bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cerebellar targets of visual pontine cells in the cat
Authors: Robinson Farrel R. , Cohen Janet L. , May Jack , Sestokas Anthony K. , Glickstein Mitchell 
Published: January 2005

AbstractThe cerebellum receives visual mossy fiber input from the cerebral cortex via visual cells in the pons. We identified the regions of cat cerebellum that receive cerebral visual input by injecting orthograde tracers among physiologically identified visual pontine cells. Cerebellar labeling following these injections indicates that the contralateral paraflocculus and the rostral folium of the uvula (vermal lobule IX) receive the heaviest projection from cortically activated pontine visual cells. Lighter visual input reaches much of the rest of the contralateral posterior lobe. A second experiment combined, in the same animal, orthograde tracing of the visual corticopontine pathway with retrograde tracing of the pontocerebellar projection. The results of this experiment confirm that the paraflocculus and uvula receive more cortical visual input than do other regions of the cerebellum. This experiment also shows that uvula‐projecting and paraflocculus‐projecting cells occupy different parts of the ventromedial pons. Uvula‐projecting cells cluster immediately adjacent to the ventral and medial borders of the pyramidal tract and near the midline. Paraflocculus‐projecting cells lie ventral and medial to the pyramidal tract but displaced from its border. There are few paraflocculus‐projecting cells near the midline.
A diffuse αMSH‐immunoreactive projection to the hippocampus and spinal cord from individual neurons in the lateral hypothalamic area and zona incerta
Authors: Köhler Christer , Haglund Lena , Swanson Larry W. 
Published: January 2005

AbstractThe course, distribution, and possible neurotransmitter specificity of a projection from the lateral hypothalamic area (LHA) and zona incerta to the hippocampal formation (dentate gyrus, Ammon's horn, subicular region, and entorhinal area) and spinal cord were examined anatomically in the adult rat. First, small injections of the fluorescent tracer fast blue were made into either the septal part of the dentate gyrus and Ammon's horn or the entorhinal area, and the distribution of retrogradely labeled cells was plotted. In each experiment many cells were labeled in the LHA and zona incerta, and little evidence for a topographically organized projection to different parts of the hippocampal formation was found. Second, a combined retrograde transport‐immunofluorescence method was used to show that some 95% of the fast blue‐labeled neurons in the LHA and zona incerta were also stained with an antiserum to the opiate peptide α‐melanocyte‐stimulating hormone (αMSH), but not an antiserum to adrenocorticotropin (ACTH)1–24. It was also found that small numbers of retrogradely labeled neurons were stained with antisera to somatostatin 14 and 28, dynorphin (1–17), and angiotensin II. Third, the distribution of αMSH‐immunoreactive fibers was plotted, and they were found to form a diffusely organized plexus throughout all of the subfields of the hippocampal formation. These fibers were virtually eliminated after transections of the fimbria and the region between the entorhinal area and the caudal amygdala. Fourth, the course of fibers from the LHA and zona incerta was examined with the anterogradely transported lectin Phaseolus Vulgaris Leucoagglutinin (PHAL). Such fibers reach the hippocampal formation by a dorsal route through the septal region and fimbria, and by a ventral route through the amygdala. And fifth, double retrograde transport and immunohistochemical methods were used to show that at least some αMSH‐stained neurons in the LHA and zona incerta give rise to collaterals that innervate both the hippocampal formation and the spinal cord. αMSH‐stained fibers in the spinal cord also form a widely scattered plexus with no obvious circumscribed terminal fields. It is suggested that the diffusely organized projection from the LHA to the cerebral cortex and spinal cord may play a role in the general arousal associated with a variety of motivated behaviors.
Topography of primary visual centres in the brain of the chick, Gallus gallus
Authors: Ehrlich David , Mark Richard 
Published: January 2005

AbstractIn a previous paper (Ehrlich and Mark,'83b) the primary visual centres of the chick were described. In this paper patterns of retinotopy are examined by means of silver degeneration and autoradiographic techniques following discrete laser lesions of the retina.Well‐defined and complete retinotopic maps are found in each of the following visual centres: tectum, lateral anterior thalamus, lateroventral geniculate nucleus, superficial synencephalic nucleus, ectomammillary nucleus, and tectal grey. In the dorsolateral anterior thalamus, pars lateralis, and external nucleus there is some evidence of a retinotopic innervation, yet not as well defined as those nuclei mentioned previously.Retinotopic maps were not observed in other retinorecipient regions. These include the ventrolateral thalamus, dorsolateral anterior thalamus, magnocellular part and rostrolateral part, pretectal optic area, and diffuse pretectal nucleus.Within the lateroventral geniculate, lateral anterior thalamus, superficial synencephalic nuclei, and the tectal grey, the ventral to dorsal retinal axis is mapped along the rostrocaudal axis, the reverse of the orientation seen in the tectum, which may have implications for explanations of how retinotopic maps are formed.The poor retinotopy in dorsolateral anterior thalamus, lateral part, is discussed with respect to the view that it may be the avian homologue of the mammalian lateral geniculate nucleus.
Postnatal differentiation of rat optic nerve fibers: Electron microscopic observations on the development of nodes of Ranvier and axoglial relations
Authors: Hildebrand C. , Waxman S. G. 
Published: January 2005

AbstractThe postnatal differentiation of rat optic nerve fibres was examined by transmission electron microscopy. The results show that many early developing axons contain clusters of vesiculotubular profiles prior to Myelination. At places vesicular elements appear to fuse with the axolemma, and, in addition, some axons exhibit deep axolemmal invaginations and axoplasmic lamellated bodies. It is suggested that these feature might reflect axolemmal remodeling, possibly involving axoglial signalling and/or functional differentiation of the axolemma. The size distribution of unmyelinated optic nerve axons changes little during development. Ensheathment of larger axons commences 6 days postnatally. The subsequent formation of compact sheaths are a few microns long and separated by long bare axon segments. In optic nerves from 10–12‐day‐old rat pups, a few sheaths consisting of about five layers border primitive asymmetric nodes with a patchy axolemmal undercoating. Extensions from one of the terminating sheaths are often associated with undercoated patches of axolemma. Relatively differentiated nodes of Ranvier first appear 14–16 days after birth. The continued nodal maturation involves establishment of a regular nodal geometry, increasing distinctness of the axolemmal undercoating, and formation of perinodal astrocytic processes embedded in an extracellular node gap substance. The results are compared with available data on the conduction properties of rat optic nerve fibres during development.
Development and degeneration of retina in rds mutant mice: Electron microscopy
Authors: Jansen H. G. , Sanyal S. 
Published: January 2005

AbstractIn the retina of mice homozygous for the retinal degeneration slow (rds) gene, receptor outer segments failed to develop and typical disc structures were never observed. However, cilia surrounded by a plasma membrane were regularly present. At the time when outer segments grew in the normal retina, the optic ventricle in the mutant showed an accumulation of membrane‐bound vesicles of varying size and density. The vesicles declined in frequency at later stages of degeneration. After initial growth, the inner segments in the mutant retina remained stunted but maintained their morphological differentiation, including the ciliary structures. Their number declined with loss of visual cells.In the mutant retina development of synapses, between the receptor cells and the processes of the horizontal cells and the bipolar cell dendrites, followed in normal sequence. Formation of spherule terminals of the rods, with one triad synapse, and of pedicle terminals of the cones, with multiple triad synapses, was recorded in the same way as in the normal retina. With loss of visual cells in the mutant retina, some of the profiles of the surviving spherule terminals showed an increased occurrence of two, three, or more synaptic sites. This growth resulted from enlargement and branching of the ribbons and sprouting from the postsynaptic elements. Similar changes were not observed in the pedicle terminals.The pigment epithelial cells in the mutant mice appeared initially normal, but phagolysosomal structures were absent. However, various inclusion bodies appeared within the pigment epithelial cells following degenerative changes in the retina. In some places, the basal infoldings deepened their furrows while thinning the cytoplasmic part of the epithelium.Failure to form the outer segments and the subsequent lysis of the visual cells appear to be the primary effects of the rds gene, whereas the synaptic growth in the sperule terminals and the changes in the pigment epithelium appear to be consequential to those defects.
The development of photoreceptors in the zebrafish, Brachydanio rerio. I. Structure
Authors: Branchek Theresa , Bremiller Ruth 
Published: January 2005

AbstractMorphological development of photoreceptors in the central retina of the zebrafish, Brachydanio rerio, was studied by using light and electron microscopic techniques. Outer segments (OS) first appeared at 2.5 days postfertilization (d2.5). On d3, synaptic elaborations were seen. By d8, two OS types were present and were identified as cones. The first indication of rod formation was also evidenced at this time, when vitreally positioned nuclei were observed and rodlike cells were infrequently detected in electron micrographs. At d12, the full complement of zebrafish photoreceptors, rods and four cone types, was identified. From this time on cells grew until adult dimensions were reached at d24. These structural observations are consistent with results of functional studies which utilized physiological and behavioral techniques.
Regional (14C) 2‐deoxyglucose uptake during forelimb movements evoked by rat motor cortex stimulation: Cortex, diencephalon, midbrain
Authors: Sharp Frank R. 
Published: January 2005

AbstractThe caudal forelimb region of right “motor” cortex was repetitively stimulated in normal, conscious rats. Left forelimb movements were produced and (14C) 2‐deoxyglucose (2DG) was injected. After sacrifice, regions of increased brain (14C) 2DG uptake were mapped autoradiographically.Uptake of 2DG increased about the stimulating electrode in motor (MI) cortex. Columnar activation of primary (SI) and second (SII) somatosensory neocortex occurred. The rostral or second forelimb (MII) region of motor cortex was activated.Many ipsilateral subcortical structures were also activated during fore‐limb MI stimulation (FLMIS). Rostral dorsolateral caudate‐putamen (CP), central globus pallidus (GP), posterior entopeduncular nucleus (EPN), sub‐thalamic nucleus (STN), zona incerta (ZI), and caudal, ventrolateral substantia nigra pars reticulata (SNr) were activated. Thalamic nuclei that increased (14C) 2DG uptake included anterior dorsolateral reticular (R), ventral and central ventrolateral (VL), lateral ventromedial (VM), ventral ventrobasal (VB), dorsolateral posteromedial (POm), and the parafascicular‐centre median (Pf‐CM) complex. Activated midbrain regions included ventromedial magnocellular red nucleus (RNm), posterior deep layers of the superior colliculus (SCsgp), lateral deep mesencephalic nucleus (DMN), nucleus tegmenti pedunculopontinus (NTPP), and anterior pretectal nucleus (NCU).Monosynaptic connections from MI or SI to SII, MII, CP, STN, ZI, R, VL, VM, VB, POm, Pf‐CM, RNm, SCsgp, SNr, and DMN can account for ipsilateral activation of these structures. GP and EPN must be activated polysynaptically, either from MI stimulation or sensory feedback, since there are no known monosynaptic connections from MI and SI to these structures. Most rat brain motor‐sensory structures are somatotopically organized. However, the same regions of R, EPN, CM‐Pf, DMN, and ZI are activated during FLMIS compared to VMIS (vibrissae MI stimulation). Since these structures are not somatopically organized, this suggests they are involved in motor‐sensory processing independent of which body part is moving. VB, SII, and MII are activated during FLMIS but not during VMIS.
Laminar origin and septotemporal distribution of entorhinal and perirhinal projections to the hippocampus in the cat
Authors: Witter Menno P. , Groenewegen Henk J. 
Published: January 2005

AbstractThe Projections o the entorhinal and perirhinal cortices to the hippocampus in the cat have been studied with retrograde and anterograde tracing techniques. Retarogradely transported tracers, which were injected at different levels along the septotemporal longitudinal hippocampal axis, result in labeled neurons in superficial entorhinal cortical layers II and III. Occasionally, labeled cells were also observed in the deepest entorhinal layer as well as in the superficial layers of the perirhinal area 35. It could further be shown that labeled neurons located superficially in the entorhinal cortex corresponds to a septotemporal gradient along the longitudinal axis of the hippocampus. This topographical organization of the entorhinal‐hippocampal projection system could be substantiated by the use of anterograde tracing of radioactively labeled amino acids. Injections in the entorhinal cortex produce labeled fibers in the hippocampus. Injections in the perirhinal area 35 result also in labeling over the hippocampus, whereas area 36 does not seem to distribute fibers to the hippocampus. As anticipated from the results of the retrograde tracing experiments, injections located laterally, in or close to the posterior rhinal sulcus, produce prominent labeling over the septal pole of the hippocampus, whereas progressively more medially located injections result in progressively more temporally located labeling. This topographical distribution of perforant path fibers along the septotemporal axis of the hippocampus, which is related to a lateromedial axis in the entorhinal cortex, has been observed following injections in the lateral entorhinal area (LEA) as well as in the medial entorhinal area (MEA). The present observations are discussed in regard of other connectional and putative functional differences between the septal and temporal hippocampus.
Collateral innervation of the medial and lateral prefrontal cortex by amygdaloid, thalamic, and brain‐stem neurons
Authors: Sarter Martin , Markowitsch Hans J. 
Published: January 2005

AbstractThe distribution of the afferents to the rat's prefrontal cortex originating in the thalamic mediodorsal nucleus and the amygdala was investigated with two fluorescent tracers. Special emphasis was laid on detecting the loci of neurons which project via axonal collaterals into both lateral and medial portions of the prefrontal cortex.It was found that a high number of neurons of the anterior portion of the basolateral amygdaloid nucleus terminate via collaterals in both the medial and lateral subfields of the prefrontal cortex. On the other hand, only a small number of mediodorsal thalamic cells were found to project to both sides of the prefrontal hemisphere via bifurcating axonal collaterals. These cells were situated exclusively in the lateral part of the medial segment of the mediodorsal nucleus. The majority of both thalamic and amygdaloid neurons with bifurcating axons originate from subregions whose cells innervate primarily the medial prefrontal cortex. In brain‐stem, neurons of the nucleus raphé dorsalis also project via collaterals to the medial and lateral prefrontal regions. Furthermore, neurons of the dorsal and ventral premamillary nuclei, the lateral mamillary nucleus, the ventral tegmental area of Tsai, and the ventral tegmental nucleus of Gudden were found to project to the medial prefrontal cortex.Our results indicate a differential collateral organization of thalamic and amygdaloid afferents to prefrontal cortical fields. The anterior basolateral amygdala (which innervates via collaterals both the medial and lateral prefrontal subfields) may add a common input to either subfield, such as information on the significance of incoming stimuli to the animal's behavior, while the mediodorsal nucleus (whose segments are principally connected to only one prefrontal subfield) may add segment‐specific information, for example, of a spatial‐cognitive nature for the lateral segment and of an emotional nature for the central and medial segments.The existence of a basolateral limbic circuit, composed of the amygdala, the thalamic mediodorsal nucleus, and the prefrontal cortex, is confirmed and knowledge on its interconnectivity is extended. From an anatomical point of view these data provide arguments for both unitary and diverging functions of the prefrontal cortex.
The morphological diversity and receptive fields of spiking local interneurons in the locust metathoracic ganglion
Authors: Burrows M. , Siegler M. V. S. 
Published: January 2005

AbstractTwenty‐one types of spiking local interneurons are described in a segmental ganglion of the locust. All have their cell bodies in a group at the ventral midline of the metathoracic ganglion. The interneurons are characterized by their shape as revealed by intracellular injection of dye, and by their physiology as revealed by intracellular recording. Each interneuron conforms to a basic plan, but the characteristic shape of each is derived from the elaboration of branches in some regions of the neuropil and by their absence in other regions. Some interneurons have ventral branches that extend over most of one‐half of the metathoracic neuropil, whilst others have ventral branches restricted to a small region of neuropil. A few interneurons have dorsal branches that enter the first abdominal neuromere. Each type of interneuron is excited by a specific array of mechanoreceptors on the hind leg ipsilateral to its neuropilar branches. Some interneurons have a wide receptive field that encompasses most of the surfaces of the distal three parts of a leg, whilst others have a field limited to the spurs at the distal end of the tibia. The relationship between the shape of an interneuron and the size or orientation of its receptive field is discussed.
Replication and differentiation of olfactory receptor neurons following axotomy in the adult hamster: A morphometric analysis of postnatal neurogenesis
Authors: Samanen David W. , Forbes William B. 
Published: January 2005

AbstractRegeneration of olfactory receptor neurons following unilateral olfactory nerve section was studied in Syrian golden hamsters by morphometric procedures. Characteristic structural and histochemical features of olfactory receptor neurons were compared on the sectioned and intact sides of the nasal septum at 6, 12, 18, 33, and 130 days following axotomy. The parameters measured were epithelial thickness and the numbers of nuclei, hematoxylin‐staining olfactory vesicles, olfactory marker protein (OMP)‐containing neuronal perikarya, and OMP‐containing olfactory vesicles. The olfactory receptor neuron population was severely depleted 6 days after axotomy. In the succeeding 12‐day period there was an initially rapid, then slower return of receptor neuron numbers. Though the regenerating olfactory epithelium appeared normal by gross inspection 33 days after the lesion, morphometric analysis revealed a substantial increase in the number of olfactory receptor neurons between 33 and 130 days postlesion. At our longest survival interval, all quantitative parameters had returned to 91–99% of control values. The numbers of OMP‐containing perikarya and olfactory vesicles on the sectioned side were unchanged between the sixth and 12th postlesion days, thus suggesting that neural turnover was depressed for several days following surgery. Marker protein developed in newly formed receptor neurons between 6 and 12 days after the formation of the olfactory vesicle. Consequently, the ratio between OMP‐containing olfactory vesicles and hematoxylin‐staining vesicles (O/H) was used as an index of neural differentiation. The O/H ratio on the sectioned side was minimal 12 days following axotomy when stem‐cell division was well under way but OMP antigenicity had not yet been expressed in newly formed neurons. At 33 days postlesion, O/H ratios were slightly but significantly greater than the control value, reflecting a degree of synchrony in the regenerating receptor neuron population. The average O/H ratio on the unlesioned side was 0.667. This value, together with our other observations, was used to derive an estimate of the life span of hamster olfactory receptor neurons, approximately 25–35 days.
Distribution of enkephalin, substance P, tyrosine hydroxylase, and 5‐hydroxytryptamine immunoreactivity in the septal region of the rat
Authors: Gall Christine , Moore Robert Y. 
Published: January 2005

AbstractImmunocytochemical methods were used to define the distribution of enkephalin (ENK), substance P (SP), tyrosine hydroxylase (TH), and serotonin (5‐hydroxytryptamine: 5HT) in the rat septum. A dense plexus of axons containing enkephalin‐like immunoreactivity is found in the intermediate lateral septal nucleus. This is surrounded laterally by SP‐containing cell bodies and axons and medially by ENK‐containing cell bodies. Both SP‐ and ENK‐immunoreactive axons form pericellular and peridendritic terminal arbors around lateral septal neurons. TH‐positive axons are distributed throughout the septum and form dense pericellular terminal baskets around scattered neurons in the medial half of the intermediate lateral septal nucleus and in the extreme lateral septum. Very few SP and TH immunoreactive axons are present in the ENK immunoreactive plexus zone. 5HT‐immunoreactive axons are most dense at the lateral edge of the ventral and intermediate lateral septal nuclei but form pericellular terminal arbors only in the dorsal lateral septal nucleus, in the septofimbrial nucleus, and in the dorsal cap of the medial septal nucleus. These results indicate that the dorsal and intermediate lateral septal nuclei include three histochemically distinct laminated subfields: (1) an ENK immunoreactive axonal plexus within the lateral aspect of the intermediate lateral septal nucleus, (2) a more medial region of scattered ENK immunoreactive perikarya and similarly scattered TH immunoreactive pericellular baskets, and (3) a dorsolateral zone occupied by SP neurons and 5HT‐containing pericellular baskets. Thus, the data suggest that SP‐ and ENK‐containing neuronal populations in the lateral septum receive different monoaminergic inputs. Further, the somewhat exclusive laminated pericellular termination of peptide‐ and catecholamine‐containing axons in the lateral septum predicts very different functional and pharmacological properties among zones.