bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dendritic arbors of spiny neurons in the primate striatum are directionally polarized
Authors: Walker Ruth H. , Graybiel Ann M. 
Published: January 2005

AbstractDespite the relatively unfeatured cytoarchitecture of the striatum, this large subcortical region has been found to have a modular macroscopic substructure comprising the neurochemically distinct striosomes and matrix, and, within the matrix, patchy input and output arrangements called matrisomes. In the study reported here, we explored the possibility that the cellular architecture of the striatum is also more specialized than previously suspected. We injected medium spiny neurons in lightly fixed slices of the squirrel monkey caudate nucleus, reconstructed their dendritic arbors, and analyzed the orientations of these arbors with respect to the cardinal planes of the striatum. The data were unequivocal in suggesting that many spiny neurons, whether near striosomes or not, have dendritic arbors with preferred orientations along a diagonal axis running from rostral, dorsal, and medial to caudal, ventral, and lateral. This axis corresponds to the orientations of many striosomes and matrisomes in the squirrel monkey's caudate nucleus. We therefore suggest that the primate striatum is characterized not only by a macroscopic organization dividing it into striosomes and matrisomes, but also by a microscopic architecture observed by the dendritic arbors of many of its projection neurons. We obtained comparable supplementary observations for the ferret caudate nucleus, suggesting that such spatial alignment of spiny dendritic arbors may be a general feature of striatal organization. These polarized dendritic arrangements could provide a cellular framework for compartmental input‐output processing within the striatum. © 1993 Wiley‐Liss,Inc.
Neurotoxic effects of neonatal injections of monosodium L‐glutamate (L‐MSG) on the retinal ganglion cell layer of the golden hamster: Anatomical and functional consequences on the circadian system
Authors: Chambille I. , Serviere J. 
Published: January 2005

AbstractIn rodents, daily injection of neurotoxic monosodium L‐glutamate (MSG) during the postnatal period induces retinal lesions, optic nerve degeneration with an alteration of visual pathway and an absence of the b‐wave in the electroretinogram. Despite this damage, electrophysiological responses subsist in the lateral geniculate bodies and synchronization of circadian rhythms to the light/dark cycle can still occur. Using two formal properties of the circadian system (entrainment and phase‐shift by light), we assessed the functionality of retinal projections to the circadian clock in MSG‐treated hamsters. Displaced amacrine and ganglion cell populations were quantified and retinal terminals in the suprachiasmatic nuclei were estimated. Animals received daily doses of glutamate during the first ten days after birth according to two protocols. The two treatments similarly destroyed 56% of the overall population of the ganglion cell layer: 30% of displaced amacrine and 89% of ganglion cells. Surviving ganglion neurons (7,500 cells) were evenly distributed across the entire retina except in one area of high cell density located in the temporoventral quadrant. Retinal projections of the “image‐forming” pathway were drastically reduced in the dorsal lateral geniculate bodies, less in their ventral part. The “nonimage‐forming” pathway was also affected since the volume of labeled terminals in the suprachiasmatic nuclei was reduced by one‐half to one‐third. Nevertheless, treated hamsters exhibited a free‐running locomotor activity rhythm after several months in constant darkness, could be entrained by the light/dark cycle and phase‐shifted by light pulses. These results suggest that a damaged retinohypothalamic tract can still assume the photic entrainment of the circadian clock. 1993 Wiley‐Liss, Inc. © 1993 Wiley‐Liss, Inc.
Prenatal development of the retinohypothalamic pathway and the suprachiasmatic nucleus in the sheep
Authors: Torrealba F. , Parraguez V. H. , Reyes T. , Valenzuela G. , Serón‐Ferré M. 
Published: January 2005

AbstractCircadian rhythms are present during fetal life in several mammalian species. To characterize the ontogeny of the neural mechanisms that account for circadian rhythmicity in a precocious species, we studied the prenatal development of the retinohypothalamic pathway in lambs (gestation period of 147 days), using horseradish peroxidase and wheat germ agglutinin as anterograde tracers. The suprachiasmatic nucleus was present as early as embryonic day 52 (E52). After E58, the suprachiasmatic nucleus reached its full number of neurons, estimated by the disector method in about 160,000 cells per nucleus at E62. The retinohypothalamic axons invaded the suprachiasmatic nucleus from E58, while neuroblasts were still migrating to the nucleus. At E62, there was a strong retinal projection that evolved until E121, when the retinal afferents established their definitive pattern of distribution in the ventral and central regions of the suprachiasmatic nucleus, and adjacent hypothalamic structures. The development of the retinohypothalamic pathway was delayed by about a week relative to the innervation of other subcortical visual centers.The present findings demonstrated an early prenatal development of the visual pathways in lambs, including the retinohypothalamic pathway, suggesting that the mechanisms for the visual entrainment of circadian rhythms in lambs may be functioning several weeks before birth. © 1993 Wiley‐Liss, Inc.
Serotonin‐like immunoreactivity in the adult and developing retina of the leopard frog Rana pipiens
Authors: Liu Qin , Debski Elizabeth A. 
Published: January 2005

AbstractRecent work in nonmammalian vertebrate retinas has suggested that other cell types besides the generally accepted amacrine cells may contain serotonin. We have used immunocytochemical methods to study serotonin‐like immunoreactivity (5‐HTLI) in the retina of the developing and mature frog Rana pipiens. In the adult, two types of serotonin immunoreactive (5‐HT‐ir) cells were found in the inner nuclear layer (INL) of the retina. Additionally, a large population of cells in the retinal ganglion cell layer (RGCL) had 5‐HTLI. These cells were grouped into three types based on their soma size and their primary dendritic branching pattern. The optic nerve fiber layer was also intensely stained with serotonin antisera although staining intensity decreased progressively as the fibers approached the optic nerve head. Severing the optic nerve resulted in 5‐HT‐ir elements that extended up the optic nerve shaft from the lesion site toward the retina. Both regional and temporal changes in the pattern of 5‐HTLI were seen. In middle regions of retina, approximately 30% of the cells in the RGCL were 5‐HT‐ir. Nasal and temporal regions of central retina had significantly fewer 5‐HT‐ir cells. Early in development only scattered cells in the RGCL were 5‐HT‐ir. As the animals matured there was an increase in both the proportion and the staining intensity of these cells. Our results suggest that in studying the function and development of the visual system in this animal, the role of serotonin must be examined. © 1993 Wiley‐Liss, Inc.
Localization of NADPH diaphorase in the lumbosacral spinal cord and dorsal root ganglia of the cat
Authors: Vizzard Margaret A. , Erdman Susan L. , Erickson Vickie L. , Stewart Robert J. , Roppolo James R. , De Groat William C. 
Published: January 2005

AbstractThe distribution of NADPH‐d activity in the spinal cord and dorsal root ganglia of the cat was studied to evaluate the role of nitric oxide in lumbosacral afferent and spinal autonomic pathways. At all levels of the spinal cord NADPH‐d staining was present in neurons and fibers in the superficial dorsal horn and in neurons around the central canal and in the dorsal commissure. In addition, the sympathetic autonomic nucleus in the rostral lumbar segments exhibited prominent NADPH‐d cellular staining whereas the parasympathetic nucleus in the sacral segments was not well stained. The most prominent NADPH‐d activity in the sacral segments occurred in fibers extending from Lissauer's tract through laminae I along the lateral edge of the dorsal horn to lamina V and the region of the sacral parasympathetic nucleus. These fibers were very similar to VIP‐containing and pelvic nerve afferent projections in the same region. They were prominent in the S1–S3 segments but not in adjacent segments (L6–L7 and Cx1) or in thoracolumbar and cervical segments. NADPH‐d activity and VIP immunoreactivity in Lissauer's tract and the lateral dorsal horn were eliminated or greatly reduced after dorsal‐ventral rhizotomy (S1–S3), indicating the fibers represent primary afferent projections. A population of small diameter afferent neurons in the L7–S2 dorsal root ganglia were intensely stained for NADPH‐d. The functional significance of the NADPH‐d histochemical stain remains to be determined; however, if NADPH‐d is nitric oxide synthase then this would suggest that nitric oxide may function as a transmitter in thoracolumbar sympathetic preganglionic efferent pathways and in sacral parasympathetic afferent pathways in the cat. © 1994 Wiley‐Liss, Inc.
Colocalization of excitatory and inhibitory neurotransmitter markers in striatal projection neurons in the rat
Authors: White Leonard E. , Hodges Harlan D. , Carnes Kenneth M. , Price Joseph L. , Dubinsky Janet M. 
Published: January 2005

AbstractThe principle neuronal output of the neostriatum comes from medium spiny neurons that project from the caudate/putamen to the globus pallidus and substantia nigra. Although current evidence generally indicates that γ‐aminobutyric acid (GABA) is the principal neurotransmitter in this pathway, this cannot account for the excitatory synaptic activity present among cultures of striatal neurons or the short latency excitatory postsynaptic potentials which often proceed or obscure inhibitory activity evoked by striatal stimulation. In this study, retrograde transport of [3H]D‐aspartate has been used to demonstrate striatopallidal and striato‐nigral neurons that possess a high‐affinity uptake system for glutamate and aspartate and are therefore putatively glutamatergic. Injections of [3H]D‐aspartate into the globus pallidus or substantia nigra, pars reticularis of the rat retrogradely labeled mediumsized neurons throughout the rostral‐caudal extent of the neostriatum. To characterize this population further, adjacent sections were immunoreacted with antibodies to either GABA, glutamic acid decarboxylase (GAD), calbindin, or parvalbumin prior to autoradiographic processing. Under these conditions, autoradiographically labeled neurons displayed positive immunoreactivity for GABA, GAD, or calbindin. Autoradiographic label did not colocalize with parvalbumin immunoreactivity. The colocalization of anatomical markers of GABAergic and glutamatergic neurotransmission raises the possibility that both neurotransmitters are functionally expressed within single striatal projection neurons. © 1994 Wiley‐Liss, Inc.
Corticofugal connections between the cerebral cortex and brainstem vestibular nuclei in the macaque monkey
Authors: Akbarian Schahram , Grüsser Otto‐Joachim , Guldin Wolfgang O. 
Published: January 2005

AbstractThe distribution of cortical efferent connections to brainstem vestibular nuclei was quantitatively analysed by means of retrograde tracer substances injected into different electrophysiologically identified parts of the brainstem vestibular nuclear complex of five Java monkeys (Macaca fascicularis). Three polysensory vestibular areas were found to have a substantial projection to the vestibular nuclei: area 2v located at the tip of the intraparietal sulcus, the parietoinsular vestibular cortex (PIVC) covering the most occipital part of the granular insula (Ig) and the retroinsular area (Ri or reipt), and the dorsolateral part of the somatosensory area 3a (“area 3aV” neck/trunk region). From physiological recording experiments, these three cortical fields were known to contain many neurons responding to stimulation of semicircular canals as well as to optokinetic (area 2v, PIVC) and somatosensory stimuli (PIVC, area 3a). These three regions form the inner cortical vestibular circuit. Besides these polysensory vestibular cortical fields, three other circumscribed cortical regions of the macaque brain were also found to project directly to the brainstem vestibular nuclei: a circumscribed part of the postarcuate premotor cortex (area 6pa), part of the agranular and the adjacent dysgranular cortex located around the cingulate sulcus (area 6c/23c), and a predominantly visual (optokinetic) association field located at the fundus of the lateral sulcus (area T3). These areas are known to have connections with the structures of the inner cortical vestibular circuit. Only a few efferent connections to the brainstem vestibular nuclei were found for the different parts of cytoarchitectonic area 7. Significant differences were found between the efferent innervation patterns of the axons originating in the six cortical areas mentioned and ending in the various compartments of the vestibular nuclear complex. Vestibular nuclei with a dominant output to the gaze motor system of the brainstem receive efferent connections preferably from the parietoinsular vestibular cortex. Vestibular structures with their primary output to skeletomotor centers, however, receive stronger efferent connections from areas 6pa and 3a. The ventrolateral nucleus, which sends efferent axons to both the oculomotor and skeletomotor systems of the brainstem and the spinal cord, also receives its main cortical efferents from the somatomotor area 6 and from area 3aV. Through these connections the cortical somatomotor system may directly influence vestibuloocular and vestibulocollic reflexes. It is speculated that the corticofugal connections to the vestibular brainstem nuclei are predominantly inhibitory, suppressing vestibular reflexes during cortically controlled goal‐directed movements. © 1994 Wiley‐Liss, Inc.
Reorganization of visual interneurons during metamorphosis in the swallowtail butterfly Papilio xuthus
Authors: Ichikawa Toshio 
Published: January 2005

AbstractThe metamorphic fate of larval visual interneurons in the swallowtail butterfly Papilio xuthus has been examined by using reduced silver impregnation and immunocytochemistry of γ‐amino butyric acid (GABA). Visual interneurons in the second larval optic neuropile (medulla) can be followed throughout metamorphosis because of large somata located in the anterior edge of the imaginal medulla. Ten to 12 neurons in the larval medulla were immunoreactive to a GABAantiserum. They arborize in the larval medulla and extend dendritic processes to the first larval optic neuropile (lamina). After pupation, the medulla neurons lose GABA‐immunoreactive larval processes and differentiate new processes that enter tangentially into the developing imaginal medulla. Axons of the surviving larval neurons follow an optic tract between the lobula and the lobula plate and extend to the lateral area of the protocerebrum. Thus, larval visual interneurons are incorporated into the imaginal optic lobe and may play a new role in the visual processing of the butterfly. © Wiley‐Liss, Inc.
Inverse patterns of myelination and GAP‐43 expression in the adult CNS: Neurite growth inhibitors as regulators of neuronal plasticity?
Authors: Kapfhammer Josef , Schwab Martin E. 
Published: January 2005

AbstractIn the central nervous system (CNS) myelin is present not only in white matter, but also in varying amounts in many gray matter areas. In addition to the function of electrical insulation of axons, myelin and oligodendrocytes contain molecules that are powerful inhibitors of neurite growth. Nevertheless plastic changes involving sprouting of nerve terminals occur in several brain regions of adult animals after partial lesions. In this study we have tried to correlate the plastic potential of CNS regions with the degree of their myelination. The expression of the growth‐associated protein GAP‐43 was used as an indicator of the potential for plastic changes, and a histological myelin stain was used to assess myelination. We have found that myelination and GAP‐43 expression have strikingly inverse expression patterns in the majority of CNS gray matter areas. Densely myelinated regions, that is, most brainstem nuclei, the tegmentum, and the inferior colliculus, are low in GAP‐43. In contrast, unmyelinated or lightly myelinated areas, such as the substantia gelatinosa of the spinal cord, the nucleus of the solitary tract, or the septum, express high levels of GAP‐43. Areas known to show lesion‐induced sprouting are typically high in GAP‐43 and only lightly myelinated. During postnatal development the myelination pattern precedes the GAP‐43 pattern, a sequence that is consistent with a role of myelin and the associated neurite growth inhibitors in modifying GAP‐43 expression.Our results support the hypothesis that myelin‐associated neurite growth inhibitors are involved in regulating the stability of neural connections. © Wiley‐Liss, Inc.
Localization of preganglionic neurons of the accessory ciliary ganglion in the midbrain: HRP and WGA‐HRP studies in the cat
Authors: Kuchiiwa Satoshi , Kuchiiwa Toshiko , Nakagawa Shiro 
Published: January 2005

AbstractLocalization of preganglionic neurons of the accessory ciliary ganglion (ACG), including ectopic intraocular ganglion cells, was investigated in the cat with the aid of horseradish peroxidase (HRP) and HRP‐conjugated wheat germ agglutinin (WGA‐HRP) methods. When HRP or WGA‐HRP was injected into the anterior and posterior chambers of the eye, no retrogradely labeled cells were found in the visceral oculomotor nuclei, although most neurons of the ACG and the main ciliary ganglion (CG) were intensely labeled. When a microsyringe needle was inserted into the ciliary body, the tracer diffused into the suprachoroid lamina and the intraocular ganglion cells, and a small number of labeled neurons appeared in the midplane between each side of the somatic oculomotor nuclei. After injection into the ACG, many labeled neurons were observed in the anteromedian nucleus, Edinger‐Westphal nucleus, and midplane between the somatic oculomotor nuclei, their ventral continuations of the ventral tegmental area, and the periaqueductal gray. HRP /WGA‐HRP injection into the CG labeled cells in all these areas and in the lateral border zones of the anteromedian, Edinger‐Westphal and somatic oculomotor nuclei, and their ventral continuations of the ventral tegmental area. These findings indicate that the visceral oculomotor neurons which project to the ACG tend to be located more medially than those to the CG. © Wiley‐Liss, Inc.
Map of the synapses formed with the dendrites of spiny stellate neurons of cat visual cortex
Authors: Anderson John C. , Douglas Rodney J. , Martin Kevan A. C. , Nelson J. Charmaine 
Published: January 2005

AbstractThe synaptic input of six spiny stellate neurons in sublamina 4A of cat area 17 was assessed by electron microscopy. The neurons were physiologically characterized and filled with horseradish peroxidase in vivo. After processing the neurons were reconstructed at the light microscopic level using computer‐assisted methods and analyzed quantitatively. The extensive branching of the dendritic tree about 50 μm from the soma meant that the distal branches constituted five times the length of proximal dendrite. Proximal and distal portions of a single dendrite from each neuron were examined in series of ultrathin sections (1,456 sections) in the electron microscope. The majority (79%) of the 263 synapses examined were asymmetric; the remainder (21%) were symmetric. Symmetric synapses formed 35% of synapses sampled on proximal dendrites and were usually located on the shaft. They formed only 4% of synapses sampled on distal dendrites. Spines accounted for less than half of the total asymmetric synapses (45%); the remainder were on shafts. Symmetric synapses formed with four of 92 spines. Nine spines formed no synapses. Spiny stellate neurons in cat visual cortex appear to differ considerably from pyramidal neurons in having a significant asymmetric (excitatory) synaptic input to the dendritic shaft.
Ultrastructural organization of GABA in the rabbit superior colliculus revealed by quantitative postembedding immunocytochemistry
Authors: Mize R. Ranney , Whitworth Richard H. , Nunes‐Cardozo Bob , Want Johannes Van Der 
Published: January 2005

AbstractWe have studied the organization of gamma‐aminobutyric acid (GABA)ergic profiles in the superior colliculus of the rabbit to determine whether the synaptic types found in cat and monkey also exist in a mammalian species whose visual system has a different organization. Ultrastructure of GABAergic profiles was examined by use of a polyclonal antibody to GABA and quantitative postembedding immunocytochemistry.Three distinct types of vesicle‐containing profiles were labeled by the GABA antibody in the rabbit superior colliculus. One type was a putative presynaptic dendrite (PSD profile) that received synaptic input from other profiles and contained pleomorphic synaptic vesicles scattered throughout the profile. These PSD profiles frequently received retinal input and formed dendrodendritic synapses. A second type of profile was a large caliber dendrite, often horizontal in orientation (H profile), that had one or more discrete clusters of pleomorphic synaptic vesicles at sites of synaptic contact with conventional dendrites. These H profiles received few synaptic contacts. A third profile type was a putative axon terminal (F profile) with smaller, more flattened synaptic vesicles that densely and uniformly filled the profile. Quantitative analysis of gold particle density revealed that F profiles had a significantly higher gold particle density (14.3/ μm2) than did PSD or H profiles (10.4 and 10.2/ μm2), suggesting that GABAergic profile types contain different concentrations of GABA. The vesicle density of these profile types also differed, but no obvious relationship between vesicle and particle distributions was observed. We conclude that the profiles labeled by GABA in rabbit superior colliculus are similar to those in cat and monkey and must represent a phylogenetically conserved organization common to many mammals, and that particle density analysis of postembedding immunocytochemistry can distinguish different GABAergic profile types.