bluuebunny/crossref_metadata_2025_split huggingface dataset:
Degeneration of thalamic neurons in “Purkinje cell degeneration” mutant mice. II. Cytology of neuron loss
Authors: O'Gorman Stephen 
Published: January 2005

AbstractThe cytology of thalamocortical relay neuron degeneration in the ventral medial geniculate nucleus (vMG) of mice homozygous for the autosomal recessive Purkinje cell degeneration (pcd) mutation has been studied by light and electron microscopy. More limited sampling of the submedial and mediodorsal nuclei suggested that cytological alterations in the vMG were typical of all degenerating thalamic nuclei. The number of vMG neurons in pcd mutants was comparable to controls at and prior to postnatal day 40 (P40). By P60 seventy percent, and by P90 approximately 9%, of the original complement of vMG neurons had degenerated in mutant mice. At P30, the general cytological organization of vMG neurons closely resembled that of neurons in littermate (+/+ or +/pcd) controls, but neurons in mutants were distinguished by the presence of small aggregates of fine granules (approximately 9 nm in diameter) that were commonly associated with otherwise normal cisternae of rough endoplasmic reticulum; neither the number nor the size of these granular aggregates increased in older mutants. By P50 cytoplasmic organelles were curiously distributed in more severely affected neurons: large areas of cytoplasm were occupied exclusively by polysomes, while profiles of endoplasmic reticulum and the Golgi apparatus appeared to be reduced. Before frank degenerative changes were apparent (at P50), all classes of synaptic terminals identified in normal mice were found to have made morphologically normal synaptic contacts on mutant vMG neuron dendrites. In contrast to the homologous nuclear complex in the cat, presynaptic dendrites were not apparent in synaptic glomeruli in wild‐type or mutant murine vMG. Cytopathological alterations in the neuropil of P50 and older mutants were dominated by degenerating dendritic profiles; there was no evidence that the loss of thalamic neurons in pcd mutants was associated with synaptic agenesis or dysgenesis or the prior or concurrent degeneration of afferent synaptic terminals.
Telencephalic connections of the trigeminal system in the pigeon (Columba livia): A trigeminal sensorimotor circuit
Authors: Wild J. M. , Arends J. J. A. , Zeigler H. Philip 
Published: January 2005

AbstractA combination of autoradiography and horseradish peroxidase histochemistry was used to identify telencephalic structures linking the sensory and motor components of the trigeminal system in the pigeon. A direct telencephalic projection from the principal trigeminal sensory nucleus upon the nucleus basalis via the quintofrontal tract was confirmed. Nucleus basalis projects upon a belt of neurons within the overlying neostriatum. This region (neostriatum frontale, pars trigeminale: NFT) gives rise to the fronto‐archistriate tract which terminates both in the archistriatum intermedium and in the overlying neostriatum caudale, medial to the ventricle (neostriatum caudale, pars trigeminale: NCT). NCT projects, in turn, upon a region of archistriatum intermedium containing cell bodies of the occipito‐mesencephalic tract. This pathway provides a link between the telencephalon and premotor areas within the lateral (parvicellular) reticular formation of the lower brainstem. The trigeminal sensorimotor circuit defined in these experiments has been implicated by neurobehavioral studies in the control of pecking, grasping, and feeding in the pigeon.
Depth segregation of retinal ganglion cells projecting to mouse superior colliculus
Authors: Hofbauer Alois , Dräger Ursula C. 
Published: January 2005

AbstractThe retinotectal projections in the mouse were analyzed with injections of horseradish peroxidase into the superior colliculus and of radioactive amino acids into the eye. At least 70% of the ganglion cells, and possibly all of them, were found to project to the superior colliculus, including ganglion cells of all sizes. Small injections revealed that ganglion cells of different sizes terminate at different levels in the superior colliculus. The small ganglion cells that form the vast majority of all cells project predominantly to the upper stratum griseum superficiale. A small population of mainly medium‐sized and large ganglion cells project to the deep stratum griseum superficiale and to the stratum opticum. The ipsilateral projection is restricted to the deep stratum griseum superficiale and stratum opticum and consists predominantly of medium‐sized and large ganglion cells.
Fine structure of peptidergic and catecholaminergic nerve fibers in the anterior cerebral artery and their interrelationship: An immunoelectron microscopic study
Authors: Matsuyama Tomohiro , Shiosaka Sadao , Wanaka Akio , Yoneda Shotaro , Kimura Kazufumi , Hayakawa Toru , Emson Piers C. , Tohyama Masaya 
Published: January 2005

AbstractThis study shows (1) the ultrastructure of vasoactive intestinal polypeptide (VIP)‐, substance P (SP)‐, and neuropeptide Y (NPY)‐containing nerve fibers in the walls of the cerebral arteries and (2) the relationship between these peptidergic (VIP, SP, and NPY) and catecholaminergic (CA) nerve terminals by immunohistochemistry combined with false transmitter (5‐hydroxydopamine) histochemistry under the electron microscope. VIP‐, SP‐, and NPY‐like immunoreactivity (VIPI, SPI, and NPYI) were found diffusely in the axoplasm and around the small clear vesicles in the nerve terminals. In a few cases, SPI was found within the large vesicles. Most of the VIPI terminals were ensheathed by the cytoplasm of the Schwann cells together with CA terminals, identified as those with a number of small granulated vesicles. In some cases, they were directly apposed to the smooth muscle cells at a distance of about 100 nm. SPI terminals were frequently solitary but about 30% were located together with CA and other (neither SPI nor CA) terminals ensheathed by Schwann cells, directly apposed to the smooth muscle cells at a distance of about 100 nm. On the other hand, NPYI terminals were also identified as CA terminals, indicating the coexistence of these two substances. These findings suggest a close interrelationship between peptidergic and CA nerve terminals in the neurogenic control of cerebral blood vessel function.
Efferent connections of the centromedian and parafascicular thalamic nuclei: An autoradiographic investigation in the cat
Authors: Royce G. James , Mourey Robert J. 
Published: January 2005

AbstractThe efferent projections of the centromedian and parafascicular (CM‐Pf) thalamic nuclear complex were analyzed by the autoradiographic method. Our findings show that the CM‐Pf complex projects in a topographic manner to specific regions of the rostral cortex. These fibers distribute primarily to cortical layers I and III; however, the projection to layer I is more extensive.Following an injection into the rostral portion of the CM‐Pf complex, label is found within the lateral rostral cortex, particularly within the presylvian, anterior ectosylvian, and anterior lateral sulci, and within the rostral medial cortex where label is present within the cruciate and anterior splenial sulci and anterior cingulate gyrus. An injection into the caudal dorsal portion of the CM‐Pf complex results in label within the more ventral portions of the rostral lateral cortex where it is present within the anterior sylvian gyrus, presylvian regions, and gyrus proreus; and within the rostral medial cortex, where it is present within the rostral cingulate gyrus, and within the cruciate sulcus, and an extensive region ventral to the cruciate sulcus which includes the anterior limbic area. Injections into the caudal ventral portion of the CM‐Pf complex result in virtually no cortical label, although a few labeled fibers are found in the subcortical white matter.The subcortical projection from the CM‐Pf complex terminates within the caudate nucleus, putamen, globus pallidus, subthalamic nucleus, zona incerta, fields of Forel, hypothalamus, thalamic reticular nucleus, and rostral intralaminar nuclei. Prominent silver grain aggregates are also present within the ventral lateral, ventral anterior, ventral medial, and lateral posterior nuclei, and ventrobasal complex. The aggregates in the thalamus appear to be fibers of passage, but whether these are also terminals cannot be determined with the techniques used in the present study.
Corticopontine projection in the macaque: The distribution of labelled cortical cells after large injections of horseradish peroxidase in the pontine nuclei
Authors: Glickstein Mitchell , May Jack G. , Mercier Barbara E. 
Published: January 2005

AbstractWe studied the distribution of corticopontine cells in the monkey cerebral cortex. Horseradish peroxoidase (HRP) was injected into the brainstem of monkeys in an attempt to fill the pontine nuclei on one or both sides. In control animals we injected the medullary pyramids or varied the route, size, or location of pontine injections. All retrograde filled corticopontine neurons were layer V pyramidal cells. Corticopontine cells were distributed within a largely continuous area of cortex which extended from the cingulate cortex medially to the sylvian fissure laterally; from the superior temporal fissure caudally to the medial part of the frontal granular cortex rostrally. Areas 4 and 6 of Brodmann (1905) contained the highest density of filled cells. In the primary visual cortex, area 17, there were a few labelled cells restricted to the rostral portion of the upper bank of the calcarine fissure, in a region representing the lower periphery of the visual field. The results are discussed in relation to the possible functions of the corticopontine system, especially the role of the extrastriate visual areas in visually guided movement.
Neuronal connections in the primary auditory cortex: An electrophysiological study in the cat
Authors: Mitani Akira , Shimokouchi Minoru 
Published: January 2005

AbstractNeuronal connections in the primary auditory cortex (AI) of the cat were studied electrophysiologically by using intracellular recording techniques. Fast‐conducting fibers from the medial geniculate nucleus (MG) projected monosynaptically onto AI neurons in layers III–VI (mainly in layer IV), whereas slow‐conducting MG‐fibers projected monosynaptically onto AI neurons in layer I. AI neurons which received monosynaptic inputs from the auditory association cortices (AII and Ep) and/or from the contralateral AI were distributed in all layers of the AI; the commissural fibers from the contralateral AI were divided into fast‐ and slow‐conducting ones.AI neurons were categorized into seven types: type I neurons which received monosynaptic inputs from slow‐conducting MG‐fibers were located in layer I. Type II neurons which received polysynaptic inputs from the MG were located in layers II–VI. Type III neurons which sent their axons to the AII or Ep were mainly located in layer III. Type IV neurons which sent their axons to the contralateral AI were located mainly in layer III. Type V neurons which received monosynaptic inputs from fast‐conducting MG‐fibers were located mainly in layer IV. Type VI neurons which projected onto the inferior colliculus were located in the upper part of the layer V. Type VII neurons which projected onto the MG were located in layers V and VI.
Light microscopic analysis of golgi‐impregnated rat subthalamic neurons
Authors: Afsharpour Salman 
Published: January 2005

AbstractThe neuronal morphology of the rat subthalamic nucleus (STH) was studied using Golgi techniques and Nissl stain. The results show that the somatic shapes of STH neurons vary from fusiform to oval or polygonal. Soamtic cross‐sectional areas vary between 140 μm2 and 440 μm2. Some of the cells have a few somatic spines. Two to six primary dendrites gave rise to tapering daughter dendrites which extend up to 500 μm. These dendrites are sparsely covered with spines. Some distal dendrites and primary dendrites of the STH also bear filiform appendages. Neurons located in the deep portion of the STH have oval dendritic fields whose long axis is parallel to the long axis of the nucleus in frontal or sagittal planes. Some of these neurons have one or two dendrites which cross the borders of the STH into the zona incerta, the lateral hypothalamus, or the cerebral peduncle. Generally, neurons located at the borders of the STH have their dendritic fields extending parallel to the borders and are confined to the nucleus. However, some neurons adjacent to the ventrolateral border of the nucleus have some dendrites extending into the cerebral peduncle. Quantitative analysis of the STH neurons showed a unimodal distribution of somatic sizes as well as the number of primary dendrites. No neurons with obvious Golgi type II characteristics were found.Two types of afferent fibers were observed entering the STH. One type consists of axon collaterals arising from the cerebral peduncle ventrolaterally, or the internal capsule rostrally, while the other enters the nucleus after crossing the internal capsule rostrally.These results suggest that the rat STH is an open nucleus in contrast to other species such as man, monkey, and cat, where it is closed, and that the rat STH may contain only one type of neuron.
Distribution of central cholinergic neurons in the baboon (papio papio). I. General morphology
Authors: Satoh K. , Fibiger H. C. 
Published: January 2005

AbstractThe morphological characteristics of cholinergic neurons in the central nervous system (CNS) of the baboon (Papio papio) were studied by choline acetyltransferase (ChAT) immunohistochemistry and acetylcholinesterase (AChE) pharmacohistochemistry. The distributions of central cholinergic neurons as visualized by these two histochemical techniques were similar in most, but not all regions of the brain and spinal cord. Based upon these observations, central cholinergic neurons that are immunoreactive to ChAT and intensely stained for AChE by the pharmacohistochemical procedure can be divided into four major groups: (1) those in the caudate nucleus, putamen, nucleus accumbens and anterior perforated substance. These ChAT‐containing and AChE‐intense neurons are large and multipolar, and are scattered throughout these structures. (2) The rostral cholinergic column, which consists of a continuous mass of cholinergic perikarya situated in the medial septal nucleus, nucleus of the diagonal band, and nucleus basalis (Meynert). The ChAT‐immunoreactive and AChE‐intense cell bodies of the nucleus basalis are a prominent feature in the basal forebrain of the baboon. The labeled neurons are large, multipolar, and hyperchromic and show a tendency to aggregate in cell clusters. These cells are distributed within the full extent of the substantia innominata, often being associated with sub‐cortical fiber networks such as the medullary laminae of the globus pallidus. (3) The caudal cholinergic column, which consists of a continuous group of cholinergic neurons in the caudal midbrain and pontine tegmentum. The rostral component of this group of cells is the nucleus tegmenti pedunculopontinus (subnucleus compacta) and it extends caudally to include the later‐odorsal tegmental nucleus. Compared to that in other species the nucleus tegmenti pedunculopontinus in the baboon appears to occupy a relatively greater volume and is composed of a greater number of cholinergic neurons. The cells of the caudal column are large and hyperchromic. (4) Nuclei of origin of somatic and visceral efferents of the cranial nerves (III, IV, V, VI, VII, IX, X, XI, XII) and spinal nerves. In addition to these major cholinergic cell groups, a small population of ChAT‐positive and AChE‐intense cell bodies can be observed at the floor of the fourth ventricle and in lamina VII and X of the cervical cord. The present findings indicate that although some differences exist, the overall distribution and morphological features of cholinergic cell bodies identified in the baboon brain and spinal cord are similar to those demonstrated previously in investigations of the rhesus monkey and nonprimates.
Organization of the nigrothalamocortical system in the rhesus monkey
Authors: Ilinsky I. A. , Jouandet M. L. , Goldman‐Rakic P. S. 
Published: January 2005

AbstractThe nigrothalamocortical connections and their topography were analyzed by autoradiography and double or triple retrograde labeling with the fluorescent dyes Fast Blue, Diamidino Yellow, and Propidium Iodide. Injections of tritiated leucine into different parts of the substantia nigra (SN) revealed that the medial SN projects to the medial magnocellular subdivisions of the ventral anterior (VAmc) and mediodorsal (MDmc) nuclei of the thalamus while the lateral SN projects to the more lateral and more posterior part of the VAmc, and the paralaminar, parvicellular, and densocellular subdivisions of the mediodorsal nucleus (MDmf, MDpc, and MDdc). With the exception of the MDmf, terminal areas observed in the mediodorsal nucleus were in the form of scattered clusters of grains. Analysis of the thalamus in cases with fluorescent dye injections into the lateral orbital gyrus (Walker's area 11), principal sulcus (area 46), anterior bank of the arcuate gyrus (areas 8 and 45), supplementary motor area (area 6), and motor cortex (area 4) revealed topographic organization of the nigrothalamocortical projection system. The parts of the VAmc and MDmc which receive afferents from the medial part of the SN in turn project to the most anterior regions of the frontal lobe including principal sulcus and orbital cortex. The lateral posterior VAmc, MDmf, MDpc, and MDdc, all of which receive afferents from the lateral part of the SN, project to more posterior regions of the frontal lobe including, in addition to the principal sulcus, the frontal eye field and also areas of the premotor cortex. These findings indicate that the SN has preferential targets in the thalamus and cerebral cortex which are segregated from those of the globus pallidus and cerebellum. Whereas the motor cortex is the primary target of cerebellar output (Asanuma et al., 1983b), and the premotor cortex is the target of pallidal output (Schell and Strick, 1984), the SN output appears to be directed more anteriorally—;to the prefrontal cortex.
Ontogeny of phenylethanolamine N‐methyltransferase‐ and tyrosine hydroxylase‐like immunoreactivity in presumptive adrenaline neurones of the foetal rat central nervous system
Authors: Foster G. A. , Schultzberg M. , Goldstein M. , Hökfelt T. 
Published: January 2005

AbstractThe appearance of phenylethanolamine N‐methyltransferase (PNMT)‐and tyrosine hydroxylase (TH)‐like immunoreactivity (LI) in the foetal rat central nervous system has been investigated. Antibodies raised against PNMT and TH were used in an indirect immunofluorescence method. Attention was focussed on areas containing putative adrenaline‐containing nerve cell bodies or fibres and, using an elution‐restaining technique, it was possible to analyze whether neurones contained PNMT‐LI, TH‐LI, or both. PNMT‐immunoreactive neurones could first be visualized on day 13 of gestation, in the ventrolateral and dorsal medulla oblongata, and probably corresponding to those of the C1 and C2 groups. The number of positive cell bodies and the intensity of their fluorescent staining in these areas were not dissimilar at this stage to the number and intensity observed at 1 day postnatal, the final age studied. At day 16, PNMT‐positive cells were observed for the first time in midline areas of the rostral dorsal medulla oblongata‐caudal pons, associated with the medial longitudinal fasciculus. These cells probably composed the C3 cell group. Many PNMT‐immunoreactive fibres could be seen at day 13 of gestation, in the medulla, and coursing both in an ascending bundle around the mesencephalic flexure and in a descending bundle toward the spinal cord. The extent of the bundles increased with gestational age, such that dense meshworks of PNMT‐immunoreactive varicose fibres were visible ventral to the aqueductus Sylvii, and the periventricular and lateral regions of the hypothalamus by days 18 to 19, and in the paraventricular nucleus, the septum, and the thoracic spinal cord by day 1 after birth. A sparser fibre plexus was observed in the amygdala at day 1 postnatal.In contrast to the explosive appearance of PNMT‐immunoreactive cells at day 13 of gestation, the development of TH‐LI within these same neurones was much more protracted. Only rarely were TH‐LI awl PNMT‐LI colocalized at day 13, and even at birth TH‐LI could not be visualized in 5% of PNMT‐immunoreactive cells in the ventrolateral medulla oblongata, and in 50% of those in the dorsal vagal complex. A similar tardy appearance of TH‐LI in PNMT‐immunoreactive fibres was observed also. It should be emphasized that strongly TH‐immunoreactive neurones were found already at gestational day 10.5 in the medulla oblongata, caudal to the PNMT‐immunoreactive cells.It is concluded that the expression of enzymes involved in the synthesis of adrenaline is not unitarily controlled, and may be partly dependent on other than epigenetic factors. Furthermore, ascription of the term adrenergic to a class of neurones appears to require the identification of more than a single synthetic enzyme.
An immunocytochemical study of the development of central serotoninergic neurons in the chick embryo
Authors: Wallace James A. 
Published: January 2005

AbstractThe development of central serotoninergic neurons in the chick embryo has been investigated immunocytochemically by utilizing an antiserum to serotonin (5‐HT). Immunoreactive neurons are first detected in the brain‐stem on embryonic day 4 (E4, stage 23), days earlier than 5‐HT systems have been detected previously by biochemical techniques. The earliest 5‐HT‐containing cells at E4 appear rostral to the pontine flexure, yet by E5, 5‐HT neuronal groups are observed throughout the brainstem from just caudal to the mesencephalic flexure to the cervical flexure. During this and subsequent phases of development, two distinct patterns of cellular migration seem to be involve‐l in the formation of the various 5‐HT neuronal groups. One pattern involves a ventral migration of 5‐HT cells, which appears dependent upon the directional guidance of midline radial processes (formed by floor plate cells) that extend across the neuroepithelium. The other pattern involves a lateral migration of cells, followed by an aggregation and rearrangement of 5‐HT neurons into distinct subgroups or clusters. Through these patterns of migration most components of the 5‐HT neuronal system can be recognized as early as E12, with the mature organization of the 5‐HT cell groups occurring by E17. One unexpected finding was the comparatively late appearance (between E9 and E12) of 5‐HT neurons in the paraventricular organ of the hypothalamus. Thus, in comparison to the initial observation of the majority of brainstem 5‐HT neurons at E4 to E5, the hypothalamic 5‐HT cells appear after a delay of between 5 and 7 days. Such differences illustrate the fact that neurons sharing a common neurotransmitter phenotype do not necessarily share the same developmental timetable for the expression of that particular phenotype, or they may undergo neurogenesis during considerably different periods of embryogenesis.