bluuebunny/crossref_metadata_2025_split huggingface dataset:
An atlas of the primary visual projections in the brain of the chick Gallus gallus
Authors: Ehrlich David , Mark Richard 
Published: January 2005

AbstractThe localisation of the primary visual centres in the chick mesencephalon and diencephalon was determined by autoradiographic anterograde transport and degeneration techniques. Strong visual projections were found in the tectum, lateral anterior thalamic nucleus, lateroventral geniculate nucleus, superficial synencephalic nucleus, external nucleus, ectomammillary nucleus, tectal grey, dorsolateral anterior thalamus, rostrolateral part, and the pretectal optic area. Weaker retinal projections were found in the ventrolateral thalamus, two subregions of the dorsolateral anterior thalamus, lateral part, diffuse pretectal nucleus, dorsolateral anterior thalamus, magnocellular part, and the hypothalamus. An atlas of the retinal projections was constructed from sections.
An immunocytochemical study of the serotonergic innervation of the thalamus of the rat
Authors: Cropper E. C. , Eisenman J. S. , Azmitia E. C. 
Published: January 2005

AbstractThe serotonergic innervation of the rat thalamus was studied with an indirect immunocytochemical technique using an antiserum raised against a serotonin‐hemocyanin conjugate in animals pretreated with L‐tryptophan and a monoamine oxidase (MAO) inhibitor. When pretreatment was not used there was a decrease in the number of immunoreactive fibers observed in the thalamic region.Innervation was greatest in nucleus ventralis corporis geniculati lateralis, and in the following midline nuclei: nucleus periventricularis, nucleus rhomboideus, and nucleus reuniens. Also well labeled were nucleus anterior ventralis, the intralaminar nuclei, and nucleus lateralis dorsalis. Moderate innervation was found in nucleus reticularis, nucleus anterior dorsalis, nucleus ventralis medialis, nucleus lateralis pars posterior, the posterior complex, and in nucleus dorsalis corporis geniculati lateralis. Very few serotonergic fibers were observed in nucleus paratenialis, nucleus gelatinosus, nucleus anterior medialis, nucleus medialis dorsalis, nucleus ventralis, nucleus ventralis pars dorsomedialis, or in nucleus corporis geniculati medialis. Serotonin immunoreactivity was also noted in a number of fiber bundles in the thalamic region. These include the fasciculus retroflexus, the fasciculus mamillothalamicus, the stria medullaris, and the stria terminalis.These results differ from those of previous descriptions of the serotonergic innervation of thalamic nuclei most notably in the midline nuclei and in the posterior complex. In this study the midline nuclei, nucleus rhomboideus, and nucleus reuniens were more densely innervated than had been described, and in the posterior complex a moderate, rather than sparse, innervation was observed. The more densely innervated nuclei of the anterior and lateral nuclear groups, nucleus lateralis dorsalis and nucleus anterior ventralis, also contained a greater number of labeled fibers than had been indicated.
Distribution of immunoreactive substance P neurons in the hypothalamus and pituitary of the rhesus monkey
Authors: Rønnekleiv Oline K. , Kelly Martin J. , Eskay Robert L. 
Published: January 2005

AbstractThe distribution of immunoreactive substance P (IR‐SP) neurons was examined in the hypothalamus and pituitary gland of the rhesus monkey by using the peroxidase‐antiperoxidase immunocytochemical technique. Immunoreactive SP cell bodies were observed in the arcuate nucleus, in the region lateral to the arcuate nucleus, and in the median eminence (ME). Immunoreactive SP cells were also seen in the periventricular area of the dorsal tuberal region. A rich network of SP fibers was concentrated in the arcuate region, and the fiber stain was particularly dense in the external zone of the median eminence and in the external layer of the infundibular stalk. Also, substance P fibers were seen in the internal layer of the pituitary stalk and in the neural lobe of the pituitary gland. Outside the hypothalamus a dense network of IR‐SP fibers was observed in the globus pallidus.
The development of retinal ganglion cells in a tetraploid strain of Xenopus laevis: A morphological study utilizing intracellular dye injection
Authors: Sakaguchi D. S. , Murphey R. K. , Hunt R. K. , Tompkins R. 
Published: January 2005

AbstractThe morphological development of retinal ganglion cells was examined in a tetraploid strain of Xenopus frogs. The enlarged cells of the tetraploid strain facilitate the application of intracellular techniques. Using an in vitro retinal preparation and Nomarski optics, intracellular recording and dye injection were carried out under visual control on ganglion cells in central retina from 2 days of development (stags 24) to metamorphosis (stage 64).We identified three phases in the morphological differentiation of ganglion cells. During the first phase (stages 24–30), all cells were neuroepitheliallike in form and possessed robust resting potentials in the range of ‐35 to ‐60 mV, and dye‐coupling was occasionally observed between neighboring cells. During the second phase of ganglion cell development (stages 31–45) the neurons had begun to elaborate axons and dendrites. These cells possessing neurites had resting potentials between ‐15 and ‐30 mV, and no dye‐coupling was observed between neighbors. During the third and final phase of maturation, from stage 46 onward, three distinct morphological types of ganglion cells could be identified. Type I cells had the smallest somata and the smallest‐diameter dendritic arborizations. The profusely branched dendrites of these cells ramify extensively throughout the inner plexiform layer. Type II cells had large somata, intermediate‐diameter dendritic fields, and a highly elaborate dendritic branching pattern. These cells were seen to arborize within two sublamina in the inner plexiform layer. Type III cells had large somata, the largest‐diameter dendritic fields, and a dendritic arbor with long primary branches but little higher‐order branching. These large dendritic fields were confined to a single sublamina of the inner plexiform layer, abutting the inner nuclear layer. While most phase 3 cells showed radial axon trajectories from the soma to the optic disc, a minority of cells (1–5%) with erratic and nonradial axon trajectories were also observed.Our data provide a morphological description of ganglion cell maturation in the central retina of Xenopus. We show that very early in development (as early as stage 46) three distinct morphological types of retinal ganglion cells are Present, which corresnond to the three classes of ganglion cells previously described in adult Xenopus (Chung et al., '75).
Ultrastructural correlates of electrical‐chemical synaptic transmission in goldfish cranial motor nuclei
Authors: Hackett J. T. , Buchheim A. 
Published: January 2005

AbstractThe output connections of the cranial relay neurons, part of the Mauthner cell network, were examined in goldfish with light and electron microscopic techniques. Either lueifer yellow or horseradish peroxidase (HRP) was injected into cranial relay neuron axons to demonstrate that they diverge to several motor nuclei and to many motoneurons within one nucleus. Retrograde transport of the enzyme from injections of mandibular muscles was used to label the trigeminal motoneurons.In the electron microscope, cranial relay neuron processes were distinguished by the granular appearance of the electron‐opaque polymer formed enzymatically by HRP, while the retrogradely labeled motoneurons had the polymer enclosed in lysosomes. The cranial relay neuron terminals contained many presynaptic vesicles which concentrated the HRP reaction product. Active zones and synaptic clefts were evident. At some synapses, both gap junctions and presynaptic vesicles were found.The mechanism of synaptic transmission was investigated by simultaneous recording with two intracellular microelectrodes from cranial relay neuron‐motoneuron pairs. Composite postsynaptic potentials in a trigeminal motoneuron were evoked by intracellular stimulation of a cranial relay neuron axon. The earliest excitatory postsynaptic potential (EPSP) component had a latency of 0.25 sec and had a peak amplitude that was not depressed by repetitive stimulation. A second component had larger peak amplitudes which were reduced easily by repetitive stimulation. Antidromic action potentials were not transmitted from motoneurons to the cranial relay neuron axons.Thus, both electrical and chemical transmission probably occur at the cranial relay neuron‐motoneuron synapses. Since the cranial relay neurons fire synchronously and receive excitatory chemical synapses, the function of the gap junctions and electrical transmission is unclear. Perhaps the importance of these gap junctions is more for transport of small molecules than for impulse transmission.
Topographic organization of the olivocochlear projections from the lateral and medial zones of the superior olivary complex
Authors: Guinan John J. , Warr W. Bruce , Norris Barbara E. 
Published: January 2005

AbstractBy anterograde tracing using autoradiography, we have found topographic organizations in the projections of both medial and lateral olivocochlear (OC) systems in the cat. Lateral‐zone injections show an ipsilateral cochleotopic projection pattern with more medial injections projecting more basally in the cochlea. In the contralateral cochlea, in contrast, the projections from all of the lateral‐zone injections were predominantly to the apex. However, detailed analysis suggests the possibility that the contralateral lateral‐zone projections may have the same cochleotopic organization as the ipsilateral projections but with a heavy bias toward the apex. Medial‐zone injections show a pattern in which more dorsal regions project more basally in both cochleas. The ipsilateral projections of lateral OC neurons appear to connect regions with similar best frequencies but the projections of medial OC neurons do not. Summation of data from all of the injections in each zone indicates that lateral OC projections are relatively evenly distributed throughout the ipsilateral cochlea but are predominantly to the apex in the contralateral cochlea. Medial OC projections are predominantly to the middle and basal parts of the cochlea on both sides with contralateral projections somewhat more basal than ipsilateral projections.
The distribution of substance P in turtle nervous system: A radioimmunoassay and immunohistochemical study
Authors: Reiner Anton , Krause James E. , Keyser Kent T. , Eldred William D. , McKelvy Jeffrey F. 
Published: January 2005

AbstractThe distribution of a substance P‐like material in turtle brain, spinal cord, dorsal root ganglion, and retina was determined using radioimmunoassay (RIA) and immunohistochemistry. High levels of a substance P‐like material were found in turtle neural tissue, particularly in basal telencephalon, hypothalamus, and tegmentum. In many regions, the concentration of a substance P‐like material in turtle nervous tissue was found to be similar, in a region‐to‐region comparison, to that previously reported for birds and mammals, particularly for the more “phylogenetically conservative” parts of the nervous system (such as the basal ganglia, tegmentum, and hypothalamus). The slopes of substance P RIA dose‐response curves for tissue extracts from nearly all regions of the turtle nervous system examined were parallel to a standard dose‐response curve for synthetic substance P (SP). The immunohistochemical results, with anti‐substance P antisera from guinea pig or rabbit, or with a monoclonal antibody, were consistent with the RIA data. Regions showing high concentration of an SP‐like material by RIA were observed to contain numerous neurons and/or fibers containing an SP‐like material. The immunohistochemical results provide evidence for the presence in turtle of numerous SP‐containing pathways, several of which (e.g., an SP‐containing strionigral pathway, an SP‐containing striopallidal pathway and an SP‐containing dorsal root ganglia‐spinal dorsal horn pathway), have been described in birds and mammals. The present results thus suggest that the neuropeptide SP has had a largely stable evolutionary history as a transmitter or modulatory agent during amniote brain evolution.
Peptide‐like immunoreactivity in anuran optic nerve fibers
Authors: Kuljis Rodrigo O. , Krause James E. , Karten Harvey J. 
Published: January 2005

AbstractUnilateral section, crush, or ligation of the optic nerve was performed in Rana pipiens. Following optic nerve disruption, Substance P (SP)‐, leucine‐enkephalin (LENK)‐, cholecystokinin octapeptide (CCK8)‐, and bombesin (BOM)‐like immunoreactivities were analyzed in the retinae and optic nerves. Peptide‐like immunoreactivity developed in the retinal stump of disrupted optic nerves within 1 hour after surgery and was retained until at least 30 days. Peptide‐positive staining in the retinal stump of the optic nerves was abolished by preabsorption of each of the antibodies/antisera with the corresponding synthetic substances. No massive peptide‐like immunoreactivity was observed in the cerebral stump of the ligated side, nor in the contralateral, nonoperated, optic nerve. No change in the pattern of peptide‐like immunoreactivity was apparent in the retina ipsilateral or contralateral to the experimental procedure. The optic tectum contralateral to the surgical procedure displayed those changes in peptide‐like immunoreactivity described previously following retinal deafferentation (Kuljis and Karten, '82a, '83a).Peptide‐like immunoreactivity in the stump retinad to the surgical procedure occurred in the form of beaded and fibrillar elements often ending in an irregular expansion near the lesion site. Fluorescent double‐label antibody methods demonstrated that SP‐like immunoreactivity is present in different processes than those containing LENK, CCK8, or BOM. Electron microscopical immunocytochemistry revealed that peptide‐like immunoreactivity is contained within unmyelinated and possibly also within myelinated axons in the stump retinad to the traumatic procedure. Radioimmunoassay studies of SP demonstrated a four‐ to sixfold increase in SP‐like content in the retinal stump of ligated nerves, compared with both the cerebral stump and with the contralateral nonoperated optic nerves.These findings demonstrate the presence of peptide‐like immunoreactivity in retinal ganglion cell processes, which is compatible with either a posttraumatic expression of previously repressed peptide‐like phenotypes, or, most likely, with the existence of various classes of peptide‐containing retinal ganglion cells. The latter prospect strongly suggests that peptide‐specific subsets of retinal ganglion cells terminate in highly specific laminae in the optic tectum (Kuljis and Karten, '81, '82a‐83a) and presumably differ in their physiological role in vision. Thus, these observations provide direct anatomo‐chemical evidence in support of Lettvin et al. ('59) and Maturana et al. ('60), regarding the differential laminar termination of physiologically diverse classes of retinal ganglion cells in the tectum.
The location and morphology of preganglionic neurons and the distribution of visceral afferents from the rat pelvic nerve: A horseradish peroxidase study
Authors: Nadelhaft Irving , Booth August M. 
Published: January 2005

AbstractPreganglionic neurons of the sacral parasympathetic nucleus (SPN) were located almost exclusively (98%) within the L6‐S1 spinal cord segments. The SPN contained approximately 550 neurons of medium size (10 × 20 μm). These were mainly located in the intermediolateral gray matter and had dendrites that extended into the dorsolateral funiculus, along the lateral marginal zone of the dorsal horn, and medially into the dorsal gray commissure. Labeled dorsal root ganglion cells were almost all located (95%) in the L6 and S1 ganglia. An average of approximately 1,500 sensory neurons were found. These were small cells (17 × 25 μm) whose central processes entered Lissauer's tract from which two groups of collaterals emerged: 1) a prominent lateral pathway along the lateral margin of the dorsal horn that extended into the region of the SPN and also into the dorsal gray commissure, 2) a less prominent medial pathway extending around the dorsal margin of the dorsal horn to terminate in the dorsal gray commissure. These two collateral groups formed fiber bundles that were spaced by approximately 100 μm between centers when observed in the horizontal plane. A third afferent bundle, composed of rostrocaudally oriented fibers, was located in the sagittal plane immediately ventral to the central canal. Comparisons are made between the results in rats and the results of similar experiments performed in cats and monkeys.
Temporal and spatial constraints on the collateral sprouting of low‐threshold mechanosensory nerves in the skin of rats
Authors: Jackson Patrick C. , Diamond Jack 
Published: January 2005

AbstractWe have studied the collateral sprouting of intact low‐threshold mechanosensory nerves into adjacent denervated skin in rats. An “isolated” field was produced by extensive denervations of the surrounding skin; sprouting of the remaining cutaneous nerve supplying the field was looked for in the form of field expansion into the surrounding denervated territory at various postoperative intervals. Such isolated fields failed to expand in the adult rat for periods up to at least 85 days. “Nonfunctional” sprouting is unlikely to explain this failure. However, similar experiments done in very young animals gave a different result. In rat pups aged less than 20 days, isolated fields did expand, but this ceased at about 20 days, and attempts to evoke it after this time were unsuccessful. There seems to be a critical period for sprouting of these touch‐sensitive nerves into denervated skin, and our evidence suggests that it may not begin until about 15 days of age. Within this developmental window the sprouting that occurs is spatially constrained, an isolated field expanding preferentially into denervated skin of the parent dermatome; if only skin of neighboring dermatomes is available there is no expansion. In contrast, low‐threshold nerves regenerated readily after a crush at all ages studied, and the mechanosensory fields established by regenerating nerves expanded progressively into denervated skin without apparent constraints at dermatomal boundaries. The temporal and spatial constraints found for the sprouting of intact low‐threshold axons are in marked contrast to their absence for the well‐described sprouting of high‐threshold (nociceptive) nerves.
Relationships between the nigrotectal pathway and the cells of origin of the predorsal bundle
Authors: May Paul J. , Hall William C. 
Published: January 2005

AbstractThe goal of this study was to define the anatomical relationships between the terminal field of the nigrotectal pathway and the tectal neurons which project to contralateral brainstem gaze centers by way of the predorsal bundle. The distribution and morphology of the cells of origin for the predorsal bundle were determined by using a modification of the retrograde horseradish peroxidase technique which homogeneously filled their somas and dendrites. The terminal distribution of the nigrotectal tract was determined using both anterograde horseradish peroxidase and autoradiographic procedures.The results indicate that, in the grey squirrel (Sciurus carolinensis), the predorsal bundle cells are a heterogeneous population whose dendritic fields form a well‐defined band confined to the inner half of stratum griseum intermediale. This inner sublamina also can be identified in Nissl and myelin stains. The same sublamina is the major target of the nigrotectal tract. The striking anatomical correspondence between the distribution of nigrotectal terminals and the cells projecting in the predorsal bundle supports a proposal, based on recent physiological investigations, that the nigrotectal tract plays an important role in the initiation of the saccade‐related activity of the deep tectal cells (Chevalier et al., '81; Hikosaka and Wurtz, '83a–d).
Neurotensin in the ventromedial mesencephalon of the rat: Anatomical and functional considerations
Authors: Kalivas Peter W. 
Published: January 2005

AbstractNeurotensin is an endogenous neuropeptide that fulfills some of the criteria for a neurotransmitter in the mammalian central nervous system. It exists in high concentrations in the ventral tegmental area and adjacent midline nuclei of the ventromedial mesencephalon, and recent microinjection studies have demonstrated that neurotensin can act in this brain region to produce both a decrease in colonic temperature, and an increase in spontaneous motor activity. In this study it was found that hypothermia was most successfully evoked following neurotensin injection along the midline of the ventral mesencephalon, corresponding to the nucleus linearis centralis. In contrast, behavioral hyperactivity was produced with greatest consistency in the ventral tegmental area, corresponding to the nucleus paranigralis and nucleus parabrachialis pigmentosus. However, in its caudal aspect, the nucleus paranigralis was found unresponsive to neurotensin. Behavioral hyperactivity was also observed after neurotensin injection along the midline into the nucleus interfascicularis. Only injections made into the nucleus linearis rostralis produced hypothermia and hyperactivity in the same rat. This distribution of neurotensin‐responsive nuclei corresponded to the distribution of neurotensin containing perikarya and fibers. With the exception of the nucleus interfascicularis, neurotensin‐containing neurons were distributed throughout the rostral portion of the ventromedial mesencephalon, the nucleus parabraehialis pigmentosus containing the greatest density. However, in the caudal portion, neurotensin neurons were found almost exclusively in the nucleus linearis centralis. Neurotensin‐containing fibers were of greatest density in the nucleus interfascicularis and the nucleus linearis centralis. Considering the known capacity of neurotensin to activate dopamine neurons in the ventromedial mesencephalon, and the partial mediolateral topographical distribution of dopaminergic projections from this region to the limbic forebrain, it is possible that neurotensin may be activating two distinct populations of dopamine neurons to produce hypothermia and behavioral hyperactivity.