bluuebunny/crossref_metadata_2025_split huggingface dataset:
The terminations of corticospinal tract axons in the macaque monkey
Authors: Ralston Diane Daly , Ralston Henry J. 
Published: May 2005

AbstractThis study examined the corticospinal tract in monkey by utilizing the anterograde transport of wheat germ lectin conjugated to horseradish peroxidase (WGA HRP) at the light microscopic level and the axonal transport of 3H‐proteins with both light and electron microscopic autoradiographic techniques. The animals survived 3–9 days after the injections of 3H‐leucine or 3H‐leucine/WGA HRP into either motor or sensory cortices. With the laminar schema of Rexed as a guide to the layers of the spinal gray matter, qualitative and quantitative analyses of labeled projections of the corticospinal tract (CST) were made. With the light microscope, axons from the sensory cortex labeled with WGA‐HRP could be observed in the contralateral spinal gray from lamina I to the border of laminae VI/VII, the heaviest distribution being located in medial III–VI. There was a small ipsilateral projection to V and VI. With 3H label, laminae I and II revealed few overlying silver grains; many grains overlay laminae III–VI. Projections from the motor cortex labeled with either WGA‐HRP or 3H extended from the contralateral laminae III/IV border into the motor nucleus (lamina IX) and were seen to be somewhat more dense in the lateral areas of the spinal gray. The motor cortex projected heavily to ipsilateral VIII, and in sparse amounts to ipsilateral V and VI.Electron microscopy of radioactive axons from the sensory cortex to dorsal horn revealed many radioactive myelinated fibers and some labeled non‐myelinated axons. Labeled terminals contacted medium to small dendrites; there were a few labeled C‐type profiles in glomeruli and occasional axo‐axonal or dendro‐axonal contacts, the labeled cortical axons being the postsynaptic structure. In ventral horn following motor cortex injections, the labeled axons were all myelinated. The synaptic contacts were found on small, medium, and large proximal dendrites as well as on cell bodies. Labeled terminals which formed the central element in glomeruli were also seen in this region. Most of the labeled corticospinal terminals in dorsal and ventral horn contained rounded vesicles, but a significant number revealed pleomorphic vesicles. The relationship of these morphological findings to physiological studies of the CST is presented.
The long visual fibers of the dragonfly optic lobe: Their cells of origin and lamina connections
Authors: Armett‐Kibel Christine , Meinertzhagen I. A. 
Published: May 2005

AbstractA pair of long visual fibers projects from each ommatidium of the compound eye of the dragonfly Sympetrum. They arise from retinular cell R7 and its slender partner R6. To investigate the segregation of lamina input pathways between these and the well‐described short retinular terminals, we have examined the cell morphology and en passant synaptic involvements of R7 and 6 in the ventral lamina using serial‐EM and combined Golgi‐EM. In the retinula, R7 has a large apical rhabdomere with microvilli aligned along the animal's horizon, and a basal axon. R6 has a few microvilli at all depths, which align with those of neighboring rhabdomeres. In the lamina, R7 and 6 neighbor on MV, the fifth monopolar cell. The stout axon of R7 has many diffusely distributed spines which contact the neighboring terminals of R5 and 8, and MIL In one entire cartridge R7 was presynaptic to MII at 24 dyads and triads throughout the lamina and also to MV at dyads exclusively in the distal lamina. Another class of element which derives from the unidentified processes called a was also postsynaptic to R7 at dyads, and, mostly in the proximal lamina, was reciprocally presynaptic to R7, along with R5 and 8. R6 is slender with a single conspicuous spine. At a total of three zones in the proximal lamina and distal chiasma it was presynaptic at 38 dyads—also upon MII and MV and often in combination with other elements; it was not postsynaptic in the lamina. R6 and 7 thus provide the sole input to MV and contribute to the general retinular input to MIL They form the lowest ratios of triad:dyad synapses of all lamina retinular elements. Comparison is made with the long visual fibers of other arthropods but known examples are too diverse to detect functional commonalities.
Pituitary afferents originating in the paraventricular organ (PVO) of the goldfish hypothalamus
Authors: Fryer James N. , Boudreault‐Chateauvert Chantal , Kirby Richard P. 
Published: May 2005

AbstractThe diencephalon of nonmammalian vertebrates contains aminergic perikarya situated beneath the ependyma lining the third ventricle, known as the paraventricular organ (PVO). Catecholamines were visualized in the goldfish forebrain by formaldehyde‐glutaraldehyde‐induced fluorescence. Neuronal somata containing catecholamines were found in three paraventricular nuclei—the nucleus recessus posterioris (NRP), the nucleus recessus lateralis(NRL), and the nucleus posterioris paraventricularis (NPPv)—which may be considered to constitute the PVO of the goldfish. Lesion‐degeneration investigations were conducted to determine whether the PVO contributes to the innervation of the goldfish pituitary. Following electrothermic lesions of the NRP, degenerating axons and nerve terminals were observed in the rostral pars distalis and in the proximal pars distalis, but not in the neurointermediate lobe of the pituitary. Following lesions of the NRL or of the NPPv, degenerating axons and nerve terminals were observed in the rostral pars distalis, the proximal pars distalis, and in the neurointermediate lobe. These observations demonstrate that the PVO is a source of pituitary afferents in the goldfish and suggest that the PVO is a source of the catecholaminergic innervation of the teleost pituitary.
Projections from the nucleus tractus solitarii to the rostral ventrolateral medulla
Authors: Ross Christopher A. , Ruggiero David A. , Reis Donald J. 
Published: May 2005

AbstractProjections from the nucleus tractus solitarii (NTS) to autonomic control regions of the ventrolateral medulla, particularly the nucleus reticularis rostroventrolateralis (RVL), which serves as a tonic vasomotor center, were analyzed in rat by anterograde, retrograde, and combined axonal transport techniques.Autonomic portions of the NTS, including its commissural, dorsal, intermediate, interstitial, ventral, and ventrolateral subnuclei directly project to RVL as well as to other regions of the ventrolateral medulla. The projections are organized topographically. Rostrally, a small cluster of neurons in the intermediate third of NTS, the subnucleus centralis, and neurons in proximity to the solitary tract selectively innervate neurons in the retrofacial nucleus and nucleus ambiguus. Neurons generally located in more caudal and lateral sites in the NTS innervate the caudal ventrolateral medulla (CVL). The RVL, CVL, and nucleus retroambiguus are interconnected.A combined retrograde and anterograde transport technique was developed so as to prove that projections from NTS to the ventrolateral medulla specifically innervate the region of RVL containing neurons projecting to the thoracic spinal cord or the region of the nucleus containing vagal preganglionic neurons.When the retrograde tracer, fast blue, was injected into the thoracic spinal cord, and wheat germ agglutinin‐conjugate horseradish peroxidase (HRP) was injected into the NTS, anterogradely labeled terminals from the NTS surrounded the retrogradely labeled neurons in the RVL and in the nucleus retroambiguus in the caudal medulla. Among the bulbospinal neurons in the RVL innervated by the NTS were adrenaline‐synthesizing neurons of the C1 group.When fast blue was applied to the cervical vagus, and HRP was injected into the NTS, anterogradely labeled terminals from the NTS surrounded retrogradely labeled neurons in the rostral dorsal motor nucleus of the vagus, the region of the nucleus ambiguus, the retrofacial nucleus, and the dorsal portion of the RVL, a region previously, shown to contain cardiac vagal preganglionic neurons. This combined anterograde and retrograde transport technique provides a useful method; for tracing disynaptic connections in the brain.These data suggest that the RVL is part of a complex of visceral output regions in the ventrolateral medulla, all of which receive afferent projections from autonomic portions of the NTS. Bulbospinal neurons in the RVL, in particular the C1 adrenaline neurons, may provide a portion of the anatomic substrate of the baroreceptor and other visceral reflexes.
Comparison between the dimensions of dendritic spines in the cerebral cortex of newborn and adult guinea pigs
Authors: Schüz Almut 
Published: May 2005

AbstractDendritic spines in the cerebral cortex of newborn and adult guinea pigs were compared quantitatively. An increase in the average diameter of the head by 21% and in the diameter of the stalk by 29% was found. No difference could be measured in the average length of the spines of both age groups.When plotting the individual measurements against each other, a slight correlation could be found only between the size of the spine head and the thickness of the stalk.
Location of motoneurones projecting to the cat distal forelimb. II. Median and ulnar motornuclei
Authors: Fritz Norbert , Illert Michael , Reeh Peter 
Published: May 2005

AbstractThe position of the motornuclei projecting through the median (Mn) and ulnar (Ul) nerves to the cat distal forelimb has been investigated. 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 were carefully denervated. The position and the architecture of the individual rotornuclei were traced with HRP. The topographical relations between the nuclei were established with application of up to three different Fl compounds in the same animal. The Mn motoneurones had a bimodal distribution in the brachial spinal cord. The motoneurones to the pronator teres and flexor carpi radialis muscles were located in C7 and the other Mn motoneurones were located in C8 and Thl. In C7 the Mn motoneurones occupied a single representation area, which is located some distance medially of the lateral funiculus. In C8 and Th1 two Mn representation areas were found: A dorsal one that contacts the lateral funiculus and is located at the level of the central canal; a ventral one that is located ventrally in the ventral horn. The dorsal area is occupied by the motornuclei projecting to the intrinsic hand muscles and the ventral one by the nuclei projecting to the limb. The Ul motoneurones extend with an unimodal distribution from the caudal C7 to the caudal Thl segments. They occupy a single, broad representation area. The dorsal part, which contacts the lateral funiculus, is located at the level of the central canal and harbours the nuclei to the intrinsic hand muscles. The other Ul nuclei are located ventromedially deep in the ventral horn. These results, together with those from the companion paper on the location of the deep radial motornuclei, provide important anatomical information for the investigation of the cat brachial enlargement.
Development of connections between the mediodorsal nucleus of the thalamus and the prefrontal cortex in the rat
Authors: Van Eden C. G. 
Published: May 2005

AbstractThe postnatal ingrowth of thalamocortical fibers from the mediodorsal nucleus to the prefrontal cortex was investigated in relation to the development of cortical lamination. Like the dopaminergic fibers in the prefrontal cortex and the thalamic fibers in the visual cortex, the mediodorsal fibers have entered the prefrontal cortex at birth. Most of the fibers are found in the developing layer VI, but, in contrast to the above‐mentioned systems, a considerable number of mediodorsal fibers have already penetrated into the upper, most immature part of the cortical plate on postnatal day 1. From day 1 to day 7 an increasing number of mediodorsal fibers reach the upper cortical plate, which by then is developing layer 111, the terminal layer of these fibers. The reciprocal connection from the layer VI cells of the prefrontal cortex to the mediodorsal nucleus develops between day 4 and day 9. Finally, the projection from the contralateral prefrontal cortex to the mediodorsal nucleus is established around day 10. The early presence of the mediodorsal fibers in the upper, differentiating cortical plate might indicate an important role for the mediodorsal fibers in the laminar development of the prefrontal cortex.
Frontal eye field efferents in the macaque monkey: II. Topography of terminal fields in midbrain and pons
Authors: Stanton G. B. , Goldberg M. E. , Bruce C. J. 
Published: May 2005

AbstractFrontal eye field (FEF) projections to the midbrain and pons were studied in nine macaque monkeys that were used to study FEF projections to the striatum and thalamus (Stanton et al.: J. Comp. Neurol. 271:473‐492, '88). Injections of tritiated amino acids or WGA‐HRP were made into FEF cortical locations where low‐level microstimulation (≤50 μA) elicited saccadic eye movements, and anterograde axonal labeling was mapped. The injections were made into the anterior bank of the arcuate sulcus from dorsomedial sites where large saccades were evoked (lFEF) to ventrolateral sites where small saccades were evoked (sFEF).The largest terminal fields of FEF fibers were located in the ipsilateral superior colliculus (SC). Projections to SC were topographically organized: lFEF sites projected to intermediate and deep layers of caudal SC, sFEF sites projected to intermediate and superficial layers of rostral SC, and FEF sites between these extremes projected to intermediate locations in SC. Patches of terminal labeling were located ipsilaterally in the lateral mesencephalic reticular formation near the parabigeminal nucleus and the ventrolateral pontine reticular formation. These patches were larger from lFEF injections. Small, dense terminal patches were seen in the ipsilateral pontine gray, mostly along the medial and dorsal borders of these nuclei but occasionally in central and dorsolateral regions. Patches of label like those in the pontine nuclei were located ipsilaterally in the reticularis tegmenti pontis nucleus in lFEF cases and bilaterally in sFEF cases.Small terminal patches were found in the nucleus of Darkschewitsch and dorsal and medial parts of the parvicellular red nucleus in most FEF cases. In the pretectal region, labeled terminal patches were consistently found in the nucleus limitans of the posterior thalamus, but we could not determine if label in the nucleus of the pretectal area and dorsal parts of the nucleus of the posterior commissure marked axon terminals or fibers of passage.We found small, lightly labeled terminal patches in the pontine raphe between the rootlets of the abducens nerve (three cases) or in the adjacent paramedian pontine reticular formation (one case). Omnipauser cells in this region are important in initiating saccades. In one sFEF case, very small patches of label were located in the supragenual nuclei anterior to the abducens nuclei and in the ipsilateral nucleus prepositus hypoglossi posterior to the abducens nucleus. Presaccadic burster neurons in the periabducens region are known to fire immediately before horizontal saccades. Neither IFEF or SFEF projections appeared to terminate in the rostral interstitial nucleus of the medial longitudinal fasciculus, the interstitial nucleus of Cajal, or the motor nuclei of the extraocular muscles.
Distribution and some projections of cholinergic neurons in the brain of the common marmoset, Callithrix jacchus
Authors: Everitt Barry J. , Sirkiä Taina E. , Roberts Angela C. , Jones Graham H. , Robbins Trevor W. 
Published: May 2005

AbstractThe distribution of choline acetyltransferase‐immunoreactive (ChAT‐IR) neurons was studied in the brain of the common marmoset by using immunohistochemistry. ChAT‐IR neurons were found in the medial septal nucleus, vertical and horizontal limb nuclei of the diagonal band, the nucleus basalis of Meynert, pedunculopontine nucleus and laterodorsal tegmental nucleus, and also in the striatum, habenula, and brainstem cranial nerve motor nuclei. The organization of ChAT‐IR neurons in the basal forebrain, midbrain, and pons is consistent with the Ch1–Ch6 nomenclature introduced by Mesulam et al. ('83). The combination of the retrograde transport of HRP‐WGA with ChAT immunohistochemistry revealed the distribution of neurons in the Ch4 cell group projecting to the dorsolateral prefrontal cortex. The activity of ChAT was highest in limbic cortical structures, such as the hippocampus, and lowest in association areas of the neocortex. Lesions at various loci in the basal forebrain resulted in differential patterns of ChAT loss in the cortex, which suggests some degree of topographical organization of Ch4 projections to the cortical mantle.
Neural control of leg movements in a metamorphic insect: Sensory and motor elements of the larval thoracic legs in Manduca sexta
Authors: Kent Karla S. , Levine Richard B. 
Published: May 2005

AbstractDuring the metamorphosis of the hawkmoth Manduca sexta the larval thoracic legs degenerate to be replaced in the adult by legs of very different form and function. This change must be accompanied by a reorganization of the neural circuits controlling leg movements. As an initial step in the study of this reorganization we describe here the sensory and motor elements of this circuitry in the larval stage of life. Sensory neurons innervating mechanoreceptive hairs on the thoracic surface were stained individually with cobalt. Those innervating hairs on the general thoracic surface project topographically into two ventral regions of the segmental ganglia. Sensory neurons innervating leg sensilla also map topographically to the more ventral of these regions but in addition have arborizations in a midlateral region. The density of branching within this lateral “leg neuropil” is greatest for sensory neurons from sensilla on the more distal leg segments.Leg motor neurons were identified with intracellular recording and cobalt injection techniques. Those innervating muscles controlling distal leg segments have dense dendritic arbors in the lateral “leg neuropil,” while motor neurons controlling more proximal segments and muscles of the ventral body wall have extensive arborizations in a dorsomedial region of the ganglion. In general, flexor motor neurons are excited by medial and inhibited by lateral leg sensilla, while the opposite is true of extensors. Distal segment motor neurons respond most strongly to sensory neurons from distal segments, thus suggesting some interaction within the lateral “leg neuropil.” Thus, in the larval nervous system a highly ordered array of of sensory and motor elements underlies the specific behavioral responses of the legs to tactile stimulation.
Nucleus sagulum: Projections of a lateral tegmental area to the inferior colliculus in the cat
Authors: Henkel Craig K. , Shneiderman Amiram 
Published: May 2005

AbstractThe nucleus sagulum, an area of the midbrain tegmentum, has been considered a component of a lateal tegmental system within the ascending auditory pathway to the thalamus. In this study, connections of the nucleus sagulum within the midbrain were investigated in adult cats. Tracing methods using anterograde and retrograde axonal transport of markers were employed. The nucleus sagulum was identified as a region of principally small neurons (261 ± 79 μm2) at the margin of the midbrain and neighboring the nuclei of the lateral lemniscus. Injections of tritiated leucine in the nucleus sagulum labeled axons that ended in dense patches within the superficial layers of the caudal portion of the dorsal cortex of the inferior colliculus on the ipsilateral side. Retrograde experiments confirmed this connection. Other axonal projections labeled in the anterograde studies included fibers ending in the dorsomedial nucleus, the superficial layers of the dorsal cortex, and the rostral nucleus of the inferior colliculus with some bilateral distribution. Outside of the inferior colliculus, sagulum injections labeled other axons ending in the ventral intercollicular tegmentum on both sides and in a dorsal and rostral region of the contralateral nucleus sagulum that appeared contiguous with the dorsal nucleus of the lateral lemniscus. The latter region included a population of larger neurons (340‐540 μm2) and had different connections with the inferior colliculus. The distribution of axonal labeling after injections in the nucleus sagulum was contrasted with the distribution of projections from several neighboring areas of the lateral tegmentum, including the dorsal nucleus of the lateral lemniscus. None of these areas exhibited connections with the superficial layers of the caudal cortex of the inferior colliculus, which was the major target in the inferior colliculus of the nucleus sagulum. Thus, the results indicated that the nucleus sagulum is distinguished from adjacent regions of the lateral tegmentum by its connectivity. Its association with midbrain auditory pathways is supported by these connections as well as ascending ones to the auditory thalamus.
Gamma‐aminobutyric acid in the medial rat nucleus accumbens: Ultrastructural localization in neurons receiving monosynaptic input from catecholaminergic afferents
Authors: Pickel Virginia M. , Towle Andrew C. , Joh Tong H. , Chan June 
Published: May 2005

AbstractNeurons containing gamma‐aminobutyric acid (GABA) in the medial portion of the adult rat nucleus accumbens were characterized with respect to their ultrastructure, sites of termination, and catecholaminergic input. Antisera against GABA‐conjugates and the catecholamine‐synthesizing enzyme, tyrosine hydroxylase (TH), were localized within single sections by means of peroxidase‐antiperoxidase (PAP) and immunoautoradiographic labeling methods. Peroxidase reaction product indicating GABA‐like immunoreactivity (GABA‐LI) was seen in medium‐size (15‐20 μm) perikarya containing either round and unindented or invaginated nuclear membranes. The cells with invaginated nuclei were few in number and usually exhibited more intense peroxidase reaction product in sections collected at the same distance from the surface of the tissue. Reaction product for GABA was also detected in proximal (1.5‐3.0 μm) dendrites, axons, and terminals. Terminals with GABA‐LI formed symmetric junctions on perikarya, proximal dendrites, and dendritic spines of neurons that usually lacked detectable immunoreactivity. Many of the GABAergic terminals also were apposed directly to other unlabeled terminals and to terminals exhibiting either peroxidase labeling for GABA or immunoautoradiographic labeling for TH. Many of the unlabeled terminals associated with the GABAergic axons formed asymmetric junctions on dendritic spines.From 138 TH‐labeled, principally dopaminergic terminals that were examined in the medial nucleus accumbens, 4% were associated with the somata of GABAergic neurons and another 14% formed symmetric junctions with proximal dendrites showing GABA‐LI. The remaining TH‐immunoreactive terminals either lacked recognizable densities or formed symmetric synapses on unlabeled dendrites and spines. A few of the unlabeled dendrites, as well as those containing GABA‐LI, received symmetric synapses from both catecholaminergic and GABAergic terminals.We conclude that in the medial portion of the rat nucleus accumbens, GABA is localized to two morphologically distinct types of neurons, one or both of which receive monosynaptic input from catecholaminergic afferents, and that GABAergic terminals form symmetric synapses on other princi‐pally non‐GABAergic neurons. The results also support earlier physiological evidence showing that GABA may modulate the output of other GABAergic and non‐GABAergic neurons through presynaptic associations.