bluuebunny/crossref_metadata_2025_split huggingface dataset:
Localization of primary sensory afferents in the prothoracic ganglion of the wood ant (Formica lugubris Zett.): A combined light and electron microscopic study of secondary degeneration
Authors: Lamparter Hans‐Eckart , Akert Konard , Sandri Clara 
Published: December 2004

AbstractSecondary degeneration of foreleg afferents was traced in the prothoracic ganglion of the common wood ant (Formica lugubris Zett) with the aid of phase contrast and electron microscopy. The legs were amputated at the coxal level in 43 workers; 1–35 days were allowed for degeneration. Localization of degenerated sensory nerves in the entering nerve root and within the neuropil of the ganglion was opumal after 4‐10 days. Afferent fibers were found predominantly in the ipsilateral half of the ganglion. However, a few fibers seemed to cross the midline and to end in the medial portion of the contralateral side. No degenerations could be located within the cranial and caudal connectives. The significance of the findings with respect to the problem of functional localization pattern in the neuropil of an insect ganglion is discussed.
Quantitative teased‐fiber and histologic studies of human sural nerve during postnatal development
Authors: Gutrecht Jose A. , Dyck Peter J. 
Published: December 2004

AbstractQuantitative histologic and teased‐fiber measurements were made on specimens of sural nerves of man in the first two decades of life, thus providing normal data not previously availabel. As previously reported for nerves from adults, there was a linear relationship between diameter and length of internodes: large fibers had long internodes and small fibers had short internodes. The slopes of the regression lines calculated for this relationship for each of these nerves became steeper with increasing age. In the second decade the slope became similar to that of nerves of adults.The transverse fascicular area increased particularly during the first five years of life. The number of myelinated fibers per nerve varied from approximately 4,000 to 12,300, the lowest value occurring in the nerve of the newborn. The frequency distribution of the myelinated fibers was unimodal in the newborn and was already bimodal by the seventh month. Whereas the peak of the small fiber group remained in the 2.0 to 2.9–μ size group in all nerves, the peak of the large fiber group shifted to larger size categories with increasing age, reaching adults values just after the age of five years. This correlates well with the age at which maximal conduction velocities are attained in the ulnar nerve.The diameter of the axis cylinder bore a linear relationship to the diameter of the whole myelinated fiber: small fibers had thin myelin sheaths and large fibers had thick ones. The value of the ratio of the diameters incresed progressively from small to large fibers, a result which is probably spurious. The slope of the regression lines for the relationship of diameter of axis cylinder to diameter of the whole fiber was the same for nerves of persons of different ages.
Exceptions to bilateral symmetry in the epithalamus of lower vertebrates
Authors: Braitenberg Valentino , Kemali Milena 
Published: December 2004

AbstractFifty series of sections through the frog's brain, four series of the newt's brain and two series of the eel's brain were searched for asymmetries in the epithalamic region. Marked differences between the right and left habenular nuclei were found in all cases, in the sense that the left one had a more lobate structure than its right counterpart.
Anatomical connections of visual system with limbic cortex of monkey
Authors: MacLean Paul D. , Creswell George 
Published: December 2004

AbstractThe question of anatomical connections between the visual system and the temporo‐occipital limbic cortex was investigated in 24 squirrel monkeys (Saimiri sciureus) with the utilization of stains for showing fine degenerating cortical fibers. Lesions of various size were placed in the geniculo‐pulvinar complex by electrocoagulation. Electrodes were usually inserted in the Horsley‐Clarke frontal plane, but in two cases lesions of the lateral geniculate body were made by an extracerebral approach.With a lesion well confined to the ventrolateral part of the lateral geniculate body, heavy degeneration appeared in the inferior longitudinal fasciculus and continued into its ventromedial extension designated as band 3 in the core of the posterior hippocampal gyrus. Some degenerating fibers could be traced from band 3 into the cortex of this gyrus, as well as into adjoining cortical areas in the fusiform and lingual gyri. Sparse degeneration in the postsplenial cortex could not be excluded as arising from the lesion made by an electrode in approaching the lateral geniculate body in the frontal plane. Degeneration in band 3 did not extend as far forward as the entorhinal cortex in the anterior hippocampal gyrus. In two animals with small rostral lesions of the lateral geniculate body made by the extracerebral approach, some degeneration also extended into band 3, supporting other control observations that such degeneration is not dependent on the destruction of tissue made by an electrode in approaching the lateral geniculate body in the frontal plane.When a lesion involved the inferior pulvinar as well as the lateral geniculate body, heavier degeneration appeared in the posterior hippocampal, fusiform, and lingual cortex. With a large lesion of the inferior pulvinar, a band of degeneration appeared ventrolateral to the optic radiations and was traced into these same cortical areas.The anatomical results are discussed in the light of recent microelectrode findings of photically responsive units in the cortex of posterior hippocampal gyrus and adjoining cortical areas. The combined evidence suggests an explanation for the temporal detour made by that part of the optic radiations commonly referred to as Meyer's temporal loop.
Nigrofugal connections in the primate brain
Authors: Mettler Fred A. 
Published: December 2004

AbstractThe great mass of large cells which make up the compact part of the substantia nigra send their stout primary axons to the ipsilateral globus pallidus. A much smaller‐ipsilateral striatal projection can also be easily substantiated. This comes chiefly from cells in the reticulata but not exclusively so. In general, the lateral reticulata projects to the putamen and the medial to the caudate. If the synapses in the ventrolateral part of the thalamus, which have been described to degenerate to degenerate after lesions in the nigra, are established by nigrofugal, rather than by other fiber systems, they would seem to be the endings of collaterals given off en route to the lentiform nucleus, rather than primary projection elements. If any fibers from the nigra cross the midline, or descend, they must be very few.
Formation and migration of neuroblasts in the spinal cord of the chick embryo
Authors: Langman Jan , Haden Cheryl C. 
Published: December 2004

AbstractTo determine the origin, migration pattern and final localization of the neurons in the spinal cord, chick embryos ranging in age from two to eight days were treated with two doses of tritiated thymidine with an interval of two to four hours and sacrificed at various days thereafter. As a result of this labeling procedure, all neuroepithelial cells were labeled; hence all neuroblasts arising from the neuroepithelial cells after the treatment were labeled, while those formed earlier were unlabeled. By examining the position of the unlabeled neuroblasts at daily intervals, the migration route and final localization of these neurons could be determined.Neuroblasts formed on days two and three are initially found along the inside of the basement membrane in the ventrolateral as well as the dorsolateral region of the cord. During the following days, however, the neuroblasts found in the dorsolateral region disappear and by day 8 the majority of the two‐and three‐day neuroblasts is concentrated in the lateral region of the anterior horn. Since no evidence for degeneration of neuroblasts was found in the alar plate region, it is probable that „alar plate neuroblasts”︁ migrate to the region of the anterior horn.The majority of the neuroblasts formed on days 3 and 4 finds its final position in the lateral region of the anterior horn; the majority of those formed on days 5 and 6, however, occupies a position in the medial region of the anterior horn. Hence, the majority of the motor neurons innervating the muscles of the extremities is formed earlier than those innervating the trunk musculature.The neuroblasts of the internuncial zone are formed on days 2 through 7, that is, during the entire period that neuroblast formation in the spinal cord occurs. The majority of the neuroblasts for the posterior horn arises on days 6 and 7, while the last ones are formed on day 8. Despite the fact that the majority of the neuroblasts for the anterior horn is formed before those of the internuncial zone and these in turn before those of the posterior horn, none of the cell groups in either region is formed within a sharply delineated time period.
Observations on initial segments of axons in the prepyriform cortex of the rat
Authors: Westrum Lesnick E. 
Published: December 2004

AbstractLayers II and III of the prepyriform cortex of rats were studied with the electron microscope and with a rapid Golgi method. Initial segments of axons were identified according to the criteria previously established. The fixative optimum for demonstrating microtubules and differentiating initial segments from dendrites must include glutaraldehyde. Initial segments were found to possess lateral projections, herein referred to as axonic spines and their fine structural features and synaptology are described. The synapses on initial segments and axonic spines predominately contain flattened vesicles and a spine apparatus‐like organelle is often present. The problem of the origin of these synapses is discussed.
The effect of unilateral deprivation on visual centers in rats
Authors: Fifková E. 
Published: December 2004

AbstractThe effect of unilateral visual deprivation by lid suture on visual centers was studied in rats. In animals with previous visual experience this caused a decrease in volume of the dorsal nucleus of the lateral geniculate body and nucleus lateralis pars posterior of 10% and 8% respectively, a decrease in the thickness of layers II to IV of the visual cortex of 8% and an increase in cell density in cortical layers III and IV of 12% and 10% respectively. These changes were of the same magnitude as in rats which had no previous visual experience. Quantitative changes in deprived visual centers were detectable ten days after lid suture; the process reached its maximum after 30 days. The number of spines on the apical dendrites of pyramidal cells of layer V, observed in layer IV, was reduced by 17% after ten days of visual deprivation and by 28% after 30 days. Reopening of the eye for 10 and 30 days following two months of lid closure caused no recovery in the deprived visual centers.
Effects of hyothalamic lesions at different loci on development of hyperinsulinemia and obesity in the weanling rat
Authors: Bernardis Lee L. , Frohman Lawrence A. 
Published: December 2004

AbstractBilateral electrolytic lesions were produced in eight different hypothalamic areas in weanling female rats to localize the area associated with hypothalamic obesity. Animals were maintained for five weeks and food intake measured. After sacrifice, changes in carcass fat content, plasma insulin and plasma glucose were compared to value obtained from sham‐operated controls. Only rats with lesions primarily in the ventromedial hypothalamic nuclei had significantly elevated plasma insulin levels and carcass fat content despite normoglycemia, normophagia and normal to reduced body weight gain. The results indicate the existence in the rat hypothalamus of a locus limited to the region of the ventromedial nuclei which affects insulin secretion and lipogenesis. The possible mechanisms responsible for this phenomenon are discussed.
The anatomy of the brain of the bottlenose dolphin (Tursiops truncates). Rhinic lobe (rhinencephalon). I. The paleocortex
Authors: Jacobs Myron S. , Morgane P. J. , McFarland Willard L. 
Published: December 2004

AbstractThe bottlenose dolphin, Tursiops truncatus, lacks olfactory bulbs and peduncles as do the other members of the odontocete suborder of Cetacea. Nevertheless the dolphin as well as the other cetacean species studied possess a rhinencephalon or rhinic lobe consisting of prominent olfactory lobes and a very reduced hippocampus covered over, respectively, by small epistriatal (frontal, especially orbital lobes and insula) and huge epihippocampal (parietal, occipital and temporal lobes) Portions of the hemisphere.In the dolphin the demarcation of the rhinic lobe from each hemisphere bilaterad to it is particularly clear and consists of a continuous circular groove (rhinic cleft) composed of posterior parolfactory, anterior and posterior rhinal, rhinohippocampal, hippocampal and callosal segments. Along the trajectory of the rhinic cleft, the cytoarchitectonic demarcation of the paleocortex (olfactory lobes) and archicortex (hippocampus) from the neocortex in the border (limbus) of each hemisphere is equally clear. The rhinic lobe in Tursiops and other Cetacea so far examined thus appears to be a formation of the telencephalon whose distinctness in these species is dramatically emphasized.Topographic disposition of the cytoarchitectonic areas of the paleocortex in Tursiops, Which have not heretofore been described, has been found in this study to be essentially similar to that of other placental mammals. These areas of the paleocortical division of the rhinic lobe (Prepyriform, tubercular, diagonal and periamygdalar areas) are as easily differentiated from one another in this species as in many other mammalian forms.
Reticulospinal fibers of the opossum, Didelphis virginiana I. Origin
Authors: Beran Robert L. , Martin George F. 
Published: December 2004

AbstractComplete and partial cervical cord hemisections were placed at different levels according to a modification of the Gudden method (Brodal, '40), as applied to the opossum. Nissl staining techniques were employed and either acute retrograde cellular change of cell loss was studied following 7to 65 day survival periods. The results of a previous cytoarchitectonic study which followed the terminology of Meessen and Olszewski ('49) and Olszewski and Baxter ('54) served as controls.Chromatolysis or cells loss was found in medium‐sized (20–29 μ), large (30–44 μ) and giant (45–60 μ) cells in the pontine and medial medullary reticular formation. Retrograde changes in the pontine reticular formation were found in the nucleus pontis centralis oralis, the nucleus pontis centralis caudalis and the rostral nucleus gigantocellularis. Within the pons, chromatolysis was particularly evident in the large and giant cells. Following cervical cord lesions, the medullary reticular formation contained chromatolytic neurons within the nucleus gigantocellularis, the nucleus paragigantocellularis dorsalis, the paramedian reticular nucleus and the nucleus interfascicularis hypoglossi.At pontine levels, chromatolytic cells were present mainly on the side of the lesion. However, cells were found to have undergone retrograde changes in specific areas of the contralateral side. Although the greatest number of reactive cells within the medullary reticular formation were also located on the side of the lesion, there was more contralateral involvement than was the case in the pons.
Rapid phase of axoplasmic flow and synaptic proteins: An electron microscopical autoradiographic study
Authors: Schonbach J. , Schonbach Ch. , Cuénod M. 
Published: December 2004

AbstractElectro microscopic autoradiography was used to study the distribution of labeled proteins in the pigeon optic tectum, 12 hours after intraocular injection of 3H‐1‐leucine. More than 65% of the grains were detected over synaptic endings, in the fifth layer which is rich in retino‐tectal axon terminals. In the first layer which contains retino‐tectal fibers 70% of the grains were over axons. These data support the proposition that synaptic proteins migrate rapidly in the axon. Detailed examination showed that silver grains were predominatly located over the axolemma and agranular endoplasmic reticulum in axons, and over mitochondria and synaptic vesicles in neuronal endings.
The projection of the visual field to the lateral geniculate and medial interlaminar nuclei in the cat
Authors: Sanderson K. J. 
Published: December 2004

AbstractDetailed and complete projection maps of the visual field to the whole of the dorsal lateral geniculate (LGNd) and medial interlaminar nucleus (MIN) of the cat have been prepared by plotting the receptive fields of single units in the two nuclei with tungsten‐in‐glass microelectrodes. The standard projection maps show the pattern of isoazimuths (“horizontals”) and isoelevations (“verticals”) in the two nuclei. Particular attention has been given to the projection of the upper visual field to the posterior part of the LGNd/MIN complex where the shape and relationship of the cellular laminae are changing rapidly. A separate projection of the visual field to the nucleus perigeniculatus (NPG) is also described, but the retinotopic organization of this projection is not as precise as for the LGNd and the MIN. Most of the cells in the NPG are binocularly‐activated and the receptive fields have ON/OFF centers. Further observations have been made concerning the distribution of the crossed and uncrossed fibers in the LGNd. In lamina B there is a thick dorsal zone of contralaterally‐activated cells and below this is a zone in which ipsilaterally‐activated cells are occasionally found. A few binocularly‐activated cells were found in the vicinity of the interlaminar regions.
Survival of pattern vision after removal of striate cortex in the adult cat
Authors: Doty Robert W. 
Published: December 2004

AbstractBehavioral, anatomical and electrophysiological data are presented for three cats. One had complete removal of area 17 as evidenced by gross and histological examination of the remaining cortex and by the degeneration in the lateral geniculate body. Dorsal portions of areas 18 and 19 were essentially intact and much of the central and medial interlaminar nuclei of the lateral geniculate body survived. This cat had excellent pattern vision. So too did a cat in which all of the posterior suprasylvian gyrus, dorsal surface of the middle suprasylvian gyrus and much of anterior marginal gyrus had been extirpated. In contrast, an animal lacking area 18 and most of area 19 in addition to area 17, and thus having near “total” degeneration of the lateral geniculate body, was incapable of pattern discrimination. Photically evoked potentials could nevertheless be demonstrated throughout an extensive suprasylvian field in the latter animal. It is concluded that area 17 is not essential for pattern vision in the cat, but that in its absence, even in the case of ablations performed neonatally, cortex receiving major projection from the central and medial interlaminar nuclei, i.e., areas 18 and 19, is required.
Mutual contact inhibition of extension of chick sensory nerve fibres in vitro
Authors: Dunn Graham A. 
Published: December 2004

AbstractMethods were devised for measuring various aspects of the geometry of nerve fibre outgrowths from chick dorsal root ganglia in short‐term plasma clot cultures. Optical birefringence was used as a measure of the magnitude and direction of stresses which developed within the plasma clots during the incubation period. The data obtained indicated that contact guidance of nerve fibres, along fibrin micelles of the medium, is not of prime importance in determining the courses of nerve fibres in non‐fasciculated outgrowths. A mutual contact reaction, between nerve fibres, was observed using time lapse cine‐photomicrography, and the patterns of nerve fibre outgrowths could be largely attributed to such a reaction. This contact reaction is similar, in many respects, to contact inhibition of locomotion in cultured fibroblasts; and it is proposed that the reaction be termed “contact inhibition of extension.”
Binocular competition in the control of geniculate cell growth
Authors: Guillery R. W. 
Published: December 2004

AbstractIt has been shown previously that, in kittens, geniculate laminae that are visually deprived by a unilateral lid‐suture grow less than normal. However, cell growth is affected only where the deprived laminae lie opposite a normally innervated lamina. The most lateral part of lamina A, which is innervated from the monocular crescent of the visual field and which extends beyond the edge of lamina A1, is not affected by lid‐suture. One interpretation of this result is that a binocular competition controls geniculate cell growth and that the normal competitive balance is upset by the lid‐suture.In order to test this interpretation further, four kittens had the lids of one eye sutured and in the other eye a patch of temporal retina was destroyed. After 5.5 to 12 weeks′ survival lamina A1 showed a patch of transneuronal degeneration produced by the ipsilateral retinal lesion. Most of lamina A showed a reduced cell growth contralateral to the suture. However, the part of this lamina lying opposite the zone of transneuronal degeneration contained cells that were larger than would be expected if there were no competitive effect. These results show that geniculate cells compete during development, probably for available synaptic surfaces upon cortical cells, perhaps in terms of interlaminar inhibitory mechanisms. Success in this competition depends upon the nature of the visual input. The present results provide no evidence that visual deprivation can change geniculate cell growth by any direct, non‐competitive effect.
Origin and termination of the hippocampal perforant path in the rat studied by silver impregnation
Authors: Hjorth‐Simonsen A. , Jeune B. 
Published: December 2004

AbstractA detailed study of the origin and termination of the so‐called perforant path of the hippocampal region has been made in the rat. This tract connects the entorhinal area with the hippocampus and the fascia dentata. At all dorso‐basal levels of the hippocampus, the terminal field has been shown to occupy the middle part of the molecular layer of the fascia dentata and that level of the stratum lacunosum‐moleculare of the hippocampal subfield CA3 which is close to the stratum radiatum. The outer and inner parts of the dentate molecular layer, the stratum lacunosum‐moleculare of subfield CA1, and the superficial part of the latter layer in CA3 contained fibers en passage only. The origin of the perforant path has been found to be in the medial part of the entorhinal area, from the most dorsal to the most ventral levels. The fibers arise in part at least from cells in layers I—III. Lesions of the lateral part of the entorhinal area leave the perforant path unaffected. A topical organization has been demonstrated: Lesions dorsal in the entorhinal area evoke terminal degeneration in antero‐rostral (septal) parts of the hippocampus only. More ventral lesions produce degeneration in increasingly caudal (temporal) segments of the hippocampus. Earlier descriptions of the route traversed by the perforant path have been confirmed. In addition, the axons to the most rostral parts of the hippocampus and fascia dentata have been shown to course superficially in the dorsal and rostral parts of the subiculum and CA1 which form an exposed part of the medial aspect of the hemisphere.