bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultrastructural analyses of afferent terminals in the subthalamic nucleus of the cat with a combined degeneration and horseradish peroxidase tracing method
Authors: Moriizumi Tetsuji , Nakamura Yasuhisa , Kitao Yasuko , Kudo Motoi 
Published: January 2005

AbstractThe synaptic organization of the feline subthalamic nucleus (STN) was studied electron microscopically. Following horseradish peroxidase (HRP) injections into the globus pallidus (GP) and electrolytic lesions of the nucleus tegmenti pedunculopontinus pars compacta (TPC) in the same cat, both degenerating and HRP‐labeled terminals were found in the STN with abundant retrogradely HRP‐labeled neurons. Degenerating terminals of TPC origin were medium‐sized and characterized by asymmetric synaptic contacts. They synapsed widely on the STN neuronal surface, including the somata, dendrites of varying dimensions, dendritic spines and vesicle‐containing processes. They formed 25.1%, 65.1%, 4.7%, and 4.7%, respectively, of all TPC efferent terminals. Some of the postsynaptic components were labeled with HRP. Occasionally both degenerating terminals and HRP‐labeled terminals were in synaptic contact with the same HRP‐labeled neuron: therefore, afferents of TPC and GP converge on the same STN projection neuron.In order to discover the origin of these HRP‐labeled terminals, a mixed solution containing HRP and kainic acid was injected into the GP. Numerous degenerating terminals were observed to synapse with HRP‐labeled STN neurons, but no HRP‐labeled terminal was observed. These degenerating terminals were similar in appearance to the above‐mentioned HRP‐labeled terminals. They were characterized by their relatively large size, predominantly symmetric synapses, and preferential distribution on the somata and large or medium‐sized dendrites. They formed 39.6%, 20.1%, and 31.1%, respectively, of all GP efferent terminals. Therefore, it became clear that both the HRP‐labeled terminals of the first experiment and the degenerating terminals of the second experiment originated from the GP.Following surgical ablations of the primary sensorimotor cortex (Cx), some axon terminals in the STN showed degeneration. These degenerating terminals were small and formed asymmetric synapses mainly with dendritic spines, small dendrites and vesicle‐containing processes. They formed 48.0%, 28.0%, and 12.0%, respectively, of all Cx efferent terminals.These electron microscopic investigations reveal the convergence of TPC and GP afferents and that STN projection neurons relay the TPC and pallidal inputs directly to the GP.
Electron microscopic analysis of the synaptic organization of the globus pallidus in the cat
Authors: Okoyama Shigeo , Nakamura Yasuhisa , Moriizumi Tetsuji , Kitao Yasuko 
Published: January 2005

AbstractThe synaptic organization of the feline globus pallidus (GP) was studied electron microscopically. The axon terminals were classified into five types on the basis of the size and shape of synaptic vesicles and the type of postsynaptic differentiations. Type I and II axon terminals were characterized by large, pleomorphic vesicles and by a symmetric and an asymmetric synaptic contact, respectively. Type III and IV axon terminals were characterized by small, pleomorphic vesicles and by a symmetric and an asymmetric synaptic contact, respectively. Type V axon terminals were characterized by elongated and large round vesicles and by a symmetric synaptic contact.The origins of these terminals were determined by a combined degeneration and HRP tracing technique. Following injections of HRP into the caudate nucleus or electrolytic lesions in this nucleus, type I terminals were anterogradely labeled with HRP or degenerated, respectively. Although type III, IV, and V terminals were labeled with HRP after HRP injections into the subthalamic nuclear region, only type IV and V terminals degenerated after lesions in that area. Type II terminals did not show any alterations following such treatment. These results suggest that type I terminals originate from the caudate nucleus, that type IV and V terminals come from the subthalamic nucleus or caudal to it, and that type III terminals are the terminals of intrinsic axon collaterals of GP neurons which send axons to the subthalamic nucleus.Occasionally convergence of different kinds of axon terminals on the same GP neuron was also observed. These terminals originated from the caudate nucleus and the subthalamic nucleus or caudal to it. The similarity between the synaptic organization of the GP and the entopeduncular nucleus is briefly discussed.
Proctolin‐like immunoreactive neurons in the blowfly central nervous system
Authors: Nässel Dick R. , O'shea Michael 
Published: January 2005

AbstractThe pentapeptide proctolin (H‐Arg‐Tyr‐Leu‐Pro‐Thr‐OH) is a well‐studied bioactive substance in insects. With an antiserum against proctolin we have mapped proctolinlike‐immunoreactive (PLI) neurons in the nervous system of the blowfly Calliphora erythrocephala. In the brain, including the suboesophageal ganglia, 80–90 neurons were found to be PLI. A further 200–250 PLI neurons innervate the lobula of the optic lobe. The thoracic ganglia contain 100–130, and the abdominal ca. 60 PLI neurons. In the brain and ventral ganglia the immunoreactive neurons are of different types: interneurons, efferents (possibly some motorneurons), and neurosecretory cells. Some of these neurons are individually identifiable; others can be identified collectively as clusters. Identifiable neurons innervate protocerebral neuropil associated with the pars intercerebralis and the β‐lobes of the mushroom bodies as well as tritocerebral neuropil. Some of the prominent clusters innervate the central body of the protocerebrum, tritocerebrum, and possibly leg motor neurons. One abdominal cluster is of special interest because it consists of efferent neurons with processes in the lateral abdominal nerves. Some of these processes are located in the neural sheath in neurohaemal regions, and electron microscopy demonstrates that their terminals are outside the blood‐brain barrier. The PLI processes in the proto‐cerebrum contain large granular vesicles and form chemical synapses with different kinds of nonimmunoreactive neural elements. Thus, in Calliphora the proctolinlike substance may be used as a central transmitter/modulator, a neuromuscular transmitter, and a neurohormone released into the circulation.
Distribution and morphological characteristics of efferent neurons innervating end organs in the ear and lateral line of the european eel
Authors: Meredith G. E. , Roberts B. L. 
Published: January 2005

AbstractNeurons that provide the efferent innervation to the labyrinthine and lateral line sense organs of the eel were located by applying horseradish peroxidase to branches of the appropriate cranial nerves. Retrogradely labeled neurons were found in a single median column, the octavolateralis efferent nucleus (OEN), located immediately rostral to and overlapping with the facial nucleus of the branchiomotor column. We estimate that on each side of the brain the efferent nucleus contains about 60–70 neurons, most of which supply the ear and the lateral line system of the head. Most neurons (∼90%) are ipsilateral to the targets they innervate. There is no crisp topographical order within the nucleus because neurons supplying different end organs intermingle. However, the head lateral line is supplied by rostrally located neurons, and the body system by more caudal neurons.There are no marked differences in cell form between neurons supplying different targets. Most are multipolar, relatively uniform in size, and have extensive dendrites. The dendrites of some cells extend to the contralateral side of the brain. Efferent axons are of small diameter (∼3 μm). Two neurons are sufficiently constant in size and location that they can be consistently recognized from fish to fish. Their axons branch to supply more than one target. Nearly all efferent neurons stain for acetylcholinesterase and some, bordering the midline, consistently stain weakly.
Identification of motor neurons that contain a FMRFamidelike peptide and the effects of FMRFamide on longitudinal muscle in the medicinal leech, Hirudo medicinalis
Authors: Norris Brian J. , Calabrese Ronald L. 
Published: January 2005

AbstractExcitatory motor neurons in the leech are cholinergic. By using a combination of intracellular Lucifer yellow injection and indirect immunofluorescence, we localized FMRFamidelike immunoreactivity to a number of the motor neurons innervating longitudinal and dorsoventral muscle in the leech. All excitatory motor neurons innervating longitudinal muscle (cells 3, 4, 5, 6, 8, L, 106, 107, 108) were labeled with an antiserum to FMRFamide, while the inhibitory motor neurons innervating longitudinal muscle (cells 1, 2, 7, 9, 102) were not. The excitatory motor neuron innervating medial dorsoventral muscle (cell 117) was labeled, while the excitatory motor neuron innervating lateral dorsoventral muscle (cell 109) was not. The inhibitory motor neuron innervating dorsoventral muscle (cell 101) was also labeled. Nerve terminals along dorsoventral muscle were also labeled with the antiserum.FMRFamide was bath applied to strips of longitudinal muscle while recording tension, and the muscle's response was compared to its response to the previously identified neuromuscular transmitter ACh. Brief applications of FMRFamide caused a contraction approximately one‐tenth as large as that caused by an equimolar amount of ACh. The muscle response to FMRFamide was unaffected by curare. During extended exposures, FMRFamide caused a maintained contraction in longitudinal muscle without any apparent desensitization of the FMRFamide receptors and occasionally triggered an irregular myogenic rhythm. This extended exposure to FMRFamide caused a post‐exposure potentiation of the longitudinal muscle's response to ACh that shorter applications of FMRFamide did not. Thus FMRFamide may act as a transmitter or modulator in cholinergic motor neurons innervating longitudinal and dorsoventral muscles in the leech.
Topographic organization of the middle temporal visual area in the macaque monkey: Representational biases and the relationship to callosal connections and myeloarchitectonic boundaries
Authors: Maunsell John H. R. , van Essen David C. 
Published: January 2005

AbstractWe have used physiological and anatomical techniques to address three general issues concerning the topographic organization of the middle temporal visual area (MT) of the macaque monkey. First, we carried out a quantitative analysis of irregularities and asymmetries in the visual representation in MT. This analysis revealed a striking overemphasis on a restricted portion of the visual field that runs obliquely through the inferior contralateral quadrant and largely avoids both the horizontal meridian and the inferior vertical meridian. This corresponds to the portion of the visual field that would be maximally stimulated during visually guided hand movements. Second, the physiologically determined topographic organization of MT was compared to the pattern of callosal inputs in the same hemisphere, which are known to be distributed irregularly within MT. Callosal inputs tended to be densest near the representation of the vertical meridian, but there were numerous exceptions to this trend. Thus, topographic irregularities account for only part of the irregularities in callosal inputs to MT. Finally, comparison of these data with previous reports shows a strong correlation between body weight and the average size of MT. The representation in myeloarchitectonically defined MT was found to include much of the visual periphery, although it is unclear from our data whether this representation is invariably complete.
Metamorphosis of identified neurons innervating thoracic neurohemal organs in the blowfly: Transformation of cholecystokininlike immunoreactive neurons
Authors: Nässel Dick R. , Ohlsson Lennart G. , Cantera Rafael 
Published: January 2005

AbstractWith antisera to gastrin/cholecystokinin, we studied the postembryonic development of neurons in the thoracic ganglia of the blowfly Calliphora erythrocephala. There are some changes in the population of thoracico‐abdominal neurons displaying gastrin/CCK‐like immunoreactivity (CCKLI): some CCKLI neurons cannot be found after pupariation; other neurons become immunoreactive during metamorphosis. Six large thoracic CCKLI neurons could, however, be followed through metamorphosis. These CCKLI neurons innervate neuropil in thoracic ganglia and segmental neurohemal organs in the larva. In the adult insect the same neurons innervate many regions of thoracic neuropil and extensive neurohemal areas dorsally in the fused thoracico‐abdominal ganglia. The immunoreactive terminals are located in the neural sheath, and electron microscopy shows that only an extracellular basal lamina separates them from the circulating hemolymph. On the basis of the location of their terminals, it can be suggested that the six CCKLI neurons have functions as neurosecretory cells both in the larva and in the adult. In both developmental stages the neurons can interact with large portions of the thoracic nervous system and release bioactive substance into the circulation. A CCK‐like substance may be used both as a transmitter/neuromodulator and as a neurohormone by the same neuron. The larval neurohemal organs are described here for the first time. They show characteristics of thoracic perisympathetic organs known to exist in more primitive insects. The adult neurohemal regions on the other hand are typical of higher insects. Since the neurohemal areas are continuously (during development) innervated by the six large CCKLI neurons, we conclude that the larval neurohemal organs metamorphose into the adult neurohemal area in the neural sheath.
Glycoconjugate boundaries during early postnatal development of the neostriatal mosaic
Authors: Steindler Dennis A. , O'brien Thomas F. , Cooper Nigel G. F. 
Published: January 2005

AbstractThe dispositions of galactosyl‐containing glycoconjugates were studied during postnatal development of the caudate putamen in mice. The binding of the lectin peanut agglutinin, which has an affinity for galactosyl B‐1,3 N‐acetylgalactosamine residues, was compared to acetylcholinesterase staining and tyrosine hydroxylase immunoreactivity in the immature and adult neostriatum.The binding of peanut agglutinin conjugated to horseradish peroxidase, in sections that were processed for peroxidase histochemistry, was extremely pronounced in the neostriatum through the first postnatal week and constituted ringlike or polygonally shaped structures, which, overall, produced a variegated mosaic, These structures consist of outer rims of dense lectin‐associated reaction product surrounding lightly labeled centers. Lectin delineations of the neostriatal mosaic are no longer visible in the second postnatal week. When adjacent sections were processed for lectin binding or acetylcholinesterase histochemistry, the dense lectin binding sites represented borders of acetylcholinesterase‐rich and ‐poor zones. The distribution of dense patches of tyrosine hydroxylase immunoreactive fibers and terminals also coincides with the acetylcholinesterase‐rich zones during the same times, and thus the glycoconjugate‐delineated boundaries can also be directly compared with the distribution of nigrostriatal dopaminergic projections.The findings presented here represent the first demonstration of a probe that recognizes apparent borders of neostriatal compartments during a limited period of development. They are consistent with previous observations made on transient glycoconjugate “hidden boundaries” during development of other central nervous system structures, including the somatosensory cortical barrel field, and thalamic and brainstem nuclei (Cooper and Steindler, '86a, b; Steindler and Cooper, in press). In those studies, glia were shown to be the major source of glycoconjugate‐associated patterns, and thus, glia and glycoconjugates that they synthesize during pattern formation events may be involved in the formation and stabilization of neurochemically distinct components of the neostriatal mosaic.
Synaptic connections between primary trigeminal afferents and acccessory abducens motoneurons in the monitor lizard, Varanus exanthematicus
Authors: Barbas‐Henry Heleen A. , Wouterlood Floris G. 
Published: January 2005

AbstractWe studied the anatomical pathway underlying the nictitating reflex in the monitor lizard Varanus exanthematicus by the anterograde degeneration technique combined with retrograde transport of horseradish peroxidase (HRP) and electron microscopy.After application of HRP to the abducens nerve, retrogradely labeled neurons were observed in the ipsilateral principal and accessory abducens motor nuclei. The transection, in the same experiments, of the root of the trigeminal nerve resulted in massive degeneration of myelinated fibers in the descending trigeminal tract. In the ipsilateral accessory abducens nucleus, we observed electron‐dense degenerating axon terminals that formed asymmetric synaptic contacts with the primary and secondary dendrites of large neurons retrogradely labeled with HRP. A few of the degenerating terminals could be traced in serial sections to myelinated axons. No terminal degeneration was found in the contralateral accessory abducens nucleus or in the ipsilateral and contralateral principal abducens nuclei. The present results are complementary with the findings of previous light microscopic experimental tracing studies (Barbas‐Henry, H.A., and A.H.M. Lohman, J. Comp. Neurol. 1986, 254:314–329; see also J. Comp. Neurol. 1988, 267:370–386), and strongly suggest the existence in Varanus of a monosynaptic, unilateral reflex pathway in which trigeminal fibers, presumably originating from the cornea, synapse with motoneurons of the bursalis and retractor bulbi muscles, which are located in the accessory abducens nucleus. This monosynaptic pathway may mediate a rapid unilateral eyeball retraction and nictitating membrane extension.
Intracortical connections and their physiological correlates in the primary auditory cortex (AI) of the cat
Authors: Matsubara Joanne A. , Phillips D. P. 
Published: January 2005

AbstractWe studied the functional and anatomical properties of the intrinsic connections in the primary auditory cortex (AI) of the cat by using physiological mapping and retrograde tracing methods. Our results revealed that a focal micro inject ion of tracer labeled as many as five intracortical patches in AI. The patches contained labeled pyramidal and non‐pyramidal cell types, most of which were clustered in the middle layers. A densely distributed anterograde‐like reaction product was present in the superficial layers above the labeled cells. The distribution of the patches was anisotropic, with most patches occurring dorsal, ventral, and anterior to the injection site. We examined the correlation between the characteristic frequency (CF) and binaural response properties of the injected and labeled regions. We found local labeling in regions possessing CFs equivalent to or slightly greater than that of the injected area. This appears to be a specific connection since we were able to predict the general location of many of the patches on the basis of the organization of the isofrequency domains. Patches were more numerous dorsoposterior to the injection site when the isofrequency contours ran obliquely (i.e., dorsoposterior to ventroanterior) across AI. The binaural response properties of the injected and labelled regions, however, were unrelated.
Differences in synaptic inputs to preganglionic neurons in the dorsal and lateral band subdivisions of the cat sacral parasympathetic nucleus
Authors: Leedy Mitzi G. , Bresnahan Jacqueline C. , Mawe Gary M. , Beattie Michael S. 
Published: January 2005

AbstractIn the cat, preganglionic neurons (PGNs) found in the dorsal portion of the sacral parasympathetic nucleus (dorsal band or DB cells) participate in bowel control, while those found along the lateral edge (lateral band or LB cells) influence bladder function. In order to determine whether differences in the synaptic inputs exist between these two populations, HRP was applied to the sacral ventral rootlets of cats, and the S2 cord segment was prepared for sequential light and electron microscopy. When measured with light microscope, the LB somata had greater cross‐sectional areas than did the DB cells. Ultrastructurally, the LB cells had a significantly greater percentage of their membrane apposed by synaptic active sites than did the DB cells. Also, the proximal dendrities of the labelled neurons received greater synaptic input than did the somata. No difference was found in the proportion of terminals containing dense cored vesicles (DCVs) when comparing LB and DB somata; however, the LB proximal dendrites had a higher proportion of their surface contacted by DCV‐containing terminals than did the DB dendrites. These ultrastructural results offer evidence that these two populations of preganglionic neurons differ with respect to their synaptic input as well as their peripheral targets.