bluuebunny/crossref_metadata_2025_split huggingface dataset:
Topological analysis of the brain stem of the crossopterygian fishLatimeria chalumnae
Authors: Kremers Jan‐Willem P. M. , Nieuwenhuys Rudolf 
Published: January 2005

AbstractThe ventricular sulcal pattern and the cellular structure of the brain stem of the single surviving crossopterygian speciesLatimeria chalumnaehave been studied in transversely cut Nissl, Klüver‐Barrera and Bodian staine serial sections. Five longitudinal sulci, the sulcus medianus inferior, the sulcus medianus superior, the sulcus intermedius ventralis, the sulcus limitans and the sulcus intermedius dorsalis could be delimited. The latter three of these sulci are confined to the rhombencephalon. The walls of the mesencephalon also display some longitudinal grooves, but none of these could be traced into continuity with any of the rhombencephalic sulci. Although the neuronal perikarya in many places show a diffuse arrangement, 27 cell masses could be delineated; eight of these are primary efferent nuclei, seven are primary afferent centers, seven nuclei are considered as components of the reticular formation, and the remaining five cell masses may be interpreted as “relay” nuclei.In order to study the zonal pattern of the brain stem, this structure was subjected to a topological analysis (cf., Nieuwenhuys, 1974, and fig. 16). This analysis yielded the following results. The sulcus limitans divides the greater part of the rhombencephalon into a basal plate and an alar plate. In the basal plate the sulcus intermedius ventralis marks the boundary between an area ventralis and an area intermedioventralis. The area ventralis contains two somatic motor centers (i.e., the rostral end of the spinal motor column and the nucleus of IV) and almost the entire rhombencephalic medial reticular formation. The latter may be primarily considered as a somatic motor coordinating center. The area intermedioventralis contains the visceral motor nuclei of V, VII, IX and X. However, the basal plate also harbours a number of non‐motor centers, for example the sensory princeps nucleus of V and the inferior olive. The alar plate is subdivided by the sulcus intermedius dorsalis into an area intermediodorsalis and an area dorsalis. The area intermediolateralis is largely occupied by the common visceral sensory center of VII, IX and X; however, this area also contains a number of somatic sensory cell masses, as e.g. the nucleus descendens of V and the magnocellular vestibular nucleus. The area dorsalis is entirely occupied by two large lateral line centers. The cell masses in the isthmus region do not exhibit a clear‐cut morphological pattern. As regards the mensencephalon, the medial part of the tegmentum, which contains a primary somatic motor center (the nucleus of III) and a somatic motor coordination center (the nucleus of the f.l.m.) may be considered a direct rostral continuation of the area ventralis. The remainder of the midbrain contains a number of somatic sensory centers of primary and higher order.
Origin, course and terminations of the rubrospinal tract in the pigeon (Columba livia)
Authors: Wild J. Martin , Cabot John B. , Cohen David H. , Karten H. J. 
Published: January 2005

AbstractThe red nucleus and its spinal projections in the pigeon (Columba livia) have been studied using both normal and experimental material. The cytoarchitecture of the nucleus is described on the basis of Nissl‐stained sections and reveals an organization generally similar to that of mammals. The large neurons (40‐50μm) tend to be located dorsomedially and ventrolaterally at more caudal nuclear levels, while the small‐and medium‐sized neurons (15‐35μm) predominate at rostral levels. However, neurons of all sizes are present throughout the nucleus.Following lesions of the nucleus, the course of degenerating axons stained with the Fink‐Heimer method has been traced throughout the brainstem and spinal cord. The rubrospinal tract crosses the midline, courses past the ventrocaudal aspect of the contralateral nucleus ruber, and then descends rostroventral and lateral to the nucleus tegmenti pontinus. In its caudal continuation the tract lies ventral to the brachium conjunctivum and the entering radix of the trigeminal nerve. It then assumes a ventrolateral position in the caudal brainstem before shifting to a dorsolateral position in the lateral funiculus of the spinal cord. Within the spinal grey the rubrospinal tract terminates in laminae V, VI and to a lesser extent VII.The possibility of a topographical organization of the nucleus was investigated with injections of horseradish peroxidase into brachial, thracic and lumbar spinal cord. Regardless of the level of injection, labelled neurons of all sizes were present throughout the contralateral nucleus ruber, indicating the absence of an obvious topography.
Descending inputs to the caudal cochlear nucleus of the cat: Degeneration and autoradiographic studies
Authors: Kane Eileen S. , Conlee John W. 
Published: January 2005

AbstractDescending paths from the inferior colliculus (IC) and dorsal (DNLL) and ventral (VNLL) nuclei of the lateral lemniscus and their terminations in the caudal cochlear nucleus in cats were studied both in silver degeneration material following central lesions and in autoradiographs following central injections of tritiated leucine (3H‐leu). Eight adult cats received electrolytic lesions of the IC, the IC and DNLL, or the IC, DNLL and VNLL. Control cats were subjected either to surgery alone or to a lesion in a non‐auditory nucleus. After survival periods of 1 to 16 days, all cats were killed and their brain stems prepared by modified Nauta methods. Twenty‐two other cats received injections of 3H‐leu into the dorsal IC, the ventral IC and DNLL, or the DNLL and VNLL. Their brains were prepared for LM autoradiography. After lesions of the IC, Nauta material contained moderate degeneration of fine fibers that coursed predominantly in the lateral lemniscus, and partially decussated in the caudal trapezoid body to enter the cochlear nuclei of both sides. Sparse, mainly peridendritic degeneration of fine fibers occurred in the PVCN, while moderate, peridendritic and perisomatic degeneration occurred in the deep and innermost fusiform cell layers of the dorsal cochlear nucleus (DCN). Lesions of both the ventral IC and the DNLL showed additional bilateral degeneration of medium‐caliber axons in the descending tracts as well as preterminal degeneration of these larger axons sparsely distributed in the deep layers of the DCN. The density of medium‐caliber axonal degeneration (particularly in the deep DCN) increased when lesions also included the VNLL. After 3H‐leu injections into the tectum and/or upper pons, autoradiographs confirmed the presence of sparse bilateral inputs from both the IC and from the DNLL and VNLL to ventral cochlear nucleus neurons, including some octopus cell dendrites. The autoradiographic studies also clearly revealed a predominant input to the outer layer of the DCN from the dorsal IC, a predominant input to the middle layer from the ventral IC, and a predominant input to the deeper DCN from the lateral lemniscal nuclei. Limited evidence of a topographic, perhaps tonotopic, order within the descending connections was best seen in Nauta material. The differences shown here in fiber types, trajectories, and target sites from the IC, the DNLL, and the VNLL are discussed in terms of possible functional differences among the descending influences on neurons of the caudal cochlear nucleus.
The development of vibrissae representation in subcortical trigeminal centers of the neonatal rat
Authors: Belford Gary R. , Killackey Herbert P. 
Published: January 2005

AbstractIn every station of the trigeminal system of the young rat, the segmented activity of the mitochondrial enzyme succinic dehydrogenase (SDH) clearly delineates the representation of the mystacial vibrissae. In the trigeminal complex of the medulla, three parallel representations can be seen, two in the spinal trigeminal nucleus and one in the principal trigeminal nucleus. In the next station, the ventrobasal complex of the thalamus, a single representation occurs. Likewise, layer IV of somatosensory cortex contains one representation of the vibrissae. Further, neonatal damage to the mystacial vibrissae results in anomalies within each representation.The present study delineates both the normal development of subcortical trigeminal stations and the aberrant organization seen after vibrissae removal. The results of a similar study on somatosensory cortex (Killackey and Belford, '79) and the present data allow the comparison of the development of each of the five vibrissae representations in the trigeminal system.In the brainstem, each of the three trigeminal complex representations are present at birth, although the pattern becomes more distinct over the first several days of life. Interestingly, vibrissae removal at birth induces an aberrant pattern that is distinct by postnatal Day 3. Although details are not equally discernible in each representation, the abnormalities appear to be similar. The SDH segmentation in the ventrobasal complex develops during postnatal Days 1 through 4. At Day 1, portions of the matrix of high density SDH activity break up into bands. Clusters can be discerned within these bands on Day 2. By Day 4 the pattern is sharply delineated. Vibrissae removal at birth results in anomalies that are a part of the initial development of segmentation, not a later reorganization.Comparison of the present data with that of our previous studies indicates that there is a sequential development of the central somatosensory structures related to the vibrissae, beginning with the most peripheral station. Further, there are many similarities in the development of each station. There are also differences which are particularly important in comparing the trigeminal nuclei with the later stations. The unique features in the abnormal development of the trigeminal nuclei are likely due to their direct connections with the periphery.
Development of the diencephalon in the rat. VI. Re‐evaluation of the embryonic development of the thalamus on the basis of thymidine‐radiographic datings
Authors: Altman Joseph , Bayer Shirley A. 
Published: January 2005

AbstractThe development of the thalamus was examined in normal and X‐irradiated embryos from day 13 (E13) to the day before birth (E22). The differentiating, radioresistant neurons of the lateral habenular nucleus, derived from a portion of the superior neuroepithelial lobule (SL1), were settling by day E15 and by this time the habenulopeduncular tract was forming. The neurons of the reticular nucleus, derived from the middle neuroepithelial lobe, began to settle on day E15 but a massive migration was still evident on day E16. Adjacent to the reticular nucleus the internal capsule appeared on day E16; this fiber bundle seemed to be continuous with fibers embedded in the first transitory zone of cells issuing from the dorsal neuroepithelial lobe. Because of the immaturity of the neocortex at this time, it was postulated that thalamocortical fibers of the dorsal thalamus are the earliest components of the internal capsule. By day E17 all the sensory relay nuclei of the thalamus were recognizable and it was assumed that the second transitory zone issuing from the receding dorsal neuroepithelial lobe contained the neurons of the later forming intralaminar nuclei. Suggestive evidence was obtained that the late arising neurons of the medial thalamus (the anterior nuclei, the mediodorsal nucleus, and some or all of the midline nuclei) originate in a portion of the superior neuroepithelial lobule designated as SL2.Our present and previous studies showed that the major divisions of the hypothalamus and thalamus are derived embryonically from distinguishable parts of the third ventricle neuroepithelium. This implies that the third ventricle neuroepithelium has a “mosaic” organization and suggests that the fate of hypothalamic and thalamic neurons may be determined to some extent while their precursors are still proliferating.
Patterns of connections from the striate cortex to cortical visual areas in superior temporal sulcus of macaque and middle temporal gyrus of owl monkey
Authors: Montero Vicente M. 
Published: January 2005

AbstractDouble label‐emulsion autoradiography has been used in rhesus monkeys to study cortico‐cortical connections, arising from two separate sites of the striate cortex, and going in the same hemisphere into the cortex in the medial part of the posterior (or ventral) bank of the superior temporal sulcus (area STS). The projections from a single cortical locus are segregated into several patches of labeled terminals in layers III–IV, which from bands in consecutive sections. Fields of distribution of these bands from two sites of area 17 may completely overlap, when they arise from neighboring regions, or may partially overlap, when they arise from more separated regions. The latter show a retinotopical order in these connections and, consequently, of area STS itself: central visual field is lateral and ventral in STS to peripheral visual field, and upper visual field is ventral and medial to lower visual field. Connections from area 17 to area MT in owl monkey were analyzed in a comparative study. Results show that these connections are also highly segregated into bands, and that those arising in separate, but neighboring regions of 17, may greatly overlap in MT. The retinotopy of these connections was not studied, however. The similar divergent distribution of area 17 connections to STS and MT, and the similarity of the topography of STS connections and of the known retinotopy of area MT, are considered as elements of homologies between these areas. Functional implications of these divergent patterns of connections to these motion‐sensitive areas (Zeki, '74), are considered.
Representation of the body surface in somatic koniocortex in the prosimian Galago
Authors: Sur Mriganka , Nelson R. J. , Kaas J. H. 
Published: January 2005

AbstractMicroelectrode mapping methods were used to determine the organization of somatosensory cortex in galagos, a prosimian primate. A systematic representation of the controlateral body surface was found within somatic koniocortex with an organization comparable to that of Area 3b of parietal cortex of monkeys (S‐I proper) and primary somatosensory cortex (S‐I) of other mammals. Limited studies of the response properties of single neurons within the representation revealed further similarities with the 3b field of monkeys. We conclude that somatic koniocortex of galagos and Area 3b of monkeys are homologous, and suggest the term S‐I proper for the representation in both prosimians and monkeys. Differences in the details of S‐I proper in galagos and monkeys suggest a more primitive organization in galagos.
Noradrenergic innervation of the adult rat hippocampal formation
Authors: Loy Rebekah , Koziell David A. , Lindsey James D. , Moore Robert Y. 
Published: January 2005

AbstractThe noradrenaline (NA)‐containing innervation of the hippocampal formation arises exclusively in the brainstem nucleus locus coeruleus. The projection is 75–90% ipsilateral, originating predominantly in the large, multipolar cells of the compact component of the nucleus. The axons course into the hippocampal formation by three pathways. Ammon's horn receives its NA innervation principally through the ventral amygdaloid bundle‐ansa peduncularis, with smaller contributions from the fornix and ipsilateral fasciculus cinguli. The innervation of the area dentata is to a larger extentbilateral, with the greatest contribution arising from the ipsilateral fasciculus cinguli and approximately equal proportions of fibers traveling via the contralateral cingulum, fornix, and the ventral path. In general, the endogenous content of NA is greater in the area dentata than in Ammon's horn, and in both structures is greater in the temporal than in the septal ends. The pattern of NA innervation is similar at all septotemporal levels, however. The densest plexuses of preterminal and terminal elements appear in the infragranular hilus of the area dentata, stratum lucidum of CA3, and in the molecular layer of the subiculum. Fluorescent varicosities often appear in perisomatic clusters, or, closely apposed to dendrites of granule and pyramidal cells.
Normal and abnormal uncrossed retinotectal pathways in rats: An HRP study in adults
Authors: Lund R. D. , Land P. W. , Boles J. 
Published: January 2005

AbstractHorseradish peroxidase was injected into the superior colliculus of normal pigmented and albino rats and rats which had been unilaterally enuleated at birth, in order to identify the retinal ganglion cells which contribute normal and abnormal uncrossed retinotectal axons. The results show that while in pigmented rats, the normal uncrossed pathway derives solely from the lower temporal retina and distributes to the anterior and medial parts of the colliculus, occasional cells throughout the retina of albino rats contribute to the uncrossed pathway and the terminal distribution is broader in the tectum. These findings are confirmed with orthograde pathway tracing methods.After neonatal unilateral eye enucleation, many more ganglion cells in the remaining eye of both pigmented and albino rats project ipsilaterally. It is notable from both HRP studies and from further degenration experiments that cells in part of the lower temporal retina do not restrict their distribution to a mirror togographic position in the ipsilateral tectum but send axons across all but the posterolateral part of the colliculus.No single class of ganglion cell (defined by soma diameter) appears responsible for the expanded ipsilateral projection, although more large cells from the lower temporal retina are involved. These may be the result of enlargement of cells with expanded terminal fields rather than necessarily indicating a preferential contribution from one retinal ganglion cell class.
Early postnatal development of the monkey neostriatum: A Golgi and ultrastructural study
Authors: Difiglia Marian , Pasik Pedro , Pasik Tauba 
Published: January 2005

AbstractPaired specimens of the neostriatum were taken from monkeys at zero (newborn), one, two, four, eight, and 16 weeks of age, and prepared for Golgi impregnations and electron microscopy. Light microscopy shows that in the first postnatal week, the structure contains the five neuronal types and four categories of afferent axons described in the adult, as well as some cells too undifferentiated to classify. Most neurons exhibit immature dendritic features, including local enlargements, terminal growth cones with filopodia, and filiform processes. In spiny type I cells, various levels of maturity may coexist in regions of a single dendrite, in different dendrites of the same neuron, and among individual cells. Spine density increases progressively with age, but the relative distribution of spine types remains about the same. Spiny type II neurons show some decline in spine density, and generally mature sooner than spiny type I cells. The long axons of spiny neurons have varicosities which disappear at about eight weeks. In younger animals (newborn and one week), the dendrites of aspiny neurons (types I, II, and III) may have a “spiny” appearance, exhibiting many spine‐like and filiform processes. Concurrently, the short axons vary in degree of arborization from very immature to well developed.Electron microscopy corroborates the developmental features recognized in the Golgi material: dendritic and axonal growth cones, filopodia and varicosities, as well as various stages of maturation in somata and dendrites. Degenerating elements, mostly of an axonal nature, are seen up to eight weeks. The synapses which reach maturity at birth are of the asymmetric axospinous type, in which the axonal profile contains small round vesicles, and of the symmetric axodendritic class, with the presynaptic elements having pleomorphic vesicles. Some synapses are slower to mature and appear at one to eight postnatal weeks. These include those made by profiles with pleomorphic vesicles, forming either symmetric contacts with somata and axon initial segments, or asymmetric contacts with spines. The same applies to the asymmetric axodendritic synapses made by elements containing small round vesicles. Finally, profiles containing large round or flat vesicles are the latest to participate in mature synapses formation.Findings indicate that a considerable degree of qualitative and quantitative change takes place in the monkey neostriatal neuropil during early postnatal development, especially in the first eight‐week period.
Somatotopic organization of the embryonic chick trigeminal ganglion
Authors: Noden Drew M. 
Published: January 2005

AbstractHorseradish peroxidase (HRP) has been injected into periocular, upper beak, or lower jaw tissues of chick embryos aged 6–8 days of incubation. Subsequent mapping of the distribution of labeled neurons in the trigeminal ganglion indicates that the somatotopic organization of neurons is essentially identical to that found after hatching.At these stages most labeled cells are in the distal parts of the bilobed ganglion. There is no indication that any of these neurons, most but not all of which are derived from epidermal placodes, establish any erroneus projections. Most of the proximo‐central or core neurons, which are of neural crest origin, are immature at these stages. On the eighth day of development, by which time the embryo is responsive to tactile stimulation of the beak, few of these core cells have established projections to more distal (rostral) periocular or upper beak areas or to the lower jaw. In contrast, injection of HRP above the eye results in labeling of many of the core neurons. This suggests that there is an asymmetry in the time of neurite outgrowth from core neurons that is correlated with their peripheral projections but not with their time of terminal mitosis.Following injection of HRP into temporal periocular tissues, most of the core cells in the maxillo‐mandibular lobe contain peroxidase. This is probably due to uptake by growth cones emerging along the maxillary ramus.Examination of contralateral trigeminal ganglia indicates that the transmedian projections of these sensory fibers form later in development. Branches of the mandibular motor nerve extend throughout the lower jaw and presumptive jaw‐closing muscle anlagen, as evidenced by incorporation of HRP into motoneurons of the trigeminal nucleus.