pk cells located not more than 500 μm medial or lateral to each other terminated in different nuclei.Basically, the organization of the corticonuclear projection from the IAL is longitudinally organized while the PML has a much more complex arrangement in which the Pk cells projecting to the NIA and NIP are interspersed.
Efferent projections of the dorsal ventricular ridge and the striatum in the Tegu lizard, Tupinambis nigropunctatus
Authors: Voneida Theodore J. , Sligar Catherine M. 
Published: January 2005

AbstractA H3 proline‐leucine mixture was injected into the dorsal ventricular ridge (DVR) and striatum of the Tegu lizard in order to determine their efferent projections. The brains were processed according to standard radioautographic technique, and counterstained with cresyl violet. DVR projections were generally restricted to the telencephalon, while striatal projections were limited to diencephalic and mesencephalic structures. Thus the anterior DVR projects ipsilaterally to nuclei sphericus and lateralis amygdalae, striatum (ipsilateral and contralateral) ventromedial nucleus of the hypothalamus, nucleus accumbens, anterior olfactory nucleus, nucleus of the lateral olfactory tract and lateral pallium. Posterior DVR projections enter ipsilateral anterior olfactory nucleus, lateral and interstitial amygdalar nuclei, olfactory tubercle and bulb, nucleus of the lateral olfactory tract and a zone surrounding the ventromedial hypothalamic nucleus. Labeled axons from striatal injections pass caudally in the lateral forebrain bundle to enter (via dorsal peduncle) nuclei dorsomedialis, medialis posterior, entopeduncularis anterior, and a zone surrounding nucleus rotundus. Others join the ventral peduncle of LFB and enter ventromedial nucleus (thalami), while the remaining fibers continue caudally in the ventral peduncle to the mesencephalic prerubral field, central gray, substantia nigra, nucleus intercollicularis, reticular formation and pretectal nucleus posterodorsalis. These results are discussed in relation to the changing notions regarding terminology, classification and functions of dorsal ventricular ridge and striatum.
An anatomical reinvestigation of the termination of the spinothalamic tract in the monkey
Authors: Boivie Jörgen 
Published: January 2005

AbstractThe projections of the spinothalamic tract in the macaque monkey have been reinvestigated using the Wiitanen modification of the Fink‐Heimer technique. In agreement with previous studies in the monkey (Mehler, Bowsher, Kerr) it was found that the spinothalamic tract ascends outside the medial lemniscus, enters the thalamus just dorsal to this structure, and terminates in the posterior, intralaminar and ventral regions, as well as in the zona incerta.The posteromedial nucleus (POm) receives a dense spinothalamic projection medially and ventromedially; elsewhere in the POm the projection is more scattered. The fibers to the intralaminar region terminate in the nucleus centralis laterials (CL) with a distinct pattern of the distribution. The nucleus centralis medialis (CeM) has a minute projection. There was no evidence for somatotopic organization in the projections to the POm or to the intralaminar region.The distribution of the terminal degeneration in the ventral nuclear region was more complex. Although present in the whole nucleus ventralis posterolateralis (VPL), the degeneration was unevenly distributed and also extended beyond the VPL. So‐called clusters of dense degeneration lay in the outskirts of the forelimb and hindlimb representation areas, namely at its ventral, ventrolateral, dorsolateral, and medial borders. Centrally the degeneration was scattered. Thus, most of the VPL receives only a sparse spinothalamic projection, but a small portion contains dense networks of terminal spinal fibers. A somatotopic pattern was evident, for after low thoracic lesions most of the medial VPL lacked degeneration.Spinothalamic fibers pass beyond the VPL to terminate in a zone of transition (nucleus ventralis intermedius or V.im of Hassler, '59; Mehler, '71) between the rostral pole of the VPL and the nucleus ventralis lateralis (VL). This zone also reportedly receives cerebellar and vestibular afferent fibers.Observations suggesting that the evolution of the spinothalamic tract and the spino‐cervico‐thalamic pathway in carnivores and primates may be linked are discussed. The spinothalamic clusters in the monkey's VPL appear to be homologous to much of the cervicothalamic tract projection to the VPL in the cat.
An electronmicroscopic analysis of the optic nerve in the golden hamster
Authors: Rhoades Robert W. , Hsu Linda , Parfett Gail 
Published: January 2005

AbstractThe electronmicroscopic examination of sections taken from the hamster's optic nerve 5 mm behind the globe indicated that the nerve contains 110,165 ± 4,177 (p < 0.05) fibres of which 96.4% are myelinated. The fibre diameter distribution is unimodal with a peak at 1.2 μm and axon diameters ranging from 0.20 μm to 3.93 μm. Fibres of all sizes are distributed uniformly throughout the cross section of the nerve. The thickness of the myelin sheath surrounding a given axon is highly (0.80) correlated with axonal diameter and the degree of myelination for a fibre of a given size is nearly constant throughout the nerve's cross section. In nerve sections taken just posterior to the globe most (64%) of the fibres counted are unmyelinated and the percentage of unmyelinated axons is highest near the peripheral boundary of the nerve. The process of myelination is essentially complete in sections taken 3.5 mm behind the eye. These differences in the myelination of the proximal and distal nerve most probably account for the discrepancy between the results reported here and those provided by a previous study (Tiao and Blakemore, '76) concerned with the structure of the optic nerve in this species.
Membrane specializations and cytoplasmic channels of Schwann cells in mammalian peripheral nerve as seen in freeze‐fracture replicas
Authors: Kruger L. , Stolinski C. , Martin B. G. H. , Gross M. B. 
Published: January 2005

AbstractMammalian Schwann cells in rat, rabbit and human fetal nerves were studied using several cryoprotective agents for electron microscopic study of freeze‐fracture replicas. The findings in fixed and unfixed tissue reveal surface plasmalemma caveolar specializations and the outer layer membrane junctional complexes found in non‐mammalian species. The plasmalemma also reveals a complex arrangement of contours outlining cytoplasmic channel networks distinct from the long‐recognized Schmidt‐Lanterman incisures and paranodal cytoplasmic loops. A specialized interconnected channel system in the outer “loose” myelin layer displays relatively uniform dimensions comparable in diameter to nodal microvilli, paranodal loops and some incisures. An adaxonal tubular channel system constituting the “axon‐Schwann network” is found in the internodal region in addition to other variants of the adaxonal Schwann plasmalemma. The several forms of sequestration of Schwann cell cytoplasm presumably underlie the specialized needs of cytoplasmic continuity in a dynamic functional entity in which large domains of cytoplasm have been displaced by the formation of compact myelin.
A Golgi study of the class V cell in the visual thalamus of the cat
Authors: Updyke B. V. 
Published: January 2005

AbstractGolgi methods were used to study class V cells within the cat visual thalamus. Counterstaining was combined with Golgi staining to assess the distribution of dendrites relative to cytoarchitectural boundaries. Class V cells were encountered within all laminae of the lateral geniculate nucleus, the medial interlaminar nucleus, and the lateral posterior complex. The cells possess medium‐sized perikarya and smooth and varicose or moniliform dendrites. Dendritic appendages are sparse and occur as single or serial swellings on thin processes. Many class V cells exhibit large, sparse dendritic arbors which span laminar or nuclear borders; dendrites were seen to lie within and to cross the interlaminar zones of the lateral geniculate nucleus, and extend beyond this nucleus into the perigeniculate nucleus and medial interlaminar nucleus. Class V cells of the lateral posterior complex send dendrites into the external medullary lamina. Indirect evidence favors the interpretation that the class V cells are thalamo‐cortical relay cells.