bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thalamic projections to fields A, AI, P, and VP in the cat auditory cortex
Authors: Morel Anne , Imig Thomas J. 
Published: January 2005

AbstractThalamocortical projections to four tonotopic fields (A, AI, P, and VP) of the cat auditory cortex were studied by using combined microelectrode mapping and retrograde axonal transport techniques. Horseradish peroxidase (HRP) or HRP combined with either tritiated bovine serum albumin or nuclear yellow was injected into identified best‐frequency sites of one or two different fields in the same brain. Arrays of labeled neurons were related to thalamic nuclei defined on the basis of their cytoarchitecture and physiology. In some cases, patterns of labeling were directly compared with thalamic best‐frequency maps obtained in the same brain. We compared only patterns of labeling resulting from injections into similar parts of the frequency representation in different fields to insure that observed differences in patterns of labeling did not simply reflect differences in the frequency representation at the injection sites.The thalamic projection to the four fields is divided among seven nuclei, three tonotopic nuclei (ventral nucleus, V; lateral part of the posterior group of thalamic nuclei, Po; and dorsal cap nucleus, d) and four nontonotopic nuclei (caudodorsal nulceus, cd; ventrolateral nucleus, vl; and small, Ms, and medium‐large, Mg, cell regions of the medial division). Projections to each field differ, and each field receives inputs from tonotopic and nontonotopic nuclei. Field A receives its major inputs from Po and Mg, and a minor input from V. Field AI receives its major inputs from V, Po, and Mg, although Po and Mg have heavier projections to field A. Field P receives its major inputs from V, d, and vl; and minor inputs from cd, Ms, Mg, and Po. Field VP receives major inputs from V, vl, and cd; and minor inputs from d, Ms, and Mg.There are segregated territories in V and Po in which most neurons project to one cortical field (major projection), and a smaller proportion projects to one or more other fields (minor projections). Field VP receives a major projection from the caudal pole of V. Field P receives a major projection from the caudal half of V, and from a thin band along the dorsal border of rostral V. Field AI receives a major projection from most of the rostral one‐half of V, and smaller areas in Po and the caudal half of V exclusive of its caudal pole. Field A receives a major projection from most of Po.Neurons with collateral projections to at least two cortical fields have been found in small proportions in most areas projecting to tonotopic cortex. In V and Po at least one‐third of the minor‐projection fibers appear to be collaterals of major‐projection fibers.
Segmental origins of the cricket giant interneuron system
Authors: Jacobs Gwen A. , Murphey R. K. 
Published: January 2005

AbstractThe segmental origins of the cricket giant interneuron system have been studied by staining these neurons with cobalt during the last half of embryonic development. The results demonstrate that the interneurons are derived from three distinct clusters of embryonic neurons that form a serially repeating pattern in each abdominal ganglion. Some of the neurons previously described in adults (Mendenhall and Murphey, '74; Murphey, '85) have been identified in embryos and are described here with respect to this pattern. These neurons include both giant interneurons and several non‐giant mechanosensory interneurons that mediate several different sensory modalities. The anatomical organization of this system is compared to similar mechanosensory systems in other insects and crustacea.
Dopaminergic regulation of horizontal cell gap junction particle density in goldfish retina
Authors: Baldridge William H. , Ball Alexander K. , Miller Rodman G. 
Published: January 2005

AbstractLight‐ or dark‐adapted goldfish (Carassius auratus) retinas were treated with dopamine, which is believed to uncouple horizontal cells via D1 receptors, or with the dopamine antagonist haloperidol. Aldehyde‐fixed retinas were freeze‐fractured and the replicas examined by electron microscopy to identify horizontal gap junctions. The density (number per μm2) of intra‐membrane particles of horizontal ceil soma gap junctions was significantly lower in light‐adapted and dopamine‐treated retinas than in dark‐adapted and haloperidol‐treated retinas. There was no statistically significant difference between gap junction particles densities in (I) light‐adapted (untreated) and in dopamine‐treated (light‐ or dark‐adapted) retinas, or between (II) dark‐adapted (untreated) and haloperidol‐treated (light‐ or dark‐adapted). These results suggest that the uncoupling of horizontal cell somas by dopamine is accompanied by a decrease in gap junction particle density and that there is a greater release of dopamine during light‐adaptation than dark‐adaptation. Unlike horizontal cell somas, horizontal cell axon terminals did not show consistent changes in gap junction particle density with light‐ or dark‐adaptation. Although the data suggests that there may be a reduction in axon terminal gap junction particle density with dopamine treatment, this effect is not reversible with haloperidol treatment. Our results suggest that the regulation of gap junctions may differ at two sites within the same cell.
Overlap in the distribution of cholinergic and catecholaminergic neurons in the upper brainstem of the ferret
Authors: Henderson Z. 
Published: January 2005

AbstractThe distribution of catecholaminergic and cholinergic neurons in the upper brainstem of the ferret were mapped by staining immunohistochemically two adjacent series of sections of brainstem for tyrosine hydroxylase and choline acetyltransferase, respectively. As in other species, large numbers of tyrosine‐hydroxylase‐positive neurons are localized in the ventral tegmental area (A10), the substantia nigra (A9), and in A8. Tyrosine‐hydroxylase‐positive neurons in the dorsolateral pontine tegmentum (A4, A6, and A7‐the locus coeruleus complex) of the ferret are rather diffusely distributed, as has been observed in other carnivore species such as the cat and the dog, but unlike in the cat, these cells in the ferret display a relative uniformity in size and morphology.Choline‐acetyltransferase‐positive neurons which extend in the ferret's pedunculopontine tegmental nucleus and ventral parabrachial area (Ch5) are relatively large cells that stain intensely for choline acetyltransferase, and their dendrites form prominent bundles in regions where unstained fibre tracts are prevalent. Choline‐acetyltransferase‐positive neurons distributed in the laterodorsal tegmental nucleus (Ch6) are smaller than the cholinergic cells of Ch5, and they stain less intensely for choline acetyltransferase.Rostrally, there is little overlap between the catecholaminergic cell groups A8, A9, and A10 and the cholinergic cell groups of Ch5 and Ch6. Caudally, the Ch5 neurons extend some considerable extent into the locus coeruleus complex. In the region of overlap, no cells with staining for both tyrosine hydroxylase and choline acetyltransferase were observed, as was ascertained with a double staining method employing a combination of tyrosine hydroxylase immunofluorescence and choline acetyltransferase peroxidase‐antiperoxidase immunohistochemistry.In conclusion, the ferret has a typically carnivore pattern for the distribution of catecholaminergic cells in the upper brainstem, and there is a significant overlap between the catecholaminergic and cholinergic cell groups in the dorsolateral pontine tegmentum.
FMRFamidelike peptides of homarus americanus: Distribution, immunocytochemical mapping, and ultrastructural localization in terminal varicosities
Authors: Kobierski Linda A. , Beltz Barbara S. , Trimmer Barry Andrew , Kravitz Edward A. 
Published: January 2005

AbstractThe distribution of FMRFamidelike peptides was studied in the nervous system of the lobster Homarus americanus by using immunocytochemical and radioimmunological techniques. By radioimmunoassay FMRF‐amidelike immunoreactivity (FLI) was found in low levels (ca. 1 pmol/mg protein) throughout the ventral nerve cord and in much higher amounts (60–100 pmol/mg protein) in the neurosecretory pericardial organs. Immunocytochemical studies showed FLI in approximately 300–350 cell bodies, and in distinct neuropil regions, neuronal fiber tracts, and varicose endings. Specificity of the immunostaining was tested by preabsorbing the antiserum with FMRFamide, with peptides having similar carboxyl termini to FMRFamide (Met‐enkephalin‐Arg‐Phe, Phe‐Met‐Arg‐Tyr‐amide), with several amidated peptides (α‐melanocyte‐stimulating hormone, substance P, oxytocin), and with proctolin, a peptide found widely distributed in the lobster nervous system. Of these substances, only FMRFamide blocked the staining.In addition to the pericardial organs, significant levels of FLI were found in neurosecretory regions associated with thoracic second roots and in the connective tissue sheath that surrounds the ventral nerve cord. In all three regions, immunocytochemical studies showed the FLI to be localized to fine fibers and associated terminal varicosities lying close to the surface of the tissue, with no obvious target in their immediate vicinity. When examined at the ultrastructural level, the immunoreactive varicosities of the thoracic second roots and of the ventral nerve cord sheaths were found a few microns from the surface of the tissue and contained electron‐dense granules. In the immunoreactive nerve cord sheath endings, in addition to the large, dense granules, small, clear vesicles were found. The appearance and location of these terminals suggest a neurohormonal role for FMRFamidelike peptides in lobsters. The observation that low levels of FLI are found in the hemolymph supports this suggestion. In addition, the localization of FLI to particular neuronal somata, fiber tracts, and neuropil regions suggests possible functional roles for these peptides in (1) integration of visual and olfactory information, (2) function of the anterior and posterior gut, and (3) the control of exoskeletal muscles.
Transection of the infraorbital nerve in newborn hamsters alters the somatosensory but not the visual representation in the superior colliculus
Authors: Mooney Richard D. , Nikoletseas Michael M. , Rhoades Robert W. 
Published: January 2005

AbstractThe experiments described in this report were designed to determine whether changing the somatosensory representation in the deep laminae of the hamster's superior colliculus would result in a corresponding reorganization in the visual map in the overlying superficial layers. The somatosensory representation was altered by transecting the infraorbital (IO) nerve on the day of birth. This trigeminal branch supplies, among other targets, the snout and mystacial vibrissa follicles. These peripheral structures compose a major portion of the somatosensory representation in the deep collicular laminae. The effects of these lesions were assessed in anatomical and physiological experiments when the animals reached adulthood.Retrograde tracing with true blue demonstrated a 48% reduction in the number of trigeminocollicular neurons in the partially deafferented subnucleus interpolaris (the main source of trigeminal input to the rodent colliculus–e.g., Killackey and Erzurumlu: J. Comp. Neurol. 201:221–242, '81), but anterograde tracing with horseradish peroxidase (CHRP) and wheat germ agglutinin‐conjugated HRP showed that the terminal field of the trigeminocollicular projection from the deafferented subnucleus was essentially normal. This pathway terminated as a series of patches along the border between the stratum griseum intermediate and stratum album intermedium and encompassed approximately 75% of the rostrocaudal extent of the colliculus.The electrophysiological experiments revealed a marked change in somatosensory collicular topography. There was an underrepresentation of the vibrissae and the entire IO peripheral field in the deep laminae of the nerve‐damaged animals, and neurons with trigeminal ophthalmic and mandibular receptive fields were recorded from portions of the colliculus in which only whisker‐sensitive neurons would be normally isolated. There were no corresponding changes in the organization of the visual representation.These results support the conclusion that the organization of the visual representation in the superficial laminae and the organization of the somatosensory map in the deep layers of the mammalian superior colliculus follow independent developmental programs.
Distribution of GABA‐like immunoreactivity in the rat amygdaloid complex
Authors: Nitecka L. , Ben‐Ari Y. 
Published: January 2005

AbstractThe distribution of GABA‐like (GABA‐Li) immunoreactivity in the rat amygdaloid complex was studied by using an anti‐GABA antibody. GABA‐Li positive neurons and processes were present in every nucleus of the complex. Three patterns of immunoreactivity were revealed: (1) the intercalated masses and the lateral olfactory tract nucleus exhibited the most intense staining of the neuropil, and virtually every neuron was labeled, (2) the central and medial nuclei contained intensely labeled neuropil and moderately labeled neurons, and (3) in the remaining nuclei, the neuropil was weakly labeled, and relatively numerous GABA‐Li neurons were present. Our results suggest that: (1) the intercalated masses and lateral olfactory tract nucleus consist of large aggregates of GABA‐Li immunoreactive neurons, and (2) the lateral, basal dorsal, and the posterior cortical nuclei may constitute a significant source of GABAergic connections to other amygdaloid nuclei, in particular to the medial and central nuclei.
Distribution of specific intermediate‐filament proteins in the goldfish retina
Authors: Jones Paul S. , Schechter Nisson 
Published: January 2005

AbstractThe intermediate‐filament proteins expressed in the goldfish retina were investigated by immunohistochemistry and by immunoblotting. Polyclonal antibodies that previously had been raised against the goldfish optic nerve neurofilament (ON1 and ON2) and glial filament (ON3 and ON4) proteins were used in this study. Anti‐ON1/ON2 antiserum reacted on a retinal immunoblot with two proteins having molecular weights and isoelectric points corresponding to those of ON1 and ON2. Histologically, the most pronounced anti‐ON1/ON2 reactivity was observed in the ganglion cell layer of the goldfish retina. The anti‐ON3/ON4 antiserum reacted with a single protein on a retinal immunoblot. This protein had a molecular weight and isoelectric point which corresponded to the goldfish optic nerve glial filament proteins. This anti‐serum labeled horizontal cells in retina sections. Three previously unidentified goldfish visual‐pathway intermediate‐filament proteins sharing a molecular weight of 60K were observed on two‐dimensional gels of retinal cytoskeletal proteins and on retinal immunoblots which were probed with a monoclonal antibody which recognizes an epitope common to all intermediate Filament proteins.The possible existence of homologs of mammalian GFAP and vimentin in the goldfish retina was also explored. Antibodies directed against mammalian GFAP and vimentin labeled the Müller fibers and the cone horizontal cells, respectively. However, immunoblot analysis and a comparison of the two‐dimensional gel electrophoresis patterns of goldfish retinal and rat spinal cord cytoskeletal proteins demonstrated a lack of goldfish proteins identical to the mammalian intermediate‐filament proteins.
Distribution of substance P‐like immunoreactive retinal ganglion cells and their pattern of termination in the optic tectum of chick (Gallus gallus)
Authors: Ehrlich D. , Keyser K. T. , Karten H. J. 
Published: January 2005

AbstractSubstance P‐like immunoreactive (SP‐LI) neurons were identified within the inner nuclear layer and ganglion cell layer of the chick retina. The SP‐LI cells in the inner nuclear layer consisted of several subtypes of neurons, differing in soma size and dendritic arborization. In the ganglion cell layer a population of moderately labelled SP‐LI neurons was also present. About 6–9 m̈m in diameter and spaced 50–80 m̈m apart, they formed a regular array across the entire retina, with a density of about 400 cells/mm2 in the superior temporal retina, declining to less than 100 cells/mm2 in the peripheral retina. The total number of SP‐LI cells in the ganglion cell layer was approximately 75,000. Individual axons could be followed toward the optic nerve head. Lesions near the optic nerve head resulted in axotomy of ganglion cells within a limited portion of the retina. Two days postaxotomy there were numerous SP‐LI swellings in the proximal segments of axotomized axons. SP‐LI neurons in the axotomized zone were larger, more numerous, and showed increased staining of their processes. Fourteen days following a retinal lesion, there was depletion of all SP‐LI cells in the ganglion cell layer within the axotomized zone, but the SP‐LI neurons in the inner nuclear layer were not noticeably affected.Following a localized injection of rhodamine‐coupled latex beads into the optic tectum, a population of retinal ganglion cells (RGCs) in the contra‐lateral retina was retrogradely labelled. Many of these cells also exhibited SP‐like immunoreactivity.Examination of the optic tectum indicated the presence of SP‐LI fibres in laminae 2–13 (nomenclature of Cajal: Histologie du Systems Nerveux. Vol. 2. Paris: Maloine, '11), with immunoreactive terminal regions present mainly in laminae 2–4, 7, and 9–13. SP‐LI cell bodies were found predominantly in laminae 10–12 and 13. Fourteen days following a retinal lesion, SP‐LI processes and terminals were depleted from laminae 2 and 3. Immunoreactive cells and processes in the remaining laminae of the optic tectum were not noticeably altered.The present report confirms the existence of SP‐LI retinal ganglion cells in the chick retina and demonstrates their contribution to lamina specific SP‐LI arborization in the optic tectum.
Afferent and efferent connections of the primary octaval nuclei in the clearnose skate, Raja eglanteria
Authors: Barry Michael A. 
Published: January 2005

AbstractHorseradish peroxidase techniques were employed to trace the central projections of afferents from the individual endorgans of the membranous labyrinth and to delineate the efferent projections from the primary octaval nuclei to the spinal cord and midbrain octavolateralis area in the clearnose skate, Raja eglanteria. First‐order octaval afferents project ipsilaterally to five primary octaval nuclei, namely: magnocellular, descending, posterior, anterior, and periventricular. Octaval afferents also terminate in the reticular formation, nucleus intermedius (primary mechanoreceptive lateral‐line nucleus), and vestibulolateral lobe of the cerebellum. Each primary octaval nucleus receives afferent input from each labyrinthine endorgan, with the possible exception of macula neglecta input to the magnacellular nucleus. Within the anterior, descending, and to a lesser extent posterior and magnocellular nuclei, this input is largely nonoverlapping. Semicircular canal cristae afferents terminate ventrally, saccular and lagenar afferents dorsally, utricular afferents laterally, and macula neglecta afferents course ventrally but terminate largely dorsally within these nuclei. In the vestibulolateral lobe of the cerebellum, cristae afferents project primarily to the pars medialis, whereas macular endorgan afferents terminate in the pars lateralis. Primary afferent input to the reticular formation is predominantly from the horizontal canal crista. The densest projections to nucleus intermedius are from the utriculus and sacculus. Vestibulospinal projections originate primarily from the magnocellular and descending nuclei. Secondorder auditory neurons are most likely located in dorsomedial parts of the descending and anterior nuclei. Cells in these nuclei project directly to the auditory area of the midbrain octavolateralis complex, but projections to this area originate predominantly from nuclei C1 and C2, which are possible superior olivary homologues.
Distribution of catecholaminergic cells in the retina of the rat, guinea pig, cat, and rabbit: Independence from ganglion cell distribution
Authors: Mitrofanis John , Vigny Annette , Stone Jonathan 
Published: January 2005

AbstractBy using an antibody against tyrosine hydroxylase (TH), the rate‐limiting enzyme in the production of catecholamines, we have examined the morphology and distribution of catecholaminergic cells in the retinas of the rat, guinea pig, cat, and rabbit. In the albino rat, as reported by others, most TH‐immunoreactive (TH‐IR) cells were amacrine cells, and formed two morphological classes. Cells of one class (class 1) are stellate amacrine cells, the somata of most being in the inner part of the inner nuclear layer (INL). Cells of the second class (class 2) were seen only as small somata, also in the inner part of the INL. Cells of both classes were found in all areas of the retina, with a distinct but broad concentration around the superior‐temporal margin of the retina. A small number of TH‐IR interplexiform cells was seen. In the pigmented rat, only class 1 cells were recognized, also concentrating at the superior‐temporal margin. In the guinea pig, cat, and rabbit, TH‐IR cells also seemed to form one morphological class of amacrine cells, which resembled the class 1 cells of the albino rat. In the guinea pig and cat, their distribution resembled that seen in the rat, with the cells concentrating at the superior‐temporal margin of the retina. In the rabbit, TH‐IR cells concentrated weakly in the visual streak, but at both ends of the streak the concentration of TH‐IR cells extended farther peripherally than the concentration of ganglion cells. Overall, the distribution of TH‐IR cells seems largely or (in the rabbit) partially independent of the distribution of ganglion cells. This independence raises questions of the development and function of this group of amacrine cells.
Morphology and ultrastructure of physiologically identified substantia gelatinosa (lamina II) neurons with axons that terminate in deeper dorsal horn laminae (III–V)
Authors: Light Alan R. , Kavookjian Anahid M. 
Published: January 2005

AbstractIn order to determine their local circuit function, we have examined physiologically characterized, intracellularly labeled neurons in laminae I and II with light and electron microscopes. Single neurons in the spinal substantia gelatinosa (lamina II) of the cat and monkey were recorded intracellularly and characterized physiologically. Following characterization, the neurons were labeled with horseradish peroxidase that was iontophoretically ejected from the recording micropipette. After fixation and sectioning, histochemical reaction allowed visualization of the neuron soma, dendrites, and axon. The four nociceptive neurons reported here (three from cats and one from a monkey) had axons that distributed terminal collaterals to deeper laminae of the spinal cord, including laminae III, IV, and V. Electron microscopy of the axons demonstrated that the parent axons were myelinated and that the terminal collaterals established synaptic contact with neurons in the deeper laminae. These results suggest that some substantia gelatinosa neurons relay nociceptive information to neurons in deeper regions of the spinal dorsal horn via myelinated axons.