bluuebunny/crossref_metadata_2025_split huggingface dataset:
Physiological response properties of cells labeled intracellularly with horseradish peroxidase in cat dorsal cochlear nucleus
Authors: Rhode W. S. , Smith P. H. , Oertel D. 
Published: December 2004

AbstractThe physiology and morphology of fusiform cells in the dorsal cochlear nucleus were studied using extracellular and intracellular recording and intracellular injection of horseradish peroxidase. Fusiform cells displayed a variety of responses to tone pips presented at the characteristic frequency; most often these cells exhibited the pauser/buildup pattern defined in earlier studies. The response pattern of each neuron was dependent on frequency and sound‐pressure level. Tone pips evoked short‐lasting depolarizations of about 10 mV and long‐lasting hyperpolarizations of about 10 mV in cells whose resting potentials were −50 to −65 mV. The time courses of both the excitation and the inhibition depended on frequency and sound‐pressure level. Generally the depolarization was sustained for the duration of the tone pip, whereas the hyperpolarization could last as long as 600 ms after the end of the tone pip. Often a neuron exhibited a sustained chopper pattern after microelectrode impalement. This was probably a result of a decrease in membrane potential which altered the relative effectiveness of the excitatory and inhibitory inputs. The large, bitufted fusiform cells had many apical dendrites, which branched one to five times and were covered with spines, and fewer basal dendrites, which exhibited little branching and had few appendages. The morphology of fusiform cells varied systematically as a function of location within the dorsal cochlear nucleus. Response patterns for tone pips were not exclusive to individual cell types as two nonfusiform cells were found to exhibit a buildup pattern. Axons of injected neurons left the nucleus via the dorsal acoustic stria and 14 of 15 had collaterals within the dorsal cochlear nucleus.
Morphology and origin of axonal endings in nucleus laminaris of the chicken
Authors: Parks Thomas N. , Collins Patricia , Conlee John W. 
Published: December 2004

AbstractThe axonal endings on the somata and dendrites of third‐order auditory neurons in nucleus laminaris (NL) were measured and classified in thin‐sectioned material from adult chickens. Two methods were used to deter‐mine which ending types arise from second‐order auditory neurons in nu‐cleus magnocellularis (NM): (1) degeneration of axonal endings in NL after transection of the crossed dorsal cochlear tract (CTrX) carrying the axons of each NM to the contralateral NL, and (2) injection of horseradish per‐oxidase (HRP) into NM or the CTrX to label endings in NL by anterograde transport. About 42% of the perikaryl surface of NL neurons and 63% of the dendritic surface are apposed by axon terminals arising from NM; these endings are also prevalent on the axon hillock and initial segment. The NM endings are characterized by round, clear synaptic vesicles‐distributed at an average density of 76/μm2 behind small punctate synaptic junctions with thick synaptic densities. These endings degenerate preferentially after tran‐section of the CTrX and are the only endings consistently labeled after HRP injections. About 31% of the perikaryl surface of NL and 10% of the distal dendritic surface are apposed by a prominent non‐NM axonal ending type This ending is characterized by a synaptic vesicle density of 135/ μm2 a single large area of synaptic contact which bears very slight densities on both pre‐ and postsynaptic membranes. On the perikaryon, about 80% of these non‐NM terminals end on the cell body proper, with the rest found on proximal dendrites or capping the short somatic processes or spines occasionally seen in NL. The distribution of the two ending types does not differ significantly along the posterior‐to‐anterior axis of NL.
Effects of visual deprivation upon the geniculocortical W‐cell pathway in the cat: Area 19 and its afferent input
Authors: Leventhal Audie G. , Hirsch Helmut V. B. 
Published: December 2004

AbstractWe studied the receptive field properties of 206 single units in area 19 of normal cats and 228 single units in area 19 of cats deprived of vision for 9‐14 months by monocular lid suture. The ocular dominance of a sample of cells in area 17 of normal cats was studied for comparison. In some of these monocularly deprived animals, we also studied the sizes of relay cells in the parvocellular C laminae of the dorsal lateral geniculate nucleus labeled by electrophoretic injections of horseradish peroxidase into area 19.In area 19 of normal cats, the large majority of cells, regardless of their laminar location and the retinal eccentricity of their receptive fields, were binocular. Most responded equally well to the two eyes. In area 17, (see also Leventhal and Hirsch, ′78, ′80) but not in area 19, the cells which had the narrowest receptive fields tended to be activated unequally by the two eyes.In area 19 of monocularly deprived cats, virtually all cells (97%), re‐gardless of their laminar location and receptive field eccentricity, responded only to stimulation of the normal eye. Thus, the effects of monocular dep‐rivation upon area 19 are apparently more severe than those reported for area 17. In area 17 significant numbers of neurons in layer 4 can be activated by the deprived eye (Shatz and Stryker, ′78). Within the limits of our tech‐nique, measurements of relay cells in the parvocellular C laminae labeled by injections into area 19 of deprived cats indicated that cell size in the deprived C laminae was unaffected by the deprivation. In contrast, cells in the deprived A laminae of these cats were severely shrunken.These findings suggest that the types of relay found in the parvocellular C laminae (referred to collectively as W‐cells) are not affected by visual deprivation as severely as are the X‐ and Y‐cells in the A laminae. Since laminar location and receptive field width are related to binocularity in area 17 but not in area 19 and the sizes of relay cells in the parvocellular C laminae (see also Hickey, ′80) are not seriously affected by monocular deprivation, it is suggested that binocular interactions in area 19aremninly determined by connections among cortical cells.
Origin of various enzymes released from the substantia nigra and caudate nucleus: Effects of 6‐hydroxydopamine lesions of the nigro‐striatal pathway
Authors: Greenfield Susan A. , Grünewald R. A , Foley P. , Shaw S. G. 
Published: December 2004

AbstractVarious enzymes are released from the nigro‐striatal pathway. The hypothesis that these enzymes–i.e., acetylcholinesterase, nonspecific cho‐linesterase, aminopeptidase, and lactate dehydrogenase–originate from do‐paminergic nigro‐striatal neurons was investigated. Following a 6‐hydrox‐ydopamine lesion of the rat nigro‐striatal pathway, the spontaneous release of all four enzymes was reduced, in both the caudate nucleus and substantia nigra. In both structures the reduction in release of aminopeptidase and lactate dehydrogenase was less marked than that seen for acetylcholines‐terase and nonspecific cholinesterase. In nonlesioned rats, application of 50 mM KC1 to the substantia nigra led to an increase in enzyme release locally, accompanied by a decrease in release from the caudate nucleus. These changes were observed in release of acetylcholinesterase, aminopeptidase, and lac‐tate dehydrogenase, but nonspecific cholinesterase remained unchanged. In rats with 6‐hydroxydopamine lesions, nigral application of potassium no longer induced a significant decrease in release from the caudate nucleus in any of the enzymes. In perfusates of the treated group, however, a po‐tassium‐evoked increase in nigral aminopeptidase and lactate dehydrogen‐ase release was still detectable. Nigral acetylcholinesterase release was not affected by potassium in animals with 6‐hydroxydopamine lesions. It ap‐pears that lactate dehydrogenase and aminopeptidase are released together from both dopamine‐ and non‐dopamine‐containing cells in the caudate nucleus and substantia nigra; this release may be related to neuronal de‐polarization. A high proportion of nonspecific cholinesterase is released from nigro‐striatal dopamine‐containing cells but appears not to be dependent on depolarization. Acetylcholinesterase, which is released in the caudate nucleus and substantia nigra following neuronal depolarization, originates almost exclusively from dopamine‐containing nigro‐striatal neurons.
Dendritic reorganization in the denervated dentate gyrus of the rat following entorhinal cortical lesions: A Golgi and electron microscopic analysis
Authors: Caceres Alfredo , Steward Oswald 
Published: December 2004

AbstractThe organization of the dendritic tree and the morphology of individual dendrites of the dentate granule cell were analyzed qualitatively and quantitatively by means of the rapid Golgi technique 2, 4, 8, 10, 14, 30, 60, and 250 days after unilateral lesions of the entorhinal cortex (EC). Three dendritic field parameters were analyzed from camera lucida drawings of de‐nervated granule cells at each survival time: (1) dendritic field spread, (2) dendritic length, and (3) dendritic branching. Cells in the contralateral dentate gyrus served as controls. Spines were counted at each postlesion interval from material stained with a modification of the Golgi‐Kopsch method. The amount of tissue occupied by dendritic shafts at different postlesion intervals was also evaluated in samples of the ventral leaf of the dentate gyrus prepared for electron microscopy. After unilateral lesions of the EC, dendrites of the granule cells undergo modifications which appear to represent deterioration and recovery. When the dendrites reach the denervated zone, they abruptly change their orientation and tend to follow a course parallel to the granule cell layer. In contrast to normal dendrites, those in the denervated neuropil only occasionally reach the outer boundaries of the molecular layer. At the time of maximal denervation there is often a sudden reduction in dendritic diameter as the dendrite enters the denervated zone. Varicosities are also prominent. The alterations in individual dendrites are not evident 2 days after the lesion, are fully developed 10 days after deafferentation; and disappear for the most part by 30 days postlesion. The quantitative analysis of Golgi‐stained granule cells reveals that there is a 40% reduction in the total length of the granule cell dendritic tree. Electron microscopic analysis confirms the Golgi observations, indicating that the amount of neuropil occupied by dendritic shafts in the denervated zone is initially reduced and later recovers to values close to those observed in control animals. While the apparent dendritic loss is mainly restricted to the denervated zone, significant modifications occur in the inner npnde‐nervated molecular layer; there is an increase in the length of primary dendrites as evidenced by an increase in the distance to the first branch point. There is also a polarized redistribution of 1st, 2nd, 3rd, and 4th branch points toward the middle and outer molecular layer that persists even 30 days after the lesion. The results are discussed in terms of the capabilities of the granule cells of the dentate gyrus to reorganize and remodel their dendritic surface after partial deafferentation.
Neural basis of developing salt taste sensation: Response changes in fetal, postnatal, and adult sheep
Authors: Mistretta Charlotte M. , Bradley Robert M. 
Published: December 2004

AbstractTo learn whether salt taste responses change during mammalian development, we recorded from multifiber preparations of the chorda tympani while stimulating the anterior tongue in sheep fetuses, lambs, and adults. Stimuli were 0.5 M NH4C1, KC1, NaCl, and LiCl, and 0.05–0.75 M concentration series of the first three salts. Ultrastructural studies were made of taste buds at different ages to determine whether morphological elements such as microvilli and tight junctions are present in young fetuses.Substantial changes occur in relative salt taste responses, throughout development. In fetuses that are beginning the last third of gestation, NaCl and LiCl elicit much smaller response magnitudes than NH4C1 and KC1. Throughout the rest of gestation and postnatally, the NaCl and LiCl responses gradually increase in magnitude relative to NH4C1 and KCL In adults, NaCl, LiCl, and NH4Cl all elicit similar response magnitudes and KC1 is less effective as a taste stimulus. At ages when response ratios for the 0.5 M salts are changing, there are no changes in shapes of the response/concentration functions for individual salts. Furthermore, microvilli are present on taste bud cell apices and tight junctions are found between cells in the youngest fetuses studied. Therefore, initial stimulus‐receptor membrane contacts are probably similar to those in adults.Our data suggest that different membrane components interact with the various monochloride salts and that taste receptors contain different proportions of these various membrane components at different developmental stages. Therefore young taste bud cells do not have the same salt response characteristics as mature cells, and a changing neural substrate underlies development of salt taste function, both pre‐ and postnatally.
The morphology of intracellularly labeled rat subthalamic neurons: A light microscopic analysis
Authors: Kita H. , Chang H. T. , Kitai S. T. 
Published: December 2004

AbstractLight microscopic analysis of rat subthalamic (STH) neurons which were intracellularly labeled with horseradish peroxidase, following the acquisition of electrophysiological data, revealed the following: (1) The somata of STH neurons were polygonal or oval with occasionally a few somatic spines. Uusally three or four primary dendrites arose from the soma. Dendritic trunks tapered slightly and divided into long, thin, sparsely spined branches. Dendrites of some STH neurons extended into the cerebral peduncle. (2) Reconstruction of the dendritic field was made in three different planes. In either sagittal or frontal planes, the dendritic field was usually oval and the long axis was parallel to the main axis of STH. In the horizontal plane, the dendritic field of all neurons was polygonal. (3) The axons of all the neurons analyzed originated from the soma and were traced beyond the borders of STH, thus indicating that they were projection neurons. All the parent axons bifurcated at least once. After bifurcation, one axon branch coursed dorsolaterally within the cerebral peduncle and terminated in the globus pallidus. The other branch coursed caudally or mediocaudally and arborized in the substantia nigra. Frequently, the axon branches projecting toward the globus pallidus emitted fine axon collaterals within the entope‐duncular nucleus. (4) About one‐half of the analyzed STH neurons had intranuclear axon collaterals. The neurons with intranuclear collaterals had a higher dendritic tips/stems ratio than neurons without intranuclear collaterals. This observation indicated that STH neurons could be divided into two groups according to their axonal morphology. (5) The axonal terminal arborization observed in all the target sites (i.e., globus pallidus, entopeduncular nucleus, STH, and substantia nigra) were formed with varicose collateral branches which also gave rise to short filaments with beaded endings. Some of these projection neurons could therefore communicate with the target neurons in the globus pallidus, substantia nigra, entopeduncular nucleus, as well as STH through their collateral system.
Cytology of periolivary cells and the organization of their projections in the cat
Authors: Adams Joe C. 
Published: December 2004

AbstractProjections of cells located near principal nuclei of the superior olive, periolivary cells, were studied by injecting horseradish peroxidase or fluorescent tracers into the cochlea, cochlear nucleus, and inferior colliculus. At least two distinct cytological classes of periolivary cells were found to project to each of these structures. “Large” and “small” olivocochlear cells were labelled. Their cytology and locations were found to be as had been previously described. Some olivocochlear cells also project to the cochlear nucleus. Other major periolivary cell classes that project to the cochlear nucleus include a lateral group of multipolar cells whose members are located around the ipsilateral lateral superior olive and have coarse, darkly staining Nissl substance. The other major periolivary cell class that projects to the cochlear nucleus is the small cell of the ventral nucleus of the trapezoid body. This cell is characterized by its size and by only one or two intensely staining clumps of Nissl substance. Projections of these cells to the cochlear nucleus is from both sides. Periolivary cells that project to the inferior colliculus include medial and lateral groups. Cells of the lateral group project from both sides. These cells are multipolar in shape and contain lightly staining, floccu‐lent Nissl substance. They are predominantly located immediately ventral to the lateral superior olive. Projections from the medial group are predominantly ipsilateral and arise from the region medial to the medial superior olive. The cells are multipolar and contain clumped Nissl substance. They often lie near “large” olivocochlear cells, which they resemble in Nissl material, but are distinguished from the latter in Protargol material by having ring‐type axosomatic endings. The appearance and locations of these six classes of periolivary cells make it possible to recognize them in nonexperi‐mental material and to infer with confidence what their projections are. These results show considerable organization of these previously little understood structures.
Language functions explored in normal subjects by positron emission tomography: A critical review
Authors: Démonet J. F. , Wise R. , Frackowiak R. S. J. 
Published: December 2004

AbstractRecent advances in positron emission tomography techniques provide a way of studying the functional anatomy of language processes in the normal brain. A large amount of data have already been acquired using the subtractive activation method, which consists of comparing regional metabolic brain activities between two experimental conditions, a reference condition and an active condition (e. g., a language task). In spite of the potential interest of such results, their interpretation may be obscured by conflicting theoretical issues on the nature of brain‐language relationships and by various methodological problems, which are described in this review paper. The exact nature of the language task and stimuli used in the activation paradigms appear to be critical for this topic. Moreover, the strictly hierarchical, unidimensional subtractive method, previously described by Petersen et al. ([1988]: Nature 331:585–589) seems not to be adequate for generating appropriate contrasts between activation conditions in most language paradigms. Further progress in the analysis of task‐related changes in distribution of cerebral activities, are expected from: (1) other methods that should complement the subtractive approach, such as analysis of interregional correlations of cerebral activity which would account for the distributed anatomy of language functions; and (2) single‐subject studies in which issues of anatomical and cognitive interindividual variability may be addressed. © 1993 Wiley‐Liss, Inc.
Preoperative assessment of the cerebral hemispheric dominance for language with CBF PET
Authors: Pardo José V. , Fox Peter T. 
Published: December 2004

AbstractThis study evaluated whether cerebral blood flow positron emission tomography (CBF PET) could provide assessments of language dominance comparable to the invasive reference method, the Wada test (selective intracarotid injection of amytal with cognitive testing subsequent to the anesthesia of each hemisphere). In 9 of 11 patients with partial complex epilepsy who were operative candidates, the Wada test lateralized unequivocally; in two subjects Wasa results were indeterminate (no speech arrest following injection of either carotid). Of four brain regions selected a priori for PET analysis based on techniques developed from studies of normal volunteers, anterior frontal cortex (AFC) was most consistently detectable and lateralized. AFC laterality agreed with Wada laterality in eight of the nine subjects lateralized by Wada. In both subjects having an indeterminate Wada, PET demonstrated clear laterality. In one subject both PET and Wada lateralized, but in disagreement; anterior temporal lobectomy in the hemisphere indicated by PET as language‐dominant caused long‐lasting language impairment. We conclude that CBF PET: (1) provides an effective, noninvasive adjunct to the Wada test; and (2) permits assessment of language dominance in normal research volunteers. © 1993 Wiley‐Liss, Inc.
Etudes sur les matières végétales volatiles. XLV. — Présence d'ionones dans l'essence concrète de Boronia megastigma Nees
Authors: Naves Y. R. , Parry G. R. 
Published: December 2004

AbstractL'essence concrète de Boronia megastigma Nees., préparée par l'un de nous, renferme, outre de l'eugénol, un mélange de β‐ionone, de d‐α‐ionone et de d,l‐α‐ionone.
Recherches sur l'action chimique des décharges électriques XXXII. Rectifications à apporter aux déterminations, par la méthode oscillographique, des rendements énergétiques des synthèses chimiques au moyen de l'arc à haute fréquence; emploi de méthodes photométrique et calorimétrique
Authors: Briner E. , Höfer H. , Kundig J. J. 
Published: December 2004

AbstractUne étude critique de la méthode oscillographique, utilisée dans les recherches précédentes pour la détermination des puissances mises en jeu dans l'arc électrique, a mis en évidence certaines causes d'erreurs qui affectent cette méthode en haute fréquence (lo7), et les précautions qu'il y a lieu de prendre pour les atténuer.
The Absolute Configuration of the Glutarimide Antibiotics Streptimidone and 9‐Methylstreptimidone
Authors: Becker Anna Maria , Rickards Rodney W. 
Published: December 2004

AbstractChemical and spectroscopic studies have established the absolute configuration of the glutarimide antibiotics streptimidone and 9‐methylstreptimidone, which can now be represented as the (2R,5S,6E)‐structures 14 and 15, respectively.
Die Epoxysulfoncyclofragmentierung, eine neue Ringerweiterungsmethode. Synthese von rac.‐Muskon
Authors: Fischli Albert , Branca Quirico , Daly John 
Published: December 2004

A new ring expansion method using the cyclofragmentation of epoxysulfones; a synthesis of rac. muscone.Starting from the readily available cyclododecanone 1 the hydroxy sulfone 5 has been prepared using standard procedures. Subsequent dehydration followed by an acidic equilibration resulted in a mixture of two endocyclic olefines, from which the olefin 7 showing the (E)‐configuration could be isolated by fractional crystallization. Oxidation of 7 produced the epoxy sulfones 8 and 9. The epoxy sulfone 8 was cyclized to the hydroxy sulfone 10 without any detectable amount of the corresponding epimer 11. Fragmentation of the intermediate 10 using KOTB produced pure (E)‐4‐muscenone 12. The epoxy sulfone 9 was cyclized to a mixture of the two epimeric hydroxy sulfones 14 and 15. Fragmentation of the two crystalline hydroxy sulfones 14 or 15 with KOTB produced a mixture of 12 and 16. The ‘one‐pot’ preparation of (E)‐4‐muscenone 12 starting from 8 could also be accomplished. The configurational assignements within this serie are based upon the data of an X‐ray analysis of the hydroxy sulfone 10.