bluuebunny/crossref_metadata_2025_split huggingface dataset:
Anatomical investigation of projections to the basis pontis from posterior parietal association cortices in rhesus monkey
Authors: Schmahmann Jeremy D. , Pandya Deepak N. 
Published: January 2005

AbstractThe projections to the basis pontis from cytoarchitectonically defined subregions of the superior (SPL) and inferior (IPL) parietal lobules were investigated in 14 rhesus monkeys by using the anterograde tracing techniques of autoradiography and horseradish peroxidase histochemistry. The results of our study confirm and complement available information regarding the parietopontine projections. The projections are found in clusters distributed in lamellae approximately concentric to the peduncle. They are directed most heavily towards the peripeduncular and lateral nuclei of the pons. There are also lesser, but nevertheless substantial projections to other nuclei including the intrapeduncular, ventral, dorsolateral, extreme dorsolateral, and dorsal nuclei. The dorsomedial, paramedian, and NRTP nuclei receive only minor projections. The SPL projections are relatively widespread with respect to the more focussed IPL projections. The IPL projections are, in general, situated more laterally and at more rostral levels of the pontine nuclei than are those of the SPL.The sulcal cortex of the SPL (area PEa) favors the dorsolateral, extreme dorsolateral, and ventral nuclei compared to the light projections to these nuclei from the convexity of the SPL. The sulcal cortex of the IPL, area POa, differs from the gyral cortex in favoring the ventral and extreme dorsolateral nuclei. The rostral IPL differs from the caudal IPL in that the intrapeduncular nucleus receives projections only from rostral regions, while the lateral nucleus receives projections preferentially from caudal regions. The pontine projections from the medial SPL, area PGm, are unique in the parietal lobe in that they include the paramedian nucleus. Projections arising from multimodal regions located caudally in the SPL (areas PEa and PGm) and IPL (areas PG and Opt) are more strongly represented and more laterally placed within the pontine nuclei than projections arising from more rostral, unimodal, posterior parietal regions.The heavy projections to the pontine nuclei from the posterior parietal cortex, and particularly from those caudal parietal regions that have prominent associative and limbic connections, seem to suggest that the corticopontocerebellar pathways permit a cerebellar contribution not only to the coordination of movement, but also to the modulation and integration of higher function.
A subpopulation of dorsal unpaired median neurons in the blood‐feeding insect Rhodnius prolixus displays serotonin‐like immunoreactivity
Authors: Orchard Ian , Lange Angela B. , Cook Heather , Ramirez Jan‐Marino 
Published: January 2005

AbstractWe describe, for the first time in insects, the presence of serotonin‐like immunoreactive dorsal unpaired median (DUM) neurons. In unfed, untreated Rhodnius prolixus, the cell bodies of these DUM neurons displayed only faint serotonin‐like immunofluorescence without any detectable fluorescence in the axons. There was, however, an extensive serotonin‐like immunoreactive peripheral complex. We have enhanced the immunostaining of the cell bodies and axons of these DUM neurons by using 5,7‐dihydroxytryptamine (5,7‐DHT) and nerve transection, and have further defined their morphology with cobalt backfilling and Lucifer yellow injection.Injection of 5,7‐DHT resulted in enhanced serotonin‐like immunostaining, after 24 hours, of five DUM neurons in the mesothoracic ganglionic mass. Each DUM neuron possessed bifurcating serotonin‐like immunoreactive axons projecting to the periphery via one of the five bilaterally paired abdominal nerves. Concomitant with the enhanced immunostaining in the cell body and axons of these DUM neurons was the depletion of a serotonin‐like immunoreactive neurohaemal area lying on each of the abdominal nerves and the depletion of serotonin‐like immunoreactive processes on the body wall. Enhancement of cell body and axon immunostaining was also observed in preparations in which the abdominal nerves had been transected 24 hours previously.The location and morphology of these DUM neurons were studied in further detail by using cobalt backfilling of the abdominal nerves and intracellular injection of Lucifer yellow followed by immunohistochemistry. The five serotonin‐like immunoreactive DUM neurons were found to represent a sub‐population in a group of ten DUM neurons located in the mesothoracic ganglionic mass and associated with the abdominal nerves. Each abdominal nerve received projections from two DUM neurons, only one of which was serotonin‐like immunoreactive.Electrophysiological recordings revealed that the serotonin‐like immunoreactive DUM neurons of Rhodnius had similar properties to previously described octopaminergic DUM neurons of insects.The five DUM neurons in Rhodnius appear to represent a subpopulation of DUM neurons containing serotonin.
Modality‐specific axonal projections in the CNS of the flies Phormia and Drosophila
Authors: Murphey R. K. , Possidente Debra , Pollack Gerald , Merritt D. J. 
Published: January 2005

AbstractThere is a rich history of behavioral and physiological studies on the leg sensory systems of flies. Here we examine the anatomy of the sensory axons of two species of fly and demonstrate that the location of the axonal projections in the CNS can be correlated with the modality they encode. We studied receptors associated with proprioceptive, tactile, and multimodal hairs. Proprioceptive hairs occur in clusters, called hair plates, and are situated near joints. The neuron innervating each proprioceptive hair has a large axon and coarse arborization in the intermediate neuropil. Tactile receptors have smaller arbors, which are located in a ventral region of the thoracic neuromere. Finally, the multimodal hairs are each innervated by one tactile and four chemosensory neurons. The single tactile neuron has a central arbor that is indistinguishable from those of the tactile hairs; the four chemosensory neurons project to yet a third region of neuropil near the ventral surface of each neuromere. Thus there is a clear modality‐specific segregation of axonal arbors in the CNS. This organization is identical in Phormia and Drosophila and thus apparently highly conserved within the Diptera. We presume that, as in other insect sensory systems, this anatomical specificity is linked to synaptic specificity.
Demonstration of two separate descending noradrenergic pathways to the rat spinal cord: Evidence for an intragriseal trajectory of locus coeruleus axons in the superficial layers of the dorsal horn
Authors: Fritschy Jean‐Marc , Grzanna Reinhard 
Published: January 2005

AbstractThe rat spinal cord receives noradrenergic (NA) projections from the locus coeruleus (LC) and the A5 and A7 groups. In contradiction to previous statements about the distribution of descending NA axons, we have recently proposed that in the rat LC neurons project primarily to the dorsal horn and intermediate zone, whereas A5 and A7 neurons project to somatic motoneurons and the intermediolateral cell column. The aim of the present study was to determine the funicular course and terminal distribution of descending NA axons from the LC and from the A5 and A7 groups. The organization of the coeruleospinal projection was analyzed by using the anterograde tracer Phaseolus vulgaris leucoagglutinin in combination with dopaminehyphen;β‐hydroxylase immunohistochemistry. The trajectory of A5 and A7 axons was studied in spinal cord sections of rats following ablation of the coeruleospinal projection with the neurotoxin DSP‐4. To assess the relative contribution of the LC and the A5 and A7 groups to the NA innervation of the spinal cord, unilateral injections of the retrograde tracer True Blue were made at cervical, thoracic, and lumbar levels, and retrogradely labeled NA neurons were identified by dopamine‐β‐hydroxylase immunofluorescence.The results of the anterograde tracing experiments confirm our previous findings that LC neurons project most heavily to the dorsal horn and intermediate zone. Analysis of horizontal sections revealed that LC axons descend the length of the spinal cord within layers I and II. In contrast to the intragriseal course of LC fibers, A5 and A7 axons travel in the ventral and dorsolateral funiculi and terminate in the ventral horn and the intermediolateral cell column. Retrograde transport studies indicate that the contribution of the A5 and A7 groups to the NA projection to the spinal cord is greater than that of the LC. We conclude that descending axons of the LC and A5 and A7 groups differ in their course and distribution within the spinal cord. The documentation of a definite topographic order in the bulbospinal NA projections suggests that the LC and the A5 and A7 groups have different functional capacities. The LC is in a position to influence the processing of sensory inputs, in particular nociceptive inputs, whereas A5 and A7 neurons are likely to influence motoneurons.
Correlation of monosynaptic field potentials evoked by single action potentials in single primary afferent axons and their bouton distributions in the dorsal horn
Authors: Koerber H. Richard , Mendell Lorne M. , Brown Paul B. 
Published: January 2005

AbstractThe relationship between structure and function of the projections of single identified primary cutaneous axons was investigated by recording cord dorsum potentials at 4 sites in response to electrical stimulation of the single axon and visualizing the boutons of the axon stained by intracellular injection of horseradish peroxidase. The rostrocaudal extent of boutons differed from fiber to fiber ranging from 4.14–11.50 mm; their location in the dorsal horn also varied in agreement with the known somatotopy of the presynaptic neuropil and dorsal horn neurons. Rostrocaudal distributions of cord dorsum potentials and boutons of individual fibers revealed good agreement. Cord dorsum potential amplitude and length of the spinal projection were positively correlated with number of boutons, but no correlation with bouton density was found. The spinal projection of afferents innervating slowly adapting type 1 mechanoreceptors exhibited a greater rostrocaudal extent (mean: 8.48 mm) than those innervating rapidly adapting mechanoreceptors (i. e., hair follicle and field receptors: mean: 5.87 mm). Although the mean total number of boutons was greater for axons with slowly adapting receptors (7,250/fiber) than for axons of rapidly adapting receptors (4,677/fiber), no differences in the longitudinal density of boutons (boutons/mm) were observed. Likewise, summed amplitudes of cord dorsum potentials at the 4 recording electrodes were larger for SA1 afferents than for those of field and hair follicle afferents. A major role for the number of boutons in determining these differences is supported by the finding that the calculated average contribution per bouton to cord dorsum potentials (expressed as an amplitude coefficient a) was similar for slowly and rapidly adapting afferents. No evidence was found for regions in which boutons did not contribute to the cord dorsum potential.
Fibre organization of the monkey's optic tract: II. Noncongruent representation of the two half‐retinae
Authors: Reese B. E. , Cowey A. 
Published: January 2005

AbstractThe representations of the two half‐retinae were examined in the monkey's optic tract. Intravitreal injections of tritiated amino acids were made to reveal the distributions of the crossed and uncrossed populations of optic axons, while localized implants of horseradish peroxidase (HRP) were made into different regions of the optic tract in order to examine the distributions and morphological types of retrogradely labelled cells at corresponding loci in the two half‐retinae.Crossed and uncrossed optic axons are intermingled throughout most of the optic tract, but uncrossed axons are very sparse or absent along both the deep and superficial extremes of the tract. Implants of HRP into the deeper regions of the tract demonstrate that the crossed and uncrossed optic axons of the Pβ retinal ganglion cells are slightly out of binocular registration, with the uncrossed map being shifted to a slightly superficial location relative to the crossed map. The optic axons for the remaining cell classes, revealed by implants of HRP into the superficial portion of the tract, are much more conspicuously out of binocular registration (in particular, the Pβ optic axons); but in their cases, the uncrossed optic axons are shifted to deeper locations relative to the crossed optic axons. Further evidence that these optic axon classes are markedly out of binocular registration comes from the two optic tracts of a bilaterally destriated monkey, in which most of the Pβ optic axons have undergone a transneuronal retrograde degeneration. Following a uni‐ocular injection of tritiated amino acids, the distributions of the remaining crossed and uncrossed axonal labelling occupied different positions within the tract rather than being intermingled, with the uncrossed optic axons situated deep to the majority of crossed optic axons.These results demonstrate that the optic chiasm does not combine binocularly corresponding optic axons of similar type. They also demonstrate that noncongruent field defects should be a common consequence of damage to the optic tract in humans.If the fibre order in the mammalian optic tract arises as a consequence of the sequence of axonal addition during development, then differences in the relative times of genesis for nasal and temporal members of any cell class, and/or differences in the relative pathlengths between the eye and two optic tracts, may produce the fibre ordering described herein.
Schwann cell‐neuronal interactions in the rat involve nerve growth factor
Authors: Urschel Bethany A. , Hulsebosch Claire E. 
Published: January 2005

AbstractTo gain some insight into possible functions of nerve growth factor (NGF), we suppressed the endogenous levels of NGF in newborn rats by subcutaneous injections (3 μl/g body weight) of rabbit antibodies to purified mouse β‐NGF (ANTI‐NGF). Fiber and axonal areas and perimeters were measured for unmyelinated and myelinated sensory fibers in T9 dorsal roots (DR) in three groups of animals: (1) ANTI‐NGF treated littermates, (2) preimmune sera treated littermates (PREIMM), and (3) untreated littermates (UNTR). In some rats, fibers in ventral roots (VR) were measured and, in other rats, sensory processes in peripheral nerves (PN) were measured following radical ventral rhizotomy. The only outer area and perimeter measurements that were statistically different were those in the ventral root (P < 0.013 and P < 0.043, respectively). However, myelin thickness was significantly thinner in the dorsal roots of the ANTI‐NGF group than in the dorsal roots of the UNTR and PREIMM groups (P < 0.000009 and P < 10−6, respectively). Myelin thickness in the ventral roots of the ANTI‐NGF group was also statistically thinner than that in the UNTR group (P < 0.001). There were no statistically significant differences when comparing the UNTR group to the PREIMM group. In the peripheral nerves studied, there was no significant change in the myelin thicknesses between the ANTI‐NGF and UNTR groups of animals. These results indicate that Schwann cell‐neuronal interactions are altered by the inactivation of NGF, and that (1) the central processes of sensory fibers are affected and not the peripheral processes and (2) motor fiber myelination is altered. Therefore, we propose that NGF is not only a neurotrophic and neurotropic molecule but is also an important instructive molecule for the initiation and progress of normal myelination.
Identification of neurons producing long‐term potentiation in the cat motor cortex: Intracellular recordings and labeling
Authors: Keller Asaf , Iriki Atsushi , Asanuma Hiroshi 
Published: January 2005

AbstractIntracellular, in vivo recordings were used to identify and subsequently to label neurons in the cat motor cortex in which long‐term potentiation (LTP) was induced. Thirty‐nine motor cortical neurons that produced excitatory postsynaptic potentials (EPSPs) in response to microstimulation in areas 1‐‐2 (SI) or in area 5a (SIII) were studied. Amplitudes of EPSPs produced in response to test stimulation (1 Hz) were recorded before and after tetanic stimulation (200 Hz, 20 seconds). In 25/39 cells (64%), EPSP amplitudes were significantly increased following the tetanic stimulation (65 ± 51% average increase), and remained at the potentiated level as long as stable recordings could be maintained (20 ± 18 minutes, maximum = 90 minutes). LTP was induced exclusively in cells that produced monosynpatic EPSPs in response to area 1‐‐2 or area 5a stimulation. Of the 39 analyzed cells, 13 were labeled by intracellular injections of 5% biocytin. Neurons in which LTP was induced included both pyramidal and nonpyramidal cells and were located exclusively in layers II or III of the motor cortex; cells in deeper cortical layers were not potentiated. These findings indicate that various corticocortical inputs can increase the efficacy of synaptic transmission in a subset of motor cortical neurons. We propose that this plasticity in synaptic transmission constitutes one of the bases of motor learning and memory.
Intraocular projections from the pterygopalatine ganglion in the cat
Authors: Kuchiiwa Satoshi 
Published: January 2005

AbstractThe intraocular projection of the cat pterygopalatine (sphenopalatine) ganglion was examined by using retrograde axoplasmic transport techniques in order to investigate the possibility of the involvement of the facial nerve in ocular parasympathetic innervation. Following an injection of horseradish peroxidase (HRP) or wheat germ agglutinin‐HRP into the eye, retrogradely labeled cells were observed in the ipsilateral pterygopalatine ganglion, principally in the caudal part. By dissection of silver‐impregnated, acetylcholinesterase‐ and cholinesterase‐stained orbital preparations, it was determined that two different nerve pathways link the pterygopalatine ganglion and the eye. One took a retrograde course to join the retro‐orbital plexus and then traveled forward accompanying the ciliary artery, the long ciliary nerve, the short ciliary nerve, and/or the optic nerve sheath. The other entered the orbit directly, fused with the ethmoidal nerve or the infratrochlear nerve in a retrograde fashion, and then turned forward along the long ciliary nerve to enter the eye. All these nerves arose from the caudal part of the ganglion. These results are discussed in relation to recent biochemical and histochemical data demonstrating the involvement of the facial nerve in the control of ocular blood flow and intraocular pressure.
Distribution of aromatase in the brain of the Japanese quail, ring dove, and zebra finch: An immunocytochemical study
Authors: Balthazart Jacques , Foidart Agnes , Surlemont Chantal , Vockel Angela , Harada Nobuhiro 
Published: January 2005

AbstractAn immunocytochemical peroxidase‐antiperoxidase procedure using a purified polyclonal antibody raised against human placental aromatase was used to localize aromatase‐containing cells in the brain of three avian species: the Japanese quail, the ring dove, and the zebra finch. In quail and dove, immunoreactive cells were found only in the preoptic area and hypothalamus, with a high density of positive cells being present in the medial preoptic area, in the septal area above the anterior commissure, in the ventromedial nucleus of the hypothalamus, and in rostral part of the infundibulum. Immunoreactivity was weaker in zebra finches, and no signal could therefore be detected in the ventromedial and tuberal hypothalamus. The positive material was localized in the perikarya and in adjacent cytoplasmic processes, including the full length of axons always leaving a clear unstained cell nucleus. These features could be observed in more detail on sections cut from perfused brains and stained with an alkaline phosphatase procedure. The distribution of aromatase immunoreactivity was similar in the three species although minor differences were observed in the preoptic area. The localization of labelled neurons coincided with the distribution of aromatase activity as studied by in vitro radioenzyme assays on brain nuclei dissected by the Palkovits punch method. There was one striking exception to this rule: no immunoreactivity was detected in the zebra finch telencephalon, while assays had shown the presence of an active enzyme in several nuclei such as the robustus archistriatalis, the hyperstriatum ventrale pars caudale, and the hippocampus and area parahippocampalis. The origins of this discrepancy and the functional role of the aromatase observed in the axons are discussed.
Morphological and physiological characterization of small multimodal ocellar interneurons in the American cockroach
Authors: Ohyama Takahiro , Toh Yoshihiro 
Published: January 2005

AbstractThe morphology and physiology of small multimodal ocellar interneurons (SM‐neurons) have been examined in the cockroach Periplaneta americana. The SM‐neuron is monopolar with its cell body in the tritocerebrum near the esophagus. In axon ascends to the protocerebrum and extends into the ocellar neuropil through the ocellar tract and the ocellar nerve. The axon sends a long collateral process towards the optic tract. The SM‐neuron responded with spike discharges to various sensory stimuli. The collateral and many side branches along the axon in the deutocerebrum appear to be input regions from those sensory afferents. Cereal stimulation triggered most effectively a train of spikes in the SM‐neuron: some of seven giant axons in the ventral nerve cord were involved in this pathway. Cereal stimulation also evoked depolarization in the large second order ocellar neurons (L‐neurons). A possible neural connection between SM‐neurons and L‐neurons was examined pharmacologically. Interaction of ocellar illumination and cereal stimulation in the L‐neuron was also examined. These data are discussed in relation to the ocellar function of cockroaches and in comparison with data obtained in other insects.