bluuebunny/crossref_metadata_2025_split huggingface dataset:
Localization of glycine receptor alpha subunits on bipolar and amacrine cells in primate retina
Authors: Jusuf Patricia R. , Haverkamp Silke , Grünert Ulrike 
Published: May 2005

AbstractThe major inhibitory neurotransmitter glycine is used by about half of the amacrine cells in the retina. Amacrine cells provide synaptic output to bipolar, ganglion, and other amacrine cells. The present study investigated whether different bipolar and amacrine cell types in the primate retina differ with respect to the expression of glycine receptor (GlyR) subtypes. Antibodies specific for the α1, α2, and α3 subunits of the GlyR were combined with immunohistochemical markers for bipolar and amacrine cells and applied to vertical sections of macaque (Macaca fascicularis) and marmoset (Callithrix jacchus) retinae. For all subunits, punctate immunoreactivity was expressed in the inner plexiform layer. The GlyRα2 immunoreactive (IR) puncta occur at the highest density, followed by GlyRα3 and GlyRα1 IR puncta. Postembedding electron microscopy showed the postsynaptic location of all subunits. Double immunofluorescence demonstrated that the three α subunits are clustered at different postsynaptic sites. Two OFF cone bipolar cell types (flat midget and diffuse bipolar DB3), are predominantly associated with the α1 subunit. Two ON bipolar cell types, the DB6 and the rod bipolar cell, are predominantly associated with the α2 subunit. The glycinergic AII amacrine cell is presynaptic to the α1 subunit in the OFF‐sublamina, and postsynaptic to the α2 subunit in the ON‐sublamina. Another putative glycinergic cell, the vesicular glutamate transporter 3 cell, is predominantly presynaptic to the α2 subunit. The dopaminergic amacrine cell expresses the α3 subunit at a low density. J. Comp. Neurol. 488:113–128, 2005. © 2005 Wiley‐Liss, Inc.
Development of A9/A10 dopamine neurons during the second and third trimesters in the African green monkey
Authors: Morrow Bret A. , Redmond D. Eugene , Roth Robert H. , Elsworth John D. 
Published: May 2005

AbstractDisruption in the development of dopamine‐containing neurons has been postulated to underlie several CNS disorders. However, there have been no quantitative studies on the normal development of primate dopamine neurons. Thus, the fetal maturation of primate midbrain dopamine neurons was examined to establish changes that occur in the A9/A10 groups during the second and third trimesters. Eleven fetal African green monkey midbrains were immunostained for tyrosine hydroxylase (TH‐ir) as a marker for dopamine neurons and quantified using stereological techniques (nucleator method). The number and size of defined dopamine neurons and the volume occupied by A9/A10 neurons increased in near linear fashion throughout the term. The estimated number of defined dopamine neurons in each hemisphere rose from ∼50,000 at embryonic day (E) 70 to 225,000 at birth (E165), similar to the adult population. The size and the area occupied by them at birth were, however, well below the estimated adult levels. Additionally, the younger fetal midbrains had far less diversity in dopamine cell volumes compared with older fetuses and adult brains. Until midway through gestation (E81), clusters of apparently immature midbrain TH‐ir cells were observed, but could not be counted. Even though the majority of cells destined to become dopamine neurons are generated in the first trimester, phenotypical maturation of A9 and A10 cell bodies continues steadily throughout gestation and extends well into the postnatal period. These data have relevance to transplantation studies that employ fetal dopaminergic grafts, and to disorders hypothesized to result from damage to developing midbrain dopamine neurons. J. Comp. Neurol. 488:215–223, 2005. © 2005 Wiley‐Liss, Inc.
Synaptic patterns in the visual cortex of the cat and monkey. Electron microscopy of Golgi Preparations
Authors: LeVay Simon 
Published: May 2005

AbstractPrimary visual cortex (area 17) from macaque monkeys, cats and kittens was stained by a rapid Golgi method modified to give optimal preservation of fine structure. Single impregnated neurons were identified in the light microscope, and then cut in serial thin sections for electron microscopy. As in conventional E.M. material, synapses in the Golgi preparations could be classified into types 1 and 2: type 1 synapses possessed round vesicles in the axon and a pronounced postsynaptic opacity; type 2 synapses had smaller, flattened vesicles in the axon and a slight postsynaptic opacity. Synapses onto impregnated cells were identified by the presynaptic opacities (dense projections), and classified as type 1 or 2 according to the shape and size of the vesicles.Pyramidal cells and spiny stellate cells (found in layer 4) had a similar synaptic environment: type 1 synapses occurred only on the spines, while type 2 synapses were found on dendritic shafts, cell bodies, and axon initial segments. Spinefree stellate cells possessed both type 1 and type 2 synapses on the cell body and on the dendritic shafts, the type 2 synapses being most frequent near to, the type 1 synapses far from, the cell body.Synapses formed by the axon terminals of nine cells were located, and were classified as type 1 or 2 on the basis of the thickness of the postsynaptic opacity. The axons of pyramidal and spiny stellate cells formed type 1 synapses; those of spinefree and sparsely spinous cells formed type 2 synapses. In the 12‐day old to 5‐week old kittens, cells corresponding to the spinefree cells of the adult cat did possess spines. These transient spines were commonest on and near the cell body, and were the sites of type 1 synapses.On these and other grounds, the spiny stellate cells of layer 4 were concluded to be closely related to pyramidal cells, and quite distinct from the class of spinefree and sparsely spinous cells. The interpretation of conventional E.M. preparations of cerebral cortex is discussed.
Heart rate and blood pressure responses to electrical stimulation of the central nervous system in the pigeon (Columba livia)
Authors: MacDonald Robert L. , Cohen David H. 
Published: May 2005

AbstractAn extensive stereotaxic stimulation study of the pigeon brain was conducted with monitoring of heart rate, arterial blood pressure and respiration. Rostrally, short latency tachycardia, hypertension and hyperpnea were elicited from the archistriatum, occipitomesencephalic tract and hypothalamus. In addition, blood pressure decreases followed by long latency tachycardia were elicited from the septal complex, although occasionally slight bradycardia occurred.Tachycardia, hypertension and hyperpnea were elicited from many midbrain sites including the lateral reticular formation, ventrolateral tegmentum, ventral area of Tsai, the midline region between nucleus interpeduncularis and the oculomotor complex, and nucleus mesencephalicus lateralis, pars dorsalis. In addition, moderate tachycardia and hypotension were elicited from the central gray and nucleus intercollicularis while tachycardia, hypertension and hyperpnea were elicited from the tegmental area in the region of the occipitomesencephalic tract.At pontine levels, hypertension and cardioacceleration were elicited from a sparsely celled region lateral to the nucleus abducens and from a ventrolateral tegmental region. With respect to respiratory responses, hyperpnea was elicited from the ventrolateral brainstem at all pontine levels and from the dorsomedial region at rostral pontine levels. In caudal pons apnea was the consistent respiratory response to stimulation of the dorsomedial brainstem. In addition, cardio‐acceleration, hypertension and apnea were elicited from the region of the deep cerebellar nucleus cerebellus internus and from its major outflow, the uncinate fasciculus.Finally, stimulation in the medulla elicited bradycardia and hypotension from the vagal rootlets, solitary complex, descending vestibular nucleus and lateral aspect of the dorsal motor nucleus just rostral to the obex. Tachycardia and hypertension were elicited from the medial aspect of the dorsal motor nucleus, medullary reticular formation ventral to the vagal rootlets and ventrolateral medulla.
Neural and vascular ultrastructure of the area postrema in the rat
Authors: Dempsey Edward W. 
Published: May 2005

AbstractElectron microscopy of the area postrema reveals two types of small blood vessels, a large sinusoidal variety and one of smaller diameter. Both are surrounded by perivascular connective tissue sheaths bounded on both inner and outer aspects by well developed basal laminae. In experimental argyria, dense granules are massively deposited in the basal laminae of the large sinusoidal vessels, and more delicately in the laminae of smaller capillaries. By analogy with the similar massive deposits of silver in renal glomeruli, this suggests an extensive transport of fluid from the sinusoids into the perivascular spaces. Neurons, their processes and endings are present in the perivascular spaces, indicating an endocrine function to this neural structure. Scanning electron microscopy coupled with x‐ray analysis reveals the dense granules in argyric animals to contain both silver and sulfur, thus suggesting that much if not all of the stored silver is in the form of its sulfide.
Connections of the anterior commissure in the pigeon (Columba livia)
Authors: Zeier Hans J. , Karten Harvey J. 
Published: May 2005

Abstract
The projections of the anterior commissure of the pigeon (Columba livia) were studied experimentally using the Fink‐Heimer methods. The anterior commissure was sectioned immediately to one side of the midline, and animals sacrificed from 2 to 17 days post‐operatively.
The anterior commissure divides into two major fascicles on crossing the midline: a relatively diffuse anterior medial branch (or pars bulbaris), and a more compact laterally directed posterior branch (the pars temporalis).
The pars bulbaris passes rostrally medial to the lateral forebrain bundle (FPL), terminating, in course, in an area ventrolateral to the nucleus accumbens, the lobus parolfactorius, the dorsal portions of the olfactory tubercle, and in restricted regions on the medial edge of PA, neostriatum, and hyperstriatum ventrale. At the rostral end of the telencephalon the pars bulbaris converges with the pars temporalis in the region of the hyperstriatum intercalatus superior (HIS).
The pars temporalis of the anterior commissure terminates in the anterior one‐third of the contralateral archistriatum. Numerous fibers leave the archistriatum and follow two separate trajectories: a dorsolaterally projecting pathway terminating in the temporo‐parieto‐occipital corticoid area (TPO of Edinger 1903), which continues anterolaterally to HIS; a ventrolateral rostrally directed path which parallels the tractus fronto‐archistriaticus, terminating in the deep layers of the piriform cortex. At rostral levels this latter bundle turns dorsally to merge with the anteromedial and dorsolateral trajectories in the region of HIS.
The pattern of termination in the archistriatum indicates the presence of several discrete subnuclei within the anterior archistriatum. A tentative terminology is suggested for the major subdivisions of the anterior archistriatum.
There were no commissural projections to those specific sensory neuronal fields in direct receipt of thalamic efferents such as the ectostriatum, Field L or the visual wulst.
The structure of the dorsal lateral geniculate nucleus in the mouse. A golgi and electron microscopic study
Authors: Rafols Jose A. , Valverde F. 
Published: May 2005

AbstractTwo types of neurons have been distinguished in Golgi and electron microscopic preparations of the dorsal lateral geniculate nucleus of young mice. In addition to a thalamo‐striate relay cell (TSR neuron) with brush‐like dendritic arbors and a thick, unbranched axon, a small tomedium size cell (PA neuron) of oval or spindle shaped body and few, long and seldom branched dendrites is frequently identified in our Golgi preparations. This second type of cell may exhibit none, one or several sparsely branched axon‐like processes which terminate in the vicinity of the cell body. The dendrites of the PA neurons show characteristically large, spheroidal processes (p) 1–3 m̈ in diameter issuing forth singly, in clusters or as a “string of beads” from delicate, often long, pedicles attached to the dendritic shafts. Profiles comparable to these processes and in apparent continuity with PA dendrites have been identified with the electron microscope and show synaptic vesicles and a system of sacs of smooth E.R. The portions of the dendrites from which these vesicle‐containing processes issue also show clusters of vesicles, ribosomes and an orderly array of microtubules.Golgi impregnated axons are followed from the optic tract and seen terminating as irregular enlargements (2–6 m̈) on proximal dendrites of relay cells and on distal dendrites of the PA neuron. The intimate contact of the terminal branches of an optic collateral with a distal PA dendrite is carefully illustrated. Small calibered axons are likewise traced from the internal medullary lamina and seen to end by means of end‐knobs on distal dendrites of both types of neurons.Electron microscopic observations substantiate the Golgi images and reveal three different types (I, II, III) of endings in the geniculate neuropil. The large type I endings correspond to the retinal afferents which generally make asymmetric synapti contact with type II profiles and/or with clusters of microspines on the TSR dendrites. Type II, thought to be the spheroidal dendritic appendages of the PA neurons, form symmetrical synaptic contacts with profiles of its own kind or more commonly with dendrites of the TSR neuron. The type III ending, probably cortical in origin, establishes asymmetrical synaptic contacts with small dendritic profiles. Only profiles of types I and II endings, together with those of other dendritic profiles, form part of the nest‐like junctions known as the synaptic glomeruli. The significance of the unusual polarization of the geniculate interneurons is discussed.
Genesis of glioblasts in the human spinal cord as revealed by Feulgen cytophotometry
Authors: Fujita S. 
Published: May 2005

AbstractTo study gliogenesis in the spinal cord, Feulgen cytophotometry was carried out on cells in the cervical cord of human embryos ranging from 7–45 mm in crown‐rump length. Glioblasts synthesizing DNA are first detectable at eight‐week‐stage in the mantle and marginal zones in the basal plate and immediately thereafter in the alar plate. Coincidentally the matrix layer changes into a single‐layered ependymal lining. This pattern of the incipient stage of gliogenesis in the human spinal cord closely resembles that of the chick embryo.Silver carbonate staining of the spinal cord at this stage showed diverse morphology of the glioblasts at their earliest stage of differentiation. The pattern of glioblast formation coincides with that of the genesis of the so‐called microglioblasts so far reported, not only in the space‐time relationships in embryogenesis but also in the morphology of the cells occurring at this stage. It is concluded that the so‐called genesis of the microglia in the spinal cord is nothing but the stage of glioblast formation from the matrix cells.
The central connections of the anterior lateral line nerve of Gnathonemus petersii
Authors: Maler L. , Karten H. J. , Bennett M. V. L. 
Published: May 2005

AbstractThe central connections of the lateral line nerve ganglia, the eithth nerve ganglia and the fused fifth‐seventh ganglion of Ganathonemus petersii have been studied with silver degeneration techniques. The anterior (NLLa) and posterior (NLLp) lateral line nerves have a topographically organised projection upon the posterior lateral line lobe. NLLa, representing the head region, distributes to the rostral half of the posterior lobe, while NLLp, representing the trunk, distributes to the caudal half of the posterior lobe. The lateral line nerves also end in the anterior nucleus of the anterior lobe. There is some overlap within the middle third of the anterior nucleus, although NLLp tends to have a more caudal distribution than NLLa. N VIII terminates within n. tangentialis and n. octavius; there appears to be little or no overlap between VIII and lateral line nerve territories.The V–VIIth ganglion projects to entirely different parts of the brainstem. Terminal areas of V–VII are the sensory nucleus of the vagus, the nucleus of the descending trigeminus, and the funicular nuclei.
Time of neuron origin in the hippocampus and dentate gyrus of normal and reeler mutant mice: An autoradiographic analysis
Authors: Caviness V. S. 
Published: May 2005

AbstractThe hippocampus and dentate gyrus of reeler mutant mice contain the normal neuronal classes. The majority of cells are included in laminar aggregates reminiscent of normal structure though these are irregular in outline, interrupted at points, and less densely packed. Many hippocampal neurons and granule cells of the dentate gyrus are scattered in the external plexiform zone (strata radiatum and lacunosum‐moleculare) of the hippocampus rather than being included in the laminar aggregates.Neurons in the reeler are generated at the same time as their normal homologs. However, the relationship of adult cell position to sequence of cell generation is abnormal in two general ways in the mutant. First, although in both the mutant and normal, cells in the external plexiform zone of the hippocampus are among the earliest formed, a relatively greater proportion of cells generated through a relatively longer embryonic time are destined to be scattered in this distal location in the mutant. Secondly, within the laminar aggregates of the hippocampus in reeler, the more superficial cells tend to be formed earlier, and the more deeply located ones are the latest formed. A reversed relationship exists in the normal in which the deepest cells are formed earliest, the more superficial ones last. The observations are consistent with the view that a mechanism which provides for orderly lamination of cells in the normal is defective in reeler.
Organization of pallidothalamic projections in the rhesus monkey
Authors: Kuo Jon‐Son , Carpenter Malcolm B. 
Published: May 2005

AbstractAttempts were made to: (1) define the regions of origin of the ansa lenticularis (AL) and the lenticular fasciculus (LF), and (2) determine if particular regions of the medial pallidal segment (MPS) project in an organized fashion to thalamic nuclei. The MPS was divided into rostral and caudal (by a plane through the LF), dorsal and ventral (by an appropriate plane), and medial and lateral (by the accessory medullary lamina) parts. Attempts were made to categorize various lesions of the MPS and degeneration was studied in transverse, sagittal and horizontal sections stained by the Nauta and Wiitanen technics. Corresponding Nissl‐stained sections were used to delineate thalamic nuclei.Localized lesions in portions of the MPS (11 rostral and 10 caudal) were worthy of anatomical analysis in 21 monkeys. Data support the thesis that fibers of the AL arise predominantly from the outer part of the MPS and pass ventrally and medially through portions of the inner part of the MPS to their site of emergence. Fibers of the LF appear to arise from the inner part of the MPS and project dorsomedially through the internal capsule.Pallidothalamic projections to the rostral ventral tier thalamic nuclei [the ventral anterior (VApc) and the ventral lateral (VLo)] appear topographically organized in three cardinal dimensions. Rostral parts of the MPS project pre‐dominantly to parts of VApc, while caudal parts of the MPS project primarily to parts of VLo. There also is a dorsoventral and mediolateral correspondence in the pallidal projection to VApc and VLo which exhibits overlap. Pallidothalamic projections to the contromedian nucleus (CM) terminate preponderantly in rostral and medial regions of the nucleus, and there appears to be a definite correspondence between parts of the MPS and parts of CM, only in the dorsoventral dimension.
Brain mechanisms and feeding behavior in the pigeon (Columba livia) I. Quinto‐frontal structures
Authors: Zeigler H. Philip , Karten Harvey J. 
Published: May 2005

AbstractLesions were placed stereotaxically in the principal sensory trigeminal nucleus (PrV), the quinto‐frontal tract (QFT) and the nucleus basalis (NB) of the pigeon and their effects upon food and water intake were studied. Bilateral lesions of these three “quinto‐frontal” structures are followed by periods of aphagia and by a hypophagia whose persistence and severity are approximately proportional to the bilateral extent of the lesion. Such lesions also disrupt the neurosensory control of the consummatory response of feeding.No effects upon food or water were seen following control lesions placed in a wide variety of regions at several levels of the brain, including the hypothalamus. Moreover, despite their marked effects upon feeding behavior, lesions of quinto‐frontal structures do not impair drinking.The results have helped clarify previous studies of forebrain mechanisms in feeding behavior and they suggest that PrV, QFT and NB are afferent components of a network of structures controlling feeding behavior in the pigeon.
Degeneration and regeneration of severed crayfish sensory fibers: An ultrastructural study
Authors: Nordlander Ruth H. , Singer Marcus 
Published: May 2005

AbstractIn crayfish peripheral nerve, terminal processes of most sensory fobers degenerated within two to three weeks of nerve severance. First, large clear vesicles appeared in the axoplasm which subsequently lost its substructure, became more dense and compact, and was finally reduced to dense inclusions within glial cytoplasm. Considerable traumatic degeneration was also observed in proximal segments of severed axons. The rate of fiber degeneration was generally more rapid in the smallest fibers and slower in the larger intermediate axons. Large numbers of regenerating axons were first seen crossing the lesion site after four weeks. Growing fibers, found in bundles wrapped by glial processes, were at first small and tightly packed with no glial processes separating them. Later fibers enlarged and acquired wrapping patterns typical of normal sensory fibers. Growth cones were observed during early stages of regeneration. Some secondary degeneration may occur.
Maturation of oligodendroglia and myelinogenesis in rat optic nerve: A quantitative histochemical study
Authors: Hirose Genjiro , Bass Norman H. 
Published: May 2005

AbstractMicrochemical techniques correlated with histologic observations were used to study rat optic nerve at 5, 10, 15, 20, 30, 40 and 50 days of postnatal development. Cell enumeration was accomplished by combining DNA as says with previously reported differential cell counts in electron microscopic montages (Vaughn, '69). At 5 days of age, the optic nerve contained unmyelinated axons, and its volume and total number of glia (DNA) were less than 40% of 50‐day‐old values. The cell population was composed of equal numbers of fibrous astrocytes and glial stem cells but contained only 7% oligodendrocytes. Between 5 and 20 postnatal days, mitotic proliferation of these stem cells resulted in a 3‐fold increase of DNA, while numbers of oligodendroglia increased 10‐fold. The cell population of the nerve at 20 postnatal days was similar to that found in the adult, with oligodendrocytes constituting 60% of the total cell population. Although these cells continuously formed myelin throughout postnatal development, their maximal rate of myelin lipid deposition (cerebrosides and cholesterol) occurred between 5 and 20 postnatal days. Hence, the most rapid rate of myelinogenesis in rat optic nerve occurred during the first three weeks of postnatal life and was synchronous with the mitotic proliferation and cellular differentiation of interfascicular oligodendroglia.