bluuebunny/crossref_metadata_2025_split huggingface dataset:
The pregeniculate nucleus of the monkey (Macaca mulatta). II. A study at the electron microscopic level
Authors: Babb Richard S. 
Published: May 2005

AbstractAn electron microscope study of the ultrastructure of the pregeniculate nucleus of the monkey (Macaca mulatta) shows it to contain three neuronal types and four varieties of presynaptic terminals. Type I neurons are found only in the inner lamina, have small rounded profiles with few axosomatic synapses; the cytoplasm is poor in organelles and the nucleus is deeply infolded. Type II neurons were observed infrequently and only in the outer lamina; they have large oblong profiles, exhibiting many axosomatic contacts, and containing abudant cytoplasm rich in organelles, particularly arrays of granular and agranular endoplasmic reticulum. Type III neurons were the most frequently seen and are found in both laminae; their profiles are elliptical and exhibit only a few axosomatic synapses. The cytoplasm surrounding the infolded nucleus is moderately rich in organelles with agranular endoplasmic reticulum predominating. These three neuronal types were found to correlate well with types of neurons found in material stained with cresylecht violet or impregnated by the Golgi method.Four presynaptic terminal types were discerned: a small cup‐shaped profile containing spheroid vesicles and found predominantly in the outer lamina, a larger elliptical profile containing flattened spheroid vesicles, a large ramifying profile also containing round vesicles and largely restricted to the inner lamina, and a rounded profile containing larger flattened vesicles. Three days after eye enucleation, darkened degenerating profiles containing vesicles and forming asymmetric synapses were observed in the inner lamina, while the third terminal type described above could no longer be seen. The first three are usually associated with asymmetric synaptic densities, whereas in the case of the last type, the postsynaptic synapse is symmetrical. The profile of this last terminal type was also sometimes observed to be both postsynaptic as well as presynaptic to other profiles; however, it was never observed to contain ribosomes. Such a pre‐ and postsynaptic terminal always forms part of the in series or triadic configuration of terminals occasionally observed in the pregeniculate nucleus.
Subcortical afferent connections of the amygdala in the monkey
Authors: Mehler William R. 
Published: May 2005

AbstractThe cells of origin of the afferent connection of the amygdala in the rhesus and squirrel monkeys were analyzed by means of the retrograde axonal transport of the enzyme horseradish peroxidase (HRP) injected into various quadrants of the amygdala. Tabulation of the relative numbers of HRP labeled cells found in each brain section through various nuclei in a series of injected brains revealed several patterns of ipsilateral subcortical nuclear connections with the amygdala. The dorsal thalamic nuclei most consistently exhibiting large numbers of labeled cells in all experiments were the ipsilateral halves of the midline nucleus paraventricularis thalami and both the parvo‐ and magnocellular parts of the nucleus subparafascicularis. All of the subdivisions of the midline nucleus centralis complex (Olszewski, '52) exhibit HRP labeled cells in most cases. A cell group corresponding to the nucleus reuniens ventralis (Kuhlenbeck, '54) and one identified as the nucleus interventralis of Aronson and Papez ('34) also were found to contain labeled cells.The largest populations of HRP labeled cells in the hypothalamus appear chiefly in the middle and posterior parts of the ipsilateral, lateral hypothalamic area in all cases and densely in the ventromedial hypothalamic nucleus only in cases with medial amygdalar quadrant injections. Scattered HRP positive cells frequently can be found in the supramammillary and dorsomedial nuclei and the posterior hypothalamic area. A limited but consistent number of labeled cells can be located in Tsai's ventral tegmental area. In the midbrain some labeled cells can be demonstrated in the rostral and caudal subdivisions of the nucleus linearis, and scattered groups of HRP positive cells can be localized in the dorsal raphe nucleus, chiefly on the side ipsilateral to the injection.The most conspicuous subdiencephalic source of amygdalar afferent connections found in the present study is the pars lateralis of the nucleus parabrachialis located in the dorsolateral pontine tegmentum. Cells in this nucleus are heavily labeled in all cases, while only a few HRP positive cells are occasionally found in the pars medialis. A few labeled cells can be differentiated from pigmented cells in the locus coeruleus, but the labeling of cells scattered throughout the caudal half of the nucleus of the tractus solitarius and in a paravagal cell group is accepted with reservations because both cell groups frequently display endogenously pigmented cells in normal, non‐injected monkeys.
Distribution of chemosensitive primary sensory afferents in the central nervous system of the rat
Authors: Jancsó G. , Király Elizabeth 
Published: May 2005

AbstractBy making use of the selective neurotoxic effect of capsaicin on chemosensitive primary sensory neurons, a new experimental approach has been made for the direct morphological demonstration of the distribution of unmyelinated primary sensory afferent fibers to the spinal cord and sensory nuclei of cranial nerves. Chemosensitive primary sensory neurons are known to take part in the transmission of a specific sensory modality, i.e., chemogenic pain.For the demonstration of axon terminal degeneration, the Fink‐Heimer technique I was used. It was shown that the chemosensitive primary afferents terminated in Rexed's laminae I and II of the spinal cord. In the brainstem degenerating fibers were found to be distributed in the spinal trigeminal nuclei and the solitary system. In the caudal part of the trigeminal nucleus caudalis degeneration argyrophilia was noted both in the subnucleus marginalis and subnucleus gelatinosus, while in the rostral part of the nucleus degeneration was almost exclusively confined to the subnucleus gelatinosus. In addition, a small number of degenerating terminals were found in the nucleus oralis. Heavy terminal degeneration was observed in the nucleus of the solitary tract and the adjoining nucleus commissuralis. Degenerating structures were also found in a small region in the dorsolateral part of the area postrema.It is concluded that the degenerating afferent fibers terminating in the sensory nuclei of cranial nerves and the spinal cord represent central projections of chemosensitive primary sensory neurons, supplying the skin, mucous membranes, and different visceral areas by the Vth, IXth, and Xth cranial and spinal nerves, respectively.The participation of chemosensitive neurons in somato‐ and viscerosensory functions, other than chemogenic pain, is also discussed. It is suggested that these chemosensitive primary sensory neurons may, at least in part, be identical with substance P‐containing sensory ganglion cells.
Cortical projections of the lateral geniculate nucleus in the cat
Authors: Geisert E. E. 
Published: May 2005

AbstractA new application of the retrograde transport method designed to demonstrate neurons that project to two cortical areas has been developed. This method depends on the retrograde axonal transport of two markers, each of which is uniquely detectable by histological methods. In this study, horseradish peroxidase (detectable by the enzymatic reation product only) and tritiated proteins (either enzymatically inactive tritiated horseradish peroxidase or tritiated bovine serium albumin, both of which are detectable by the tritium label only) were used. One of these markers was injected into cortical area 17 and the other was injected into area 18.In layers A and A1 of the lateral geniculate nucleus, 10% of the cells project to both area 17 and area 18 by axons that branch, 70% of the neurons project to area 17 only, less than 1% of the neurons project to area 18 only, and approximately 20% of the cells are probably interneurons. In the C laminae 50% of the cells project to both areas 17 and 18 by axons that branch, approximately 20% of the neurons project to area 17 only, 10% of the cells project to area 18 only, and about 20% of the neurons are unlabeled. The cells in the medial interlaminar nucleus project to area 17 only, to area 18 only, or to both of these areas by axons that branch.In addition the retrograde markers were injected into single cortical areas, either area 17, area 18, or area 19. The injections of area 17 and those of area 18 confirmed the results of the double‐label experiments, with 80% of the cells in the A laminae projecting to area 17 and approximately 10% projecting to area 18. Following injections of area 19, labeled neurons were seen in the medial interlaminar nucleus and the C laminae. Therefore, the medial interlaminar nucleus contains cells that project to areas 17, 18, and 19, with some cells projecting to both area 17 and area 18 by axons that branch. In the C laminae the analysis of the projection pattern could be carried further, for it was possible to determine the percentage of labeled neurons in this region. Since 80% of the cells project to areas 17 and 18, and since 60% of the cells of the C laminae were labeled following injections of area 19, many of the cells which project to area 19 must also project to either area 17 or area 18, and some cells must project to all three (areas 17, 18, and 19) by branching axons.
An immunohistochemical characterization of somatostatin‐28 and somatostatin‐281–12 in monkey prefrontal cortex
Authors: Lewis David A. , Campbell Michael J. , Morrison John H. 
Published: May 2005

AbstractThe distribution of the prosomatostatin‐derived peptides (PSDP) somatostatin‐28 (SS‐28) and somatostatin‐281–12 (SS‐281–12) was characterized immunohistochemically in the prefrontal cortical regions of both Old World cynomolgus monkeys (Macaca fascicularis) and New Worldsquirrel monkeys (Saimiri sciureus). Comparison of staining with antisera specific for each peptide revealed that these antigens were segregated within immunoreactive neurons such that SS‐28 was largely confined to theperinuclear region of the cell body whereas SS‐281–12 was primarily found in axons and dendrites.The laminar pattern of immunoreactive fibers was similar in all areas of the prefrontal cortex. The most dense terminal arborization was in layers I, II, and superficial III. Deep III and IV were traversed by radial fibersthat had little arborization. Layers V and VI contained both radial fibers and a moderately dense terminal plexus. Labeled fibers were less numerous in the white matter. There were marked regional differences in fiber density. Areas 12 and 24 had the greatest density of immunoreactive fibers, areas 9, 11, and 25 were of intermediate density, and areas 10 and 46 were the least dense.Most of the immunoreactive cells appeared to be multipolar or bitufted. They were found throughout all cortical layers and the white matter. The largest number were located in layers II, superficial III, and deep V and VI. There were also marked regional differences in cell body density, which paralleled the regional differences in fiber density. Area 24 (anterior cingulate) had the greatest density of immunoreactive cell bodies (148 ± 14/mm2), area 9 was of intermediate density (109 ± 13/mm2), and area 46 was the least dense (83 ± 12/mm2).Our findings indicate that PSDP compose a complex and extensive cortical system that is largely or totally intrinsic. The substantial regional heterogeneity in density exhibited by PSDP‐containing neurons has not previously been reported for an intrinsic cortical system. The laminar and regionalinnervation patterns of these fibers and cell bodies suggest that the PSDP cortical system may play an important role in the polymodal information processing that occurs in association regions of prefrontal cortex.
Quantitative comparison of retinal synapses in the dorsal and ventral (parvicellular) C laminae of the cat dorsal lateral geniculate nucleus
Authors: Mize R. Ranney , Spencer Robert F. , Horner Linda H. 
Published: May 2005

AbstractThree physiological classes of retinal ganglion cell project to the cat dorsal lateral geniculate nucleus (DLGN). The dorsal laminae A, A1, and magnocellular C receive X and Y retinal input, whereas the ventral parvicellular laminae C1 and C2 receive predominantly W input. We have compared quantitatively the retinal synaptic terminals of the dorsal and ventral laminae to determine whether there are morphological differences in the terminals that correspond to their different response properties Anterogradely labeled retinal synaptic terminals in all laminae contained pale mitochondria and large, round synaptic vesicles. However, rerminals with pale mitochondria varied in size and synaptic organization in different laminae. The terminals in the A laminae were on average, quite large and made numerous contacts with conventional dendritic profiles and with profiles that themselves contained synaptic vesicles (F2 profiles). The terminals in lamina C that contained pale mitochondria had a smaller overall mean area. Terminals with pale mitochondria in C1 and C2 were almost all small and synapsed with F2 profiles less frequently than did terminals in the A laminae or in lamina C. These results provide quantitative evidence that visual areas receiving W‐type retinal input contain smaller retinal terminals and have a different synaptic organization from that of laminae receiving X and Y input.
Rabbit cingulate cortex: Cytoarchitecture, physiological border with visual cortex, and afferent cortical connections of visual, motor, postsubicular, and intracingulate origin
Authors: Vogt Brent A. , Sikes Robert W. , Swadlow Harvey A. , Weyand Theodore G. 
Published: May 2005

AbstractThe connections of cingulate cortex with visual, motor, and parahippocampal cortices in the rabbit brain are evaluated by using a modified Brodmann cytoarchitectural scheme, electrophysiological mapping techniques, and the pathway tracers horseradish peroxidase (HRP) and tritiated amino acids. Rabbit cingulate cortex can be divided into areas 25, 24, and 29. Area 29 isof particular interest because area 29d has a lateral extension with a granular layer IV, area 29b has a caudal extension in which the connections differ from anterior area 29b, and there is a prominent area 29e. delineation of the lateral border of area 29d with area 17 closely approximates the medial edge of the visual field representation in area 17 as determined electrophysiologically.The main interconnections between visual and cingulate cortices occur between cingulate areas 24b and 29d and visual areas 18 and medial parts of area 17. Projections between areas 29d and 18 are organized in a loose topographic fashion with rostral parts of each and caudal parts of each being reciprocally connected. Neurons mainly in superficial layer II‐III of areas 17 and 18 project to layer I of area 29d, while the reciprocal projection originates from neurons in layer V of area 29d and project mainly to layer Iof areas 17 and 18.The medial portion of motor area 8 projects to areas 18 and 29d and hasa smaller projection to area 17.Postsubicular area 48 is reciprocally connected with area 29d, and it also projects to areas 29b and c. The subiculum projects to areas 29a and 29c but only to the anterior two‐thirds of area 29b not the posterior one‐third.Rostral area 29d receives the most extensive intrinsic cingulate projections including those from all major cytoarchitectural divisions. Interconnections between areas 29d and 29b appear to be topographically organized inthe rostrocaudal plane. Area 29c projects more heavily to area 29b than vice versa. Finally area 29d projects mainly to area 24b in anterior cingulatecortex.In conclusion, rostral area 29d has extensive connections with visual areas 17 and 18, motor area 8, and all subdivisions of cingulate cortex. In light of these connections, it may play a pivotal role in associative functions of the rabbit cerebral cortex including visuomotor integration.
The topographical organization of the vagal motor column in the elasmobranch fish, Scyliorhinus canicula L.
Authors: Withington‐Wray D. J. , Roberts B. L. , Taylor E. W. 
Published: May 2005

AbstractThe location within the brainstem of vagal preganglionic motoneurons has been determined in the dogfish Scyliorhinus canicula L. by means of the retrograde transport of horseradish peroxidase and cobalt applied to the vagus nerve and its component branches. Labelled vagal motoneurones were located in the ipsilateral caudal rhombencephalon from 2.1 mm caudal to 2.72 mm rostral to obex.The motoneurons of the vagal motor column are arranged as four distinct groups. Caudal to obex the column contains dorsomedial and ventromedial divisions, whilst rostrally it consists of a single rostromedial division and a short lateral division. The cells in the ventromedial division are approximately twice the size (mean area 1,094 μm2) of the other vagal neurons.The dorsomedial division contains neurons that supply the heart and viscera; the ventromedial division supplies the viscera. The heart is also innervated by the neurons of the lateral division and the visceral nerve also receives axons from the rostromedial division. All neurons supplying axons to the gill arches are located in the rostromedial division.There is a sequential topographical representation of the vagus nerve in the vagal motor column. Neurons supplying the gastrointestinal tract are located caudally; those supplying the cardiac nerves lie in the midportion of the column, and the proximal supply to the gills is given by the most rostral neurons. There is some overlap between the pools of neurons supplyingadjacent branches of the vagus.
The development and migration of large multipolar neurons into the cochlear nucleus of the North American opossum
Authors: Willard F. H. , Martin G. F. 
Published: May 2005

AbstractWe have studied the maturation of the inferior colliculus and cochlear nuclei of the North American opossum with particular emphasis on the large multipolar neurons of the cochlear nucleus. These neurons include the principal and giant cells of the dorsal cochlear nucleus (DCN) and the large neurons of the ventral cochlear nucleus (VCN), all of which can be labelled byhorseradish peroxidase (HRP) injections into the contralateral inferior colliculus (IC). The size of these neurons, their characteristic Nissl patterns, and their labelling density after injections into the IC render them distinguishable from other neurons in this nuclei, even in young animals.In Nissl‐stained sections of newborn opossums, a band of horizontally oriented neurons can be identified dorsomedial to the vestibular nerve root. This band extends from an apparent cytogenetic zone close to the sulcus limitans, to, but not within, the presumptive cochlear nucleus. Between birth and estimated postnatal day 22 (EPND 22) the band shifts laterally, eventually becoming incorporated into the cochlear nucleus. Many neurons in this band have perinuclear caps of Nissl substance similar to those present in the principal cells of the adult DCN.Injections of HRP into the IC as early as EPND 5 (17 days after conception) labelled neurons in the band referred to above but not in the presumptive cochlear nucleus. By EPND 15, labelled cells were clustered mainly within the nucleus proper. Most of these cells were located in the DCN, but a few were scattered in the dorsocentral VCN. Consistent labelling of small neurons in VCN was not obtained until sometime later. From EPND 15 to EPND 20 most of the labelled cells in DCN reoriented in the vertical plane, aligned in layer II, and differentiated into principal neurons. Some, however, remained deep to layer II and differentiated into giant neurons. The heavily labelled cells in VCN differentiated into large neurons.Our results suggest that the large multipolar neurons of the nucleus are generated in a cytogenetic zone medial to the rhombic lip and that they subsequently migrate laterally, in a band, to reach their adult locations inthe nucleus. It is during this migratory stage that their axons reach the inferior colliculus.
Light and electron microscopic study of an avian pretectal nucleus, the lentiform nucleus of the mesencephalon, magnocellular division
Authors: Gottlieb Michael D. , McKenna Olivia C. 
Published: May 2005

AbstractUsing several light microscopic methods we have identified the lentiform nucleus of the mesencephalon, magnocellular division, by its position in the pretectum, its cellular composition, and its complement of retinal afferents and have distinguished it from neighboring structures. At the light microscopic level large neurons (approximately 30 × 21 μm) and small neurons (approximately 13 × 9 μm), which are more numerous, are seen interspersed among myelinated axons. The large neurons are generally ovoid and contain an eccentrically located nucleus and large clumps of Nisslstained material. In the electron microscope the most notable feature of these neurons is the presence of ribosome rosettes and many parallel arrays of rough endoplasmic reticulum (RER). On the basis of cytological and ultrastructural features, we conclude that only one class of large neuron is present. Although in the light microscope the small neurons appear to be similar, at the ultrastructural level three neuron types have been distinguished:(1) ovoid shape with cytoplasm densely packed with organelles especially RER, (2) round shape with very little cytoplasm with few organelles, and (3) triangular shape with a pale cytoplasmic matrix with some RER. Subsurface membrane configurations are often seen in the somata of all neuron types. Inaddition, axon terminals, some containing flat vesicles, and other less frequent ones containing round vesicles are seen terminating on the somata of all neuronal cell types. In the neuropil, three types of presynaptic profiles can be identified. Two of these profiles are axodendritic and the third is dendrodendritic. The type R profile, which is often as large as 4 μm2, is the most numerous, contains large round synaptic vesicles, and is often seen synapsing on several dendritic profiles. The type F profilecontains flat vesicles and a relatively dense cytoplasm, and is smaller in area than type R. The third profile, which contains small clusters of pleiomorphic vesicles and apparently is dendritic, forms synapses with dendriticprofiles. We propose that the type R axon terminals originate mostly from the retina and the type F mostly from the visual telencephalon.