bluuebunny/crossref_metadata_2025_split huggingface dataset:
Periventricular dopaminergic neurons terminating in the neuro‐intermediate lobe of the cat hypophysis
Authors: Luppi P. H. , Sakai K. , Salvert D. , Berod A. , Jouvet M. 
Published: January 2005

AbstractThe aim of the present study was to determine the exact origins of the dopaminergic hypothalamohypophyseal projections in the cat brain. For this purpose, we used a retrograde tracer technique with horseradish peroxidase (HRP) in conjunction with tyrosine hydroxylase (TH) immunohistochemistry as a marker for the dopaminergic neurons. After injections of the tracer into the neuro‐intermediate lobe, a substantial number of HRP‐labeled neurons was observed in the supraoptic and paraventricular neurosecretory nuclei. Furthermore, a cluster of HRP‐positive neurons was found in the tuberal component of the periventricular nucleus where few, if any, neurosecretory magnocellular cells are identified. TH immunohistochemistry on the same sections further revealed that virtually all these HRP‐containing neurons showed TH immunoreactivity. These double‐labeled neurons were medium in size and fusiform or ovoid and appeared to belong to the A14 dopamine cell group. In addition to these medium‐sized double‐labeled neurons, a magnocellular type of double‐labeled cell body was identified just adjacent to the organum vasculosum of the lamina terminalis and in and around the supraoptic and paraventricular nuclei. These double‐labeled cells appeared to be members of the A14 and A15 dopamine cell groups. In conclusion, the present study indicated that the dopaminergic projections to the cat neuro‐intermediate lobe might originate mainly in the medium‐sized cells located in the tuberal periventricular nucleus and partly in the large‐sized cells located in and around the supraoptic and paraventricular neurosecretory nuclei.
Optic tectum of the eastern garter snake, Thamnophis sirtalis. II. Morphology of efferent cells
Authors: Dacey Dennis M. , Ulinski Philip S. 
Published: January 2005

AbstractTectal efferent neurons were retrogradely filled from extracellular injections of horseradish peroxidase (HRP) into pathways efferent from the tectum. Tectorotundal neurons have cylindrical dendritic trees, 80–100 μm in diameter, that extend vertically across the central and superficial tectal layers. Apical and basal dendrites are laden with complex appendages. The axon gives rise to an intratectal, collateral arbor that extends horizontally into the stratum griseum centrale beyond the cell's dendritic tree. The parent axon exits the tectum laterally in the tectothalamic tract. Tectogeniculate neurons also have narrow, radially oriented, and highly branched apical dendrites, but their basal dendrites are infrequently branched and lack appendages. An intratectal axon collateral forms a small, spherical arbor overlapping the apical dendrites in sublayer c of the stratum fibrosum et griseum superficiale. The parent axon ascends vertically and just below the stratum opticum turns rostrad to follow the optic fibers to the diencephalon. Tectoisthmi neurons have small somata and thin, radial dendrites that arborize below the pial surface in the stratum zonale. An intratectal axon collateral forms a spatially restricted arbor ventral to the soma in register with the dendritic tree. Tectoisthmobulbar neurons have dendrites that arborize extensively in sublayer a of the stratum fibrosum et griseum superficiale. The axon exits the tectum without collateralizing and joins a smallcaliber component of the ventral tectobulbar tract. Ipsilateral tectobulbar neurons have stellate dendritic fields, 150‐250 μm in diameter, that are restricted to the deep layers of the tectum. Sparsely branched dendrites are appendage‐free but bear many short, fine spicules. The axon initially ascends from the soma and recurves into the stratum album centrale without collateralizing before joining a medium‐caliber component of the ventral tectobulbar tract. Crossed tectobulbar neurons have large, stellate dendritic trees with diameters ranging from 200 to 500 μm. Like ipsilateral tectobulbar neurons, their dendrites are appendage‐free but bear spicules. Their thick‐caliber axons exit the tectum without collateralizing and course deep in the stratum album centrale to reach the dorsal tectobulbar tract.
Regeneration of the cerebellofugal projection after transaction of the superior cerebellar peduncle in kittens: Morphological and electrophysiological studies
Authors: Kawaguchi Saburo , Miyata Hirofumi , Kato Nobuo 
Published: January 2005

AbstractIn contrast to the current concept of abortive regeneration of mammalian central axons, occurrence of marked, functionally active regeneration of the cerebellofugal projection was proved in kittens after complete transection of the decussation of the brachium conjunctivum (BCX). By means of the anterograde axonal transport of horseradish peroxidase that was injected into the cerebellar lateral and interpositus nuclei, the origin, course, and destination of the, regenerated fibers were identified unamhiguorisly and the time‐course of axonal regeneration was clarified. Functional connectivity of the regenerated cerebellothalamic projection was tested electrophysiologically. In eight out of 82 animals, marked regeneration of the cerebellofugal projection occurred; in the majority of the rest of the animals, trace amounts of regenerated fibers were observed. In the former but not in the latter animals, marked cerebellocerebral responses, as in intact animals, were evoked in the frontal motor and parietal association cortices. Most of the regenerated axons took a course similar to that of the normal projection and terminated in the normal projection areas, whereas a small proportion of fibers showed an aberrant course and termination. The cut ends of axons began to swell as early as 15 minutes after transaction, and the regenerated axons produced dense terminals in the thalamus by 19 days.
The pattern of spinal and medullary projections from a cutaneous nerve and a muscle nerve of the forelimb of the cat: A study using the transganglionic transport of HRP
Authors: Abrahams V. C. , Swett J. E. 
Published: January 2005

AbstractThe transport of HRP into the spinal cord and medulla in the cat has been examined from a forelimb cutaneous nerve, the lateral superficial radial nerve (LSR), and from the muscle nerves supplying both heads of the forelimb muscle, extensor carpi radialis (ECR). HRP transported by the LSR was widely distributed in the spinal cord throughout laminae I‐IV in the vicinity of the root entry zone and from spinal segments T1 to C5. HRP was also transported from the LSR to the medulla where there was intense patchy, discontinuous labelling in the main cuneate nucleus. The pattern of labelling in the cuneate nucleus did not follow any simple somatotopic plan. Exposure of the muscle nerve to HRP led to labelling in the spinal dorsal horn in lamina I, in the deep dorsal horn on the lamina V/VI border, and in lateral and medial lamina VI at sites that contain cells of origin of spinocerebellar tracts. The medial lamina VI label was contiguous with a deposit that extended medially to the central canal. The label in lateral lamina VI was patchy and formed a discontinuous column from T1 to C5. HRP transported by the muscle nerve also produced label in the more ventral regions of the cuneate nucleus where it had a lacy appearance, in part due to its extensive distribution around dendrites. A relatively dense, patchy, and discontinuous deposit of reaction product was also present in the external cuneate nucleus after muscle nerve exposure. This deposit was most intense on the dorsomedial surface of this nucleus, but another, less intense, deposit was also present ventrally.
A light and electron microscopic analysis of the mossy fibers of the rat dentate gyrus
Authors: Claiborne Brenda J. , Amaral David G. , Cowan W. Maxwell 
Published: January 2005

AbstractThe axon collaterals of dentate granule cells have been analyzed with the aid of a computerized microscope, following intracellular injections of horseradish peroxidase in hippocampal slice preparations. The axon of each granule cell gives rise to approximately seven primary collaterals; these collaterals usually divide into secondary and tertiary branches, which form an extensive plexus within the hilar region of the dentate gyrus. Individual axon collaterals vary greatly in length, but most have been found to be between 100 and 300 μm long. On average, the summed lengths of the collaterals (exclusive of the parent mossy fiber) are approximately 2,300 μm. Except for an occasional collateral that is given off by a mossy fiber in the proximal part of field CA3 of the hippocampus, the collaterals of the granule cell axons are confined to the hilar region; they are rarely seen in the granule cell layer itself and have never been observed in the molecular layer. In the longitudinal dimension of the dentate gyros, most of the collaterals are contained within a zone about 400 μm wide. The distribution of the collaterals within the hilar region is correlated with the location of the granule cell body. Those that arise from cells near the tip of the suprapyramidal blade tend to be confined to the region above field CA3; those from cells nearer the crest and from the infrapyramidal blade ramify widely throughout the hilus.Two types of varicosities are present on the collaterals. Numerous small (∼2 μm), round varicosities are distributed unevenly along the collaterals; in electron micrographs these varicosities can be seen to make asymmetric synaptic contacts with dendritic shafts. On average, each granule cell collateral plexus his about 160 of these varicosities. The second type of varicosity is irregular in shape and ranges from 2 to 4 μm in diameter; there is usually only one sucil varicosity per collateral. In all respects except size, these varicosities rE semble the expansions found on the parent mossy fibers.Mossy fiber trajectories in the proximal part of field CA3 were studied after extracellular injections of HRP into localized regions of the granule cell layer. Granule cells at different locations around the blade send their mossy fibers to different depths within the pyramidal cell layer in the proximal part of field CA3. However, further distally, mossy fibers from all parts of the granule cell layer contribute to the suprapyramidal bundle that occupies the stratum lucidum.
Telencephalic projections from midbrain and isthmal cell groups in the pigeon. I. Locus coeruleus and subcoeruleus
Authors: Kitt Cheryl A. , Brauth Steven E. 
Published: January 2005

AbstractHorseradish peroxidase (HRP) and amino acid autoradiography were used in pigeon to determine the trajectories and projection patterns of neurons within the locus coeruleus and subcoeruleus nuclei upon the cerebral hemispheres. The specific cell groups investigated include the locus coeruleus (LoC), nucleus subcoeruleus dorsalis, and nucleus subcoeruleus ventralis.Efferents from each of these nuclei ascend to the telencephalon via the medial and lateral forebrain bundles, ansa lenticularis, and the quintofrontal and occipitomesencephalic tracts. A separate dorsally situated bundle derived from LoC neurons reaches many dorsal thalamic nuclei. The telencephalic projections of the LoC and subcoeruleus nuclei are bilateral and symmetrical, although projections to the contralateral hemisphere are sparse. Crossing fibers project to contralateral targets primarily via the dorsal supraoptic decussation and along the dorsal and ventral margins of the anterior commissure.Within the telencephalon, the following neural structures receive input from neurons in the LoC and subcoeruleus cell groups: the paleostriatal complex including the paleostriatum augmentatum and lobus parolfactorius, septal nuclei, nucleus accumbens, olfactory tubercle, hippocampus and parahippocampal area, nucleus taeniae, dorsal archistriatum, lateral neostriatum, hyperstriatum dorsale, hyperstriatum ventrale, and preoptic area.Large portions of the cerebral hemispheres including the hyperstriatum accessorium, much of the neostriatum and hyperstriatum ventrale, and all but the dorsal portion of the archistriatum receive little or no input from either the locus coeruleus or subcoeruleus cell groups. This is apparently different from the condition in mammals in which virtually all cortical fields receive input from neurons within the LoC. Moreover, the pattern of projections of the subcoeruleus nuclei upon telencephalic fields described here as well as recent histochemical data suggest that these cell groups are comparable to the lateral tegmental (A8) cell group of mammals rather than to the mammalian subcoeruleus nuclei.
Regeneration of motoneuron axons into the adult frog spinal cord. After ventral‐to‐dorsal‐root anastomosis
Authors: Liuzzi F. J. , Lasek R. J. 
Published: January 2005

AbstractMotoneuron axons routed into the adult frog spinal cord via a ventral‐to‐dorsal‐root anastomosis regenerated into the white and the gray matters. The distribution, growth patterns, and arborizations of regenerated ventral root axons were compared to those of regenerated dorsal root axons within the same environment.Within the spinal white matter, regenerating ventral root axons behaved very similarly to regenerating dorsal root axons. Here, the regenerating ventral root axons grew longitudinally beneath the pia and radially toward the spinal gray matter, particularly within the dorsolateral fasciculus. The location of the regenerating axons and the patterns of their growth within the white matter suggest that glial endfeet and radial glial processes play a major role in the determination of these axonal growth patterns.When motor axons entered the gray matter, their arborizations were very similar to those of regenerated dorsal root axons, suggesting that these two very distinct populations of axons respond similarly to local cues within the spinal gray matter. One difference between the arborizations of these two populations of axons was the relative number of varicosities along axonal branches. Regenerated motoneuronal arborizations within the spinal gray matter had fewer en passant varicosities than regenerated dorsal root axonal arborizations. This difference may reflect the synaptogenetic response of the two types of axons to targets within the gray matter. The low number of en passant varicosities associated with the ventral root axonal aborizations suggests that these axons do not synapse with all available targets and that the rules governing synaptic specificity during development may apply during regeneration in the adult frog spinal cord.
Brainstem terminations of extraocular muscle primary afferent neurons in the monkey
Authors: Porter John D. 
Published: January 2005

AbstractThe central terminations of afferent nerve fibers from the extraocular muscles of the monkey were investigated by means of transganglionic transport of wheat germ agglutinin‐conjugated horseradish peroxidase (WGA/ HRP). Following injections of selected extraocular muscles with WGA/HRP, terminal labeling was apparent in the ipsilateral trigeminal sensory and cuneate nuclei. The density of trigeminal projections varied markedly from one rostrocaudal level to the next, being heaviest within the ventrolateral portion of pars interpolaris of the spinal trigeminal nucleus. A second extraocular muscle afferent representation was noted in ventrolateral portions of the cuneate nucleus. This projection was restricted to rostral portions of pars triangularis of the cuneate nucleus, partially overlapping the afferent termination from dorsal neck muscles.It is likely that some of the problems encountered in formulating conclusions regarding the functional role of extraocular muscle proprioception are due to a lack of detailed information of the central termination pattern of muscle afferents. Taken together, the present findings should provide a basis for further anatomical and physiological studies designed to elucidate the role played by extraocular muscle proprioceptors in vision and oculomotor control.
Retinotopic and chronotopic organization of goldfish retinal ganglion cell axons throughout the optic nerve
Authors: Springer Alan D. , Mednick Adam S. 
Published: January 2005

AbstractThe organization of the retinal ganglion cell (RGC) axons within the goldfish optic nerve head and optic nerve was established by labeling select groups of axons either autoradiographically or with cobaltous lysine. In the optic nerve head, the axons are organized eccentrically with respect to their time of development. Axons of older RGCs are located dorsally and those of younger RGCs are located ventrally. The retinal sectors map across the rostrocaudal axis of the optic nerve head, resulting in four dorsoventrally oriented columns that contain, from rostral to caudal, the axons of ventronasal, dorsonasal, dorsotemporal, and ventrotemporal RGCs. Thus, the optic nerve head is organized into orthogonally oriented laminae. One dimension maps the age of the axons and the other maps the retinal sector of the axons' origin.The optic nerve is organized virtually in the same fashion as the optic nerve head. However, glial septa that invade the optic nerve severely distort, but do not eliminate, the columnar organization of the retinal sectors. These septa deflect many RGC axons and disrupt nearest‐neighbor relationships. The distortions produced by the glial septa include folding of the columns and distortion of the chronological lamination. However, the glial septa do not extend into the optic foramen. Therefore, a virtually undistorted columnar organization reappears in the optic foramen. Several roles for the glial septa are discussed.
Multiple visual areas in the caudal superior temporal sulcus of the macaque
Authors: Desimone Robert , Ungerleider Leslie G. 
Published: January 2005

AbstractAnatomical and physiological evidence indicates that, in addition to area MT, much of the cortex in the caudal superior temporal sulcus (STS) of the macaque has visual functions. Yet the organization of areas outside of MT remains unclear, and there are even conflicting data on the boundaries of MT itself. To examine these issues, we recorded from neurons throughout this region in three monkeys. Anterograde or retrograde tracers were injected into MT at the conclusion of recording to identify its projection fields. Based on differences in their visuotopic organization, neuronal properties, receptive field size, myeloarchitecture, and pattern of connections with MT, several visual areas were distinguished within the caudal STS.Area MT, defined as the heavily myelinated portion of the striate (VI) projection zone in STS, contained a systematic representation of only about the central 30°–40° of the contralateral field. The far peripheral field was represented medial to MT in MTp, which we had previously found receives projections from far peripheral V1 and V2 (Ungerleider and Desimone: J. Comp. Neurol 248:147–163, 1986). Like MT, MTp contained a high proportion of directionally selective cells, and receptive field size in MTp was the size expected of MT fields if the latter were to extend into the periphery.Areas MST (medial superior temporal) and PP (posterior parietal) were found medial to MT and MTp. Both MST and PP had a high proportion of directionally selective cells, but only MST received a direct projection from MT. Cells in MST had larger receptive fields than those in either MT or MTp butnonetheless displayed a crude visuotopic organization. Receptive fields of cells in PP were even larger, some including the entire contralateral visual field. Furthermore, unlike cells in MST, some in PP responded to auditoryor somesthetic stimuli in addition to visual stimuli.Area FST, which has a distinctive myeloarchitecture, was found anterior to MT in the fundus of the STS, for which it is named. FST received a direct projection from MT, but only about a third of its cells were directionally selective. Receptive fields of cells in FST were large, often included the center of gaze, and often crossed into the ipsilateral visual field.Area V4t (transitional V4) and a portion of V4 were found lateral to MT within the STS, and both received direct projections from MT. V4t has a distinctive, light myelination. Both areas had a low incidence of directionally selective cells, and both contained coarse representations of the lower visual field.The neuronal properties of areas in the caudal STS suggest that MT, MTp, MST, and PP, together with the superior temporal polysensory area, constitute a cortical system for motion analysis. At successive stages in this system, neurons appear to integrate motion information over an increasingly large portion of the retina, respond selectively to more complex types of motion, and respond to inputs from additional sensory modalities.
Immunohistochemical study on the distribution of neuron‐specific enolase‐ and peptide‐containing nerves in the reticulorumen and the reticular groove of cattle
Authors: Kitamura N. , Yamada J. , Yamashita T. 
Published: January 2005

AbstractThe distribution of nerves containing immunoreactivity for substance P (SP), vasoactive intestinal polypeptide (VIP), leucine‐enkephalin (LENK), gastrin‐releasing polypeptide (GRP), and somatostatin (SOM) was studied in the reticulorumen and the reticular groove of the calf and cow, use immunohistochemistry. Neuron‐specific enolase (NSE) antiserum was used to determine the general distribution of nerves, which was then compared to distribution of immunoreactive (IR) nerves stained for five kinds of peptides.Nerve fibers and cell bodies were observed in all segments examined; however, both elements showed considerable variation in different segments and age groups. The densities of nerve fibers and ganglia were most concentrated in the reticular groove and least numerous in the ruminal wall. VIP‐, SP‐, and LENK‐IR nerves were detected in all segments, whereas GRP‐ and SOM‐IR nerves were detected only in the reticular groove. NSE‐IR nerves were moderately abundant in the reticulorumen, but peptide‐IR nerves composed onlya minor population of nerves with VIP‐IR nerves being most abundant. SP‐IR nerves were less abundant and LENK‐IR nerves were rarely observed. Abundantnerves were detected in the lips of the reticular groove and of these, SP‐IR nerves were most abundant, and in order of decreasing abundance, VIP‐, LENK‐, SOM‐, and GRP‐IR nerves were observed also. Immunoreactive nerves were more abundant in the calf than in the cow. The reduced abundance of immunoreactive nerves in the cow as compared to calf was striking, particularly with‐regard to the SP‐IR nerves located in the lips of the reticular groove.