bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thalamic projections to area 17 in a prosimian primate, Microcebus murinus
Authors: Cooper H. M. , Kennedy H. , Magnin M. , Vital‐Durand F. 
Published: January 2005

AbstractElectrophysiological recording of single neurons was used to describe the representation of visual space in area 17, and the technique of retrograde transport of horseradish peroxidase (HRP) was applied to relate these results to projections from the thalamus in the prosimian primate Microcebus murinus. The visuotopic organization of area 17 was found to resemble that of other primates. On the dorsal surface, the border of area 17 corresponds to the representation of the vertical meridian. Proceeding medially across the surface the location of receptive fields descends along the vertical meridian, while moving caudally receptive fields progress temporally. Most of the dorsolateral surface is devoted to central vision and corresponds to a well developed area centralis. Following HRP injections in striate cortex, columns of labeled cells were found in the dorsal lateral geniculate (dLGN) extending orthogonally across all six layers. These columns run in a general ventrodorsal and caudorostral direction, parallel to a line connecting the cellular discontinuities corresponding to the optic disc. These discontinuities are present in magnocellular layer 1 and parvocellualr layers 5 and 6, thus receiving from the nasal retina of the contralateral eye. The representation of the vertical meridian is situated in the ventromedial portion of the dLGN, and the monocular field is represented in the dorsal extremity. Anterior dLGN projects to the calcarine fissure (lower field). and posterior dLGN projects to the ventral surface of the cortex (upper field). Exptrgeniculate input to area 17 was found to originate from the pulvinar. HRP labeled cells were located in two distinct divisions of this nucleus, the cytoarchitecture of which is described. In addition, projections to occipital cortex were found to arise form the intralaminar nuclei.
A cerebello‐pulvino‐cortical and a retino‐pulvino‐cortical pathways in the cat as revealed by the use of the anterograde and retrograde transport of horseradish peroxidase
Authors: Itoh Kazuo , Mizuno Noboru , Sugimoto Tetsuo , Nomura Sakashi , Nakamura Yasuhisa , Konishi Akira 
Published: January 2005

AbstractA cerebello‐pulvino‐cortical and a retino‐pulvino‐cortical pathways were revealed in the cat by means of the horseradish peroxidase (HRP) method. The sites of termination of the cerebellofugal and retinofugal fibers in the pulvinar nucleus (Pul) were visualized by the use of the anterograde transport of HRP. The cerebello‐pulvinar fibers were found to arise mainly from the parvicellular region of the lateral cerebellar nucleus and to terminate contralaterally in a narrow area at the extreme dorsolateral edge of the Pul at the level of the stereotaxic frontal plane A‐7.0. The area of terminal ramification of the retino‐pulvinar fibers was seen as a thin sheet lying at the extreme lateral edge of the Pul through most of the rostrocaudal extent of the Pul, bilaterally with contralateral predominance. The cerebellorecipient area in the Pul did not seem to overlap with the retinorecipient Pul area; the former appeared to be contiguous ventrolaterally to the latter. The cerebellorecipient and retinorecipient Pul areas were also observed to be connected reciprocally with the cerebral cortical areas; the former was connected with the most posterior part of the area 20, and the latter with the area 19.
Connections of the tectum of the rattlesnake crotalus viridis: An HRP study
Authors: Gruberg Edward R. , Kicliter Earl , Newman Eric A. , Kass Leonard , Hartline Peter H. 
Published: January 2005

AbstractWe have studied the connections of the tectum of the rattlesnake by tectal application of horseradish peroxidase. The tectum receives bilateral input from nucleus lentiformis mesencephali, posterolateral tegmental nuclei, anterior tegmental nuclei and periventricular nuclei; ipsilateral input from nucleus geniculatus pretectalis, and lateral geniculate nucleus pars dorsalis; and contralateral input from dorso‐lateral posterior tegmental nucleus and the previously undescribed nucleus reticularis caloris (RC). RC is located on the ventro‐lateral surface of the medulla and consists of large cells 25–45 μm in diameter. Efferent projections from the tectum can be traced to the ipsilateral nucleus lentiformis mesencephali, the ipsilateral lateral geniculate region, anterior tegmental region and a wide bilateral area of the neuropil of the ventral tegmentum and ventral medulla. We have not found any direct tectal projections from the sensory trigeminal nuclei including the nucleus of the lateral descending trigeminal tract (LTTD). We suggest that in the rattlesnake, RC is the intermediate link connecting LTTD to the tectum.
A quantitiative study of the occurrence and distribution of cytoplasmic laminated bodies in the lateral geniculate nucleus of the normal adult cat
Authors: Schmidt Marie Luise , Hirsch Helmut V. B. 
Published: January 2005

AbstractThe proportion of neurons containing cytoplasmic laminated bodies (CLB) in the dorsal lateral geniculate nucleus (dLGN) of normal cats was determined by using a new method which permitted examination of large areas of this nucleus. Near the medial border of the dLGN (projection of the area centralis) in the A‐laminae 30–60% of the neurons contain CLBs. Within the same region in lamina B only 10–30% of the nerve cells contain CLBs. In the monocular segment (MS) of lamina A 27–48% of the nerve cells contain CLBs. In the medial interlaminar nucleus (MIN) 25% of the neurons contain CLBs; these cells were distributed throughout the medio‐lateral extent of the MIN. CLBs were also observed in neurons of the perigeniculate nucleus (PN) and in nerve cells embedded in the fiber sheet separating the dLGN from the pulvinar complex. The distribution of cells containing CLBs is extremely variable in all portions of the dLGN studied.The data presented in this paper indicate that CLB‐containing cells in the dLGN may not be X‐cells, as has been suggested by LeVay and Ferster ('77) because: (1) the distribution of neurons containing CLBs in lamina A does not match the distribution of X‐cells recorded in this lamina; (2) some nerve cells in the MIN contain CLBs but very few X‐cells have been found in this region.
Postnatal differentiation of the rat trochlear nerve
Authors: Kerns James M. 
Published: January 2005

AbstractA morphometric analysis of postnatal differentiation in the rat trochlear nerve was studied by light and electron microscopy as an initial basis for understanding motor unit heterogeneity in the extraocular muscles (EOM). A total of 35 animals were examined 7–90 days postnatal (dpn). The mean number of fibers increased from 222 at 7 dpn to 274 in the adult and the size distribution became bimodal at 21 dpn. In the adult 17% of the myelinated fibers had a mean diameter of 2.5 μm and 83% were 7.3 μm. The estimated number of unmyelinated axons decreased from about 40% at 7 dpn to 20% at 14 dpn and 16% in the adult. The myelinated fiber diameter was more highly correlated with age and body weight than was fiber number. Certain organelles characteristic of active membrane growth were present in the Schwann cell cytoplasm at the paranode region. Redundant loops were prominent at 10 dpn, when many axons were still in Schwann cell bundles. During the third postnatal week a number of alterations were noted which may reflect a loss of polyneuronal innervation. These included thicker myelin sheaths and ultrastructural evidence of axonal degeneration. Branching of myelinated fibers was limited to the intramuscular portions of the nerve at 18 dpn. The g‐ratio of the largest fibers at selected ages was nearly constant at .71 and was correlated with fiber diameter (r = 0.40), except at 14 dpn. The periodicity of the myelin sheath had either an inverse or constant relationship to the number of lamellae. The significance of the results is discussed in relation to postnatal development, the size principle and heterogeneity in the EOM motor units.
Organization of the ascending striatal afferents in monkeys
Authors: Szabo Janos 
Published: January 2005

AbstractHorseradish peroxidase was injected in various parts of the caudate nucleus and the putamen of monkeys to ascertain the relative locations of striatal projecting cells in the mesencephalon. The nigrostriatal component, as expected, is the greatest but numerous cells of the mesencephalic raphe system also project to the striatum. The projections from the pars compacta are organized in a topographical manner in all principal planes. The rostral two thirds of the substantia nigra are related to the head of the caudate nucleus. Nigral neurons projecting to the putamen are more posteriorly located and display an anteroposterior topography. The medial two thirds of the pars compacta send efferents to the head of the caudate nucleus from ventromedial to laterodorsal regions, reflecting a mediolateral topographical relationship. An inverse relationship exists dorsoventrally between nigra and caudate so that ventral compacta cells project to dorsal caudate and the dorsally situated neurons project to ventral‐ventro‐medial caudate regions. The dorsal and lateral parts of the putamen are more intimately related to the lateral and posterior nigra; by contrast, the ventral and ventromedial putamen receives more afferents from medial and central regions of the substantia nigra. A large group of cells in the tegmentum dorsal and medial to the medial lemniscus shows continuity with the pars compacta, and has similar connections with the striatum. This cell group should be included with the pars compacta. Significant overlap exists between the projection fields in all planes, making the nigrostriatal topographical organization seem less than precise. This apparent lack of point‐to‐point reciprocity may be due to the considerable size difference between the striatum and the substantia nigra. The raphe nuclei project to the greater part of the striatum but more significantly to its ventral and medial regions. The paranigral cell group sends its efferents mainly to the ventral striatum.
Ascending projections from the lateral descending and common sensory trigeminal nuclei in python
Authors: Molenaar G. J. , Fizaan‐Oostveen J. L. F. P. 
Published: January 2005

AbstractThe primary sensory trigeminal system of Python is characterized by the presence of an additional nucleus which is involved in processing data obtained by infrared sensors. This so‐called lateral descending nucleus (LTTD) is strictly separated from the nuclei of the common sensory trigeminal system. The present study was undertaken in order to establish the relation between the two sensory trigeminal systems and higher brainstem structures. Further we studied whether the projections of these two systems remain separated at higher brainstem levelsIt is shown that the organization of particularly the thalamus is characterized by the presence of specific projection areas of each of the two trigeminal systems: (a) the ability of infrared perception is reflected particularly in the presence of an unique thalamic nucleus: the nucleus pararotundus and probably also in the enlargement of nucleus rotundus; and (b) distinct subnuclei in the thalamic ventral nuclear complex are related to the various nuclei of the common sensory trigeminal systemThe main ascending projection of LTTD runs via a distinct tract to the central gray layer (SGC) of the contralateral tectum mesencephali and the nucleus pararotundus (PR). Rostrally, numerous fibres decussate again via the tectal commissure and terminate ipsilaterally in the rostral part of SGC and in PRThe ascending projections of the common sensory trigeminal nuclei resemble those of mammals by gaining thalamic nuclei (ventral nuclear complex). No projections to the tectum nor to the striatum (like in birds) were observedThe two sensory trigeminal systems remain separately organised, in their projections as well as in their structure. No major connection between the two trigeminal systems is present.
Ontogeny of the retina and optic nerve in Xenopus laevis. I. Stages in the early development of the retina
Authors: Grant Philip , Rubin Eric , Cima Charles 
Published: January 2005

AbstractA staging series for retinal histogenesis is described for Xenopus laevis. It is based on scanning EM studies of intact eyes and serial section analysis of silver‐stained preparations. Retinal development is arbitrarily divided into twelve stages (I–XII) based on distinct morphological and histological changes. In general, four different phases of retinal development can be identified: an embryonic phase of rapid histogenesis (Nieuwkoop‐Faber stages 21–39) and onset of visual function; a second or functional phase completed by stage 52 is a period of growth, synaptogenesis, and the organization of visual function; a third phase ending at metamorphic climax (NF57) when mature function is achieved and binocular vision begins; and a final mature phase at the end of metamorphosis, when rod and cones are adult size and the visuotectal projection extends over the entire tectum. Ten of the twelve developmental stages are assigned to the first phase since this is the period of intense morphogenesis and differentiation.
Phylogeny of enteric serotonergic neurons
Authors: Goodrich James T. , Bernd Paulette , Sherman Diane , Gershon Michael D. 
Published: January 2005

AbstractSerotonergic neurons have previously been identified in the enteric nervous systems of humans, subhuman primates, rodents, and rabbits. The distribution of enteric serotonergic neurons in lower vertebrates was examined in order to determine if these neurons are restricted to mammals and, if they are found more generally amongst vertebrates, when they first appear in vertebrate phylogeny. Since mammalian enteric serotonergic neurons take up 3H‐serotonin by a highly specific mechanism, the radioautographic demonstration of axonal uptake of 3H‐serotonin was used as the primary tool in looking for these neurons. As controls, conditions known to interfere with 3H‐serotonin uptake by mammalian enteric neurons were also examined. These controls included incubation with 10 μ fluoxetine, a specific antagonist, incubation in Na+‐free medium, and incubation in the presence of a 100‐fold excess of nonradioactive serotonin. Radioautographic labeling had to be absent or greatly reduced under all three control conditions for labeling by 3H‐serotonin to be considered specific. Labeled enteric axons were found in cyclostomes (hagfish), teleosts (goldfish), and amphibia (bullfrog) but not in tunicates (sea squirt; sea vase) or echinoderms (sea cucumber). In addition, the serotonin concentration was measured in the intestine of two vertebrates, hagfish and goldfish, that do not have serotonin‐containing enterochromaffin cells. Serotonin was found in both; in hagfish, the amine concentration was highest in preparations of muscularis externa containing the myenteric plexus. It is concluded that enteric serotonergic neurons arose early in vertebrate evolution, possibly in an ancestral chordate resembling amphioxus, although probably not in more primitive prevertebrates, and that they are a general feature of the vertebrate bowel.
The potential binocular field and its tectal representation in rana pipiens
Authors: Grobstein Paul , Comer Christopher , Kostyk Sandra 
Published: January 2005

AbstractWe have studied binocularity in Rana pipiens using optical, behavioral, and electrophysiological assays. The first two assays yielded a consistent picture of the size and shape of the area of uniocular visual field overlap, the potential binocular field. Potential binocular field has an extent of about 90° on the horizontal in front of the frog, narrows to about 60° above the frog's head, and continues to a point well behind the frog. This differs somewhat from a previous report (Fite, '73). Uniocular visual field extent on the horizontal is in excess of 225°, permitting both a large binocular field and panoramic vision. The electrophysiological assay confirms the large uniocular visual field extent. It further shows that physiological binocularity closely reflects uniocular visual field overlap, in the sense that tectal loci representing positions in the potential binocular field, including those behind the frog's head, display convergent inputs from the two eyes.
Subnuclear organization of the ophidian trigeminal motor nucleus. II. Ultrastructural measurements on motoneurons innervating antagonistic muscles
Authors: Moody Sally A. , Meszler Richard M. 
Published: January 2005

AbstractHorseradish peroxidase (HRP), injected intramuscularly, specifically labeled motoneurons innervating antagonistic jaw muscles in the cottonmouth mocassin, Agkistrodon piscivorus piscivorus. Adductor mandibulae profundus, part 3a, motoneurons were localized in the lateral regions of the ventral and intermediate subnuclei of the trigeminal (V) motor nucleus. These were large cells containing fine, granular reaction product characteristic of α‐motoneurons. Small cells, which contained large coarse reaction granules characteristic of γ‐motoneurons were localized in a separate cluster in the lateral regions of the dorsal subnucleus of the V motor nucleus. Depressor mandibulae motoneurons were localized in the ventromedial regions of the facial (VII) motor nucleus, primarily in the caudal half. Cell sizes ranged from 30–50 μm in diameter and HRP staining characteristics were variable, indicating a mixed population of motoneuron functional types without the segregation noted in the V motor nucleus.Boutons which made synaptic contact with labeled somata or processes were classified according to morphological type and their frequency of appearance. Boutons containing spherical vesicles (S‐, C‐, T‐) were distributed similarly on motoneurons of both muscles, but more F‐boutons, those with flattened vesicles, synapsed on the adductor motoneurons.Comparison of snake bouton distribution with that in mammalian spinal cord indicates that synaptology on all these motoneurons are remarkably similar. The more frequent occurrence of C‐boutons, those with a subsynaptic cistern, on reptilian motoneurons may indicate a stronger intrasegmental input, as determined from mammalian degeneration studies.
Effect of protein malnutrition on development of mouse cortical barrels
Authors: Vongdokmai Ratree 
Published: January 2005

AbstractUndernutrition has been shown to have a profound effect on the central nervous system of maturing experimental animals, not only on gross brain weight and chemical constitution but also on cell structure and function. The present study was undertaken to determine the effect of protein malnutrition on the cortical barrels of mouse. Animals were conceived in and suckled by mothers maintained on an 8% casein diet or on a stock diet. After weaning, mouselings were maintained on their respective diets ad libitum. Four experiments were performed on these mouselings: (1) study of the development of the barrels by the Nissl method; (2) study of the effect of vibrissal damage at different postnatal ages; (3) study of the size of the barrel area and the number of neurons at different postnatal ages; and (4) study of the selectivity of the Golgi‐Cox method.The findings from comparison of malnourished mice with mice on a normal diet were: (1) a two‐day delay in the development of the barrels; (2) a two‐day lengthening of the period of vulnerability of barrel field neurons to neonatal vibrissal damage; (3) the barrel field area and the relative number of neurons were reduced, with the percentage of reduction decreasing with age; and (4) there was no significant difference in the average percentage of Golgi‐stained neurons at different ages.These results suggest that poor nutrition has a profound effect on the development and final form of a well‐defined neocortical region. The data presented here provide a useful base line against which various therapeutic regimens to reverse the effects of malnutrition on brain structure may be tested. They also suggest that inducing malnutrition may be an important way in which to manipulate the development of the nervous system in order to study the mechanisms responsible for its final form and function.
Localization of acetylcholinesterase in the main and accessory olfactory bulbs of the mouse by light and electron microscopic histochemistry
Authors: Carson Keith A. , Burd Gail D. 
Published: January 2005

AbstractExperiments were conducted to examine by light and electron microscopy the localization of acetylcholinesterase (AChE) in the main (MOB) and accessory (AOB) olfactory bulbs of the normal mouse. Evidence from the literature for cholinergic innervation of the mammalian olfactory bulb was then assessed in light of possible correlation between reported sites of termination of centrifugal fibers to the olfactory bulb and the localization of AChE.AChE‐positive nerve fibers were concentrated in the periglomerular region and internal plexiform layer of the MOB. Stained fibers were also present in the granule cell, mitral cell, and external plexiform layers as well as within glomeruli. A few neurons in all layers of the MOB contained AChE reaction product. Unlike the MOB, AChE‐positive fibers were not present in the glomerular layer of the AOB. AChE‐positive fibers were concentrated in the inner plexiform layer, whereas fewer stained fibers were observed in the external plexiform and mitral cell layer and granule cell layer. Lightly stained neurons were found in the deeper portions of the external plexiform and mitral cell layer and granule cell layer.Ultrastructurally, AChE reaction product in the MOB and AOB was predominantly associated with small unmyelinated axons. Reaction product was also observed adjacent to axon terminals and dendrites. Occasionally within the MOB, AChE activity was found within periglomerular, tufted, short‐axon, mitral, and granule cells. In the AOB, however, intracellular AChE activity was observed within some mitral/tufted cells and only a few granule cells.In conclusion, the AChE reaction product was mainly associated with axons in regions of the MOB where centrifugal fibers have been reported. Accessory olfactory bulb AChE localization was different from that of the MOB, suggesting a different pattern of cholinergic input to the AOB. The small amounts and sites of intraneuronal AChE reaction product in cells of the olfactory bulb indicate cholinoceptive rather than cholinergic function.
Histogenesis of the goldfish retina
Authors: Sharma S. C. , Ungar F. 
Published: January 2005

AbstractThe order of production of retinal cells was studied in embryos of the goldfish, Carassius auratus using 3H‐thymidine autoradiography. Cell division ceases first in the neuroepithelium at the fundus of the eye between embryonic stages 19 and 20 and gradually becomes restricted to the retinal margin by stage 24. In the fundus the cell whose nuclei will reside in the inner layer of the retina stop dividing earlier than the cells whose nuclei will reside in the outer retinal layers. Thus the ganglion cells in the fundus of the retina are produced first and the receptors and horizontal cells last.