bluuebunny/crossref_metadata_2025_split huggingface dataset:
Immunohistochemical demonstration of some putative neurotransmitters in the lamprey spinal cord and spinal ganglia: 5‐hydroxytryptamine‐, tachykinin‐, and neuropeptide‐Y‐immunoreactive neurons and fibers
Authors: Van Dongen Paul A. M. , Hökfelt Tomas , Grillner Sten , Verhofstad Albert A. J. , Sternbusch Harry W. M. , Cuello A. Claudio , Terenius Lars 
Published: January 2005

AbstractThe distribution of some putative neurotransmitters was investigated in the spinal cord and spinal ganglia of the lamprey, a primitive vertebrate, by using immunohistochemical methods. In the spinal cord a midline row of 5‐hydroxytryptamine (5‐HT)‐immunoreactive neurons was present immediately ventral to‐the central canal over the entire length of the spinal cord. The ventral processes of these neurons formed a dense ventromedial plexus of varicosities. In the dorsal, lateral, and ventral spinal axon columns, several longitudinal 5‐HT fibers were present. After chronic spinal transections the distribution of 5‐HT fibers was unchanged; it is therefore concluded that there was no substantial descending 5‐HT contribution and that the spinal 5‐HT neurons supplied the regional 5‐HT innervation. The spinal 5‐HT cells sent fibers into the dorsal and ventral roots; 5‐HT cell bodies and fibers were also present in the spinal dorsal root ganglia, in their dorsal, ventral, and lateral nerve branches, and in the dorsal and ventral branches of the ventral roots.Neurons and fibers containing peptides of the tachykinin (TK) family (to which, amongst others, substance P belongs) were found in the spinal cord. TK neurons in the spinal cord supplied the local TK innervation, as well as TK fibers in the dorsal and ventral roots. Fibers have been found containing either TK, or 5‐HT, or both compounds.Neurons containing neuropeptide‐Y (NPY)‐immunoreactive material were present in a medial column just dorsal to the central canal. The NPY neurons have longitudinal, mainly descending, fibers that provide the local NPY innervation of the lamprey spinal cord.The present results provide evidence for local spinal systems containing 5‐HT, TK, 5‐HT and TK, or NPY, but in contrast to mammals, these compounds do not seem to arise from supraspinal neurons.
The morphology of relay neurons in the dorsal lateral geniculate nucleus of the marsupial brush‐tailed possum (Trichosurus vulpecula)
Authors: Robinson Stephen R. , Webster Maree J. 
Published: January 2005

AbstractThe retinal terminal zones and the morphology of relay neurons within the dorsal lateral geniculate nucleus (LGNd) of the brush‐tailed possum (Trichosurus vulpecula) have been investigated with horseradish peroxidase (HRP) tracing techniques. Anterograde transport of HRP from the retina confirmed previous descriptions of the laminar distribution of retinal afferents in this nucleus. In addition, it was found that lamina III consists of two adjacent bands (IIIa and IIIb) of contralateral retinal input, separated by a terminal‐free zone 20–40 μm wide. This zone is not apparent with Nissl or fibre stains.Relay neurons in the LGNd were retrogradely filled following cortical injections of HRP, and two classes (A and B) were distinguished. Class A neurons are found in the alpha portion of the LGNd (laminae I, II, III, and IV) and class B neurons in the beta portion (laminae V, VI, and VII). Class A cells are more densely packed and have shorter and more numerous dendrites, less‐extensive dendritic arbors, and thicker axons than class B cells. No significant differences were found between the two classes in perikaryal size or thickness of proximal dendrites. Neurons in each lamina of the nucleus have dendritic arbors which ramify extensively within adjacent laminae, except cells in lamina IIIb, which have relatively few dendrites that cross into the cell‐free zone and lamina IV.
The organization of retinal projections to the diencephalon and pretectum in the cichlid fish, Haplochromis burtoni
Authors: Presson Joelle , Fernald Russell D. , Max Marianna 
Published: January 2005

AbstractThe organization of retinofugal projections was studied in a cichlid fish by labelling small groups of retinal ganglion cell axons with either horseradish peroxidase or cobaltous lysine. Two major findings resulted from these experiments. First, optic tract axons show a greater degree of pathway diversity than was previously appreciated, and this pathway diversity is related to the target nuclei of groups of axons. The most striking example is the formation of the medial optic tract. Fibers that will become the medial optic tract move abruptly away from their neighbors, at about the level of the optic chiasm, and coalesce at the dorsomedial edge of the marginal optic tract. The medial optic tract projects to the thalamus, the dorsal pretectum, and the deep layer of the optic tectum. The axial optic tract is a group of fibers which segregates from the most medial portion of the marginal optic tract, at about the level of the optic chiasm. The axial tract stays medial to the marginal optic tract for a few hundred microns and then curves laterally to rejoin the marginal optic tract. At least some axial trat axons terminate in the suprachiasmatic nucleus. Within the marginal optic tract, retinal ganglion cell axons from a given retinal quadrant are always segregated into at least two groups. The smaller group projects to the superficial pretectal nucleus. The larger group projects to the superficial layer of the optic tectum.Second, each nontectal retinal termination site receives a unique pattern of retinal input. Within the pretectum the parvocellular superficial pretectal nucleus receives a highly retinotopically organized input from all retinal regions; the basal optic nucleus receives a roughly retinotopically orgnaized input from all retinal regions; the dorsal pretectum receives an input from all retinal regions; and the central pretectal nucleus receives input only from the ventral hemiretina. Within the diencephalon the thalamus receives an input from all retinal regions, but this input is not retinotopically organized; the suprachiasmatic nucleus receives input from the region of central retina that lies just dorsal to the optic nerve head, via the axial optic tract. The accessory optic nucleus receives input from the dorsal hemiretina.
Heterogeneity of ganglia of the guinea pig myenteric plexus: An in vitro study of the origin of terminals within single ganglia using a covalently bound fluorescent retrograde tracer
Authors: Takaki Miyako , Wood Jackie D. , Gershon Michael D. 
Published: January 2005

AbstractExperiments were done to test the hypothesis that individual ganglia of the myenteric plexus of the guinea pig small intestine are heterogeneous with respect to the location of the neurons that provide terminals to them. The myenteric plexus, attached to the longitudinal layer of smooth muscle, was maintained in vitro. Individual ganglia were injected with a variety of potential retrograde tracers by pressure microejection from the tip (20‐μm diameter) of a glass micropipette. The fluorescent dye 4‐acetoamido, 4′‐isothiocyanostilbene‐2,2′‐disulphonic acid (SITS) was found to be an effective tracer, labeling neuronal perikarya, evidently by retrograde transport. SITS has previously been shown not to cross plasma membranes, but to be covalently bound to the outer surface of that membrane, and to be taken up by nerve terminals to be retrogradely transported to label neuronal cell bodies. SITS fluorescence was found in about 12% of the neurons within the ganglion into which it was injected and also in approximately ten times more neurons in discretely located distant ganglia. No labeling of neurons was found when SITS was injected into the bath or into the smooth muscle below the myenteric plexus. Damage to neural connectives obstructed the labeling of neurons in ganglia distal to the injection site. Individual SITS‐injected myenteric ganglia were found to vary greatly in the ratios of intraganglionic SITS‐labeled neurons to the total number of neurons within the injected ganglion. The ratios of the number of intraganglionic SITS‐labeled neurons to SITS‐labeled neurons in distant ganglia projecting to the injected ganglion from elsewhere in the myenteric plexus also varied greatly. More strikingly, individual ganglia differed over a wide range with respect to whether the neurons in distant ganglia that provided them with terminals were situated in the oral, anal, or circumferential direction. Although the majority of projections were found to be from orally located ganglia, individual ganglia were observed that received predominantly or exclusively anal or oral projections. Others received mixtures of terminals from ganglia that were anal, oral, or circumferential. This anatomical heterogeneity in the location of afferent inputs to individual myenteric ganglia is probably reflected in a functional heterogeneity as well and will have to be taken into account in further studies of the physiology of the myenteric plexus. Individual ganglia of the plexus can no longer be taken as anatomically and functionally equivalent to one another.
Distribution of neuropeptide Y immunoreactivity in the basal forebrain and upper brainstem of the squirrel monkey (saimiri sciureus)
Authors: Smith Y. , Parent A. , Kerkérian L. , Pelletier G. 
Published: January 2005

AbstractThe distribution of neuropeptide Y (NPY) immunoreactivity in the brain of the squirrel monkey (Saimiri sciureus) was studied by means of the indirect immunofluorescence, peroxidase‐antiperoxidase, and avidin‐biotin‐complex methods. The antiserum used was raised in rabbits and did not show any significant crossreactivity with related peptides including peptide YY and avian pancreatic polypeptide.In the upper brainstem of the squirrel monkey a dense NPY‐immunoreactive terminal field is seen in lateral parabrachial area, locus coeruleus, and interpeduncular nucleus. A small group of NPY‐immunoreactive cell bodies is present in the lateral habenula and a moderate number of NPY‐immunoreactive fibers occurs in periaqueductal gray and nucleus raphe pallidus. The substantia nigra (SN) appears mostly devoid of NPY immunoreactivity whereas the ventral tegmental area contains a few reactive fibers. In the hypothalamus the medial preoptic area as well as the arcuate and paraventricular nuclei receive a strikingly dense NPY innervation. In addition, numerous NPY‐positive cell bodies are found within the dorsomedial half of the supraoptic nucleus but very few are seen in paraventricular nucleus. A large number of NPY‐immunoreactive cell bodies is also present in arcuate nucleus. In the basal telencephalon NPY‐immunoreactive cells abound mostly in striatum, but some are also found in the amygdala (particularly basal, central, and lateral amygdaloid nuclei), the claustrum, and in the bed nucleus of the stria terminalis. Intensely reactive network of NPY‐immunoreactive fibers is also present in all of these structures. In striatum, the numerous, fine and nonvaricose NPY‐immunoreactive fibers, as well as the NPY‐positive cell bodies, are slightly more abundant in caudate nucleus than in putamen. The globus pallidus (GP) is mostly devoid of NPY‐immunoreactive fibers and terminals. The fact that the two major recipient structures of striatal outflow (SN and GP) do not receive significant NPY input suggests that the striatal NPY‐containing neurons are intrinsically organized.
Cytodifferentiation of photoreceptors in larval goldfish: Delayed maturation of rods
Authors: Raymond Pamela A. 
Published: January 2005

AbstractThis study describes the differentiation of photoreceptors in larval goldfish retina. The earliest photoreceptors to differentiate were cones; 3H‐fucose labeled cone but not rod outer segments in larval as well as adult goldfish. All major cone types known to be present in the adult goldfish retina (double cones, long and short single cones) were found in the larval retina by 2 days after hatching. The cones matured rapidly; within a few days they had well‐developed outer segments and synaptic pedicles that were smaller, but otherwise similar to those in adults. Rods were slower to mature. Their outer segments were at first short, wide, and misshapen; only as they grew longer and narrower did they become straight and properly aligned. Rod spherules were first seen in fish older than 1 month; immature rods contained perinuclear synaptic ribbons and invaginating processes penetrated the cell body. These results suggest that the influence of rods and cones on visual function in larval goldfish may be quite different from the adult.
The effects of a 30 day period of environmental diversity on well‐fed and previously undernourished rats: Neuronal and synaptic measures in the visual cortex (area 17)
Authors: Bhide P. G. , Bedi K. S. 
Published: January 2005

AbstractBlack and white Lister hooded rats were undernourished from the 16th day of gestation until 25 postnatal days of age. These previously undernourished rats and a set of well‐fed rats were later subjected to 30 days of environmental diversity, i.e., environmental enrichment or isolation. Two separate experiments were carried out. In experiment 1, the environmental diversity lasted from 85 to 115 days of age and in experiment 2, from 35 to 65 days of age.At the end of the period of environmental diversity, all rats were killed by perfusion with 2% phosphate‐buffered glutaraldehyde. Small pieces of tissue from the right visual cortex were embedded in Spurr's resin. For each rat two blocks of resin‐embedded tissue were randomly selected, and from these semithin sections (0.5 μm) were cut and stained with toluidine blue. Photomicrographs of cortical layers II and III were taken from these sections and used to estimate the numerical density of neurons. Ultrathin (ca. 70 nm) sections of the same region of the cortex were cut and stained with lead citrate. These sections were used to estimate the synaptic disc diameter and numerical density. Synapse‐to‐neuron ratios were calculated from the estimates of synaptic and neuronal numerical densities.In experiment 1, well‐fed rats raised in enriched environments had a significantly smaller neuronal numerical density and a greater synaptic disc diameter than well‐fed rats raised in an impoverished environment. In experiment 2, neither the well‐fed nor previously undernourished rats showed significant effects of environmental treatment on any of the features studied. The statistical interaction between nutrition and environment was not significant for any of the features in either experiment.
Topographical organization of the afferent connections of the principal ventromedial thalamic nucleus in the cat
Authors: Jiménez‐Castellanos J. , Reinoso‐Suárez F. 
Published: January 2005

AbstractThe afferent connections to the principal division of the ventromedial thalamic nucleus (VMP) were studied in the cat by means of the HRP retrograde transport technique. The large (40 nl) and small (20 nl) injections of this enzyme were delivered info the VMP using different stereotaxic approaches. The main afferents to VMP emanated bilaterally from the prefrontal, premotor, and rostral agranular insular cortices. Another important group of afferents to the VMP were those originating in the rostral third of the reticular thalamic nucleus, the entopeduncular nucleus, the substantia nigra pars reticulata, and the deep cerebellar nuclei. From the cerebellar nuclei, the contralateral lateral nucleus and the caudal third of both (ipsi and contralateral) medial cerebellar nuclei were the origin of afferents to the VMP. Other cortical areas projecting fin a lower density) to the VMP were the motor cortex, the cortex along the anterior ectosylvian sulcus, the granular insular cortex, the posterior agranular insular area, the prelimbic area, and the cortex along the posterior rhinal sulcus (SRP). Among other subcortical prosencephalic structures projecting to the VMP are the dorsal claustrum, substantia innominata, hypothalamic formations, and the zona incerta. Projections originated from the brainstem in the lateral part of the intermediate and deep layers of the superior colliculus, the central gray matter, the locus coeruleus, and the reticular formation. The nucleus tegmenti pedunculopontinus pars compacta, parabrachial nuclei, the vestibular complex, and the spinal trigeminal nucleus were also origins of projections to the VMP.We conclude by emphasizing the important bilateral cortical modulation of the different functions attributed to the VMP: recruiting‐response mediation, reticular‐activating system participation, and extrapyramidal motor integration. In light of the connections just described, the VMP may be considered as a point for impulses coming from complex association cortical areas and limbic formations to converge with those emanating from cortical and subcortical motor structures.
A morphological investigation of thalamic neurons by intracellular hrp staining in cats
Authors: Yamamoto Tetsuro , Noda Terumi , Samejima Akio , Oka Hiroshi 
Published: January 2005

AbstractMorphological analysis of 77 neurons in the ventroanterior (VA), ventrolateral (VL), ventromedial (VM), and central lateral (CL) nuclei was performed by intracellular HRP staining in combination with electrophysiological studies. The neurons were classified into four groups according to either electrophysiological or morphological criteria, i.e., 20 relay neurons 18 thalamocortical (T‐C) and two thalamocaudate (T‐Cd) relay neurons, 17 projection neurons, 36 unidentified neurons, and four presumed interneurons. All 36 unidentified neurons had morphological features similar to those of relay and projection neurons. All neurons except four presumed interneurons had dendrites sparsely covered with spinelike appendages. Most of their dendrites displayed a spherically radiating branching pattern, and a few showed a tufted or linearly oriented pattern.Sizes of somata and dendritic radii were compared in entopeduncular (Ent)‐responsive (n = 25) and cerebellar (CN)‐responsive groups (n = 37) in VA, VL, and VM nuclei. The soma size was similar in VL (18–21 × 29–34 μm) and VM (15–19 × 29–31 μm), but in VA, CN‐responsive neurons (15 × 30 μm) seemed to be smaller than Ent‐responsive ones (22 × 36 μm). The largest dendritic field of neurons in each thalamic nucleus was similar in both groups. They were about 250–320 μm in radius. Diameters of axons were also compared but no statistically significant difference was detected (i.e., 1.5 ± 0.3 mean ± S.D.) μm for the Ent group and 1.7 ± 0.5 μm for the CN group.Three types of axonal trajectories were noted, i.e., neurons projecting their axons dorsolaterally, ventrolaterally, or horizontally. Fourteen neurons out of 37 relay and projection neurons gave off several fine distal axon collaterals in the thalamic reticular nucleus, and one T‐Cd, three projection, and one unidentified neurons gave off proximal axon collaterals near the soma‐dendritic domain in addition to those in the thalamic reticular nucleus.Four neurons classified as presumed interneurons had smaller somata (9–13 × 18–23 μm) and varicose dendrites. Three of them received Ent‐induced inhibitory postsynaptic potentials (IPSPs) or CN‐induced excitatory postsynaptic potentials (EPSPs). Several presumed axon terminals were found to cover the soma of an adjacent neuron, which seemed to indicate their inhibitory nature.The proximal axon collaterals in the ventral thalamic nuclei may consist of local inhibitory circuits with presumed interneurons in addition to other inhibitory circuits with thalamic reticular neurons.
Cutaneous receptive fields of somatic and viscerosomatic neurones in the thoracic spinal cord of the cat
Authors: Cervero F. , Tattersall J. E. H. 
Published: January 2005

AbstractExtracellular single‐unit recordings were made from 121 neurones in the thoracic spiral cord of the cat. All neurones could be driven by electrical stimulation of dorsal root afferent fibres. The neurones were classified, according to the absence or presence of inputs from the ipsilateral splanchnic nerve, as “somatic” or “viscerosomatic,” respectively.Cutaneous receptive fields were identified for 75 of the neurones: 31 were somatic and 44 viscerosomatic. Only two of the somatic cells received cutaneous nociceptive inputs, compared with 33 of the viscerosomatic cells. Sixty‐four percent of the whole sample of neurones had receptive fields which included three or more dermatomes. Viscerosomatic cells tended to have larger receptive fields than the somatic neurones, and six of them had fields which did not include the corresponding (T11) dermatome.Neurones with receptive fields in the dorsal one‐third of the dermatome tended to be located in the lateral one‐third of the dorsal horn, but those with receptive fields in the ventral two‐thirds of the dermatome showed no differential distribution within the gray matter. This is discussed with respect to the results of anatomical studies on the dorsal horn projections of cutaneous afferent fibres from different regions of the dermatome.Preliminary results from intracellular staining with horseradish peroxidase reveal extensive branching of primary afferents in the dorsal horn, and large dendritic fields of dorsal horn neurones. Our physiological and morphological results indicate that the somatotopic organisation of the thoracic spinal cord is less well defined than that of the lumbosacral region.
The projection of the lateral geniculate nucleus to area 18
Authors: Geisert Eldon E. 
Published: January 2005

AbstractThe present study is concerned with the projection of the lateral geniculate nucleus onto cortical area 18. Horseradish peroxidase (HRP) was injected into area 18 of 15 cats. Drawings were made to determine the location of the injection site and the distribution of labeled neurons in the lateral geniculate nuclei of each cat. The local retinotopic maps constructed prior to the injections and the reconstructions of the lateral geniculate nucleus were used to determine the location and the extent of each of the HRP injections.In 15 of the 25 hemispheres studied, the ratio of the number of HRP‐labeled neurons in lamina A relative to the number of labeled neurons in lamina A1 was calculated. This ratio varied from 1.06 to 0.28, indicating that at least some regions of area 18 are dominated by inputs from lamina A1. However, if the HRP‐labeled neurons in lamina C are included in the counts for lamina A, then the ratio A + C/A1 has a mean of 1.11, suggesting that area 18 receives a balanced input, with inputs from the contralateral eye being relayed through laminae A and C, and inputs from the ipsilateral eye being relayed through lamina A1.When the distribution of HRP‐labeled neurons in lamina A was plotted onto a dorsal view of the lateral geniculate nucleus, the labeled neurons formed an ellipse with the long axis of the ellipse oriented parallel to the isoelevation lines. The representation of azimuth is compressed in area 18 relative to the lateral geniculate nucleus.In six hemispheres the injections were restricted to a few layers of the area 18. Following small injections into layer IV of area 18, the HRP‐labeled neurons occupied an extensive region of the lateral geniculate nucleus, indicating a considerable amount of convergence of the inputs to area 18. In hemispheres where the injections were restricted to layers I and II, labeled neurons were only seen in the medial interlaminar nucleus and the C laminae.