bluuebunny/crossref_metadata_2025_split huggingface dataset:
The length of cerebellar parallel fibers in chicken and rhesus monkey
Authors: Mugnaini Enrico 
Published: May 2005

AbstractThe cerebellar parallel fibers, which course through the molecular layer parallel to the long axes of the cortical folds known as folia, originate from ascending granule cell axons and relay the mossy fiber input to dendrites of Purkinje cells. Purkinje cell axons in the cerebellar white matter collect into sheets or zones oriented at right angles to the folia. Each of these zones, which are approximately 0.5‐1 mm wide, innervates a different portion of the deep cerebellar and the vestibular nuclei. An experimental light microscopic study was carried out to determine the maximal length of parallel fibers in long folia of avian and primate cerebellar cortex. With a fine surgical knife, vermal folia were cut perpendicular to their long axes in four adult White Leghorn hens and in three adult rhesus monkeys deeply anesthetized with sodium pentobarbital. The animals were killed 3‐5 days after the operation. Sections of the transected folia were stained with the Fink‐Heimer or the DeOlmos‐Ir.gram methods, which revealed the anterogradely degenerated parallel fibers as darkly stained dots. In both species, the pattern of parallel fiber regeneration in the molecular layer had a trapezoidal configuration with the shorter base bordering the Purkinje cell layer and the longer base bordering the pia mater. In both species, the length of parallel fibers averaged approximately 6 mm, although the range was 4‐8 mm in chickens and 4.8‐6.6 mm in monkeys. The same trapezoidal pattern of degeneration and average parallel fiber lengths of 6 mm were obtained previously from long folia of cat and rabbit cerebella. Thus, parallel fibers show only small variation in their maximal length in relation to cerebellar size. In all the species studied, parallel fibers are consistently longer than the width of single efferent cortical zones, and they modulate the activity of Purkinje cells projecting to different groups of neurons in the deep nuclei.
Axons connecting somata and axon terminals of luminosity‐type horizontal cells in the turtle retina: Receptive field studies and intracellular injections of HRP
Authors: Ohtsuka Teruya 
Published: May 2005

AbstractLuminosity (L)‐type horizontal cell responses to small and large spots of light in the turtle (Geoclemys) retina were recorded intracellularly, and each cell so studied was filled with horseradish peroxidase (HRP) by ionophoretic injection. Following histochemical reaction of the HRP with diaminobenzi‐dine (DAB), light microscopic inspection demonstrated that this type of horizontal cell has a cell body connected to a tuberous axon terminal by a fine axon. By examining the location of the cell in relation to the linear array of electrode penetrations in each preparation, it was possible to determine whether a given recording was made in the cell body or in the axon terminal. The size of the receptive field of the cell body was significantly smaller than that of the axon terminals. Although the center‐to‐center distances between the cell body and the axon terminal of some L‐type horizontal cells were as short as 50 μm, the length of the intervening axon was invariably longer and was at least 250 μm. Unless signals are amplified by some active mechanisms during their propagation along the axon, it is unlikely that current generated in the cell body spreads to the axon terminal through the thin axon, or in the opposite direction. The difference in receptive field sizes of cell body and of axon terminal may therefore indicate that these two structural subunits are electrically isolated.
The posteromedial ventral nucleus of the thalamus (VPM) of the cat: Direct ascending projections to the cytoarchitectonic subdivisions
Authors: Yasui Yukihiko , Itoh Kazuo , Mizuno Noboru , Nomura Sakashi , Takada Masahiko , Konishi Akika , Kudo Motoi 
Published: May 2005

AbstractThe post eromedial ventral nucleus (VPM) of the cat is divided cytoar‐chitectonically into the magnocellular (VPMmc), lateral parvocellular (VPMpcl), and medial parvocellular (VPMpcm) divisions. Cell bodies of neurons in the VPMpcm are small, while those in the VPMpcl are small to medium‐sized. The VPMmc contains large neurons.Direct projections from the lower brain stem structures to each of the three divisions of the VPM were examined by the retrograde horseradish peroxidase (HRP) method. When HRP injection was done into the VPMmc, labeled neurons were mainly located conlralaterally in the ventral division of the principal sensory trigeminal nucleus (Vp), in the rostral part of the oral subnucleus in the spinal trigeminal nucleus (Vsp), and in the interpolar sub‐nucleus of the Vsp; a few labeled neurons were also found contralaterally in lamina I of the caudal subnucleus of the Vsp. When HRP injection was restricted to the VPMpcl or VPMpcm, HRP‐labeled neurons were mainly observed ipsilaterally, respectively, in the dorsal division of the Vp, or in the parabrachiaJ nucleus (PBN) regions dorsomedial and ventromedial to the brachium conjunctivum. After HRP injection into the parvocellular part of the VPM (VPMpc), labeled neurons were also seen contralaterally in the Vsp, but these were far less numerous than those seen after HRP injections into the VPMmc.Thus, each of the three divisions of the VPM receives main ascending afferent fibers from different brain stem structures; the VPMpcm, VPMpcl, or VPMmc receives afferent fibers, respectively, from the PEN ipsilaterally, from the dorsal division of Vp ipsilaterally, or from the ventral division of the Vp and the Vsp contralaterally.
Afferent projections to the oral motor nuclei in the rat
Authors: Travers Joseph B. , Norgren Ralph 
Published: May 2005

AbstractProjections to the trigeminal, facial, ambiguus, and hypoglossal motor nuclei were determined by using horseradish peroxidase histochemistry. Most of the afferent projections to these motor nuclei were from the brain‐stem reticular formation, frequently in areas adjacent to other synergetic motor nuclei. The reticular formation lateral to the hypoglossal nucleus and reticular structures surrounding the trigeminal motor nucleus projected to each of these other brainstem motor nuclei involved in oral‐facial function. Afferent projections to these motor nuclei also were organized along the ros‐trocaudal axis. Within the reticular formation most of the afferent projections to the trigeminal motor nucleus originated rostral to the majority of neurons projecting to the hypoglossal and ambiguus nuclei, which in turn were rostral to the primary source of reticular afferents to the facial nucleus. In comparison, projections from the sensory trigeminal nuclei and nucleus of the solitary tract were sparse. The interneuron pools that project to the orofacial motoneurons provide one further link in understanding the brain‐stem substrates for integrating oral and ingestive behaviors.
Anatomy of the gustatory system in the hamster: Central projections of the chorda tympani and the lingual neirve
Authors: Whitehead Mark C. , Frank Marion E. 
Published: May 2005

AbstractThe sensory modalities of taste and touch, for the anterior tongue, are relegated to separate cranial nerves. The lingual branch of the trigeminal nerve mediates touch; the chorda tympani branch of the facial nerve mediates taste. The chorda tympani also contains efferent axons which originate in the superior salivatory nucleus. The central projections of these two nerves have been visualized in the hamster by anterograde labelling with horseradish peroxidase (HRP).Afferent fibers of the chorda tympani distribute to all rostral‐caudal levels of the solitary nucleus. They synapse heavily in the dorsal half of the nucleus at its rostral extreme; synaptic endings are sparser, and located lat‐erally in caudal region. These taste afferents trave caudally in the solitary tract and reach different levels by a series of collateral branches which extend medially into the solitary nucleus, where they exhibit preterminal and terminal swellings. Taste atferentaxons range in diameter from 0.2 μm to 1.5 μm. The thickest axons project exclusively to the rostral and intermediate subdivisions of the solitary nucleus; the fine ones may distribute predominantly to the caudal subdivision.Afferent fibers of the lingual nerve terminate heavily in the dorsal one‐third of the spinal nucleus of the trigeminal nerve and also as a dense patch in the lateral solitary nucleus at the midpoint between its rostral and caudal poles. This latter projection overlaps that of the chorda tympani. Thus the two sensory nerves which subserve taste and touch from coincident peripheral fields on the tongue converge centrally on the intermediate subdivision of the solitary nucleus.Efferent neurons of the superior salivatory nucleus were labelled retro‐gradely following application of HRP to the chorda tympani. These cells are located ipsilaterally in the medullary reticular formation ventral to the rostral pole of the solitary nucleus; their dendrites are oriented dorsoventrally. The efferent axons course dorsally, form a genu lateral to the facial somato‐motor genu, and course ventrolaterally through the spinal nucleus of the trigeminal nerve to exit the brain ventral to the entering facial afferents.
Spinal neurons reaching the lateral reticular nucleus as studied in the rat by retrograde transport of horseradish peroxidase
Authors: Menétrey D. , Roudier F. , Besson J. M. 
Published: May 2005

AbstractAn anatomical technique based on the retrograde transport of horseradish peroxidase (HRP) was used to investigate the projections of spinal cord neurons to the lateral reticular nucleus (LRN). Labeled cells were found at all spinal levels and in particular large numbers in cervical and lumbar segments. Various spinal areas gave rise to cells of origin of this tract, which appears to be more prominent than any other tract previously studied with a similarapproach.Labeling common to all spinal segments was observed in (1) ventro‐medial parts of both intermodiate zone and ventral horn (laminae VII, V and X), mainy contralalerally; (2) the reticular extension of the neck of the dorsal horn partly bilateral; and (3) superficial layers of the dorsal horn and nucleus ofthe dorsolaleral funiculus (NDLF), mainly contralateral and projecting essentially to the lateral zone of the LRN.Additional labeling was observed at cervical and lumbar levels, each with specific qualities: (1) the cervical enlargement, which displayed labeling in the central part of the ipsilateral intermediate zone (lamina VII): (2) the rostral lumbar levels, which had projections from the contralateral median portion of the neck of the dorsal horn. These latter projections appear to be specific to pathways reaching the lateral reticular nucleus and the inferior olive.Control injections in neighboring structures demonstrated the similarity between the afferents to the lateral reticular nucleus and the inferior olive (except lamina I and NDLF projections) and the differences between these afferents and those projecting to the dorsal reticular formation, i.e., the nucleus reticularis ventralis.
The fine structure of the rat subthalamic nucleus: An electron microscopic study
Authors: Chang H. T. , Kita H. , Kitai S. T. 
Published: May 2005

AbstractThe normal ultrastructure of the rat subthalamic nucleus (STH) was studied. The STH consisted of tightly packed neurons distributed within a neuropil filled with large numbers of blood vessels and thinly myelinated fibers. The somata of STH neurons (diameters, D, between 10 and 25 μm) contained abundant organelles but had only a small amount of both smooth and rough endoplasmic reticulum. The nuclei had deeply invaginated nuclear envelopes and pale nucleoplasm with little heterochromatin. STH neurons often were tightly apposed without any intervening glial membranes. Similar appositions were also found between somata and dendrites, dendrites and dendrites, and dendrites and initial axon segments. Although puncta adhaerentia were often observed, no gap junctions were found on any of these membrane appositions.In the neuropil, the dendrites were mostly smooth and thin (D between 0.5 and 1 μm) with an occasional stubby spine or thin dendritic appendage. At least two types of axon terminals were identified. Type 1 terminals (D up to 1 μm) contained medium‐sized round vesicles (D about 45 nm) and formed asymmetrical synapses. Type 2 terminals were often large (D up to 5 μm) and contained both round and slightly flattened vesicles (D up to 50 nm). The type 2 terminals frequently formed adherens junctions with their postsynaptic targets in addition to forming relatively symmetrical synaptic junctions. The remaining axon terminals included a small number of terminals with various morphological characteristics and possibly some tangentially sectioned type 1 and type 2 terminals. Therefore they have not been classified as individual types in this study. A quantitative analysis indicated that the type 1 terminals formed synapses mainly with thin dendrites whereas the type 2 terminals formed synapses mainly with somata and larger dendrites.
Central projections of vestibular afferents from the horizontal semicircular canal in the carpet shark Cephaloscyllium isabella
Authors: Housley Gary D. , Montgomery John C. 
Published: May 2005

AbstractThis study utilizes anterograde axonal transport of cobaltous‐lysine and conventional silver‐staining techniques to study the central projections of the horizontal semicircular canal branch of the VIII nerve within the vestibular nuclei of the carpet shark Cephaloscyllium isabella. Two major terminating axon fields were observed, one caudal and one rostral to the entrance of the VIII nerve, corresponding to the ventral vestibular nucleus and superior vestibular nucleus, respectively. Both fields appear to be located within the ventral portion of the nuclei indicating an apparent subdivision of the VIII nerve projections within the brainstem. The resolution of the sensitive cobalt tracer indicates the presence of both dendritic and pericellular termination of these primary afferent fibres. In the area immediately caudal to the entrance of the VIII nerve a number of labelled primary afferent fibres project to the ventral region of the intermediate nucleus. Other fibres follow the visceral sensory root VII and terminate proximal to the sulcus limitans of His within the dendritic field of the neurons of the nucleus magnocellularis. Some fibres turn ventromedially from the main group of the ascending fibres and terminate in the area of the inferior reticular formation.
An analysis of the time of origin of neurons in the entorhinal and subicular cortices of the cat
Authors: Wyss J. M. , Sripanidkulchai B. , Hickey T. L. 
Published: May 2005

AbstractThe [3H]thymidine autoradiographic method was used to determine the birth dates of neurons in the cat parahippocampal gyrus. Cat fetuses were exposed to a single pulse of the radioactive marker between the 20th and 55th embryonic days. All animals were delivered normally and allowed to survive for 2–6 months postnatal. The resulting autoradiographs demonstrate three spatiotemporal gradients of cell birth in the entorhinal and subicular cortices. First, an inside‐out gradient is apparent; i.e., neurons in the deeper layers are born earlier than those in the more superficial layers. Second, a rhino to dentate gradient exists. Accordingly, cells closer to the lateral entorhinal region tend to be generated earlier than those further away. Third, a temporal to septal gradient is present. Neurons close to the anterior pole of the temporal lobe are born earlier than those more caudally located. Whereas the first two gradients have been observed in other species, the latter gradient has not been reported consistently. Three exceptions to these overall gradients exist. First, neurons near the layer I/II border are born earlier than the majority of the layer II neurons. Second, neurons near the transition zone between two adjacent regions are born earlier than neurons located in the middle of each region. Third, the prosubiculum and subiculum do not exhibit a clear inside‐out or temporal to septal gradient.
Differential olivocochlear projections from lateral versus medial zones of the superior olivary complex
Authors: Guinan John J. , Warr W. Bruce , Norris Barbara E. 
Published: May 2005

AbstractAn anterograde tracer (35S‐methionine) was injected unilaterally in the superior olivary complex (SOC) at regions previously demonstrated by retrograde labeling to contain olivocochlear (OC) cell bodies. Quantitative analysis of cochlear autoradiographs from these cats demonstrates that there are two OC systems. The lateral OC system has cell bodies lateral to the medial superior olivary nucleus (MSO) and projects to the inner hair cell (IHC) region bilaterally (mostly ipsilaterally). The medial OC system has cell bodies medial, ventral, and anterior to the MSO and projects to the outer hair cell (OHC) region bilaterally (mostly contralaterally). A single medial OC neuron innervates many small patches of OHCs with substantial gaps between the patches. Medial OC neurons also appear to project to the IHC region to a small extent. A review of the literature with the medial‐lateral division of OC efferents in mind reveals many differences between these two systems. In particular, lateral OC axons are unmyelinated and innervate the dendrites of radial afferent fibers under IHCs, whereas medial OC axons are myelinated and directly innervate OHCs. Although both systems appear to be cholinergic, the lateral OC system also shows met‐enkephalin‐like immunoreactivity. The synapses of the medial OC system are formed in development before those of the lateral OC system and they degenerate more slowly after the OC axons are cut. The many differences between these two OC systems suggest that they are functionally separate systems.
An HRP study of the central course of sensory intermediate and vagal fibers in peripheral facial nerve branches in the cat
Authors: Arvidsson Jan , Thomander Lars 
Published: May 2005

AbstractPrevious studies have shown that sensory fibers of intermediate and vagal nerve origin are present in facial nerve branches to the mimetic muscles in the cat. In the present study the central course of these fibers has been examined by transganglionic transport of horseradish peroxidase (HRP). In some of these experiments the facial nerve proper was transected central to the site of HRP application. In this way, the central course of the vagal fibers could be studied separately. For comparison HRP‐conjugated wheat germ agglutinin was injected into the geniculate ganglion, revealing the central course of the entire afferent component of the intermediate nerve. The results show that labeled sensory intermediate nerve fibers, at their level of entrance in the brainstem, form a tract at the dorsal margin of the spinal trigeminal tract (5T). While some fibers ascend from this level to terminate in the main sensory trigeminal nucleus, and a few fibers terminate in the rostral part of the solitary tract nucleus, the majority take a descending course. The main site of termination for these descending fibers is in the medial part of the C2 dorsal horn. Terminal labeling is also seen in the ventrolateral part of the cuneate nucleus (CUN) and in a small area of gray substance between CUN and trigeminal nucleus caudalis. After entering the brainstem some sensory vagal fibers project to the trigeminal nucleus interpolaris and to an interstitial nucleus within the 5T, but the larger part joins the descending tract of intermediate nerve fibers. These descending vagal fibers have a terminal distribution pattern similar to the intermediate nerve fibers.
Trigeminal projections to supratentorial pial and dural blood vessels in cats demonstrated by horseradish peroxidase histochemistry
Authors: Mayberg Marc R. , Zervas Nicholas T. , Moskowitz Michael A. 
Published: May 2005

AbstractAnatomical and clinical observations suggest that supratentorial vascular structures contain afferent projections from the trigeminal ganglia. To characterize this innervation, horseradish peroxidase (HRP) and HRP conjugated to wheat germ agglutinin were applied to the pial and dural arteries and sinuses of 33 cats. HRP was restricted to the site of interest by applying it dissolved in a viscous polymer, polyvinyl alcohol (PVA), to achieve slow release and minimize diffusion. The ganglia of cranial nerves V, VII, IX, and X and the superior cervical ganglia (SCGs) were examined bilaterally for the presence of retrogradely transported protein. Horseradish peroxidase applied to the proximal middle cerebral artery was located in cell bodies occupying the portion of the ipsilateral trigeminal ganglion corresponding to the ophthalmic division and throughout both SCGs. When the tracer was applied to the right anterior or posterior superior sagittal sinus, HRP‐positive cells were present as above, predominantly in the ipsilateral trigeminal ganglia corresponding to the opthalmic division and throughout both SCG. When applied to the right middle meningeal artery, HRP was observed within neurons of ipsilateral SCG and in the ophthalmic division of trigeminal ganglia; a few enzyme‐containing cells were present in ipsilateral regions corresponding to the second and third divisions. These observations support the concept that supratentorial vascular structures receive afferent nervous projections from trigeminal neurons.