bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prenatal development of neurons in the human prefrontal cortex: I. A qualitative Golgi study
Authors: Mrzljak Ladislav , Uylings Harry B. M. , Kostovic Ivica , van Eden Corbert G. 
Published: January 2005

AbstractGolgi‐Stensaas and rapid‐Golgi staining techniques are used to study neuronal differentiation in the developing human prefrontal cortex in fetuses, premature infants, and full‐term newborns from 10.5 to 40 weeks of gestation. Horizontal neurons (Cajal‐Retzius neurons) above the cortical plate (in the marginal zone) and randomly oriented neurons below the cortical plate (in the primordial subplate) are more differentiated than the immature bipolar cortical plate neurons in the 10.5‐week fetus. During 13.5–15 weeks of gestation the fetal subplate zone can be clearly distinguished‐between the cortical plate and the intermediate zone. This subplate zone contains more mature neurons than the cortical plate, especially polymorphous neurons. The basic features of the apical and basal dendrites of pyramidal neurons develop between 17 and 25 weeks of gestation, before the thalamocortical fibres invade the cortical plate. Intensive differentiation of the subplate neurons occurs in this period, when various types of afferent fibres reside in the subplate zone. At least five neuronal types can be distinguished in the subplate, i.e., polymorphous, fusiform, multipolar, normal, and inverted pyramidal neurons. The ingrowth of afferent fibres into the cortical plate between 26 and 34 weeks of gestation coincides with intensive dendritic differentiation and the appearance of spines on dendrites of the prospective layer III and V pyramidal neurons as well as with the differentiation of the double bouquet interneurons in the prospective supragranular layers and layer IV. Multipolar nonpyramidal neurons with the dendritic features of basket neurons are observed between 32 and 34 weeks of gestation in future layer V. They are less differentiated than the double bouquet neurons. The neurons of the subplate zone continue their dendritic differentiation after 26/27 weeks of gestation and are still observed in the full‐term newborn. The axonal pattern of the subplate neurons suggests a possible functional role for them as either interneurons or projection neurons.
Quantitative analysis of the recurrent collaterals derived from Purkinje cells in zone X of the cat's vermis
Authors: Bishop Georgia A. 
Published: January 2005

AbstractIntracellular electrodes filled with 4% horseradish peroxidase (HRP) were used to impale Purkinje cells in zone x of the cat's cerebellum. Subsequent to recording responses to bilateral stimulation of the ulnar, radial, and sciatic nerves, the cells were injected with HRP. Intracellularly labeled Purkinje cells were located and correlated with the physiological data. Purkinje cells in zone x respond primarily to stimulation of the ipsilateral forelimb. However, they have broad receptive fields in that most also receive inputs from stimulation of the contralateral forelimb or from more than one forelimb nerve; a few respond to activation of the hindlimb.The distribution of the recurrent collaterals of zone x Purkinje cells has several features that are similar to those from zones a, b, and c: (1) they have a similar number of varicosities within the plexus; (2) they distribute primarily in the sagittal as compared to the transverse plane; and (3) most varicosities in the plexus are located within the Purkinje cell layer. However, several characteristics distinguish the collaterals of zone x Purkinje cells. First, they have a greater transverse extent than those derived from Purkinje cells in zones a, b, and c. Second, they have a higher percentage of collaterals that extend to more superficial aspects of the molecular layer as well as to deep levels of the granule cell layer.The rostral extent of zone x has not been clearly defined in previous studies. On the basis of anatomical and physiological data derived from the present study it appears that Purkinje cells located in lobule Va have physiological and morphological properties similar to those observed for Purkinje cells in more caudal folia of lobule V. Thus, on the basis of the organization of local circuits, it appears that zone x extends at least to the most rostral folia of lobule V.In conclusion, these data suggest that Purkinje cells in zone x may not be involved in controlling the movements of specific muscles, as may be the case in other cortical zones. Rather, it could be hypothesized that Purkinje cells in zone x have a more generalized role in coordinating agonist and antagonist muscle groups in one limb or regulating patterns of movement between limbs.
Projections of the cochlear nuclei and nucleus laminaris to the inferior colliculus of the barn owl
Authors: Takahashi Terry T. , Konishi Masakazu 
Published: January 2005

AbstractThe barn owl determines the directions from which sounds emanate by computing the interaural differences in the timing and intensity of sounds. These cues for sound localization are processed in independent channels originating at nucleus magnocellularis (NM) and nucleus angularis (NA), the cochlear nuclei. The cells of NM are specialized for encoding the phase of sounds in the ipsilateral ear. The cells of NA are specialized for encoding the intensity of sounds in the ipsilateral ear.NM projects solely, bilaterally, and tonotopically to nucleus laminaris (NL). NL and NA project to largely nonoverlapping zones in the central nucleus of the inferior colliculus (ICc), thus forming hodological subdivisions in which time and intensity information may be processed. The terminal field of NL occupies a discrete zone in the rostromedial portion of the contralateral ICc, which we have termed the “core” of ICc. The terminal field of NA surrounds the core of ICc and thus forms a “shell” around it. The projection from NL to the core conserves tonotopy. Low‐frequency regions of NL project to the dorsal portions of the core whereas higher‐frequency regions project to more ventral portions. This innervation pattern is consistent with earlier physiological studies of tonotopy. Physiological studies have also suggested that NL and the core of ICc contain a representation of the location of a sound source along the horizontal axis. Our data suggest that the projection from NL to the core preserves spatiotopy. Thus, the dorsal portion of NL on the left, which contains a representation of eccentric loci in the right hemifield, innervates the area of the right ICc core that represents eccentric right loci. The more ventral portion of the left NL, which represents loci close to the vertical meridian, innervates the more rostral portions of the right core, which also represents loci near the vertical meridian.
Autoradiographic localization of nicotinic acetylcholine receptors in the brain of the zebra finch (Poephila guttata)
Authors: Watson James T. , Adkins‐Regan Elizabeth , Whiting Paul , Lindstrom Jon M. , Podleski Thomas R. 
Published: January 2005

AbstractWe have localized nicotinic acetylcholine receptors in the zebra finch brain by using three 125I‐labelled ligands: alpha bungarotoxin and two monoclonal antibodies to neuronal nicotinic receptors (MAb 35 of Tzardos et al., J. Biol. Chem., 250:8635–8645, ′81; and MAb 270 of Whiting and Lindstrom: J. Neurosci. 6:3061–3069, ′86). Unfixed brains from intact adult male and female zebra finches were prepared for in vitro autoradiography. Lowresolution film autoradiograms and high‐resolution emulsion autoradiograms were prepared for each of the three ligands.The major brain structures that bind all three of the ligands are hippocampus; hyperstriatum dorsalis; hyperstriatum ventralis; nucleus lentiformis mesencephali; nucleus pretectalis, some layers of the optic tectum; nucleus mesencephalicus lateralis; pars dorsalis; locus ceruleus; and all cranial motor nuclei except nucleus nervi hypoglossi.The major structures labelled only by [125I]‐alpha bungarotoxin binding included hyperstriatum accessorium and the nuclei: preopticus medialis, medialis hypothalami posterioris, semilunaris, olivarius inferior, and the periventricular organ. Of the song control nuclei, nucleus magnocellularis of the anterior neostriatum; hyperstriatum ventralis, pars caudalis; nucleus intercollicularis; and nucleus hypoglossus were labelled.The binding patterns of the two antibodies were similar to one another but not identical. Both labelled nucleus spiriformis lateralis and nucleus geniculatus lateralis, pars ventralis especially heavily and also labelled the nucleus habenula medialis; nucleus subpretectalis; nucleus isthmi, pars magnocellularis; nucleus reticularis gigantocellularis; nucleus reticularis lateralis; nucleus tractus solitarii; nucleus vestibularis dorsolateralis; nucleus vestibularis lateralis; nucleus descendens nervi trigemini; and the deep cerebellar nuclei. Lobus parolfactorius and nucleus vestibularis medialis were labelled by only MAb 270, whereas only MAb 35 labelled nucleus laminaris and the medial and lateral pontine nuclei.These data extend previous reports of cholinergic participation in the song system (Ryan and Arnold: J. Comp. Neurol. 202:211–219, ′81) to suggest that the zebra finch song system may contain several closely related nicotinic receptors. In several brain nuclei it appeared that certain anatomical portions of a nucleus or a certain class of neurons were specifically labelled. Furthermore, in certain cases, the labelling appeared to be clustered around Nissl‐stained cell nuclei, thus suggesting that the receptors are concentrated on or in somata.
Colocalization of fixative‐modified glutamate and glutaminase but not GAD in rubrospinal neurons
Authors: Beitz Alvin J. , Ecklund Lorelei J. 
Published: January 2005

AbstractIn an attempt to identify putative neurotransmitters of rubrospinal neurons, immunocytochemical procedures were utilized in combination with retrograde tracing techniques in 15 adult male rats. Following injections of horseradish peroxidase (HRP) or wheat germ agglutinin conjugated to HRP (WGA‐HRP) into the spinal cord, midbrain sections were processed with a combined procedure that allowed visualization of both the retrograde tracer and one or more antigens including glutamate, glutaminase, and glutamatic acid decarboxylase (GAD). Initial colocalization studies demonstrated that glutamatelike and glutaminaselike immunoreactivities were cocontained within the same neurons. Following injections of HRP or WGA‐HRP into the spinal cord approximately 53% of retrogradely labeled neurons contained glutamate immunoreactivity. Triple‐labeling experiments indicated that glutamatelike immunoreactivity was colocalized with glutaminase immunoreactivity in retrogradely labeled rubrospinal neurons. Retrogradely labeled neurons did not contain GAD immunoreactivity. Moreover, triple labeling experiments verified that glutamatelike immunoreactive retrogradely labeled cells did not cocontain GAD immunoreactivity. These studies demonstrate that glutamate and its synthesizing enzyme, glutaminase, are present in some rubrospinal neurons and raise the possibility that a component of the rubrospinal projection may be glutamatergic. GAD, on the other hand, is not present in rubrospinal neurons. This finding supports the hypothesis that GABAergic neurons play a role as interneurons in the red nucleus.
Mamillary body in the rat: A cytoarchitectonic, golgi, and ultrastructural study
Authors: Allen Gary V. , Hopkins David A. 
Published: January 2005

AbstractThe present study provides a comprehensive light and electron microscopic analysis of the anatomical organization of the rat mamillary body. The cytoarchitecture and morphology of mamillary neurons were investigated with the aid of Nissl‐stained and Golgi‐impregnated sections cut in transverse, horizontal, and sagittal planes. The ultrastructural features of the mamillary nuclei were correlated with observations made on Golgi material. The mamillary body is comprised of a lateral and a medial nucleus, the latter being subdivided into five major subnuclei: pars lateralis, pars basalis, pars medialis, pars medianus, and pars posterior. The perikarya are medium‐sized or small with the proportions of each differing among subnuclei. The largest perikarya are found in the lateral mamillary nucleus (cell area 257.0 μm2) and have 2‐5 radially oriented aspiny dendrites that are often beaded. Small cells predominate in the pars lateralis (cell area 116.3 μm2) and pars basalis (cell area 118.3 μm2), whereas the pars medialis (cell area 196.7 μm2), pars medianus (cell area 136.5 μm2), and pars posterior (cell area 154.6 μm2) contain mainly medium‐sized cells. The dendrites of most cells in the medial nucleus are radially oriented and exhibit a variety of spines including numerous short stubby spines, spines with thin necks that end in spherical swellings, and long thin spines. Neuronal somata are often closely apposed with no intervening glial processes and contain eccentrically located nuclei with one or more invaginations of the nuclear envelope.Two main classes of axon terminals were identified in the mamillary body. One type contains round vesicles and forms asymmetric synaptic junctions (RA) with dendrites and dendritic spines. RA terminals rarely contact neuronal somata and proximal dendrites in the MB. The second type contains pleomorphic vesicles and forms mainly symmetric synaptic junctions (PS) with neuronal somata as well as dendrites and spinous processes. Dense‐cored vesicles were frequently seen in both types of terminals. Both types of terminals often synapse with two adjacent dendrites and are also found near or adjacent to each other on the same dendrite. A quantitative analysis indicated that the numbers of RA terminals in the medial nucleus almost equals the numbers of PS terminals, whereas the lateral mamillary nucleus contains considerably more PS (64%) than RA terminals (36%).
Nucleus basalis (Ch4) and cortical cholinergic innervation in the human brain: Observations based on the distribution of acetylcholinesterase and choline acetyltransferase
Authors: Mesulam M‐Marsel , Geula Changiz 
Published: January 2005

AbstractThe nucleus basalis (NB) of the human brain is a large, complex, and highly differentiated structure. Many of its neurons are magnocellular, hyperchromic, isodendritic, acetylcholinesterase‐rich, and choline‐acetyltransferase‐positive. Concurrent histochemical and immunological staining demonstrated that all choline‐acetyltransferase‐positive NB neurons in the human brain also contain acetylcholinesterase enzyme activity. Only a small minority of acetylcholinesterase‐rich magnocellular cell bodies in the NB failed to show choline acetyltransferase immunoreactivity. Sections that were counterstained for Nissl substance showed that 80‐90% of all magnocellular neurons in the NB were choline‐acetyltransferase‐positive and therefore cholinergic. These characteristics, which are very similar to those of the NB in the monkey brain, justified the designation of these cholinergic neurons in the human brain as the Ch4 (or NB‐Ch4) complex. On morphological grounds, the compact parts of the human NB‐Ch4 complex were divided into distinct sectors which appeared to show a greater level of differentiation than in the monkey brain. In addition to the compact sectors, interstitial elements of NB‐Ch4 were embedded within adjacent fiber bundles.The putative cortical projections from NB‐Ch4 were identified in the form of acetylcholinesterase‐rich fibers. These fibers formed a dense plexus in all cortical regions but also displayed laminar and regional variations. Limbic and paralimbic areas had higher concentrations of these fibers than the immediately adjacent neocortical association areas. Alzheimer's disease was associated with a marked depletion of cortical acetylcholinesterase. Two cases of Alzheimer's disease with relatively selective NB‐Ch4 cell loss supported the hypothesis that the corticopetal cholinergic pathways in the human brain may have a topographical organization similar to that in the monkey brain.
Distribution and characterization of neuropeptide Y‐like immunoreactivity in the brain of the crested newt
Authors: Perroteau Isabelle , Danger Jean‐Michel , Biffo Stefano , Pelletier Georges , Vaudry Hubert , Fasolo Aldo 
Published: January 2005

AbstractThe newt brain represents a simplified model for the increasingly complex vertebrate neuronal organization. The localization of neuropeptide Y‐like (NPY‐like) containing neurons in the brain of Triturus cristatus was studied by means of indirect immunofluorescence, peroxidase‐antiperoxidase, and avidin‐biotin techniques using a highly specific antiserum. NPY‐like positive cell bodies were observed in several areas, most notably in the telencephalon (primordium hippocampi and amygdaloid complex), the preoptic and suprachiasmatic areas, the hypothalamus, the dorsal thalamus, the tegmentum, and the rhombencephalon (laterolateral grey column and raphe area). Nerve fibres were particularly abundant in the pallium, striatum, septum, amygdaloid, preoptic neuropils, and pars intercalaris diencephali. Bundles of NPY‐immunoreactive fibres also were visualized in the dorsal thalamus and in the posterior hypothalamus. The pars intermedia lacked any NPY‐like positive fibres. Neuronal processes also were found in the tectum mesencephali and in the body of the cerebellum. A prominent NPY‐like fibre network was observed in the octavolateralis. Concentrations of NPY measured by means of a specific radioimmunoassay were threefold higher in the hypothalamus (15.2 ± 1.3 ng/mg proteins) than in the rhombencephalon (4.9 ± 0.3) and the mesencephalon (4.3 ± 0.2). The concentration found in the telencephalon was 2.1 ± 0.3 ng/mg proteins. Sephadex G‐50 gel chromatography of whole brain extracts indicated the presence of high molecular weight forms of NPY‐like material in addition to the authentic peptide. Both amphibian and mammalian NPY peptides had an apparent molecular weight of 4,000 daltons, as evidenced by immunoblotting analysis. High‐performance liquid chromatography demonstrated, however, that the newt peptide was slightly less hydrophobic than porcine NPY. The present findings indicate that NPY‐immunoreactive neurons are widely distributed in the brain of urodeles. Our data indicate that the NPY molecule has been relatively well preserved during evolution.
Local synaptic organization of cholinergic neurons in the basolateral hypothalamus
Authors: Meeker Rick B. , Swanson Debra J. , Hayward James N. 
Published: January 2005

AbstractA monoclonal antibody to choline acetyltransferase (ChAT) was utilized for immunocytochemical identification of cholinergic neurons in the basolateral hypothalamus. Light and electron microscopic examination revealed a network of cell bodies, dendrites, and axonal processes dorsolateral to the supraoptic nucleus. Within this region the cells immunoreactive for ChAT receive numerous unlabeled terminals which contact dendrites, cell soma, axons and occasional somatic spines. In a few cases, small ChAT‐immunoreactive terminals were observed contacting a cholinergic cell soma or large dendrite. Many ChAT‐immunoreactive fibers were directed toward the supraoptic nucleus forming a dense local network but very few of these fibers penetrated deeper than approximately 20 μm into the supraoptic nucleus. A total of 63 ChAT‐immunoreactive terminals were mapped within the basal hypothalamus, of which the vast majority contacted unlabeled dendrites immediately dorsolateral to the supraoptic nucleus. Labeled terminals were rare or nonexistent in the medial portions of the hypothalamus or deep within the supraoptic nucleus. This pattern of ChAT terminal densities correlates with the distribution of binding for the muscarinic cholinergic probe, [3H]quinuclidinylbenzilate, but not the binding of the putative nicotinic cholinergic probe, [125I]alpha‐bungarotoxin, which is high within the supraoptic nucleus. Thus, the cholinergic neurons of the basal hypothalamus appear to form a network of intrinsic connections which probably represent input to muscarinic cholinergic receptors. No evidence was found to suggest that cholinergic presynaptic terminals were colocalized with the alpha‐bungarotoxin binding protein within the supraoptic nucleus.
Auditory receptor of the red‐eared turtle: I. General ultrastructure
Authors: Sneary Michael G. 
Published: January 2005

AbstractThe auditory receptor of the red‐eared turtle has been the subject of intensive electrophysiological study within the last decade, yet the details of its ultrastructure have remained uninvestigated. In the present report information is derived from an analysis of specimens prepared for light, scanning electron, and transmission electron microscopy. Attention is focused on the ultrastructure of hair cells, supporting cells, and nerve fibers within the sensory epithelium as well as the basilar membrane upon which it rests. A description of the receptor's relations to surrounding sensory epithelia, the limbus of the cochlear duct, and the basilar membrane is also included. Observations are discussed in the light of similar information from other reptilian auditory receptors and the mammalian organ of Corti.
Ultrastructural characteristics of GD3 ganglioside‐positive immature glia in rat forebrain white matter
Authors: LeVine Steven M. , Goldman James E. 
Published: January 2005

AbstractImmunocytochemistry and electron microscopy were used to examine the ultrastructural features of immature neuroectodermal cells of the rat forebrain in their early stages of differentiation. We used a monoclonal antibody (AbR24) to GD3 ganglioside, which binds to cells of the subventricular zone (SVZ). R24 also labels immature cells in developing white and gray matter (LeVine and Goldman: J. Neurosci. in press, '88, and accompanying paper). Sections of developing cingulum and white matter adjacent to the cingulum were examined at E18, P4, and P10 by using a preembedding immunocytochemical technique with PAP reagents. Labeled cells seen earliest were large, with high nuclear to cytoplasmic ratios and few cytoplasmic organelles. With time, smaller forms appeared, with prominent Golgi apparatus and processes containing microtubules. Labeled cells with similar characteristics but which contained cytoplasmic vacuoles were also observed. The results indicate a series of ultrastructural transformations that are consistent with oligodendrocyte differentiation.