bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel developmental boundary in the cerebellum revealed by zebrin expression in the Lurcher (Lc/+) mutant mouse
Authors: Tano David , Napieralski Julie A. , Eisenman Leonard M. , Messer Anne , Plummer Julie , Hawkes Richard 
Published: May 2005

AbstractThe cerebellar cortex contains at least two classes of Purkinje cells, which are organized into alternating arrays of parasagittal bands. The clearest demonstration of this compartmentation is the pattern of expression of a family of polypeptide antigens, the zebrins, which are expressed selectively by Purkinje cell subsets. Furthermore, anterograde tracing experiments show that the zebrin compartments are closely correlated with both afferent and efferent projection maps. The further subdivision of long parasagittal bands into smaller modules may occur through several different mechanisms, including the intrinsic cerebellar lobulation and the selective distribution of afferent terminal fields. However, while the longitudinal subdivisions are straightforwardly shown, the mediolateral boundaries are more subtle. In this report we describe a novel mediolateral and anteroposterior compartmentation boundary in mice, running across lobule VIII, that is revealed by the consequences of the lurcher (Lc/+) allele for zebrin expression. In normal mice zebrin compartmentation develops in several discrete stages: until postnatal day 5 (PD5) there is no zebrin expression; from PD5–PD7 zebrin is found only in the posterior lobe vermis, with immunoreactive Purkinje cells in lobules X, IX, and VIII but not elsewhere; from PD7–PD12 most Purkinje cells in the vermis become zebrin+ from PD12–PD15 immunoreactivity also appears in the hemispheres so that almost all Purkinje cells now are zebrin+ and finally, from PD15–PD25 zebrin is gradually suppressed in those Purkinje cells that are zebrin‐ in the adult until the mature pattern of parasagittal compartments is revealed. In the Lc/+ mutant the normal developmental progression is interrupted at around PD7. As a result, the pattern of zebrin expression becomes frozen at that stage when immunoreactive Purkinje cells are confined exclusively to the posterior lobe vermis. A reproducible boundary between expressing and nonexpressing zones runs mediolaterally across the dorsal surface of lobule VIII. Apart from zebrin expression itself, there are no obvious structural correlates of this transition. This mediolateral boundary identifies a developmental unit in the posterior lobe vermis of the cerebellum, and provides further evidence that the cerebellum is a highly heterogeneous structure. © 1992 Wiley‐Liss, Inc.
Development of the olivocerebellar projection in the rat: I. Transient biochemical compartmentation of the inferior olive
Authors: Wassef Marion , Chedotal Alain , Cholley Béatrice , Thomasset Monique , Heizmann Claus W. , Sotelo Constantino 
Published: May 2005

AbstractIn the present study the early phases of the development of the inferior olive were examined by using immunocytochemical techniques. We observed that, from embryonic day 16 onward, antibodies against the calcium binding proteins parvalbumin and calbindin and the calcitonin gene related peptide stain partially overlapping territories of the inferior olive. This staining delimits a biochemical zonation of the inferior olive which is combinatory and transient. We have previously observed a biochemical parcellation of the cerebellar Purkinje cells which, like that of the inferior olive, is first observed, at E16, involves the combined expression of marker proteins and is also transient. In order to know whether the biochemical compartmentations of the cerebellum and inferior olive arise independently, the time course of the development of the olivocerebellar projection was studied by anterograde and retrograde in vitro axonal tracing by using the fluorescent carbocyanine dye DiI. The olivocerebellar axons were found to reach the limit of the cerebellar plate at E16 and to enter it at E17. Even at this age the great majority of the climbing fibers are tightly fasciculated, which minimizes their interactions with the PC clusters. These observations indicate that the topographical heterogeneity of Purkinje cells and inferior olive neurons arise independently. The transient biochemical individualization of subgroups of neurons during development could contribute to recognition mechanisms. © 1992 Wiley‐Liss, Inc.
Myelin‐Axon relationships in the rat phrenic nerve: Longitudinal variation and lateral asymmetry
Authors: Fraher John P. 
Published: May 2005

AbstractIt is known that the myelin sheath thickness‐axon perimeter relationship varies between peripheral nerves. This study examines the possibility that that relationship may vary between levels along a given nerve or between corresponding levels of the right and left examples of the same nerve. The relationship is examined for large and small fibre classes at well separated upper and lower intrathoracic levels in the rat phrenic nerve. The study shows that the myelin‐axon relationship differs between levels along the same nerve bundle in the same (intrathoracic) environment. Thus, for a given increase in the perimeter of large axons, sheath thickness increases significantly more at lower than at upper levels. In addition, myelin sheath thickness shows a statistically significant lateral asymmetry in favour of the left side for the large fibre class at the upper thoracic level. The setting of the myelin sheath thickness‐axon perimeter relationship also differs between the large and small fibre classes at each level examined. Large fibres have proportionately thicker sheaths than small fibres and this difference is reflected in the significantly smaller g‐ratio of the former. Systematic differences in the setting of the myelin sheath thickness‐axon perimeter relationship between large and small fibre classes may be a widely occurring phenomenon. It may be concluded that the myelin‐axon relationship varies significantly both within and between nerves and also between fibre classes. Accordingly, morphometric studies of normal or pathological nerves should take into account possible consistent longitudinal variation or lateral asymmetry in fibre parameters and myelin‐axon relationships within a given nerve bundle or fibre class, in order to avoid introducing systematic bias and to minimize variance between samples. © 1992 Wiley‐Liss, Inc.
Effects of sex and androgen treatment on dendritic dimensions of neurons in the sexually dimorphic preoptic/anterior hypothalamic area of male and female ferrets
Authors: Cherry James A. , Tobet Stuart A. , DeVood Timothy J. , Baum Michael J. 
Published: May 2005

AbstractA sexually dimorphic group of cells at the dorsal border of the preoptic/anterior hypothalamic area (POA/AH) of ferrets has been previously identified in Nissl‐stained tissue. In this study, Golgi‐stained tissue was examined in order (1) to determine whether sex differences exist in dendritic dimensions of neurons from this region, and (2) to assess the effects of adult androgen treatment on dendritic morphology in ferrets of both sexes. Brains from adult ferrets given daily injections of testosterone propionate (5 mg/kg body weight) or oil vehicle for 5 weeks after gonadectomy were impregnated by Golgi‐Cox procedures. After sectioning at 120 μm, 78 multipolar neurons were selected from the sexually dimorphic POA/AH of 12 ferrets and reconstructed in three dimensions with the aid of a computer‐assisted neuron tracing system. Large sex differences were observed in somal area and most aspects of dendritic morphology, including total length, number of branches, and total dendritic surface area. Androgen also appeared to accentuate dendritic arborization in both sexes, but this effect was weaker than the sex effect, more apparent in males than females, and restricted to fewer variables. The most statistically significant effects of adult androgen treatment in males were found for total dendritic surface area and percentage of fourth order dendrites, and in females, average dendritic thickness. These data show that strong sex differences exist in dendritic structure of neurons in the POA/AH, and suggest that alterations in levels of gonadal steroids in adulthood may promote synaptic remodeling in a region of the brain involved in the control of sexually dimorphic behaviors. © 1992 Wiley‐Liss, Inc.
Time of ganglion cell genesis in relation to the chiasmatic pathway choice of retinofugal axons
Authors: Reese B. E. , Guillery R. W. , Mallarino C. 
Published: May 2005

AbstractThe time of generation of retinal ganglion cells in fetal cats has been related to the course taken later by their axons in the optic chiasm. The ganglion cells were labelled with tritiated thymidine either on embryonic day (E) 26 or on E‐301. When the cats were mature, ganglion cells were retrogradely labelled with horseradish peroxidase injected into one optic tract. The distribution of double‐labelled cells showed that cells in the temporal retina generated on E‐26 all have axons that take an uncrossed course in the chiasm, whereas, of the cells generated on E‐30 in the temporal retina, some take a crossed course and others take an uncrossed course. The uncrossed axons of the E‐26 cohort come from cells having a central distribution on the retina. For the E‐30 cohort, the uncrossed axons come from cells having a relatively peripheral distribution, whereas the crossed axons come from more central cells.The present results suggest that the mechanism which serves to direct temporal retinal axons into the ipsilateral optic tract weakens as development proceeds. In principle, the change may occur in either a chiasmatic signal, read by temporal but not nasal optic axons, or in a retinal label, carried by temporal but not nasal cells and their processes. Since temporal retinal cells born concurrently at different places can project to opposite optic tracts, a retinal signal that deteriorates with time in a centroperipheral fashion is favored by the present results.
Topography of ganglion cells in the dog and wolf retina
Authors: Peichlcu Leo 
Published: May 2005

AbstractThe topographical distribution of retinal ganglion cells in seven breeds of dog (Canis lupus f. familiaris) and in the wolf (Canis lupus) was studied in retinal wholemounts stained with cresyl violet or with a reduced silver method. A prominent feature of all wolf retinae was a pronounced “visual streak” of high ganglion cell density, extending from the central area far into both temporal and nasal retina. By contrast, either a pronounced or a moderate visual streak was found in dog retinae. It is hypothesized that a pronounced streak is an archetypal feature of Canis lupus, and that the moderate streak in some dogs is a corollary of breeding during domestication.Irrespective of the differences in streak form and retinal area, the estimated total number of ganglion cells was about 200,000 cells in the wolf and 115,000 in the dog. Ganglion cell density maxima in the central area of the wolf were about 12,000–14,000/mm2, and in the dog they ranged from 6,400/mm2 to 14,400/mm2. This implies individual differences in visual acuity. Alpha ganglion cells constituted 3–14% of all ganglion cells in the dog and 1–18% in the wolf, depending on retinal location. A distinct feature of all dogs and wolves was the absence of alpha cells in a substantial region of temporal peripheral retina. This has not been found in any other mammalian species and suggests corresponding functional deficits.
Heterogeneity of sensory hair cells in a fish ear
Authors: Chang Janet S.Y. , Popper Arthur N. , Saidel William M. 
Published: May 2005

AbstractThe ultrastructure of sensory hair cells in the utricle of the cichlid fish, Astronotus ocellatus, the oscar, was studied by transmission electron microscopy of serial ultrathin sections from different regions of the epithelium. Two distinctly different types of hair cell were found, one located in the striolar region of the epithelium and the other in the extrastriolar region. Striolar hair cells have a well‐defined perinuclear cisterna located just below the nucleus, and large perinuclear mitochondria, Synapuc bodies.of striolar cells are small and located in clusters, while those in extrastriolar cells are relatively large and individually dispersed. The extrastriolar hair cell closely resembles the amniote type II hair cell. On the basis of these data, and consistent with earlier studies, it appears that the striolar hair cells closely resemble amniote type I hair cells in many significant ways. Thus we have called them type I‐like cells. The extrastriolar hair cells appear to be typical of eighth nerve mechanorecep‐tors commonly described for fish and closely resemble the amniote type II hair cell.
Topography and collateralization of the dopaminergic projections to motor and lateral prefrontal cortex in owl monkeys
Authors: Gaspar P. , Stepniewska I. , Kaas J. H. 
Published: May 2005

AbstractThe sources and histochemical characteristics of dopaminergic projections to motor and premotor areas of cortex were investigated in owl monkeys in which information from related studies was used to subdivide cortex into motor fields. Brainstem projections to frontal cortex were identified by injections of different fluorescent dyes in the primary motor cortex (M1) and the supplementary motor area (SMA), first identified by microstimulation. Injections were also placed in dorsal premotor cortex and lateral prefrontal cortex. The distribution of retrogradely labeled neurons was related to the location of tyrosine hydroxylase immunolabeled neurons on the same or alternate brain sections to identify the dopamine (DA) neurons. All DA cortically projecting neurons were located in the A8–A10 complex, largely in its dorsal components, including the parabrachial pigmented n. of the ventral tegmental area (VTA), pars gamma of the substantia nigra compacta, and the dorsal part of the retrorubral area (A8). Fewer cells were in the midline groups of VTA (n. linearis rostralis and caudalis) and in the n. paranigralis. DA neurons projecting to M1, SMA, and prefrontal cortex were largely intermixed, and some of these neurons were double or triple labeled by the fluorescent dyes, indicating Collateralization to two or three fields; DA cells projecting to M1 were more numerous than to the other locations. The dorsal components of the A8–A10 complex from which arose the DA mesocortical projection were also characterized by the presence of calbindin‐immunoreactive neurons and by a dense neurotensin and noradrenergic terminal innervation.Compared to rodents or felines, the DA neurons projecting to the lateral frontal lobe of primates appear to be shifted dorsally and laterally in the nigral complex. The topographic overlap, partial Collateralization, and common histochemical characteristics of the DA mesocortical neurons projecting to different fields of the lateral frontal lobe suggest that some degree of functional unity exists within this projection. © 1992 Wiley‐Liss, Inc.
The termination pattern and postsynaptic targets of rubrospinal fibers in the rat spinal cord: A light and electron microscopic study
Authors: Antal M. , Sholomenko G. N. , Moschovakis A. K. , Storm‐Mathisen J. , Heizmann C. W. , Hunziker W. 
Published: May 2005

AbstractThe spinal course, termination pattern, and postsynaptic targets of the rubrospinal tract, which is known to contribute to the initiation and execution of movements, were studied in the rat at the light and electron microscopic levels by using the anterograde tracer Phaseolus vulgaris‐leucoagglutinin (PHA‐L) in combination with calbindin‐D28k (CaBP), γ‐aminobutyric acid (GABA), and glycine immunocytochemistry. After injections of PHA‐L unilaterally into the red nucleus, labelled fibers and terminals were detected at cervical, thoracic, and lumbar segments of the spinal cord. Most of the descending fibers were located in the dorsolateral funiculus contralateral to the injection site, but axons descending ipsilaterally were also revealed. Rubrospinal axon terminals were predominantly found in laminae V–VI and in the dorsal part of lamina VII at all levels and on both sides of the spinal cord, but stained collaterals were also seen in the ventrolateral aspect of Clark's column and in the ventral regions of lamina VII on both sides. The proportion of axonal varicosities revealed on the ipsilateral side varied at different segments and represented 10–28% of the total number of labelled boutons. Most of the labelled boutons were engaged in synaptic contacts with dendrites. Of the 137 rubrospinal boutons investigated, only 2 were found to establish axosomatic synaptic junctions in the lumbar spinal cord contralateral to the PHA‐L injection. With the postembedding immunogold method, 80.8% of dendrites establishing synaptic contacts with rubrospinal terminals did not show immunoreactivity for either GABA or glycine, whereas 19.2% of them were immunoreactive for both amino acids. Rubrospinal axons made multiple contacts with CaBP‐immunoreactive neurons in laminae V'VI. Synaptic contacts between rubrospinal terminals and CaBP‐immunoreactive dendrites were identified at the electron microscopic level, and all CaBP‐containing postsynaptic dendrites investigated were negative for both GABA and glycine. The results suggest that rubrospinal terminals establish synaptic contacts with both excitatory and inhibitory interneurons in the rat spinal cord, and a population of excitatory interneurons receiving monosynaptic rubrospinal input is located in laminae V'VI. © 1992 Wiley‐Liss, Inc.
Distribution of catecholamine‐containing nerves on blood vessels of the rat trachea
Authors: Baker David G. , McDonald Donald M. 
Published: May 2005

AbstractThis study was performed to determine the distribution of catecholamine‐containing sympathetic nerves on blood vessels of the rat trachea. The glyoxylic acid method was used to visualize catecholamine‐containing axons in tracheal whole mounts, and silicone vascular casts were used to elucidate the architecture of the vasculature. We also examined the relationship of these axons to the trachea's plexus of cholinergic nerves and ganglia, using tracheal whole mounts stained for acetylcholinesterase activity. We found that most catecholamine‐containing axons were associated with arterioles located between cartilaginous rings or in the posterior membrane. In both regions, catecholamine‐containing nerves were most abundant at the origin of terminal arterioles, which supplied the airway mucosa and smooth muscle. At the origin of these vessels, the fluorescent axons changed their orientation from longitudinal to circumferential. Few fluorescent axons were present beyond this region of the terminal arterioles, and none was found on capillaries or venules or on smooth muscle cells of the posterior membrane. Fluorescent axons were present in some tracheal ganglia but none enveloped neuronal cell bodies or had varicosities, and no ganglion cells had glyoxylic acid‐induced fluorescence. Catecholamine‐fluorescence was also present in clusters of small intensely fluorescent (SIF) cells, which were located in the adventitia of the posterior membrane and in the longitudinal nerve trunks which ran the length of the trachea. Pargyline pretreatment increased the fluorescence of axons and SIF cells but did not reveal a different distribution of these structures. We conclude that most catecholamine‐containing axons in the rat trachea innervate arterioles, particularly terminal arterioles, and presumably participate in the control of blood now to the airway wall. We obtained no evidence that such axons innervate the ganglia or smooth muscle of the rat trachea. © 1992 Wiley‐Liss, Inc.
Time‐course and extent of retinal ganglion cell death following ablation of the superior colliculus in neonatal rats
Authors: Harvey Alan R. , Robertson Donald 
Published: May 2005

AbstractThis study has examined the deleterious effect of superior colliculus (SC) ablation on the viability of identified retinotectally projecting ganglion cells in the neonatal rat retina. The time‐course and extent of lesion‐induced retinal ganglion cell (rgc) death has been determined and an estimate obtained for the rate of clearance of individual dying neurons. In order to demonstrate the projection of rgcs to the SC and the subsequent death of these same neurons after SC lesions, the fluorescent dye diamidino yellow (DY) was injected into the left SC of anesthetized 2 day old Wistar rats (P2: day of birth = P0). DY retrogradely labels the nuclei of tectally projecting rgcs; if these identified rgcs subsequently die, their DY‐labelled nuclei become pyknotic and can be visualized in retinal wholemounts. At P4 the rats were again anesthetized and the injected area, seen as a yellow patch in the SC, was removed by aspiration. Rats were perfused 2 to 336 hours after the lesion and retinal wholemounts of the right eye were prepared. Control rats received only DY injections and were perfused at times corresponding to the lesioned animals. In three sham‐operated rats; the injected SC was reexposed at P4 but the tectal tissue was not removed. In each of the 42 rats that were analyzed, about 10% of the retina containing retrogradely labelled rgcs was counted; the number of pyknotic versus normally labelled rgcs was determined and changes in normal cell density were also assessed. Pyknotic rates in control and sham‐operated rats were similar (average O.8%, n = 11). In SC‐lesioned rats, the proportion of pyknotic DY‐labelled rgcs increased to about 2.5% 4 to 8 hours postlesion (PL); the peak period of death occurred at 23 hours PL (8.0%). The amount of pyknosis decreased thereafter and most dying cells had been eliminated by 50 hours PL. Phagocytosis of dying cells was a common feature of retinae in SC lesioned rats. In the long‐term (336 hours) rats, counts of normal DY‐labelled rgcs in corresponding regions of control and lesioned rats revealed an average decrease in rgc density of 47.3% after P4 tectal ablation. Calculations suggest a clearance time of about 3 hours for dying neonatal rgcs. © 1992 Wiley‐Liss, Inc.