bluuebunny/crossref_metadata_2025_split huggingface dataset:
Branching of sensory axons in the dorsal root and evidence for the absence of dorsal root efferent fibers
Authors: Langford Lauren A. , Coggeshall Richard E. 
Published: January 2005

AbstractThe present study demonstrates that there are more dorsal root axons than dorsal root ganglion cells in the L6‐S1 dorsal roots of the rat. The excess fibers do not come from aberrant dorsal root ganglion cells and our control procedures indicate that there are no extraneous fibers in these dorsal roots. Accordingly many dorsal root axons must branch in the dorsal root.
Sources of subcortical projections to the superior colliculus in the cat
Authors: Edwards Stephen B. , Ginsburgh Charles L. , Henkel Craig K. , Stein Barry E. 
Published: January 2005

AbstractA comprehensive search for subcortical projections to the cat superior colliculus was conducted using the retrograde horseradish peroxidase (HRP) method. Over 40 different subcortical structures project to the superior colliculus. The more notable among these are grouped under the following categories.Visual structures: ventral lateral geniculate nucleus, parabigeminal nucleus, pretectal area (nucleus of the optic tract, posterior pretectal nucleus, nuclei of the posterior commissure).Auditory structures: inferior colliculus (external and pericentral nuclei), dorsomedial periolivary nucleus, nuclei of the trapezoid body, ventral nucleus of the lateral lemniscus.Somatosensory structures: sensory trigeminal complex (all divisions, but mainly the γ division of nucleus oralis), dorsal column nuclei (mostly cuneate nucleus), and the lateral cervical nucleus.Catecholamine nuclei: locus coeruleus, raphe dorsalis, and the parabrachial nuclei.Cerebellum: medial, interposed, and lateral nuclei, and the perihypoglossal nuclei.Reticular areas: zona incerta, substantia nigra, midbrain tegmentum, nucleus paragigantocellularis lateralis, and the hypothalamus.Evidence is presented that only the parabigeminal nucleus, the nucleus of the optic tract, and the posterior pretectal nucleus project to the superficial collicular layers (striatum griseum superficiale and stratum opticum), while all other afferents terminate in the deeper layers of the colliculus. Also presented is information concerning the rostrocaudal distribution of some of these afferent connections. These findings stress the multiplicity and diversity of inputs to the deeper collicular layers, and more specifically, identify multiple sources of the physiologically well‐known representations of the somatic and auditory modalities in the colliculus.
Tectal projections in the goldfish (Carassius auratus): A degeneration study
Authors: Grover B. G. , Sharma S. C. 
Published: January 2005

AbstractEfferents revealed by degeneration staining following tectal lesions in goldfish are presented. Four major projections were found.Ascending ipsilateral projections to pretectal‐diencephalic areas exit the tectum rostrally and laterally and terminate in the area pretectalis (AP), lateral geniculate (LGN), nucleus pretectalis (NP), and nucleus rotundus (NR). Ascending contralateral projections exit rostrally and possibly laterally, enter the posterior and postoptic commissures and terminate in the contralateral AP, LGN, NP, NR and rostral tectum. A medially directed projection enters the intertectal commissure, and some of these fibers may terminate sparsely in an area of the contralateral tectum homotopic to the lesion. A descending projection exits the tectum laterally and projects ipsilaterally to a dorsolateral tegmental nucleus (DLT) and the lateral reticular formation of the tegmentum and pons, and contralaterally to the medial reticular formation of the tegmentum and pons.
Synaptogenesis in the cervical cord of the human embryo: Sequence of synapse formation in a spinal reflex pathway
Authors: Okado Nobuo , Kakimi Shigeo , Kojima Tokuzo 
Published: January 2005

AbstractSynaptogenesis in the cervical cord was studied by light and electron microscopy in human embryos ranging from four to seven weeks of ovulation age. The stage of embryonic development was estimated on the basis of external morphology of embryos and histology of the eye ball with reference to Streeter's horizon. No synapses were found in the cervical cord of the embryo at Streeter's horizon XIV (8 mm; estimated ovulation age, 28‐30 days). A small number of axodendritic synapses appear in the motor neuropil of the cervical cord at Streeter's horizon XVII (14 mm; estimated ovulation age, 34‐36 days). Since no primary afferents are demonstrated to reach the motor neuropil at this stage (the premotile period), these synapses are considered to be formed between interneurons and motor neurons. On the other hand, the formation of synapses outside the motor neuropil of the cervical cord was recognized at Streeter's horizon XX (22 mm; estimated ovulation age, 40‐42 days), which corresponded to the period of onset of the precocious reflex, but not by horizon XIX (18 mm; estimated ovulation age, 38‐40 days). The first axosomatic synapses were found in the motor neuropil at Streeter's horizon XVII (estimated ovulation age, 34‐36 days). The present study suggests that the formation of synapses between interneurons and dendrites of spinal motor neurons precedes that of synapses between interneurons and collaterals of primary afferents. This sequence of synaptogenesis is in agreement with that reported in earlier studies with silver stain methods.
The sensory component of the facial nerve of a reptile (Lacerta viridis)
Authors: Jacobs Virgil L. 
Published: January 2005

AbstractThe sensory fibers of the facial nerve in Lacerta viridis have been studied with a silver impregnation method to follow the course of axonal degeneration. Destruction of the geniculate ganglion demonstrated the degenerated sensory component of the facial nerve adjacent to the anterior vestibular root. Within the lateral vestibular area the facial sensory fibers consist of numerous rootlets separated by vestibular fibers and cells. These rootlets may join to form a main or paired sensory tract that passes through the vestibular nuclei to enter the tractus solitarius and divide into a small ascending prefacial component and a major descending prevagal division. A few fibers continue into the postvagal part of tractus solitarius and extend caudally to terminate in the nucleus commissura infima. Prefacial fibers terminate along the periventricular gray while prevagal fibers terminate within the tractus solitarius on the dendrites of cells of nucleus tractus solitarius and near the periphery of the dorsal motor nucleus of X. There was no noticeable degeneration in the descendens tractus trigemini. Terminal degeneration to descendens nucleus trigemini and motor nucleus of VII followed the tractus solitarius course. Most facial sensory fibers are probably related to taste and other visceral information.
Anatomical organization of the primary visual cortex (area 17) of the cat. A comparison with area 17 of the macaque monkey
Authors: Lund J. S. , Henry G. H. , Macqueen C. L. , Harvey A. R. 
Published: January 2005

AbstractGolgi and axonal transport techniques have been used to examine the organization of neurons within primary visual cortex, area 17, of the cat. This organization has been compared to that of the primate cortical area 17 as described in previous studies and it is discussed in relationship to the distribution of afferents from the dorsal lateral geniculate nucleus (dLGN). The visual cortex of the cat and monkey show strong similarities in the laminar positions of neurons projecting extrinscially and also in the restriction of spiny stellate neurons to a central lamina (lamina 4) receiving input from the dLGN. However, lamina 4B in the monkey, which contains spiny stellate neurons but does not receive direct input from the dLGN, has no direct counterpart in cat area 17. Axon projections of spiny stellate neurons in the other divisions of lamina 4 differ in cat and monkey: the small, closely packed neurons in the lowermost division of lamina 4 (4B in the cat, 4Cß in the monkey) project chiefly within lamina 4 in the cat whereas in the monkey they have a strong projection to lamina 3. In the cat, spiny stellate neurons of lamina 4A project upon lamina 3 whereas in the monkey those in the apparently equivalent zone, 4Cα, project upon lamina 4B. Most non‐spiny stellate neurons examined have precisely organized interlaminar axonal projections which differ from the axon trajectories of neighboring spiny neurons.
Electron microscopic studies of serially sectioned cat spinal α‐motoneurons. I. Effects of microelectrode impalement and intracellular staining with the fluorescent dye “procion yellow”
Authors: Berthold C‐H. , Kellerth J‐O. , Conradi S. 
Published: January 2005

AbstractCat spinal α‐motoneurons were studied in the light and electron microscope after intracellular recording and staining with the fluorescent dye Procion Yellow. Generally, the ultrastructural preservation of the stained neurons improved when the amount of dye delivered was decreased, and when the duration of the microelectrode impalement of the neuron as well as the time between the intracellular staining and the tissue fixation was kept as short as possible. Utilizing the optimal experimental procedure finally arrived at, about one‐third of the stained neurons could be used for further quantitative morphometric analysis. With respect to synaptology and gross architecture these cells appeared to differ from control motoneurons mainly with regard to a focal disarrangement of the cell body periphery, probably a result of the microelectrode injury, and a certain degree of damage to some large boutons.
Preservation of binocularity after monocular deprivation in the striate cortex of kittens treated with 6‐Hydroxydopamine
Authors: Kasamatsu Takuji , Pettigrew John D. 
Published: January 2005

AbstractThe results of single unit recordings from Area 17 of monocularly deprived kittens were compared with similar ones from littermates who had been monocularly lid‐sutured for the same period of time, but who had in addition been given intraventricular injections of 6‐hydroxydopamine (6‐OHDA) to deplete brain catecholamines. The visual cortices of all catecholamine‐depleted kittens showed high proportions of binocular neurons, in contrast to the control group, a majority of whose visual cortical neurons were driven exclusively by the non‐deprived eye. Preservation of binocularity in 6‐OHDA‐treated kittens was dose‐related. Even after a 1 to 2‐week period of lidsuture which reduced binocularity to 20% in controls, normal proportions of binocular neurons (>75%) were preserved if the cumulative dose had been 10 mg 6‐OHDA or more. The density of single neurons sampled from electrode tracks through the cortex of drug‐treated kittens was high and did not differ significantly from controls. Neurons were isolated every 100 μm on the average. There was some indication that the drug's effect in preventing an ocular dominance shift disappears by six weeks following cessation of 6‐OHDA treatment. This reversal of the physiological effects in cortex is preceded by recovery from the behavioral manifestations of 6‐OHDA treatments. Binocularity was only slightly increased in a kitten who received large doses of 6‐OHDA after a period of monocular deprivation. This observation, together with control recordings from normal kittens and adults treated with 6‐OHDA, indicates that the direct effects of 6‐OHDA on cortical neurons' response properties play a minor role in comparison to its effects in reducing the sensitivity of the cortex to monocular deprivation. The overwhelming majority of cortical neurons in 6‐OHDA‐treated kittens remained normal in receptive field properties after a period of monocular deprivation. These data support the hypothesis that catecholamines are required for the maintenance of visual cortical plasticity during the critical period.
Intracellular marking with Lucifer Yellow CH and horseradish peroxidase of cells electrophysiologically characterized as glia in the cerebral cortex of the cat
Authors: Takato Michiaki , Goldring Sidney 
Published: January 2005

AbstractIntracellular microelectrodes filled with either Lucifer Yellow CH, a highly florescent dye, or horseradish peroxidase (HRP) were used to electrophysiolgically characterize and mark cells in the cerebral cortex of cat. Fifty‐eight cells, characterized electrophysiologically as glia, were marked with Lucifer Yellow CH. All were identified as protoplasmic astrocytes, and included cells in the glia limitans of the molecular layer. An additional 54 cells, similarly characterized as glia, were labeled with HRP. The results were the same; only protoplasmic astrocytes were labeled. The “staining quality” of the glia labeled with HRP was superior to that of cells injected with Lucifer Yellow; greater lengths of individual processes were revealed, and they could often be followed to blood vessels where they ended on the walls of vessels with expanded perivascular end‐feet. The observations indicate that the many previously reported studies on presumed glial cells in the cat cerebral cortex have characterized the behavior of protoplasmic astrocytes.Neurons were also marked during these experiments. The “staining” quality of the Lucifer Yellow filled neurons was excellent; dendritic spines, axons, and axon collaterals were clearly visible. These fine neuronal details were not as well revealed after HRP labeling. High resting membrane potentials (RMPs) were not a prerequisite for obtaining well‐marked neurons (mean RMP of Lucifer Yellow filled neurons was −33.6 mV; mean RMP of HRP filled neurons was 42.3 mV). In contrast, the mean RMPs of Lucifer Yellow and HRP marked glia was −68 Mv and −75 mV respectively, and the quality of “staining” appeared to be more closely related to the RMP.
Excess DNA in the nuclei of the subseophagel region of octopus brain
Authors: De Marianis Bruna , Olmo Ettore , Giuditta Antonio 
Published: January 2005

AbstractCytophotometric analyses of Feulgen‐stained nuclei present in homogenates of vertical and subseophageal lobes of octopus brain have shown that the latter region contains larger nuclei with up to several times the amount of DNA present in vertical nuclei. No obvious relationship was found between DNA content and nuclear size. Except for a rather small minority, nuclei of the vertical lobe have a uniform size and the expected diploid amount of DNA. These parameters are not substantially dependent on body weight. In contrast, the DNA content of subesophageal nuclei increases progressively with body weight. The amount of DNA found in subesophageal nuclei does not seem to be a simple multiple of the diploid or haploid value.
The specificity of innervation of regenerating motor neurons in the cockroach
Authors: Whitington Paul M. 
Published: January 2005

AbstractThe pattern of neuromuscular connections of cockroach motor neurons regenerating to an intact mesothoracic leg after crushing nerve 5 has been investigated. While a number of anatomically identified motor neurons re‐established functional connections with their correct target muscles, some of the same and other motor neurons were found to functionally innervate inappropriate muscles. Muscles, and in some cases individual fibres, were often simultaneously innervated by both correct and foreign motor neurons. The frequency of innervation errors decreased with increasing post‐operative times, although some errors persisted to the latest stages examined (227 days).
Excitatory synaptic ensemble properties in the visual cortex of the macaque monkey: A current source density analysis of electrically evoked potentials
Authors: Mitzdorf U. , Singer W. 
Published: January 2005

AbstractThe spatio‐temporal distributions of excitatory synaptic ensemble activities in A17 and A18 of the visual cortex of the macaque monkey have been investigated. The synaptic activities were elicited by electrical stimulation of the primary afferents and were localized by applying the current source density analysis to the intracortically recorded field potentials. The principal results are as follows.
In A17, two groups of activity, evoked by fast and slow afferents, respectively, were distinguishable.
The fast afferents induce monosynaptic activity in layer IV Cα and layer VI, disynaptic activity in layer IV Cα and in the supragranular layers and trisynaptic activity in layer IV B.
The slow afferents induce monosynaptic activity in lower layer IV Cβ and layer VI, disynaptic activity via strong connections in upper layer IV Cβ, further disynaptic activity in layers III and IV B and trisynaptic activity in layers V A and II.
With the exception that the CSD data reveal more polysynaptic activity within layer IV, there is good agreement between the spatio‐temporal distribution of synaptic activities and the cortical circuit diagrams proposed in anatomical studies.
In A18, activities from the slow and fast conducting afferent systems are revealed in layer IV, both most likely mediated by the monosynaptically activated target cells of A17. These activities are passed on to the supra‐ and infragranular lavers.
In the lateral geniculate nucleus the safety factor of transmission is higher for activity conveyed by slow‐ than by fast‐conducting retinal afferents.
The spatial distribution of monocularly evoked surface potentials failed to reveal the ocular dominance columns.
Comparison with the cat indicates that, with respect to the intracortical circuitry and LGN‐transmission, there are more similarities between the fast‐group activity in the monkey and the x‐system in the cat and between the slow‐group activity in the monkey and the y‐system in the cat than vice versa.
Inteneuron circuits in the lateral geniculate nucleus of monocularly deprived cats
Authors: Mooney Richard D. , Dubin Mark Wm. , Rusoff Anne C. 
Published: January 2005

AbstractThis work investigated the function of interneurons and other types of cells in the lateral geniculate nucleus (LGN) in cats raised to adulthood with one eye sutured closed. In order to understand the basis of the commonly found deficit of Y‐type relay cells in the deprived layers of the LGN, we looked for reduced or defective activity in other cells which also receive an afferent projection from Y‐type ganglion cells in the visually deprived retina.Monocular deprivation did not produce a deficit in the activity of a class of interneurons which receive direct optic inputs from the same ganglion cells in the deprived eye that also drive the Y‐type relay cells. Likewise, the Y‐type afferent input from the deprived eye to XY‐type relay cells was normal. The XY‐type cells have mixed or hybrid receptive field properties and both X and Y excitatory inputs; although the Y‐inputs to these cells are often much weaker than the X‐inputs. The normal properties of Y‐type interneurons and XY‐type relay cells in the deprived LGN suggest that neither a retinal dysfunction nor an inherent inability of the Y‐type optic tract axons to form adequate synapses onto LGN neurons are factors which would readily account for the reduction of y‐type relay cells in monocularly deprived cats.The hypothesis that the deprived Y‐type relay cells may have difficulty in forming synaptic connections onto postsynaptic, binocular neurons was supported by observations of responses of cells in the perigeniculate region. Normally, perigeniculate neurons receive a strong binocular input from Y‐type relay cells as well as an X‐input in at least some cases. In binocular perigeniculate cells of the sutured cats, no inputs from deprived Y‐type relay cells could be identified although a longer latency input, typical of that from X‐type relay cells, was present.
Postnatal neurogenesis in the kitten retina
Authors: Johns Pamela Raymond , Rusoff Anne C. , Dubin Mark Wm. 
Published: January 2005

AbstractPostnatal neurogenesis in the kitten retina was studied using 3H‐thymidine radioautography. Kittens were injected with 3H‐thymidine at 1 day, 10 days, 3 weeks or 4 weeks after birth and allowed to survive until 14 weeks of age. Labeled neuronal nuclei were not found in the ganglion cell layer in any of the retinas, but they were seen in the other nuclear layers of the same retinas. In retinas from kittens injected at one day after birth, the peripheral 80% of the length of the retina (in sections cut parallel to the dorsoventral meridian) contained labeled nuclei; the central 20%, around the optic disc, contained no labeled nuclei. Near the ora serrata most nuclei in both inner and outer nuclear layers were labeled. Away from the ora serrata the proportion of labeled to unlabeled nuclei gradually decreased. Labeled nuclei extended farther centrally in the inner than the outer nuclear layer. The same pattern of labeling was repeated in retinas from kittens injected at ten days after birth, but fewer nuclei were labeled, and the central, unlabeled region around the optic disc was longer–55% of the length of the retina. Only a few nuclei near the ora serrata were labeled in retinas from kittens injected at three weeks after birth, and no labeled neurons were found in kittens injected at four weeks.From these results we conclude that all of the ganglion cells in the kitten retina are present by one day after birth, as are all of the other neurons in the central retina. In peripheral regions of the inner and outer nuclear layers, proliferation of cells destined to become neurons continues up to three weeks after birth.
The structural organization of the inferior and lateral subdivision of the Macaca monkey pulvinar
Authors: Ogren Marilee P. , Hendrickson Anita E. 
Published: January 2005

AbstractPrevious light microscopic studies of Macaca pulvinar have demonstrated that both the inferior and adjacent portion of the lateral pulvinar subdivisions are reciprocally connected to the entire occipital lobe, including striate cortex. They differ in that inferior but not lateral pulvinar receives a projection from the superficial layers of the superior colliculus. In this study, the internal organization of these two subdivisions is compared by relating light microscopic Golgi morphology to the synaptic organization observed by electron microscopy.The Golgi impregnated neurons in inferior and lateral pulvinar are typical of other thalamic nuclei and are not qualitatively different in the two subdivisions. Projection neurons (PN) vary in cell body (15–40 μm) and dendritic tree (150–600 μm) diameters but bear the same varieties of dendritic appendages; spine‐like, hair‐like, and knot‐like. Local circuit neurons (LCN) have smaller cell body diameters (10–20 μm) but can have very large dendritic field diameters (150–600 μm). They are best distinguished from PNs by their elaborate dendritic appendages, which have been identified as pre‐synaptic dendrites in the EM. LCN axons are infrequently seen.In the EM both subdivisions contain four types of synaptic terminals. RS and RL terminals both contain round synaptic vesicles and make asymmetric synaptic contacts, but are subdivided on the basis of small (RS = 0.09 μm) versus large (RL = 2.2 μm) cross sectional diameters and organelle content. RLs contact larger caliber dendrites and frequently form synaptic complexes with presynaptic dendrites of LCNs, while RSs contact fine caliber dendrites and rarely take part in synaptic complexes. F terminals and P boutons both contain flat and pleomorphic vesicles and make symmetric synaptic contacts. They are characterized by vesicle number and cytoplasmic density. Fs are infrequently observed in pulvinar compared to P boutons and are of uncertain origin. P boutons can be equated with LCN dendritic appendages and have been identified as pre‐synaptic dendrites. The quantitative distribution of each type is very similar in both subdivisions, averaging RS 85%, RL5%, F 0.3%, P 8% and unidentified 2%.