bluuebunny/crossref_metadata_2025_split huggingface dataset:
An experimental study of the ventral striatum of the golden hamster. II. Neuronal connections of the olfactory tubercle
Authors: Newman Richard , Winans Sarah Schilling 
Published: January 2005

AbstractAs part of an experimental study of the ventral striatum, the horseradish peroxidase (HRP) method was used to examine the afferent and efferent neuronal connections of the olfactory tubercle. Following iontophoretic applications or hydraulic injections of HRP in the tubercle, neurons labeled by retrograde transport of HRP were observed ipsilaterally in the telencephalon in the main olfactory bulb, the medial, lateral, ventral, and posterior divisions of the anterior olfactory nucleus, and in the orbital, ventral, and posterior agranular insular, primary olfactory, perirhinal, and entorhinal cortices. Labeled cells were also present in the basolateral, basomedial, anterior cortical, and posterolateral cortical amygdaloid nuclei, and bilaterally in the nucleus of the lateral olfactory tract. In the diencephalon, ipsilateral HRP‐containing neurons were observed in the midline nuclei paraventricularis, parataenialis, and reuniens, and in the parafascicular intralaminar nucleus. Retrograde labeling was present in the ipsilateral brainstem in cells of the ventral tegmental area, substantia nigra, and dorsal raphe. Many of the above projections to the tubercle were found to be topographically organized.Anterograde axonal transport of HRP from the olfactory tubercle labeled terminal fields ipsilaterally in all parts of the anterior olfactory nucleus, in the ventral pallidum, and in the substantia nigra, pars reticulata. Contralaterally, terminal fields were present in the dorsal and lateral divisions of the anterior olfactory nucleus.The projections to the tubercle from the orbital, ventral, and posterior agranular insular, and perirhinal neocortices, intralaminar thalamus, and dopamine‐containing areas of the ventral mesencephalon are analogous to the connections of the caudatoputamen, as are the efferents from the tubercle to the ventral globus pallidus and substantia nigra. These connections substantiate the recent suggestion that the olfactory tubercle is a striatal structure, and provide support for the ventral striatal concept.In the present study of the olfactory tubercle, and in the first study in this series on the nucleus accumbens, the ventral striatum was found to receive projections from a number of limbic system structures, including the main olfactory bulb, anterior olfactory nucleus, amygdala, hippocampus, and subiculum, and the entorhinal and primary olfactory cortices. These findings suggest that the ventral striatum is concerned with integrating limbic information into the striatal system.
Pattern of myelination and distribution of neuroglial cells along the developing optic system of the rat and rabbit
Authors: Skoff Robert P. , Toland Denise , Nast Edward 
Published: January 2005

AbstractIn order to gather information about the factors influencing myelination and neuroglial cell formation in the central nervous system, the development of myelin and neuroglia was investigated along the length of the optic nerve and tract of rats and rabbits. The results of this study revealed complex developmental patterns for both of these processes. Furthermore, the pattern of myelination for the rat is different from that of the rabbit. Myelination of the rat optic pathway exhibits a general rostro‐caudal gradient extending from the eye to the lateral geniculate nucleus, whereas a more homogeneous pattern is present in the rabbit. Myelination along the nerves of both species shows many sharp peaks and trough, especially in the region of the optic canal. Formation of myelin begins at several different sites along the nerve, with the first fibers appearing on both sides of the optic canal. Another small site of myelination develops just in front of the optic chiasm. Myelination of the entire length of an individual axon is not homogeneous but instead it begins at several discrete sites. The number of glial cells along the nerve and tract also fluctuates sharply but their pattern does not precisely parallel that of myelination. A better correlation is obtained by comparing the distribution of axons being myelinated with that of oligodendroglial cells. The complex patterns and the species differences observed in this study indicate that myelination and neuroglial cell development must be regulated by both neuronal and local factors. The data presented here together with other available information suggest that the vascularization of the nerve and the direct effects of hormones upon glial cells are possible factors that contribute to the local variability.
Development of sensory innervation in dentin
Authors: Byers Margaret R. 
Published: January 2005

AbstractWe have labeled dental nerves of 3‐week‐ to 1‐year‐old rats by axonal transport of radioactive protein in order to detect nerves in developing dentin by autoradiography. We found that, in addition to nerve growth, two processes determine adult dentinal nerve location: (1) enclosure of nerves within circumpulpal dentinal tubules during the last few weeks of dentinogenesis, beginning at the tip of the pulp horn and spreading to include most coronal dentin; and (2) gradual loss of the nerves near the tip of the cusp because of dentinal attrition and replacement by noninnervated, reparative dentin. Several days before a molar erupts, nerves at the tip of the cusp have already begun to be enclosed by dentin; 2–3 weeks later, when dentinogenesis at the cusp tip slows down, most of the innervation for that region has been established, nerves extend up to 160 μ into dentin, and the molar has reached the has reached the stage of functional occlusion. Soon after initial occlusion, the process of dentinal attrition and replacement by noninnervated reparative dentin begins; however, simulataneous dentinogenesis in more apical regions produces new innervated dentin. We studied nerve position in relation to dentin growth lines and found that there is a long‐term association of nerve endings with specific sites in the dentinal tubules. The similarities between the development of dentinal innervation in rat molars and in human permanent teeth are discussed; it is found that as teeth mature and become more sensitive to painful stimuli, the density of dentinal nerves increases.
Studies on the somatotopy of the trigeminal system in the mallard, anas platyrhynchos L. II. Morphology of the principal sensory nucleus
Authors: Dubbeldam Jacob L. 
Published: January 2005

AbstractThe projections from the ophthalmic, maxillary, and mandibular parts of the trigeminal ganglion upon the principal sensory trigeminal nucleus (PrV) in the mallard have been studied with the Fink‐Heimer I method. PrV is a large nucleus subdivided in cell groups by layers of fibers. The orientation of the dendritic arborizations differs in the different parts of the nucleus. A dorsocaudal cell group sIX is an exclusive glossopharyngeal terminal field. A second, caudo‐ventral projection area of NIX also receives trigeminal afferents. A small n. supratrigeminalis lies medial to PrV in the pathway of the mesencephalic trigeminal root. This nucleus seems to be part of the proprioceptive trigeminal system. The rostralmost part of PrV receives opthalmic projections, the caudalmost part receives mandibular projections, the maxillary area being intermediate. Taking the stereotaxic plane of the mallard atlas (weers, '71) into account, it can be concluded that the situation is essentially not different from that in the pigeon and from the situation described for mammals.
Distribution and light microscopic features of granule cells in the cochlear nuclei of cat, rat, and mouse
Authors: Mugnaini Enrico , Warr W. Bruce , Osen Kirsten Kjelsberg 
Published: January 2005

AbstractIn the present study the cytology and the topography of the cochlear granule cell domain (a comprehensive term introduced here for all granule cell‐containing regions of the cochlear nuclear complex) have been studied light microscopically in Nissl, Bielschowsky, and Golgi‐Del Rio‐Hortega material of cats, rats, and mice; in Golgi rapid material of 0–14‐day‐old kittens; and in sections of 6‐week‐old kittens following HRP injections in the superficial dorsal cochlear nucleus (DCN). The domain has been parcellated in seven subdivisions which, in spite of some species' differences, are easily identifiable in all of the included animals. The cochlear granule cells are considered as a particular class of neuron, which is slightly different from, but nevertheless principally similar to the cerebellar granule cells in both shape and mode of neuronal connections. The digitiform terminals of the cochlear granule cells differentiate after the first two weeks of extrauterine life. In several respects these cells show larger variation among species than do the cerebellar granules, the similarity between the two classes of granule cells being most conspicuous in the rodent. The silver, Golgi rapid, and HRP material suggest that all, or at least the majority, of the granule cell axons project to the molecular layer of the DCN, forming parallel fibers similar to those of the cerebellar cortex. Also, the cochlear parallel fibers traverse the spiny apical dendrites of principal neurons (the pyramidal cells) and the smoother dendrites of molecular layer stellate cells.
An ultrastructural study of the normal synaptic organization of the optic tectum and the degenerating tectal afferents from retina, telencephalon, and contralateral tectum in a teleost, holocentrus rufus
Authors: Ito Hironobu , Butler Albert B. , Ebbesson Sven O. E. 
Published: January 2005

AbstractThe ultrastructure of the optic tectum in the squirrel fish, Holocentrus rufus, has been studied and the normal synaptic organization is described. Synaptic terminals were classified into eight types (S1‐S6, F1, F2) by their morphology and synaptic relations. The distribution pattern for each type of terminal was determined by counting the relative number of terminals in each layer. Most S1 terminals are localized in Stratum marginale (SM), whereas S2 terminals are most common in Stratum fibrosum et griseum superficiale (SFGS). S3, S4, S5, F1, and F2 terminals are limited mainly to SFGS and Stratum griseum centrale (SGC). S6 terminals are most frequently seen in SGC and Stratum griseum periventriculare (SPV).In order to determine the origins of the various types of synaptic terminals in the optic tectum, the telencephalon, eye, and optic tectum were removed unilaterally and areas of resultant degeneration examined. Electron microscopic observations show that nearly all S2 terminals in SFGS of the contralateral optic tectum degenerate after eye enucleation, whereas some S4 terminals in SFGS and SGC exhibit degernerative changes after removal of the ipsilateral telencephalon. Unilateral ablation of the optic tectum was associated with degenerative changes in occasional S5 terminals within SGC of contralateral optic tectum. All experiments resulted in some increased electron density of S3 and F terminals, some of which were identified as F2 terminals. The possible origins of S1 and S6 terminals, which were not altered in the present experiments, are discussed.
Representation pattern in the second somatic sensory area of the monkey cerebral cortex
Authors: Friedman D. P. , Jones E. G. , Burton H. 
Published: January 2005

AbstractThe body representation in the second somatic sensory area of macaques has been studied by tracing with anatomical techniques the projections from defined parts of the body representation in the first somatic sensory area (SI) to their terminal regions within the lateral sulcus. The second somatic sensory area (SII), as identified in terms of cytoarchitecture and its connection with the thalamic ventrobasal complex, is the only region of the lateral sulcus to receive a projection from SI. The nearby retroinsular area and area 7b receive a projection from area 5.Within SII the face and head representations lie anteriorly, occupying the dorsalmost part of the insula and portions of the fronto‐parietal operculum. The digits, hand, and arm are represented posterior to the face and may take up the mediolateral extent of the parietal operculum in the region immediately in front of the posterior pole of the insula. The trunk representation is lateral to the arm representation, i.e., deep within the superior circular sulcus and on the dorsal insula. The hindlimb appears behind the trunk also occupying the superior circular sulcus in addition to the deepest 2–3 mm of the upper bank of lateral sulcus immediately posterior to the insula.Areas 3b, 1, and 2 each project to SII, and their projections appear to converge within the representation of a given body part.Injections of anterogradely transported tracers in SI label vertically oriented columnar arrays of terminal ramifications in SII, resembling those previously described for other cortico‐cortical projections within the sensory‐motor region. In experiments which combined anterograde and retrograde labeling, cells projecting from SII to SI formed columns exactly coinciding with the columns of anterogradely labeled axons terminating in SII. The cells of origin of cortico‐cortical projections emanating from SII formed two distinct laminar populations, one in the supragranular layers and the second mainly in layer VI. There is evidence for fiber terminations within layer VI mainly underlying the column formed by the terminal ramifications in layers I through IV.
Organization of somatosensory receptive fields in cortical areas 7b, retroinsula, postauditory and granular insula of M. fascicularis
Authors: Robinson C. J. , Burton H. 
Published: January 2005

AbstractThe boundaries of the second somatic sensory cortex (SII) in primates are difficult to define physiologically because cutaneous stimulation activates several regions around SII that do not receive projections from the ventroposterior nucleus of the thalamus. These cortical regions, which include portions of area 7b, the retroinsular (Ri) and postauditory fields (PA), and the granular insula (Ig) are largely buried within the lateral sulcus and most lie posterior to the caudal end of the insula. The differences in somatic activity in these various cortical fields in the unanesthetized cynomolgus monkey became apparent only after the properties of many neighboring neurons could be compared. Receptive fields for area 7b and Ig neurons were generally large (> 10cm2), with bilateral, moderately defined boundaries; some neurons in area 7b had receptive fields with labile borders as a function of wakefulness. In contrast, receptive fields for Ri neurons were generally < 10cm2 and contralateral, with stable, well‐defined boundaries.Taken as an ensemble, the neurons in areas neighboring SII exhibited a very crude topography; but at the level of an individual neuron and its neighbor, there was never a pattern of gradual transition in peripheral receptive field locations between one unit and the next, like that seen in SII. In area 7b, this crude map was organized mediolaterally across the inferior parietal lobule and into the upper bank of the lateral sulcus, with the head represented medially and the lower trunk and hindlimb laterally. In Ri‐PA, an anteroposterior organization was noted along the fundus of the lateral sulcus with the head represented anterior to the lower trunk and hindlimb. No organization was apparent in Ig. Additional sensitivity to visual stimuli was noted in the more medial aspects of area 7b that were located on the exposed inferior parietal lobule. Sensitivity to auditory stimuli was principally found in PA and occasionally in Ri. The results, especially from area 7b, are discussed with respect to previous notions about the organization of SII.
Somatic submodality distribution within the second somatosensory (SII), 7b, retroinsular, postauditory, and granular insular cortical areas of M. fascicularis
Authors: Robinson C. J. , Burton H. 
Published: January 2005

AbstractSomatic response properties were determined for over 1,300 neurons isolated within and near the lateral sulci of unanesthetized and unparalyzed cynomolgus monkeys. Somatic stimuli unequivocally activated the majority of units studied in SII (93%) and in cortical fields surrounding SII: area 7b (65%), the retroinsular field (74%), and the granular insula (76%).No activation other than somatic was seen for SII neurons, and noxious somatic stimulation was rarely required. The SII units almost always responded in a rapidly adapting manner to hair or skin stimulation, but not both; however, the submodality distribution seen in SII varied as a function of peripheral receptor locations. Two small zones within SII contained neurons that responded only if the animal actively interacted with the stimulus.In contrast, one‐half of the sample of neurons from area 7b unequivocally responded only to somatic stimulation. Although many neurons in the lateral parts of area 7b were vigorously activated by innocuous tactile stimulation, others demonstrated little association with an identifiable somatic submodality, had sluggish responses, required complex, noxious, visual or other non‐somatic stimuli for activation, and had labile response properties and receptive fields. Indeed, the responses of some area 7b neurons suggested a possible relationship with the animal's attention towards or anticipation of a noxious or a novel somatic stimulus. Neurons within the retroinsular cortex (Ri), which receives projections from the posterior nucleus (PO), primarily responded to light tactile stimulation of rapidly adapting skin receptors; less than 3% responded to moderate or high threshold mechanical stimulation. The sensitivity to tactile stimulation in Ri closely resembled the responses of SII neurons. Neurons in the granular insula (Ig) often responded to gentle hair deflection within receptive fields covering large areas of the body. Ig and area 7b were the principle loci within the lateral sulcus that contained neurons responding to noxious stimulation.Owing to the great similarity in the somatic response properties within these areas in the awake and unparalyzed animal, the designation of cortical areas could only be made after correlating the recording sites with connectional and cytoarchitectonic analyses in the same animal. Consequently, previous physiological studies may have attributed to SII some of the response characteristics of neurons in neighboring areas.
Segmental localization of sensory cells that innervate the bladder
Authors: Applebaum Arnold E. , Vance W. Hugh , Coggeshall Richard E. 
Published: January 2005

AbstractThe present study labels the neuronal cell bodies that give rise to afferent fibers that innervate the bladder of cat and rat. The method used was the retrograde transport of horseradish peroxidase (HRP) from its injection site in the bladder to cells in the various dorsal root ganglia. In the rat, the labelled cells are located in the L1–L2 and L6–S1 dorsal root ganglia. In the cat, the labelled cells are located in the L2–L5 and S1–S4 dorsal root ganglia. This confirms older clinical findings, and for the first time directly demonstrates the afferent cell bodies for the bladder. The bladder afferents are small ganglion cells in both rat and cat, and because there is a correlation between the size of axon and the cell body from which it originates, we conclude that the great majority of bladder afferents are small myelinated or unmyelinated axons. In addition, by restricting the HRP to one side of the bladder, we were able to show that some afferent cell bodies send their distal processes across the midline. These results will be useful in considerations of the neural control of bladder function.
Development of spiny and aspiny neurons in the caudate nucleus of the dog during the first postnatal month
Authors: Tanaka Duke 
Published: January 2005

AbstractThe adult and developmental morphology of spiny and aspiny neurons in the dog caudate nucleus was examined using the Golgi‐Kopsch technique. In the adult, three types each of spiny and aspiny neurons were identified based upon dendritic morphology and cell soma size. They corresponded in large part to those neurons described previously in the caudate nuclei of the rat, cat, and monkey. At birth, dendrites of spiny neurons possessed varicosities, filopodia, and thick proximal dendritic stumps—all characteristic of immaturity. Maturation of these processes involved the thinning of proximal dendrites, lengthening of dendritic shafts, and growth of dendritic spines. Although most of the dendritic maturation occurred during the first postnatal month, spine densities and dendritic lengths of spiny I neurons at 30 days were still less than those seen in the adult. Aspiny I neurons were also immature at birth but lacked the filopodia and thicker proximal dendrites that characterized immature spiny neurons. Aspiny dendritic development involved primarily the lengthening of dendritic processes; by 30 days the aspiny I neurons were indistinguishable from those seen in the adult. These results suggest that dendritic development of spiny I neurons may extend well past the end of the first postnatal month and that studies investigating functional development in the caudate nucleus should consider the relatively extended time period required for maturation of these primary synaptic sites.
Innervation of embryonic rat cerebral cortex by catecholamine‐containing fibers
Authors: Schlumpf Margret , Shoemaker William J. , Bloom Floyd E. 
Published: January 2005

AbstractCatecholamine‐containing neuronal processes penetrate to the outer superficial layers of the developing neocortex via the lateral neocortex anlage by embryonic day (ED) 16, only 48 hours after the final cell division of the catecholamine neurons in the mesencephalon and pons‐medulla. Sagittal sections were taken from a series of perfused embryos at precise time‐intervals after insemination. The corpus striatum receives a large catecholamine input and serves as a reference for tracing the very fine varicose processes that course through the caudate nucleus to innervate the more rostral structures of the developing neocortex cerebri. The input fibers to the neocortex arrive via three to four small fiber bundles, entering chiefly at the ventro‐rostral aspect. The bundles then bifurcate into the deep and superficial layers of the cortex. Between ED16 to ED21 the innervation progresses in ventral to dorsal and rostral to caudal directions. Embryonically, fluorescent fibers are observed in the outermost superficial layer and in the intermediate zone, below the cortical plate; only rarely are they seen crossing the cortical plate. The demonstration of monoaminergic neuronal fibers reaching neocortical structures by ED16 adds further weight to the speculation that they may play a role in induction and differentiation, and suggests that post‐natal experimental manipulations using ascending‐bundle lesions will have been performed at least five days after the arrival of catecholamine fibers at their cortical destinations.