bluuebunny/crossref_metadata_2025_split huggingface dataset:
Location of motoneurones projecting to the cat distal forelimb. I. Deep radial motornuclei
Authors: Fritz Norbert , Illert Michael , Saggau Peter 
Published: May 2005

AbstractThe position of the motornuclei projecting through the dorsal interosseus (DR) nerve to the distal forelimb muscles has been investigated in the cat. Horseradish peroxidase (HRP) and fluorescent (Fl) compounds have been used as retrograde tracers. They were either injected into forelimb muscles or applied to the proximal end of transected forelimb nerves. Limb muscles that were not investigated have been carefully denervated. HRP was used to trace the position and the architecture of the individual motornuclei. The topographical relations between the nuclei were established with application of up to three F compounds in the same animal. The position of the labeled motornuclei was reconstructed with a computer‐assisted approach which is described in the appendix. The DR representation area extends from the caudal C5 to the caudal Thl segments. In C6 it forms a dorsoventrally oriented narrow region at the lateral border of the ventral horn; in C7 and rostral C8 it forms a broad column in the dorsolateral corner of the ventral horn. In caudal C8 and Thl this column is shifted into a ventral direction. The motoneurones projecting to the individual DR muscles are not randomly distributed in this area, but arranged in long, slender columns. These motornuclei occupy specific positions with only minimal interindividual variations. Three nuclei (brachioradialis, extensor carpi radialis, and supinator) are located in the C6 and C7 segments. They compose about onethird of the DR cell population. The nuclei to the other radial muscles are all located in C8 and Thl. Thus most of the DR motoneurones are located in these two segments. These results, together with those from the companion paper on the location of the median and ulnar motornuclei, provide important anatomical knowledge for the investigation of the cat brachial enlargement.
Ontogenetic change in the distribution of callosal projection neurons in the postcentral gyrus of the fetal rhesus monkey
Authors: Killackey Herbert P. , Chalupa Leo M. 
Published: May 2005

AbstractIn the postcentral gyrus of the mature rhesus monkey the distribution of callosal projection neurons is discontinuous. The density of callosal projection neurons, which are mainly located in the supragranular layers, varies both within and across cytoarchitectonic areas (Killackey et al., '83). In the present study, we investigated the ontogeny of corpus callosum projections of the postcentral gyrus in five fetal rhesus monkeys, ranging in age from embryonic day (E) 108 to E 133. Multiple large injections of horseradish peroxidase that involved the underlying white matter were made into the postcentral gyrus of one hemisphere and the distribution of labeled neurons in the ipsilateral thalamus and the other hemisphere was determined. The pattern of thalamic label indicated that the tracer was effectively transported from all portions of the postcentral gyrus.We found that the areal distribution pattern of labeled callosal projection neurons varied at the different fetal ages. At early fetal ages (E 108, E 111, and E 119) callosal projection neurons were continuously distributed throughout the postcentral gyrus. As in the adult animal, the vast majority of labeled callosal projection neurons were found in the supragranular layers, although a few labeled cells were located in the infragranular layers. From the earliest age, there was regional variation in the width of the band of labeled supragranular callosal projection neurons. The difference between the precentral and postcentral gyrus was most obvious, but there was also a difference between anterior and posterior portions of the postcentral gyrus. The first indication of some discontinuity in the distribution of callosal projection neurons was noted at E 126. By E 133, approximately 1 month before birth, the distribution of callosal projection neurons appeared remarkably mature.On E 119 aggregations of anterograde label could be detected in restricted portions of the posterior postcentral gyrus beneath the cortical layers. By E 133 anterograde label was found within the cortical layers (most densely in layer IV) in these regions of the postcentral gyrus. Thus, the emergence of the discrete pattern of callosal projection neurons appears to be temporally correlated with the ingrowth of callosal afferents.On the basis of these observations, as well as those of others (discussed in the text), we propose that the ontogenetic changes in the distribution of callosal projection neurons reflect the unique strategy employed by cortical projection neurons in establishing their patterns of connectivity. It is hypothesized that this strategy may involve multiple processes.
Morphology of local “Stridulation” interneurons in the metathoracic ganglion of the acridid grasshopper Omocestus viridulus L
Authors: Gramoll Siglinde , Elsner Norbert 
Published: May 2005

AbstractThe morphological characteristics of five types of local spiking interneurons in the metathoracic ganglion of the acridid grasshopper Omocestus viridulus L. have been revealed by intracellular injection of the fluorescent dye Lucifer Yellow. All these neurons are active during induced stridulation and discharge in the stridulation rhythm. They are structurally unlike any of the metathoracic local interneurons previously described in the Acrididae.
Type 1: Unilateral interneurons in the metathoracic neuromere; soma in anterior position; arborization dorsal, in anterolateral, posterolateral, and midline regions.
Type 2: Unilateral interneurons in the metathoracic neuromere; neurite with characteristic hairpin bend; soma in lateral position; arborization through the lateral neuropil region.
Type 3: Unilateral interneurons in the metathoracic and abdominal neurons; soma anterior at the base of the connective; arborization dorsal, in anterolateral, posterolateral, and midline regions, with ladderlike branches into the abdominal neuromeres.
Type 4: Symmetrically bilateral neurons; soma in ventral median position; arborization dorsal, in anterolateral, posterolateral, and midline regions. Ipsilateral branches mostly smooth, contralateral mostly varicose.
Type 5: Asymmetrically bilateral neurons, soma in ventral median position; ipsilateral branches mostly smooth, contralateral mostly varicose. The ipsilateral branches in particular penetrate all layers of the ganglion.
The main arborizations of interneurons of types 1 and 4, and to some extent those of types 3 and 5, occupy the same region, which extends very far dorsally into the vicinity of the median and lateral tracts. There are additional antero‐ and posterolateral branches in the metathoracic neuromere, in positions where in principle they can overlap with the arborizations of the motoneurons. The interneurons of type 2, and to some extent type 5, arborize mainly in a lateral region that also includes deeper layers of the ganglion and hence encompasses the projections of mechanoreceptive proprioceptors.The interneurons of types 1, 3, and 4 have so‐called “sister” neurons, identical to the typical neurons in their metathoracic arborizations but with additional collaterals that pass into the mesothoracic ganglion.
Postnatal development of microtubules and neurofilaments in the rat optic nerve: A quantitative study
Authors: Cuenca N. , Fernandez E. , de Juan J. , Carreres J. , Iniguez C. 
Published: May 2005

AbstractIn this paper the postnatal changes in the cytoskeleton of the rat optic nerve fibers are described and quantified. These changes are also compared with other parameters such as myelination and axonal caliber with the aim of describing a general pattern of optic nerve maturation from a morphological point of view. The results showed that during the first postnatal week microtubules outnumbered neurofilaments but between days 8 and 20 the neurofilaments rapidly increased and on day 20 were about twice as numerous as microtubules. This proportion remained almost unaltered from the end of the third weak to the 44th postnatal day. The comparison with other parameters suggested that the cytoskeleton, and in particular the proportion between its components, may be a more reliable index for measuring optic nerve maturation than other variables commonly used.
Frontal eye field efferents in the macaque monkey: I. Subcortical pathways and topography of striatal and thalamic terminal fields
Authors: Stanton G. B. , Goldberg M. E. , Bruce C. J. 
Published: May 2005

AbstractAnterograde tracers (tritiated leucine, proline, fucose; WGA‐HRP) were injected into sites within the frontal eye fields (FEF) of nine macaque monkeys. Low thresholds (≤50 μA) for electrically evoking saccadic eye movements were used to locate injection sites in four monkeys. Cases were grouped according to the amplitude of saccades evoked or predicted at the injection site. Dorsomedial prearcuate injection sites where large saccades were elicited were classified as lFEF cases, whereas ventrolateral prearcuate sites where small saccades were evoked were designated sFEF cases. One control case was injected in the medial postarcuate area 6.We found five descending fiber bundles from FEF; fibers to the striatum, which enter the caudate nucleus at or just rostral to the genu of the internal capsule; fibers to the claustrum, which travel in the external capsule; and transthalamic, subthalamic, and pedunculopontine fibers. Our results indicate that transthalamic and subthalamic pathways supply all terminal sites in the thalamus, subthalamus, and tegmentum of the midbrain and pons, whereas pedunculopontine fibers appear to terminate in the pontine and reticularis tegmenti pontis nucleus exclusively.Frontal eye field terminal fields in the striatum were topographically organized: lFEF projections terminated dorsal and rostral to sFEF projections. Thus, lFEF terminal fields were located centrally in the head and body of the caudate nucleus and a small dorsomedial portion of the putamen, whereas sFEF terminal fields were located in ventrolateral parts of the caudate body and ventromedial parts of the putamen. In the claustrum, lFEF projections terminated dorsal and rostral to sFEF projections. Projections from FEF terminated in ventral and caudal parts of the subthalamic nucleus without a clear topography. By comparison, terminal fields from medial postarcuate area 6 were located more caudally and laterally in the striatum and claustrum than projections from FEF, and more centrally in the subthalamic nucleus.In the thalamus, FEF terminal patches in some thalamic nuclei were also topographically organized. Projections from lFEF terminated in dorsal area X, dorsolateral medial dorsal nucleus, pars parvicellularis (MDpc), and the caudal pole of MDpc, whereas projections from sFEF terminated in ventral area X, medial dorsal nucleus, pars multiformis, and caudal medial dorsal nucleus pars densocellularis. Characteristically, projections from postarcuate area 6 terminated in central ventral lateral nucleus, pars caudalis, ventral posterior lateral nucleus, pars oralis. Projections from dorsomedial postarcuate area 6 terminated in the paracentral and central lateral nuclei.
Cytochrome oxidase staining marks dendritic zones of the rat olfactory bulb external plexiform layer
Authors: Mouradian Laurie E. , Scott John W. 
Published: May 2005

AbstractCytochrome oxidase staining of the rat olfactory bulb external plexiform layer (EPL) produces a darkly stained intermediate zone bordered by lightly stained superficial and deep zones. Similar zonal staining was seen in cats, rabbits, and hamsters. These zones vary in relative thickness around the circumference of the olfactory bulb; the deep zone is proportionally thicker in the most dorsal and ventral parts of the bulb. Tufted cell somata are unevenly distributed within the EPL; the outer part of the EPL has more somata. The distribution of the cytochrome oxidase reaction product shows that the darkly stained intermediate zone is not produced by staining of tufted cell somata.Zones of cytochrome oxidase staining correspond to the sublaminar distribution of mitral and tufted cell basal dendrites. This was demonstrated by labeling mitral and tufted cells with small extracellular horseradish peroxidase injections and processing alternate sections for horseradish peroxidase and for cytochrome oxidase. Because there was cross‐reaction of the cytochrome oxidase procedure with horseradish peroxidase, it was possible to trace many neurons through both series of sections. Middle tufted cells of the superficial EPL have basal dendrites confined to the superficial zone of light cytochrome oxidase staining. Internal tufted cells and middle tufted cells of the intermediate zone send their basal dendrites into the intermediate zone. One group of mitral cells (type I) has basal dendrites confined to the deep zone of lighter cytochrome oxidase staining. A second group of mitral cells (type II) and tufted cells of the intermediate EPL has basal dendrites primarily confined to the intermediate zone of dark cytochrome oxidase staining. The correlation of the enzyme staining with the dendritic laminar patterns supports the existence of three relatively distinct sublaminae in the EPL and supports the designation of two types of mitral cells. The staining pattern also provides an independent method for evaluating the sublaminae of the EPL without the necessity of labeling individual groups of cells. Finally, the staining pattern suggests that the intermediate zone of the EPL may be subjected to more tonic synaptic input, causing it to have an increased level of metabolic activity.
Distribution of glucagonlike peptide I (GLP‐I), glucagon, and glicentin in the rat brain: An immunocytochemical study
Authors: Jin S.‐L. C. , Han V. K. M. , Simmons J. G. , Towle A. C. , Lauder J. M. , Lund P. K. 
Published: May 2005

AbstractAlthough glucagonlike immunoreactants (GLIs) are present in the central nervous system of several mammalian species, their structural relationship with pancreatic proglucagon is not defined, and their precise anatomical distribution has not been studied extensively. To obtain further information about the structure and biological significance of brain GLIs, the anatomical distribution of three different antigenic determinants of pancreatic proglucagon‐‐glucagonlike peptide I (GLP‐I), glucagon, and glicentin‐‐was mapped in the brain of colchicine‐treated rats by immunocytochemistry using the avidin‐biotin‐peroxidase method.Neuronal cell bodies immunoreactive with antisera specific for GLP‐I, glucagon, and glicentin were found only in the caudal medulla oblongata. Within the caudal medulla immunostained cell bodies were found at levels from approximately 0.55 mm rostral to the obex to 0.45 mm caudal to the obex, and were located within the nucleus of the solitary tract (NTS) and the dorsal (MdD) and ventral (MdV) parts of the medullary reticular nucleus. The NTS contained three times more immunoreactive cell bodies than the MdD and MdV, and these cell bodies were located in the midline, medial, and lateral subnuclei of the caudal third of the NTS. Immunostaining of the same cell bodies in paired adjacent sections incubated with GLP‐I and glucagon antisera or glucagon and glicentin antisera provided evidence for coexistence of the three antigens within the same neurons of the NTS. Nerve fibers and terminals immunoreactive with GLP‐I, glucagon, and glicentin antisera were widely distributed throughout the rat brain and there was no discernible difference in the distribution of fibers and terminals immunoreactive with each of the three antisera. The highest densities of immunostained fibers and terminals were observed in the hypothalamus, thalamus, and septal regions, and the lowest in the cortex and hindbrain. The localization of neuronal cell bodies containing GLP‐I, glucagon, and glicentin within the NTS and the MdD and MdV, and the extensive distribution of immunoreactive fibers and terminals throughout the rat brain suggest a role for these peptides in the integration of autonomic as well as central nervous system functions.
Auditory hair cell innervational patterns in lizards
Authors: Miller Malcolm R. , Beck Janet 
Published: May 2005

AbstractThe pattern of afferent and efferent innervation of two to four unidirectional (UHC) and two to nine bidirectional (BHC) hair cells of five different types of lizard auditory papillae was determined by reconstruction of serial TEM sections. The species studies were Crotaphytus wislizeni (iguanid), Podarcis (Lacerta) sicula and P. muralis (lacertids), Ameiva ameiva (teiid), Coleonyx variegatus (gekkonid), and Mabuya multifasciata (scincid). The main object was to determine in which species and in which hair cell types the nerve fibers were innervating only one (exclusive innervation), or two or more hair cells (nonexclusive innervation); how many nerve fibers were supplying each hair cell; how many synapses were made by the innervating fibers; and the total number of synapses on each hair cell.In the species studies, efferent innervation was limited to the UHC, and except for the iguanid, C. wislizeni, it was nonexclusive, each fiber supplying two or more hair cells.Afferent innervation varied both with the species and the hair cell types. In Crotaphytus, both the UHC and the BHC were exclusively innervated. In Podarcis and Ameiva, the UHC were innervated exclusively by some fibers but nonexclusively by others (mixed pattern). In Coleonyx, the UHC were exclusively innervated but the BHC were nonexclusively innervated. In Mabuya, both the UHC and BHC were nonexclusively innervated.The number of afferent nerve fibers and the number of afferent synapses were always larger in the UHC than in the BHC.In Ameiva, Podarcis, and Mabuya, groups of bidirectionally oriented hair cells occur in regions of cytologically distinct UHC, and in Ameiva, unidirectionally oriented hair cells occur in cytologically distinct BHC regions.
Disruption of microfilament organization and deregulation of disk membrane morphogenesis by cytochalasin D in rod and cone photoreceptors
Authors: Williams David S. , Linberg Kenneth A. , Vaughan Dana K. , Fariss Robert N. , Fisher Steven K. 
Published: May 2005

AbstractMorphogenesis of photoreceptor outer segment disks appears to occur by an evagination of the ciliary plasma membrane (Steinberg et al., J Comp Neurol 190: 501–519, 80). We tested if polymerized actin (F‐actin) was necessary for the regulation of this postulated process by incubating Xenopus eyecups with 5 or 25 μM cytochalasin D for 6–28 hours. During the second hour, the incubation medium contained 3H‐leucine. Both concentrations of cytochalasin resulted in: (1) dissolution of the rhodamine‐phalloidin labeling pattern of photoreceptors, and (2) collapse of the calycal processes (which are normally filled with actin filaments) and disappearance of the inner segment microfilaments. In addition, the few most basal rod and cone outer segment disks appeared several times their normal diameter. These oversized disks had incorporated 3H‐leucine and extended along the margin of the outer or inner segment. The nature of the overgrown disks is consistent only with a morphogenetic process involving evaginations of the ciliary plasma membrane. Deregulation by cytochalasin D was manifest by excessive growth of a few nascent disks rather than normal growth of many. Therefore, the normal network of actin filaments is apparently not necessary for continued evagination of the membrane, but it does seem to be an essential part of the mechanism that initiates the evagination of the ciliary plasma membrane and\or the mechanism that controls how far nascent disks grow.
Development of intersecting CNS fiber tracts: The corpus callosum and its perforating fiber pathway
Authors: Hankin Mark H. , Silver Jerry 
Published: May 2005

AbstractWhat are the mechanisms acting during development at points of intersection of central nervous system fiber tracts which influence the direction taken by a population of growing axons? In order to address this question, the ontogeny of the intersecting rostral corpus callosum and its perforating fiber pathway (PF), and the microenvironment through which these fiber systems grow, were examined in a series of mouse embryos and early postnates.Our results show that the perforating fibers are identifiable in silverstained sections between embryonic days (E) 15 and 16, at least 1 day prior to the initial appearance of the callosal projection. Soon after the PF can be identified, a dense accumulation of subventricular cells surrounds the PF at a point just ventral to the location where the callosum and PF will intersect (i.e., at the corticoseptal boundary). Callosal axons, which are present at the point of intersection beginning on E17, do not join the perforating fibers, nor do they appear to penetrate the underlying population of subventricular cells. Instead, the callosal fibers turn across the PF and enter the contralateral cerebral hemisphere.Thus, the intersection of the callosal and perforating fiber systems during development may be related both to the sequential development of each pathway and to the altered nonneuronal environment at the point of intersection.
Development of projections from auditory to visual areas in the cat
Authors: Innocenti Giorgio M. , Berbel Pere , Clarke Stephanie 
Published: May 2005

AbstractIn newborn kittens, cortical auditory areas (including AI and AII) send transitory projections to ipsi‐ and contralateral visual areas 17 and 18. These projections originate mainly from neurons in supragranular layers but also from a few in infragranular layers (Innocenti and Clarke: Dev. Brain Res. 14:143–148, 84; Clarke and Innocenti: J. Comp. Neurol. 251:1–22, 86). The postnatal development of these projections was studied with injections of anterograde tracers (wheat germ agglutinin‐horseradish peroxidase [WGA‐HRP]) in AI and AII and of retrograde tracers (WGA‐HRP, fast blue, diamidino yellow, rhodamine‐labeled latex beads) in areas 17 and 18. It was found that the projections are nearly completely eliminated in development, this, by the end of the first postnatal month. Unitl then, most of the transitory axons seem to remain confined to the white matter and the depth of layer VI; a few enter it further but do not appear to form terminal arbors. As for other transitory cortical projections the disappearance of the transitory axons seems not to involve death of their neurons of origin. In kittens older than 1 month and in normal adult cats, retrograde tracer injections restricted to, or including, areas 17 and 18 label only a few neurons in areas AI and AII. Unlike the situation in the kitten, nearly all of these are restricted to layers V and VI. A similar distribution of neurons projecting from auditory to visual areas is found in adult cats bilaterally enucleated at birth, which suggests that the postnatal elimination of the auditory‐to‐visual projection is independent of visual experience and more generally of information coming from the retina.