Labeling of the retina and optic tectum gangliosides and glycoproteins of chickens in darkness or exposed to light

International Nuclear Information System (INIS)

Caputto, R.

1984-01-01

Chickens that received an intraocular injection of 3 H-ManNAc and were exposed to light had more labeled gangliosides in the retina ganglion cell layer and in the contralateral optic tectum than similarly treated animals that remained in darkness. The effect is not due to the turning on or off of the light. The sialyl groups of sialoglycoproteins showed similar effect but the labeling of proteins in chickens that received 3 H-proline did not show significant differences. So far the effect has been obtained only with retina linked to the optic tectum through the optic nerve. If the nerve is severed the effect disappears. The gangliosides GD1a and GT1 are powerful inhibitors of the GM3-N-acetylgalactosaminyl transferase. The main effect of those gangliosides is expressed when they are linked to the membranes containing the enzyme in such a form that they are not released by washing with water. The hypothesis is advanced that the utilization of gangliosides in the nerve ending during the interneuronal transmission produces a small decrease in their concentration that in turn is transmitted backwards to the neuronal perikarya where it accelerates the synthesis of new gangliosides

Seasonal Variation in Feeding Behaviour of Indian Roofed Turtle, Pangshura tectum in Bangladesh

International Nuclear Information System (INIS)

Hossain Md Lokman; Sarker, Shorab Uddin; Sarker Noor Jahan

2008-01-01

Study was conducted in nature and in captivity to observe the food contents and feeding behaviour of Indian roofed turtle, Pangshura tectum, in Bangladesh between January 1997 and December 2001. The species was found to be omnivore, fed on plants, dead fishes, insects and fecal matters. In nature, the food consumption of the turtle was 3.32% of the body weight per day that was the highest in summer (4.6%) and lowest in winter (1.7%). In captivity, the consumption was 5.8% of the body weight per day and it was highest in rainy season (7.5%) and lowest in winter (3.8%). The feeding frequency was higher in captivity than in nature. (author)

The Effects of Nicotinic and Muscarinic Receptor Activation on Patch-Clamped Cells in the Optic Tectum of Rana Pipiens

OpenAIRE

Yu, C.-J.; Debski, E. A.

2003-01-01

Both nicotinic and muscarinic cholinergic receptors are present in the optic tectum. To begin to understand how the activation of these receptors affects visual activity patterns, we have determined the types of physiological responses induced by their activation. Using tectal brain slices from the leopard frog, we found that application of nicotine (100 μM) evoked long-lasting responses in 60% of patch-clamped tectal cells. Thirty percent of these responses consisted of an increase in sponta...

Saliency mapping in the optic tectum and its relationship to habituation

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Arkadeb eDutta

2014-01-01

Full Text Available Habituation of the orienting response has long served as a model system for studying fundamental psychological phenomena such as learning, attention, decisions and surprise. In this article, we review an emerging hypothesis that the evolutionary role of the superior colliculus (SC in mammals or its homologue in birds, the optic tectum (OT, is to select the most salient target and send this information to the appropriate brain regions to control the body and brain orienting responses. Recent studies have begun to reveal mechanisms of how saliency is computed in the OT/SC, demonstrating a striking similarity between mammals and birds. The saliency of a target can be determined by how different it is from the surrounding objects, by how different it is from its history (that is habituation and by how relevant it is for the task at hand. Here, we will first review evidence, mostly from primates and barn owls, that all three types of saliency computations are linked in the OT/SC. We will then focus more on neural adaptation in the OT and its possible link to temporal saliency and habituation.

Apparent discrepancy between single-unit activity and [14C]deoxyglucose labeling in optic tectum of the rattlesnake

International Nuclear Information System (INIS)

Auker, C.R.; Meszler, R.M.; Carpenter, D.O.

1983-01-01

Autoradiographic analysis of [1- 14 C]2-deoxy-D-glucose-6-phosphate ([ 14 C]2-DG-P) accumulation in the rattlesnake brain stem and optic tectum was used in an effort to map infrared and visual neuronal pathways. Visual stimulation with a standard stimulus (a heat lamp) resulted in dense labeling of the superficial layers of the optic tectum. Infrared stimulation resulted in labeling at the first synaptic relay, the lateral descending nucleus of the trigeminal tract, but not at higher levels. Responses of infrared units in one hemitectum and visual units in the other were analyzed. There were no clear differences in the number, maximal density, spread, or rates of accommodation of visual units and infrared units, although the locus of maximal density was more superficial for visual units. In general, infrared units generated a greater number of action potentials. All infrared units responded to onset but they varied greatly in their ability to maintain discharge for the duration of the stimulus. Infrared stimuli generated single, large, triphasic on-responses, whereas visual stimulation generated complex multiphasic and long-lasting on- and off-responses. The major infrared-on peak reached maximal amplitude at greater depths and was larger than the major visual-on peak. Amplitude of the infrared peak fell off more rapidly with distance than did amplitude of the visual peak. These observations are consistent with the view that infrared stimulation is effective in discharging neurons but is not associated with intense synaptic excitation. Our observations suggest that 2-deoxy-D-glucose uptake is not necessarily correlated with the degree of action potential activation of specific neuronal pathways. The amount of [ 14 C]2-DG-P labeling may reflect the metabolic requirements for support of synaptic depolarization as well as that supporting action potentials

Feeding State Modulates Behavioral Choice and Processing of Prey Stimuli in the Zebrafish Tectum.

Science.gov (United States)

Filosa, Alessandro; Barker, Alison J; Dal Maschio, Marco; Baier, Herwig

2016-05-04

Animals use the sense of vision to scan their environment, respond to threats, and locate food sources. The neural computations underlying the selection of a particular behavior, such as escape or approach, require flexibility to balance potential costs and benefits for survival. For example, avoiding novel visual objects reduces predation risk but negatively affects foraging success. Zebrafish larvae approach small, moving objects ("prey") and avoid large, looming objects ("predators"). We found that this binary classification of objects by size is strongly influenced by feeding state. Hunger shifts behavioral decisions from avoidance to approach and recruits additional prey-responsive neurons in the tectum, the main visual processing center. Both behavior and tectal function are modulated by signals from the hypothalamic-pituitary-interrenal axis and the serotonergic system. Our study has revealed a neuroendocrine mechanism that modulates the perception of food and the willingness to take risks in foraging decisions. Copyright © 2016 Elsevier Inc. All rights reserved.

The effects of nicotinic and muscarinic receptor activation on patch-clamped cells in the optic tectum of Rana pipiens.

Science.gov (United States)

Yu, C-J; Debski, E A

2003-01-01

Both nicotinic and muscarinic cholinergic receptors are present in the optic tectum. To begin to understand how the activation of these receptors affects visual activity patterns, we have determined the types of physiological responses induced by their activation. Using tectal brain slices from the leopard frog, we found that application of nicotine (100 microM) evoked long-lasting responses in 60% of patch-clamped tectal cells. Thirty percent of these responses consisted of an increase in spontaneous postsynaptic currents (sPSCs) and had both a glutamatergic and GABAergic component as determined by the use of 6-cyano-7-nitroquinoxaline-2,3-dione (50 microM) and bicuculline (25 microM), respectively. Remaining response types consisted of an inward membrane current (16%) and an increase in sPSCs combined with an inward membrane current (14%). All responses could be elicited in the presence of tetrodotoxin (0.5 microM). Muscarinic receptor-mediated responses, induced by carbachol (100 microM) application after nicotinic receptor desensitization, produced responses in 70% of tectal cells. In contrast to responses elicited by nicotine, carbachol-induced responses could be evoked multiple times without significant decrement. Responses consisted of either an outward current (57%), a decrease in sPSCs (5%) or an increase in sPSCs, with (almost 6%) or without (almost 3%) an outward current. The response elicited by carbachol was not predicted by the response of the cell to nicotine. Our results suggest that nicotinic receptors are found predominantly at presynaptic locations in the optic tectum while muscarinic receptors are most often present at postsynaptic sites. We conclude that both of these receptor types could substantially modulate visual activity by changing either the input to tectal neurons or the level of their response to that input.

Direction selectivity in the larval zebrafish tectum is mediated by asymmetric inhibition

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Abhinav eGrama

2012-09-01

Full Text Available The extraction of the direction of motion is an important computation performed by many sensory systems and in particular, the mechanism by which direction selective ganglion cells (DS-RGCs in the retina acquire their selective properties, has been studied extensively. However, whether DS-RGCs simply relay this information to downstream areas or whether additional and potentially de-novo processing occurs in these recipient structures is a matter of great interest. Neurons in the larval zebrafish tectum, the largest retino-recipent area in this animal, show direction selective responses to moving visual stimuli but how these properties are acquired is still unknown. In order to study this, we first used two-photon calcium imaging to classify the population responses of tectal cells to bars moving at different speeds and in different directions. Subsequently, we performed in-vivo whole cell electrophysiology on these direction selective tectal neurons and we found that their inhibitory inputs were strongly biased towards the null direction of motion, whereas the excitatory inputs showed little selectivity. In addition, we found that excitatory currents evoked by a stimulus moving in the preferred direction occurred before the inhibitory currents whereas a stimulus moving in the null direction evoked currents in the reverse temporal order. The membrane potential modulations resulting from these currents were enhanced by the spike generation mechanism to generate amplified direction selectivity in the spike output. Thus our results implicate a local inhibitory circuit in generating direction selectivity in tectal neurons.

Autoradiographic localization of nicotinic acetylcholine receptors in the brain of the zebra finch (Poephila guttata)

International Nuclear Information System (INIS)

Watson, J.T.; Adkins-Regan, E.; Whiting, P.; Lindstrom, J.M.; Podleski, T.R.

1988-01-01

We 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. Unfixed brains from intact adult male and female zebra finches were prepared for in vitro autoradiography. Low-resolution 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

Color- and motion-specific units in the tectum opticum of goldfish.

Science.gov (United States)

Gruber, Morna; Behrend, Konstantin; Neumeyer, Christa

2016-01-05

Extracellular recordings were performed from 69 units at different depths between 50 and [Formula: see text]m below the surface of tectum opticum in goldfish. Using large field stimuli (86[Formula: see text] visual angle) of 21 colored HKS-papers we were able to record from 54 color-sensitive units. The colored papers were presented for 5[Formula: see text]s each. They were arranged in the sequence of the color circle in humans separated by gray of medium brightness. We found 22 units with best responses between orange, red and pink. About 12 of these red-sensitive units were of the opponent "red-ON/blue-green-OFF" type as found in retinal bipolar- and ganglion cells as well. Most of them were also activated or inhibited by black and/or white. Some units responded specifically to red either with activation or inhibition. 18 units were sensitive to blue and/or green, 10 of them to both colors and most of them to black as well. They were inhibited by red, and belonged to the opponent "blue-green-ON/red-OFF" type. Other units responded more selectively either to blue, to green or to purple. Two units were selectively sensitive to yellow. A total of 15 units were sensitive to motion, stimulated by an excentrically rotating black and white random dot pattern. Activity of these units was also large when a red-green random dot pattern of high L-cone contrast was used. Activity dropped to zero when the red-green pattern did not modulate the L-cones. Neither of these motion selective units responded to any color. The results directly show color-blindness of motion vision, and confirm the hypothesis of separate and parallel processing of "color" and "motion".

Morphogenetic and histogenetic roles of the temporal-spatial organization of cell proliferation in the vertebrate corticogenesis as revealed by inter-specific analyses of the optic tectum cortex development

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Melina eRapacioli

2016-03-01

Full Text Available The central nervous system areas displaying the highest structural and functional complexity correspond to the so called cortices, i.e. concentric alternating neuronal and fibrous layers. Corticogenesis, i.e. the development of the cortical organization, depends on the temporal-spatial organization of several developmental events: (a the duration of the proliferative phase of the neuroepithelium, (b the relative duration of symmetric (expansive versus asymmetric (neuronogenic sub phases, (c the spatial organization of each kind of cell division, (e the time of determination and cell cycle exit and (f the time of onset of the postmitotic neuronal migration and (g the time of onset of the neuronal structural and functional differentiation. The first five events depend on molecular mechanisms that perform a fine tuning of the proliferative activity. Changes in any of them significantly influence the cortical size or volume (tangential expansion and radial thickness, morphology, architecture and also impact on neuritogenesis and synaptogenesis affecting the cortical wiring. This paper integrates information, obtained in several species, on the developmental roles of cell proliferation in the development of the optic tectum cortex, a multilayered associative area of the dorsal (alar midbrain. The present review (1 compiles relevant information on the temporal and spatial organization of cell proliferation in different species (fish, amphibians, birds and mammals, (2 revises the main molecular events involved in the isthmic organizer determination and localization, (3 describes how the patterning installed by isthmic organizer is translated into spatially organized neural stem cell proliferation (i.e. by means of growth factors, receptors, transcription factors, signaling pathways, etc. and (4 describes the morpho- and histogenetic effect of a spatially organized cell proliferation in the above mentioned species. A brief section on the optic tectum

Differential expression of AMPA-type glutamate receptor subunits during development of the chick optic tectum

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Batista S.S.

2002-01-01

Full Text Available Glutamate receptors have been often associated with developmental processes. We used immunohistochemical techniques to evaluate the expression of the AMPA-type glutamate receptor (GluR subunits in the chick optic tectum (TeO. Chick embryos from the 5th through the 20th embryonic day (E5-E20 and one-day-old (P1 chicks were used. The three types of immunoreactivity evaluated (GluR1, GluR2/3, and GluR4 had different temporal and spatial expression patterns in the several layers of the TeO. The GluR1 subunit first appeared as moderate staining on E7 and then increased on E9. The mature GluR1 pattern included intense staining only in layer 5 of the TeO. The GluR2/3 subunits presented low expression on E5, which became intense on E7. The staining for GluR2/3 changed to very intense on E14 in tectal layer 13. Staining of layer 13 neurons is the most prominent feature of GluR immunoreactivity in the adult TeO. The GluR4 subunit generally presented the lowest expression starting on E7, which was similar to the adult pattern. Some instances of transient expression of GluR subunits were observed in specific cell populations from E9 through E20. These results demonstrate a differential expression of the GluR subunits in the embryonic TeO, adding information about their possible functions in the developmental processes of the visual system.

The dorsal tectal longitudinal column (TLCd): a second longitudinal column in the paramedian region of the midbrain tectum.

Science.gov (United States)

Aparicio, M-Auxiliadora; Saldaña, Enrique

2014-03-01

The tectal longitudinal column (TLC) is a longitudinally oriented, long and narrow nucleus that spans the paramedian region of the midbrain tectum of a large variety of mammals (Saldaña et al. in J Neurosci 27:13108-13116, 2007). Recent analysis of the organization of this region revealed another novel nucleus located immediately dorsal, and parallel, to the TLC. Because the name "tectal longitudinal column" also seems appropriate for this novel nucleus, we suggest the TLC described in 2007 be renamed the "ventral tectal longitudinal column (TLCv)", and the newly discovered nucleus termed the "dorsal tectal longitudinal column (TLCd)". This work represents the first characterization of the rat TLCd. A constellation of anatomical techniques was used to demonstrate that the TLCd differs from its surrounding structures (TLCv and superior colliculus) cytoarchitecturally, myeloarchitecturally, neurochemically and hodologically. The distinct expression of vesicular amino acid transporters suggests that TLCd neurons are GABAergic. The TLCd receives major projections from various areas of the cerebral cortex (secondary visual mediomedial area, and granular and dysgranular retrosplenial cortices) and from the medial pretectal nucleus. It densely innervates the ipsilateral lateral posterior and laterodorsal nuclei of the thalamus. Thus, the TLCd is connected with vision-related neural centers. The TLCd may be unique as it constitutes the only known nucleus made of GABAergic neurons dedicated to providing massive inhibition to higher order thalamic nuclei of a specific sensory modality.

Expression patterns of ion channels and structural proteins in a multimodal cell type of the avian optic tectum.

Science.gov (United States)

Lischka, Katharina; Ladel, Simone; Luksch, Harald; Weigel, Stefan

2018-02-15

The midbrain is an important subcortical area involved in distinct functions such as multimodal integration, movement initiation, bottom-up, and top-down attention. Our group is particularly interested in cellular computation of multisensory integration. We focus on the visual part of the avian midbrain, the optic tectum (TeO, counterpart to mammalian superior colliculus). This area has a layered structure with the great advantage of distinct input and output regions. In chicken, the TeO is organized in 15 layers where visual input targets the superficial layers while auditory input terminates in deeper layers. One specific cell type, the Shepherd's crook neuron (SCN), extends dendrites in both input regions. The characteristic feature of these neurons is the axon origin at the apical dendrite. The molecular identity of this characteristic region and thus, the site of action potential generation are of particular importance to understand signal flow and cellular computation in this neuron. We present immunohistochemical data of structural proteins (NF200, Ankyrin G, and Myelin) and ion channels (Pan-Na v , Na v 1.6, and K v 3.1b). NF200 is strongly expressed in the axon. Ankyrin G is mainly expressed at the axon initial segment (AIS). Myelination starts after the AIS as well as the distribution of Na v channels on the axon. The subtype Na v 1.6 has a high density in this region. K v 3.1b is restricted to the soma, the primary neurite and the axon branch. The distribution of functional molecules in SCNs provides insight into the information flow and the integration of sensory modalities in the TeO of the avian midbrain. © 2017 Wiley Periodicals, Inc.

Histological studies in developing brain after 0.5 Gy neutron irradiation in utero

International Nuclear Information System (INIS)

Antal, S.; Fueloep, Z.

1986-01-01

Pregnant mice were irradiated with 0.5 Gy neutrons on day 13, 15 or 18 of gestation. There was no significant difference in number of living young born per litter between in neutron irradiated mice and controls. Mortality of irradiated offspings increased in the first 3 days after birth. The brain weight of 21-day old animals after neutron irradiation averaged only 55, 56 and 69% of controls, resp. At six hours after irradiation morphological analysis showed nuclear pyknosis in the central nervous system. On day 13 the telencephalon was severely affected. The 30% cells were pyknotic in the wall of the cerebral hemisphere and 20% of cells in corpus striatum. In the metencephalon marked pyknosis was established in the tectal lamina of mesencephalon (16%) and in the cerebellar anlage (21%). The olfactory plate (24%), the ventricular zone of cerebral hemisphere (30%) and colliculus ganglionaris were damaged mostly (40%) after radiation on day 15 of gestation. The tectum of the mesencephali and in metencephalon the external granular layer of cerebellum and area of the rhombic lip were affected by irradiation (17-20%). The telencephalon found pyknotic but to a less extent in group irradiated on day 18 than it was on day 15. In the olfactory bulb 10% of pyknotic cells were seen and 16% of primary cortex of cerebral hemisphere more over 30% of nucleus caudatus/putamen were affected. In metencephalon 19% of external granular layer of cerebellum and 13% of trigonum cerebelli were pyknotic. In general, lesions of irradiation were rather mild in diencephalon and myelencephalon at all examined ages. Histological examinations support that defined parts of brain are damaged after neutron irradiation in utero and it may lead to the described physiological 18-20 and biochemical consequences 20,23 . (orig.)

Development of the chondrocranium of the shallow-water Cape ...

African Journals Online (AJOL)

1988-01-15

Jan 15, 1988 ... Both the auditory capsules and the occipital arches take part in the development of the tectum synoticum. The tectum posterius does not develop separately, but as a posterior extension of the tectum synoticum. Die ontwikkeling die neurokranium van Merluccius capensis word beskryf vanaf die vroegste ...

Effects of algal-produced neurotoxins on metabolic activity in telencephalon, optic tectum and cerebellum of Atlantic salmon (Salmo salar)

International Nuclear Information System (INIS)

Bakke, Marit Jorgensen; Horsberg, Tor Einar

2007-01-01

Neurotoxins from algal blooms have been reported to cause mortality in a variety of species, including sea birds, sea mammals and fish. Farmed fish cannot escape harmful algal blooms and their potential toxins, thus they are more vulnerable for exposure than wild stocks. Sublethal doses of the toxins are likely to affect fish behaviour and may impair cognitive abilities. In the present study, changes in the metabolic activity in different parts of the Atlantic salmon (Salmo salar) brain involved in central integration and cognition were investigated after exposure to sublethal doses of three algal-produced neurotoxins; saxitoxin (STX), brevetoxin (BTX) and domoic acid (DA). Fish were randomly selected to four groups for i.p. injection of saline (control) or one of the neurotoxins STX (10 μg STX/kg bw), BTX (68 μg BTX/kg bw) or DA (6 mg DA/kg bw). In addition, 14 C-2-deoxyglucose was i.m. injected to measure brain metabolic activity by autoradiography. The three regions investigated were telencephalon (Tel), optic tectum (OT) and cerebellum (Ce). There were no differences in the metabolic activity after STX and BTX exposure compared to the control in these regions. However, a clear increase was observed after DA exposure. When the subregions with the highest metabolic rate were pseudocoloured in the three brain regions, the three toxins caused distinct differences in the respective patterns of metabolic activation. Fish exposed to STX displayed similar patterns as the control fish, whereas fish exposed to BTX and DA showed highest metabolic activity in subregions different from the control group. All three neurotoxins affected subregions that are believed to be involved in cognitive abilities in fish

Resonant Cholinergic Dynamics in Cognitive and Motor Decision-Making: Attention, Category Learning, and Choice in Neocortex, Superior Colliculus, and Optic Tectum.

Science.gov (United States)

Grossberg, Stephen; Palma, Jesse; Versace, Massimiliano

2015-01-01

Freely behaving organisms need to rapidly calibrate their perceptual, cognitive, and motor decisions based on continuously changing environmental conditions. These plastic changes include sharpening or broadening of cognitive and motor attention and learning to match the behavioral demands that are imposed by changing environmental statistics. This article proposes that a shared circuit design for such flexible decision-making is used in specific cognitive and motor circuits, and that both types of circuits use acetylcholine to modulate choice selectivity. Such task-sensitive control is proposed to control thalamocortical choice of the critical features that are cognitively attended and that are incorporated through learning into prototypes of visual recognition categories. A cholinergically-modulated process of vigilance control determines if a recognition category and its attended features are abstract (low vigilance) or concrete (high vigilance). Homologous neural mechanisms of cholinergic modulation are proposed to focus attention and learn a multimodal map within the deeper layers of superior colliculus. This map enables visual, auditory, and planned movement commands to compete for attention, leading to selection of a winning position that controls where the next saccadic eye movement will go. Such map learning may be viewed as a kind of attentive motor category learning. The article hereby explicates a link between attention, learning, and cholinergic modulation during decision making within both cognitive and motor systems. Homologs between the mammalian superior colliculus and the avian optic tectum lead to predictions about how multimodal map learning may occur in the mammalian and avian brain and how such learning may be modulated by acetycholine.

Resonant cholinergic dynamics in cognitive and motor decision-making:Attention, category learning, and choice in neocortex, superior colliculus, and optic tectum

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Stephen eGrossberg

2016-01-01

Full Text Available Freely behaving organisms need to rapidly calibrate their perceptual, cognitive, and motor decisions based on continuously changing environmental conditions. These plastic changes include sharpening or broadening of cognitive and motor attention and learning to match the behavioral demands that are imposed by changing environmental statistics. This article proposes that a shared circuit design for such flexible decision-making is used in specific cognitive and motor circuits, and that both types of circuits use acetylcholine to modulate choice selectivity. Such task-sensitive control is proposed to control thalamocortical choice of the critical features that are cognitively attended and that are incorporated through learning into prototypes of visual recognition categories. A cholinergically-modulated process of vigilance control determines if a recognition category and its attended features are abstract (low vigilance or concrete (high vigilance. Homologous neural mechanisms of cholinergic modulation are proposed to focus attention and learn a multimodal map within the deeper layers of superior colliculus. This map enables visual, auditory, and planned movement commands to compete for attention, leading to selection of a winning position that controls where the next saccadic eye movement will go. Such map learning may be viewed as a kind of attentive motor category learning. The article hereby explicates a link between attention, learning, and cholinergic modulation during decision making within both cognitive and motor systems. Homologs between the mammalian superior colliculus and the avian optic tectum lead to predictions about how multimodal map learning may occur in the avian brain and how such learning may be modulated by acetycholine.

X-ray appearance of cranial lesions in hyperparathyroid osteodystuophy

International Nuclear Information System (INIS)

Spuzyak, M.M.; Tsarikovskaya, K.G.; Tkach, F.S.; David'yants, L.S.

1983-01-01

Craniographic data on 58 patients with hyperparathyroid osteodystrophy weere analyzed. Cranial changes revealed in 52 patients. Some data on the nature apd frequency of X-ray signs of cranial lesion in hyperparathyroid osteodystrophy are presented. The most frequent and typical X-ray signs of cranial lesions in hyperparathyroid osteodystrophy, are granular osteoporosis of the facial tectum and bones, the blurred contour of the internal tectum plate, foci of osteoclasia, osteoporosis of the elements of the Turkish saddle, resorption of the closing plates of the dental cavities, alterration of the thickness of the vault bones, symmetrical thinning, irregularity and obscurity of the external tectum plate, subperiosteal resorption of the cortical layer of the mandible (34.5%), partial resorption of the alveolar process of the jaw and epulis of the mandible

Organization of the torus longitudinalis in the rainbow trout (Oncorhynchus mykiss): an immunohistochemical study of the GABAergic system and a DiI tract-tracing study.

Science.gov (United States)

Folgueira, Mónica; Sueiro, Catalina; Rodríguez-Moldes, Isabel; Yáñez, Julián; Anadón, Ramón

2007-07-10

The torus longitudinalis (TL) is a tectum-associated structure of actinopterygian fishes. The organization of the TL of rainbow trout was studied with Nissl staining, Golgi methods, immunocytochemistry with antibodies to gamma-aminobutyric acid (GABA), glutamic acid decarboxylase (GAD), and the GABA(A) receptor subunits delta and beta2/beta 3, and with tract tracing methods. Two types of neuron were characterized: medium-sized GABAergic neurons and small GABA-negative granule cells. GABA(A) receptor subunit delta-like immunoreactivity delineated two different TL regions, ventrolateral and central. Small GABAergic cells were also observed in marginal and periventricular strata of the optic tectum. These results indicate the presence of local GABAergic inhibitory circuits in the TL system. For tract-tracing, a lipophilic dye (DiI) was applied to the TL and to presumed toropetal nuclei or toral targets. Toropetal neurons were observed in the optic tectum, in pretectal (central, intermediate, and paracommissural) nuclei, in the subvalvular nucleus, and associated with the pretectocerebellar tract. Torofugal fibers were numerous in the stratum marginale of the optic tectum. Toropetal pretectal nuclei also project to the cerebellum, and a few TL cells project to the cerebellar corpus. The pyramidal cells of the trout tectum were also studied by Golgi methods and local DiI labeling. The connections of trout TL revealed here were more similar to those recently reported in carp and holocentrids (Ito et al. [2003] J. Comp. Neurol. 457:202-211; Xue et al. [2003] J. Comp. Neurol. 462:194-212), than to those reported in earlier studies. However, important differences in organization of toropetal nuclei were noted between salmonids and these other teleosts. (c) 2007 Wiley-Liss, Inc.

Development of the retinotopic organization in Salmo gairdneri

International Nuclear Information System (INIS)

Pinganaud, G.

1987-01-01

The progression of the retinotopic organization in the optic nerve projections to the contralateral thalamus and tectum was studied in Salmo gairdneri from hatching stage to 3 month old stage. After quadratic lesions of the temporal, dorsal, nasal, or ventral retina, the animals were separated in two groups: one used for Fink and Heimer method or electron microscopic observation and the other one for radioautography after injection in the operated eye of [ 14 C] or [ 3 H]proline. The analysis of the projections of each retinal quadrant revealed: (1) Projections to thalamus and pretectum are ignorganized and appear progressively during development. On the contrary in tectum and corpus geniculatum, the visual projections are retinotopically organized since hatching. (2) In the whole retino-tectal system, two subsystems develop differently: the naso-ventral retina reaches precociously its permanent target (the posterior tectum), the temporo-dorsal part of the retina links to the anterior tectum and shifts laterally during the first month after hatching, from medial to antero-lateral for temporal projections. The shifting of projections is correlated with development of the medial fascicle of the optic tract. So it appears that the pathways play an important role in the spatio-temporal ordered pattern of terminations of retinal fibers on the tectal surface during development. (author)

Development of the retinotectal system in the direct-developing frog Eleutherodactylus coqui in comparison with other anurans

Directory of Open Access Journals (Sweden)

Schlosser Gerhard

2008-06-01

Full Text Available Abstract Background Frogs primitively have a biphasic life history with an aquatic larva (tadpole and a usually terrestrial adult. However, direct developing frogs of the genus Eleutherodactylus have lost a free living larval stage. Many larval structures never form during development of Eleutherodactylus, while limbs, spinal cord, and an adult-like cranial musculoskeletal system develop precociously. Results Here, I compare growth and differentiation of the retina and tectum and development of early axon tracts in the brain between Eleutherodactylus coqui and the biphasically developing frogs Discoglossus pictus, Physalaemus pustulosus, and Xenopus laevis using morphometry, immunohistochemical detection of proliferating cell nuclear antigen (PCNA and acetylated tubulin, biocytin tracing, and in situ hybridization for NeuroD. Findings of the present study indicate that retinotectal development was greatly altered during evolution of Eleutherodactlyus mostly due to acceleration of cell proliferation and growth in retina and tectum. However, differentiation of retina, tectum, and fiber tracts in the embryonic brain proceed along a conserved slower schedule and remain temporally coordinated with each other in E. coqui. Conclusion These findings reveal a mosaic pattern of changes in the development of the central nervous system (CNS during evolution of the direct developing genus Eleutherodactylus. Whereas differentiation events in directly interconnected parts of the CNS such as retina, tectum, and brain tracts remained coordinated presumably due to their interdependent development, they were dissociated from proliferation control and from differentiation events in other parts of the CNS such as the spinal cord. This suggests that mosaic evolutionary changes reflect the modular character of CNS development.

Selection of appropriate medial branch of the optic tract by fibres of ventral retinal origin during development and in regeneration: an autoradiographic study in Xenopus

International Nuclear Information System (INIS)

Straznicky, C.; Gaze, R.M.; Horder, T.J.

1979-01-01

The formation of the branches of the optic tract has been studied with the use of [ 3 H] -proline autoradiography, during development and during regeneration of the optic nerve in Xenopus with one compound ventral (VV) eye made by the embryonic fusion of two ventral eye fragments. The formation of the optic pathway was abnormal in that the lateral branch failed to develop, suggesting that fibres from a VV retina selectively entered the tectum via the medial branch during development. Three months after section of the optic nerve of a VV eye, regenerated fibres were present both in the contralateral and ipsilateral tecta. On the ipsilateral side regenerated fibres entered the tectum via the medial branch only. Retinal fibres entered the contralateral tectum through both branches in some animals and through the medial branch only in others. It is concluded that mechanical factors alone are insufficient to explain the phenomenon of selection of the appropriate medial branch fibres of ventral retinal origin either during development or in regeneration. Some form of fibre-substrate interaction seems to be necessary; and this ability of fibres from a VV eye to take the path appropriate for ventral retina argues strongly that the VV eye is not a regulated system in terms of cell specificities. 8author)

Retention of retinal axon collateral is responsible for induced ipsilateral retinotectal projections in adult goldfish.

Science.gov (United States)

Sharma, S C; Tsai, C

1991-01-01

In normal goldfish, optic axons innervate only the contralateral optic tectum. When one eye was enucleated and the optic nerve of the other eye crushed, the regenerating optic axons innervated both optic tecta. We studied the presence of bilaterally projecting retinal ganglion cells by double retrograde cell labeling methods using Nuclear Yellow and True Blue dyes. About 10% of the retinal ganglion cells were double labeled and these cells were found throughout the retina. In addition, HRP application to the ipsilateral tectum revealed retrogradely-labeled retinal ganglion cells of all morphological types. These results suggest that induced ipsilateral projections are formed by regenerating axon collaterals and that all cell types are involved in the generation of normal mirror image typography.

A simple non-invasive method for measuring gross brain size in small live fish with semi-transparent heads

Directory of Open Access Journals (Sweden)

Joacim Näslund

2014-09-01

Full Text Available This paper describes a non-invasive method for estimating gross brain size in small fish with semi-transparent heads, using system camera equipment. Macro-photographs were taken from above on backlit free-swimming fish undergoing light anaesthesia. From the photographs, the width of the optic tectum was measured. This measure (TeO-measure correlates well with the width of the optic tectum as measured from out-dissected brains in both brown trout fry and zebrafish (Pearson r > 0.90. The TeO-measure also correlates well with overall brain wet weight in brown trout fry (r = 0.90, but less well for zebrafish (r = 0.79. A non-invasive measure makes it possible to quickly assess brain size from a large number of individuals, as well as repeatedly measuring brain size of live individuals allowing calculation of brain growth.

Lateralized Feeding Behavior is Associated with Asymmetrical Neuroanatomy and Lateralized Gene Expressions in the Brain in Scale-Eating Cichlid Fish

Science.gov (United States)

Lee, Hyuk Je; Schneider, Ralf F; Manousaki, Tereza; Kang, Ji Hyoun; Lein, Etienne; Franchini, Paolo

2017-01-01

Abstract Lateralized behavior (“handedness”) is unusual, but consistently found across diverse animal lineages, including humans. It is thought to reflect brain anatomical and/or functional asymmetries, but its neuro-molecular mechanisms remain largely unknown. Lake Tanganyika scale-eating cichlid fish, Perissodus microlepis show pronounced asymmetry in their jaw morphology as well as handedness in feeding behavior—biting scales preferentially only from one or the other side of their victims. This makes them an ideal model in which to investigate potential laterality in neuroanatomy and transcription in the brain in relation to behavioral handedness. After determining behavioral handedness in P. microlepis (preferred attack side), we estimated the volume of the hemispheres of brain regions and captured their gene expression profiles. Our analyses revealed that the degree of behavioral handedness is mirrored at the level of neuroanatomical asymmetry, particularly in the tectum opticum. Transcriptome analyses showed that different brain regions (tectum opticum, telencephalon, hypothalamus, and cerebellum) display distinct expression patterns, potentially reflecting their developmental interrelationships. For numerous genes in each brain region, their extent of expression differences between hemispheres was found to be correlated with the degree of behavioral lateralization. Interestingly, the tectum opticum and telencephalon showed divergent biases on the direction of up- or down-regulation of the laterality candidate genes (e.g., grm2) in the hemispheres, highlighting the connection of handedness with gene expression profiles and the different roles of these brain regions. Hence, handedness in predation behavior may be caused by asymmetric size of brain hemispheres and also by lateralized gene expressions in the brain. PMID:29069363

RGM is a repulsive guidance molecule for retinal axons

DEFF Research Database (Denmark)

Monnier, Philippe P; Sierra, Ana; Macchi, Paolo

2002-01-01

with known guidance cues, and its messenger RNA is distributed in a gradient with increasing concentration from the anterior to posterior pole of the embryonic tectum. Recombinant RGM at low nanomolar concentration induces collapse of temporal but not of nasal growth cones and guides temporal retinal axons...

Morphological and Experimental Studies on the Development of the ...

African Journals Online (AJOL)

In embryos of Gallus, Anas and Spheniscus the posterior wall of the foramen magnum (tectum synoticum) is formed by the fusion of the two independently developing supraoccipital cartilages. Fusion of the supraoccipital cartilage with the ear capsule precedes that between the supraoccipital cartilage and the occipital ...

Lateralized Feeding Behavior is Associated with Asymmetrical Neuroanatomy and Lateralized Gene Expressions in the Brain in Scale-Eating Cichlid Fish.

Science.gov (United States)

Lee, Hyuk Je; Schneider, Ralf F; Manousaki, Tereza; Kang, Ji Hyoun; Lein, Etienne; Franchini, Paolo; Meyer, Axel

2017-11-01

Lateralized behavior ("handedness") is unusual, but consistently found across diverse animal lineages, including humans. It is thought to reflect brain anatomical and/or functional asymmetries, but its neuro-molecular mechanisms remain largely unknown. Lake Tanganyika scale-eating cichlid fish, Perissodus microlepis show pronounced asymmetry in their jaw morphology as well as handedness in feeding behavior-biting scales preferentially only from one or the other side of their victims. This makes them an ideal model in which to investigate potential laterality in neuroanatomy and transcription in the brain in relation to behavioral handedness. After determining behavioral handedness in P. microlepis (preferred attack side), we estimated the volume of the hemispheres of brain regions and captured their gene expression profiles. Our analyses revealed that the degree of behavioral handedness is mirrored at the level of neuroanatomical asymmetry, particularly in the tectum opticum. Transcriptome analyses showed that different brain regions (tectum opticum, telencephalon, hypothalamus, and cerebellum) display distinct expression patterns, potentially reflecting their developmental interrelationships. For numerous genes in each brain region, their extent of expression differences between hemispheres was found to be correlated with the degree of behavioral lateralization. Interestingly, the tectum opticum and telencephalon showed divergent biases on the direction of up- or down-regulation of the laterality candidate genes (e.g., grm2) in the hemispheres, highlighting the connection of handedness with gene expression profiles and the different roles of these brain regions. Hence, handedness in predation behavior may be caused by asymmetric size of brain hemispheres and also by lateralized gene expressions in the brain. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Unveiling the neurotoxicity of methylmercury in fish (Diplodus sargus) through a regional morphometric analysis of brain and swimming behavior assessment.

Science.gov (United States)

Puga, Sónia; Pereira, Patrícia; Pinto-Ribeiro, Filipa; O'Driscoll, Nelson J; Mann, Erin; Barata, Marisa; Pousão-Ferreira, Pedro; Canário, João; Almeida, Armando; Pacheco, Mário

2016-11-01

The current study aims to shed light on the neurotoxicity of MeHg in fish (white seabream - Diplodus sargus) by the combined assessment of: (i) MeHg toxicokinetics in the brain, (ii) brain morphometry (volume and number of neurons plus glial cells in specific brain regions) and (iii) fish swimming behavior (endpoints associated with the motor performance and the fear/anxiety-like status). Fish were surveyed for all the components after 7 (E7) and 14 (E14) days of dietary exposure to MeHg (8.7μgg -1 ), as well as after a post-exposure period of 28days (PE28). MeHg was accumulated in the brain of D. sargus after a short time (E7) and reached a maximum at the end of the exposure period (E14), suggesting an efficient transport of this toxicant into fish brain. Divalent inorganic Hg was also detected in fish brain along the experiment (indicating demethylation reactions), although levels were 100-200 times lower than MeHg, which pinpoints the organic counterpart as the great liable for the recorded effects. In this regard, a decreased number of cells in medial pallium and optic tectum, as well as an increased hypothalamic volume, occurred at E7. Such morphometric alterations were followed by an impairment of fish motor condition as evidenced by a decrease in the total swimming time, while the fear/anxiety-like status was not altered. Moreover, at E14 fish swam a greater distance, although no morphometric alterations were found in any of the brain areas, probably due to compensatory mechanisms. Additionally, although MeHg decreased almost two-fold in the brain during post-exposure, the levels were still high and led to a loss of cells in the optic tectum at PE28. This is an interesting result that highlights the optic tectum as particularly vulnerable to MeHg exposure in fish. Despite the morphometric alterations reported in the optic tectum at PE28, no significant changes were found in fish behavior. Globally, the effects of MeHg followed a multiphasic profile, where

Rapid and simple method for quantitative evaluation of neurocytotoxic effects of radiation on developing medaka brain

International Nuclear Information System (INIS)

Yasuda, Takako; Maeda, Keiko; Matsumoto, Atsuko; Maruyama, Kouichi; Ishikawa, Yuji; Yoshimoto, Masami

2008-01-01

We describe a novel method for rapid and quantitative evaluation of the degree of radiation-induced apoptosis in the developing brain of medaka (Oryzias latipes). Embryos at stage 28 were irradiated with 1, 2, 3.5, and 5 Gy x-ray. Living embryos were stained with a vital dye, acridine orange (AO), for 1-2 h, and whole-mount brains were examined under an epifluorescence microscope. From 7 to 10 h after irradiation with 5 Gy x-ray, we found two morphologically different types of AO-stained structures, namely, small single nuclei and rosette-shaped nuclear clusters. Electron microscopy revealed that these two distinct types of structures were single apoptotic cells with condensed nuclei and aggregates of apoptotic cells, respectively. From 10 to 30 h after irradiation, a similar AO-staining pattern was observed. The numbers of AO-stained rosette-shaped nuclear clusters and AO-stained single nuclei increased in a dose-dependent manner in the optic tectum. We used the number of AO-stained rosette-shaped nuclear clusters/optic tectum as an index of the degree of radiation-induced brain cell death at 20-24 h after irradiation. The results showed that the number of rosette-shaped nuclear clusters/optic tectum in irradiated embryos exposed to 2 Gy or higher doses was highly significant compared to the number in nonirradiated control embryos, whereas no difference was detected at 1 Gy. Thus, the threshold dose for brain cell death in medaka embryos was taken as being between 1-2 Gy, which may not be so extraordinarily large compared to those for rodents and humans. The results show that medaka embryos are useful for quantitative evaluation of developmental neurocytotoxic effects of radiation. (author)

Cell proliferation and apoptosis in optic nerve and brain integration centers of adult trout Oncorhynchus mykiss after optic nerve injury

Science.gov (United States)

Pushchina, Evgeniya V.; Shukla, Sachin; Varaksin, Anatoly A.; Obukhov, Dmitry K.

2016-01-01

Fishes have remarkable ability to effectively rebuild the structure of nerve cells and nerve fibers after central nervous system injury. However, the underlying mechanism is poorly understood. In order to address this issue, we investigated the proliferation and apoptosis of cells in contralateral and ipsilateral optic nerves, after stab wound injury to the eye of an adult trout Oncorhynchus mykiss. Heterogenous population of proliferating cells was investigated at 1 week after injury. TUNEL labeling gave a qualitative and quantitative assessment of apoptosis in the cells of optic nerve of trout 2 days after injury. After optic nerve injury, apoptotic response was investigated, and mass patterns of cell migration were found. The maximal concentration of apoptotic bodies was detected in the areas of mass clumps of cells. It is probably indicative of massive cell death in the area of high phagocytic activity of macrophages/microglia. At 1 week after optic nerve injury, we observed nerve cell proliferation in the trout brain integration centers: the cerebellum and the optic tectum. In the optic tectum, proliferating cell nuclear antigen (PCNA)-immunopositive radial glia-like cells were identified. Proliferative activity of nerve cells was detected in the dorsal proliferative (matrix) area of the cerebellum and in parenchymal cells of the molecular and granular layers whereas local clusters of undifferentiated cells which formed neurogenic niches were observed in both the optic tectum and cerebellum after optic nerve injury. In vitro analysis of brain cells of trout showed that suspension cells compared with monolayer cells retain higher proliferative activity, as evidenced by PCNA immunolabeling. Phase contrast observation showed mitosis in individual cells and the formation of neurospheres which gradually increased during 1–4 days of culture. The present findings suggest that trout can be used as a novel model for studying neuronal regeneration. PMID:27212918

Two visual pathways to the telencephalon in the nurse shark (Ginglymostoma cirratum). I. Retinal projections.

Science.gov (United States)

Luiten, P G

1981-03-10

The central projections of the retina in the nurse shark were studied by anterograde transport of horseradish peroxidase and tritiated proline. With regard to efferent retinal fibers, both techniques gave completely identical results. Projections were found to pretectal area, dorsal thalamus, basal optic nucleus, and optic tectum, all at the contralateral side. The retinal target cells in the dorsal thalamus are restricted to the ventrolateral optic nucleus and the posterior optic nucleus. No evidence was found for an earlier-reported projection to the lateral geniculate nucleus. The present findings show that the ventrolateral optic nucleus exhibits homological features of the dorsal lateral geniculate nucleus in other vertebrate groups, whereas the lateral geniculate nucleus of the nurse shark is much more comparable to the nucleus rotundus of teleosts and birds and would be more appropriately so named. The application of the HRP technique also allowed us to study afferents to the retina by retrograde transport of tracer. Retrogradely labeled cells were observed in the contralateral optic tectum and are apparently similar to those reported for teleosts and birds.

Distribution of N-methyl-N-nitrosourea in the Amazon molly, Poecilla formosa (Girard), after a single intraperitoneal injection

Energy Technology Data Exchange (ETDEWEB)

Woodhead, A.D.; Cao, E.H.; Melgar, T.

1985-01-01

The distribution and accumulation of labelled N-methyl-N nitrosourea (MNU) has been described in the Amazon molly following intraperitoneal injection. Two hours after injection the label was present throughout the body, with enhanced deposition in the macrophages of the atrium of the heart, the kidney and the spleen; about half of the liver cells were labelled. The compound was taken up by the cells of the renal excretory tubules, and certain cells in the optic tectum and corpus cerebelli of the brain. By 6 h, the distribution picture had changed radically. There was little label remaining, except in a few macrophages in the heart and kidneys, and in the nuclei of the renal tubule cells. There was a slight decrease in the numbers of cells in the brain that were labelled, but the amount of material that the individual cells had accumulated had increased. By 48 h there was further loss and only brain cells were labelled. Our findings indicate preferential accumulation of MNU in undifferentiated, pluripotential cells of the optic tectum and corpus cerebelli. 28 references, 3 figures, 1 table.

Biological model of vision for an artificial system that learns to perceive its environment

Energy Technology Data Exchange (ETDEWEB)

Blackburn, M.R.; Nguyen, H.G.

1989-06-01

The objective is to design an artificial vision system for use in robotics applications. Because the desired performance is equivalent to that achieved by nature, the authors anticipate that the objective will be accomplished most efficiently through modeling aspects of the neuroanatomy and neurophysiology of the biological visual system. Information enters the biological visual system through the retina and is passed to the lateral geniculate and optic tectum. The lateral geniculate nucleus (LGN) also receives information from the cerebral cortex and the result of these two inflows is returned to the cortex. The optic tectum likewise receives the retinal information in a context of other converging signals and organizes motor responses. A computer algorithm is described which implements models of the biological visual mechanisms of the retina, thalamic lateral geniculate and perigeniculate nuclei, and primary visual cortex. Motion and pattern analyses are performed in parallel and interact in the cortex to construct perceptions. We hypothesize that motion reflexes serve as unconditioned pathways for the learning and recall of pattern information. The algorithm demonstrates this conditioning through a learning function approximating heterosynaptic facilitation.

Axonal transport of proteoglycans to the goldfish optic tectum

International Nuclear Information System (INIS)

Ripellino, J.A.; Elam, J.S.

1988-01-01

The study addressed the question of whether 35 SO 4 labeled molecules that have been delivered to the goldfish optic nerve terminals by rapid axonal transport include soluble proteoglycans. For analysis, tectal homogenates were subfractionated into a soluble fraction (soluble after centrifugation at 105,000 g), a lysis fraction (soluble after treatment with hypotonic buffer followed by centrifugation at 105,000 g) and a final 105,000 g pellet fraction. The soluble fraction contained 25.7% of incorporated radioactivity and upon DEAE chromatography was resolved into a fraction of sulfated glycoproteins eluting at 0-0.32 M NaCl and containing 39.5% of total soluble label and a fraction eluting at 0.32-0.60 M NaCl containing 53.9% of soluble label. This latter fraction was included on columns of Sepharose CL-6B with or without 4 M guanidine and after pronase digestion was found to have 51% of its radioactivity contained in the glycosaminoglycans (GAGs) heparan sulfate and chondroitin (4 or 6) sulfate in the ratio of 70% to 30%. Mobility of both intact proteoglycans and constituent GAGs on Sepharose CL-6B indicated a size distribution that is smaller than has been observed for proteoglycans and GAGs from cultured neuronal cell lines. Similar analysis of lysis fraction, containing 11.5% of incorporated 35 SO 4 , showed a mixture of heparan sulfate and chondroitin sulfate containing proteoglycans, apparent free heparan sulfate and few, if any, sulfated glycoproteins. Overall, the results support the hypothesis that soluble proteoglycans are among the molecules axonally transported in the visual system

SINs and SOMs: Neural microcircuits for size tuning in the zebrafish and mouse visual pathway.

Directory of Open Access Journals (Sweden)

Alison J. Barker

2013-05-01

Full Text Available In many animals, a fast and reliable circuit for discriminating between predator-sized objects and edible (prey-sized objects is necessary for survival. How are receptive fields in visual brain areas organized to extract information about size? Recent studies from the zebrafish optic tectum and the mouse visual cortex suggest de novo shaping of receptive fields by subtypes of inhibitory neurons. Del Bene et al. (2010 describe a population of GABAergic neurons in the zebrafish optic tectum (Superficial Interneurons, SINs that are necessary for size filtering during prey capture. Adesnik et al. (2012 describe a somatostatin-expressing interneuron population (SOMs that confers surround suppression on layer II/III pyramidal cells in mouse V1. Strikingly both the SINs and the SOMs, display size-dependent response properties. Increasing visual stimulus size increases excitatory input to these neurons. Dampening SIN or SOM activity alters tuning of neighboring circuits such that they lose preference for small objects. Both results provide exciting evidence for mechanisms of size filtering in visual circuits. Here we review the roles of the SINs and the SOMs and speculate on the similarity of such spatial filters across species.

Prenatal Diagnosis of Tectocerebellar Dysraphia with Occipital Encephalocele

Science.gov (United States)

Sanhal, Cem Y; Tokmak, Aytekin; Müftüoglu, Kamil H; Danisman, Nuri

2015-01-01

Tectocerebellar dysraphia (TCD) is an extremely rare disorder and comprises the congenital abnormalities including occipital encephalocele, aplasia and/or hypoplasia of cerebellar vermis and deformity of tectum. Only few reported cases of this entity are there in the literature. However, the diagnosis in each of the previous cases had been made after birth. We herein describe the first reported case of prenatal diagnosis for TCD in a Turkish woman. PMID:26816952

Normal development of brainstem in childhood. Measurement of the area on mid-sagittal MR imaging

Energy Technology Data Exchange (ETDEWEB)

Kutomi, Kimiko [Teikyo Univ., Tokyo (Japan). Faculty of Medicine

2005-05-01

Developmental abnormality of brainstem is shown in pediatric patients with mental retardation, autism, periventricular leukomalacia, neurodegenerative disease, and so on. Our purpose here is to clarify the normal developmental pattern of the brainstem. We measured the area of tectum, midbrain tegmentum, pons, basis pontis and pontine tegmentum on mid-sagittal MR images in 111 children (newborn to 20 year old). Different growth patterns were shown in all parts of the brainstem. Tectum showed a subtle increase in area from the newborn to adult period, while midbrain tegmentum and pontine tegmenturn showed a mild and gradual increase in area. Pons and pontine tegmentum showed a rapid and prominent increase in area from newborn to infant period and gradual increase in area until the adult period. These different growth patterns seemed to be consistent with differences in the myelination cycles of the neuronal fibers, maturation of the nuclei and proliferation of glial cells in each part of the brainstem. Mid-sagittal MR imaging of the head is accurate and reproducible and is used conveniently in routine head MR study, making it very useful for the diagnosis of many central nervous diseases and anomalies. We believe that this new milestone provided in this study will be helpful in distinguishing normal children from those that have neurodegenerative disorders. (author)

Normal development of brainstem in childhood. Measurement of the area on mid-sagittal MR imaging

International Nuclear Information System (INIS)

Kutomi, Kimiko

2005-01-01

Developmental abnormality of brainstem is shown in pediatric patients with mental retardation, autism, periventricular leukomalacia, neurodegenerative disease, and so on. Our purpose here is to clarify the normal developmental pattern of the brainstem. We measured the area of tectum, midbrain tegmentum, pons, basis pontis and pontine tegmentum on mid-sagittal MR images in 111 children (newborn to 20 year old). Different growth patterns were shown in all parts of the brainstem. Tectum showed a subtle increase in area from the newborn to adult period, while midbrain tegmentum and pontine tegmenturn showed a mild and gradual increase in area. Pons and pontine tegmentum showed a rapid and prominent increase in area from newborn to infant period and gradual increase in area until the adult period. These different growth patterns seemed to be consistent with differences in the myelination cycles of the neuronal fibers, maturation of the nuclei and proliferation of glial cells in each part of the brainstem. Mid-sagittal MR imaging of the head is accurate and reproducible and is used conveniently in routine head MR study, making it very useful for the diagnosis of many central nervous diseases and anomalies. We believe that this new milestone provided in this study will be helpful in distinguishing normal children from those that have neurodegenerative disorders. (author)

Terminal distribution of retinal fibers in the tegu lizard (Tupinambis nigropunctatus).

Science.gov (United States)

Ebbesson, S O; Karten, H J

1981-01-01

The retinal projections in the tegu lizard were traced using degeneration-silver methods. Bilateral projections were found to the dorsolateral geniculate and the posterodorsal nuclei. Unilateral, crossed projections were traced to the suprachiasmatic nucleus, the ventrolateral geniculate nucleus, the mesencephalic lentiform nucleus, nucleus geniculatus praetectalis, the ectomammillary nucleus, and the optic tectum. Some of these connections are distinctly different from those reported in other reptiles and suggest that important interspecific variations occur among reptiles.

Sara John: Ethnisierte Arbeit. Eine feministische Perspektive. Marburg: Tectum Wissenschaftsverlag 2009.

Directory of Open Access Journals (Sweden)

Grit Grigoleit

2011-03-01

Full Text Available Auch bei steigender Erwerbsbeteiligung von Frauen ist der deutsche Arbeitsmarkt von einer weitverbreitenden Chancenungleichheit gekennzeichnet. Die Lebenswirklichkeiten von Migrant/-innen und ihre Einbindung in die vergeschlechtlichten Prozesse am Arbeitsmarkt wurden bislang nicht systematisch erfasst. An diesem Punkt setzt Sara John an, indem sie theoretische Konzeptionen zur Vergeschlechtlichung und zur Ethnisierung auf dem Arbeitsmarkt zusammenführt. In einem multidisziplinären Ansatz werden die zahlreichen Verschränkungen um das Phänomen ‚ethnisierte Arbeit‘ aufgegriffen, die vor dem Hintergrund der Debatte um Deutschland als Einwanderungsland zunehmend an Bedeutung und Brisanz gewinnen.Although women’s labor force participation is rising, the German job market is characterized by a widespread lack of equal opportunities. Thus far, the everyday realities of migrants and their integration into the gendered processes on the job market have not been collected systematically. This is where Sara John begins her study by combining theoretical conceptions about gendering and ethnicizing on the job market. In a multidisciplinary approach, several entanglements surrounding the phenomenon ‘ethnicized labor’ are taken into account. These entanglements keep gaining importance and topicality against the backdrop of Germany as a country of immigration.

Functional and ultrastructural neuroanatomy of interactive intratectal/tectonigral mesencephalic opioid inhibitory links and nigrotectal GABAergic pathways: involvement of GABAA and mu1-opioid receptors in the modulation of panic-like reactions elicited by electrical stimulation of the dorsal midbrain.

Science.gov (United States)

Ribeiro, S J; Ciscato, J G; de Oliveira, R; de Oliveira, R C; D'Angelo-Dias, R; Carvalho, A D; Felippotti, T T; Rebouças, E C C; Castellan-Baldan, L; Hoffmann, A; Corrêa, S A L; Moreira, J E; Coimbra, N C

2005-12-01

In the present study, the functional neuroanatomy of nigrotectal-tectonigral pathways as well as the effects of central administration of opioid antagonists on aversive stimuli-induced responses elicited by electrical stimulation of the midbrain tectum were determined. Central microinjections of naloxonazine, a selective mu(1)-opiod receptor antagonist, in the mesencephalic tectum (MT) caused a significant increase in the escape thresholds elicited by local electrical stimulation. Furthermore, either naltrexone or naloxonazine microinjected in the substantia nigra, pars reticulata (SNpr), caused a significant increase in the defensive thresholds elicited by electrical stimulation of the continuum comprised by dorsolateral aspects of the periaqueductal gray matter (dlPAG) and deep layers of the superior colliculus (dlSC), as compared with controls. These findings suggest an opioid modulation of GABAergic inhibitory inputs controlling the defensive behavior elicited by MT stimulation, in cranial aspects. In fact, iontophoretic microinjections of the neurotracer biodextran into the SNpr, a mesencephalic structure rich in GABA-containing neurons, show outputs to neural substrate of the dlSC/dlPAG involved with the generation and organization of fear- and panic-like reactions. Neurochemical lesion of the nigrotectal pathways increased the sensitivity of the MT to electrical (at alertness, freezing and escape thresholds) and chemical (blockade of GABA(A) receptors) stimulation, suggesting a tonic modulatory effect of the nigrotectal GABAergic outputs on the neural networks of the MT involved with the organization of the defensive behavior and panic-like reactions. Labeled neurons of the midbrain tectum send inputs with varicosities to ipsi and contralateral dlSC/dlPAG and ipsilateral substantia nigra, pars reticulata and compacta, in which the anterograde and retrograde tracing from a single injection indicates that the substantia nigra has reciprocal connections with

Normal myelination of the child brain on MRI - a meta-analysis; Die normale Myelinisierung des kindlichen Gehirns in der MRT - eine Metaanalyse

Energy Technology Data Exchange (ETDEWEB)

Staudt, M.; Grodd, W. [Tuebingen Univ. (Germany). Abt. fuer Neuroradiologie; Kraegeloh-Mann, I. [Tuebingen Univ. (Germany). Abt. Entwicklungsneurologie und Neuropaediatrie

2000-10-01

). Ergebnisse: Trotz deutlicher technischer und methodischer Unterschiede zwischen den einzelnen Studien konnten fuer die meisten Hirnregionen weitgehend uebereinstimmende Zeitangaben gefunden werden. Demnach muessen im Alter von einem Monat bereits folgende Regionen in T{sub 1}w und T{sub 2}w myelintypisches Signal aufweisen: Medulla oblongata, Tegmentum pontis, Pedunculi cerebellares, Vermis cerebelli, Tectum mesencephali, Decussatio pedunculorum cerebelli superiorum, Thalamus, Crus posterius capsulae internae, Radiatio optica, Corona radiata. Danach sollte myelintypisches Signal in den einzelnen Hirnregionen zu folgenden Zeitpunkten erkennbar sein (M=Lebensalter in Monaten): Vorderschenkel der Capsula interna (2 M: T{sub 1}w; 7 M: T{sub 2}w), Splenium corporis callosi (4 M: T{sub 1}w; 6 M: T{sub 2}w), Genu corporis callosi (6 M: T{sub 1}w; 8 M: T{sub 2}w), Centrum semiovale (2 M: T{sub 1}w; 7 M: T{sub 2}w). Im Grosshirn wird eine Aufzweigung des myelintypischen Signals in die einzelnen Gyri (=Arborisation) spaetestens zu folgenden Zeitpunkten sichtbar: Okzipitallappen (5 M: T{sub 1}w; 12 M: T{sub 2}w) und Frontallappen (7 M: T{sub 1}w; 14 M: T{sub 2}w). Schlussfolgerung: Retardierungen der Myelinisierung koennen mit diesen uebereinstimmenden Zeitpunkten aus mehreren Arbeiten mit hoeherer Sicherheit als pathologisch gewertet werden als mit Angaben aus Einzelarbeiten. (orig.)

Cadmium inhibits neurogenesis in zebrafish embryonic brain development

Energy Technology Data Exchange (ETDEWEB)

Chow, Elly Suk Hen [Division of Biology, California Institute of Technology, 1200 California Boulevard, Pasadena, CA 91125 (United States); Hui, Michelle Nga Yu; Lin Chunchi [Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong (China); Cheng Shukhan [Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong (China)], E-mail: bhcheng@cityu.edu.hk

2008-05-01

Cadmium is a non-essential heavy metal found abundantly in the environment. Children of women exposed to cadmium during pregnancy display lower motor and perceptual abilities. High cadmium body burden in children is also related to impaired intelligence and lowered school achievement. However, little is known about the molecular and cellular basis of developmental neurotoxicity in the sensitive early life stages of animals. In this study, we explore neurological deficits caused by cadmium during early embryonic stages in zebrafish by examining regionalization of the neural tube, pattern formation and cell fate determination, commitment of proneural genes and induction of neurogenesis. We show that cadmium-treated embryos developed a smaller head with unclear boundaries between the brain subdivisions, particularly in the mid-hindbrain region. Embryos display normal anterior to posterior regionalization; however, the commitment of neural progenitor cells was affected by cadmium. We observe prominent reductions in the expression of several proneuronal genes including ngn1 in cell clusters, zash1a in the developing optic tectum, and zash1b in the telencephalon and tectum. Cadmium-treated embryos also have fewer differentiated neurons and glia in the facial sensory ganglia as indicated by decreased zn-12 expression. Also, a lower transcription level of neurogenic genes, ngn1 and neuroD, is observed in neurons. Our data suggest that cadmium-induced neurotoxicity can be caused by impaired neurogenesis, resulting in markedly reduced neuronal differentiation and axonogenesis.

Structure of the Pollen Exine of Rhoiptelea chiliantha

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Annie Skarby

2009-06-01

Full Text Available The exine of mature pollen grains of Rhoiptelea chiliantha was studied. The size of the pollen grains is about 23 by 27 μm. They are tricolporate with short colpi that are 1-2 μm wide and 10-12 long. The spinules of Rhoiptelea are similar in form and size to those of Gentianales. The spinules consist of rods of ca 70 nm in width. These rods are evident throughout the tectum and columellae. The columellae are of two distinct sizes. The smaller ones are ca 70 nm wide and join the tectum and the larger columellae. These larger ones appear to be composed of several 70 nm in width rods. They join the distal surface of the foot layer. The proximal surface of the foot layer is marked by a white line (referred to as a junction plane where it joins the endexine. The endexine consists of a solid-appearing component adjacent to the foot layer (referred to as endexine-1 and laminar components (endexine-2 that are attached to and apparently become a part of endexine-1. There is no indication of an arcus. In well preserved grains the aperture is covered by an operculum or operculum-like component. In well-rehydrated pollen grains there is an oncus of considerable complexity under the aperture and over the intine. The Ubisch bodies have an exine ornamented with widely-spaced spinules like the spinules on the pollen exine.

Cadmium inhibits neurogenesis in zebrafish embryonic brain development

International Nuclear Information System (INIS)

Chow, Elly Suk Hen; Hui, Michelle Nga Yu; Lin Chunchi; Cheng Shukhan

2008-01-01

Cadmium is a non-essential heavy metal found abundantly in the environment. Children of women exposed to cadmium during pregnancy display lower motor and perceptual abilities. High cadmium body burden in children is also related to impaired intelligence and lowered school achievement. However, little is known about the molecular and cellular basis of developmental neurotoxicity in the sensitive early life stages of animals. In this study, we explore neurological deficits caused by cadmium during early embryonic stages in zebrafish by examining regionalization of the neural tube, pattern formation and cell fate determination, commitment of proneural genes and induction of neurogenesis. We show that cadmium-treated embryos developed a smaller head with unclear boundaries between the brain subdivisions, particularly in the mid-hindbrain region. Embryos display normal anterior to posterior regionalization; however, the commitment of neural progenitor cells was affected by cadmium. We observe prominent reductions in the expression of several proneuronal genes including ngn1 in cell clusters, zash1a in the developing optic tectum, and zash1b in the telencephalon and tectum. Cadmium-treated embryos also have fewer differentiated neurons and glia in the facial sensory ganglia as indicated by decreased zn-12 expression. Also, a lower transcription level of neurogenic genes, ngn1 and neuroD, is observed in neurons. Our data suggest that cadmium-induced neurotoxicity can be caused by impaired neurogenesis, resulting in markedly reduced neuronal differentiation and axonogenesis

Light-modulated release of RFamide-like neuropeptides from nervus terminalis axon terminals in the retina of goldfish.

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Fischer, A J; Stell, W K

1997-03-01

The nervus terminalis of teleosts, a cranial nerve anatomically associated with the olfactory system, projects to visual system targets including retina and optic tectum. It is known to contain gonadotropin-releasing hormone and RFamide-like peptides, but its function remains unknown. We have probed nervus terminalis function in goldfish by measuring peptide content in retina and tectum with a radioimmunoassay for A18Famide (neuropeptide AF; bovine morphine-modulating peptide). We found that retinal peptide content increased in the dark and decreased in the light, whereas tectal peptide content decreased in the dark and increased in the light. In addition, RFamide-like peptide content in the retina was transiently decreased by severing both olfactory tracts, increased in light-adapted eyes treated with a GABAergic agonist (isoguvacine), and decreased in dark-adapted eyes treated with GABAergic antagonists (bicuculline and picrotoxin). We also found that RFamide-like peptide release could be induced in dark-adapted isolated-superfused retinas by exposure to light or a high concentration (102.5 mM) of potassium ions. We interpret the increase and decrease in peptide content as reflecting a decrease and increase, respectively, in rate of peptide release. We propose that the release and accumulation of RFamide-like peptides in axon terminals of nervus terminalis processes in the retina are modulated primarily by neurons intrinsic to the retina and regulated by light. Peptide release appears to be inhibited tonically in the dark by GABA acting through GABAA receptors; light facilitates peptide release by disinhibition due to a reduction in GABA release. In addition, we propose that electrical signals originating outside the retina can override these intrinsic release-modulating influences.

Hardwiring of fine synaptic layers in the zebrafish visual pathway

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Taylor Michael R

2008-12-01

Full Text Available Abstract Background Neuronal connections are often arranged in layers, which are divided into sublaminae harboring synapses with similar response properties. It is still debated how fine-grained synaptic layering is established during development. Here we investigated two stratified areas of the zebrafish visual pathway, the inner plexiform layer (IPL of the retina and the neuropil of the optic tectum, and determined if activity is required for their organization. Results The IPL of 5-day-old zebrafish larvae is composed of at least nine sublaminae, comprising the connections between different types of amacrine, bipolar, and ganglion cells (ACs, BCs, GCs. These sublaminae were distinguished by their expression of cell type-specific transgenic fluorescent reporters and immunohistochemical markers, including protein kinase Cβ (PKC, parvalbumin (Parv, zrf3, and choline acetyltransferase (ChAT. In the tectum, four retinal input layers abut a laminated array of neurites of tectal cells, which differentially express PKC and Parv. We investigated whether these patterns were affected by experimental disruptions of retinal activity in developing fish. Neither elimination of light inputs by dark rearing, nor a D, L-amino-phosphono-butyrate-induced reduction in the retinal response to light onset (but not offset altered IPL or tectal lamination. Moreover, thorough elimination of chemical synaptic transmission with Botulinum toxin B left laminar synaptic arrays intact. Conclusion Our results call into question a role for activity-dependent mechanisms – instructive light signals, balanced on and off BC activity, Hebbian plasticity, or a permissive role for synaptic transmission – in the synaptic stratification we examined. We propose that genetically encoded cues are sufficient to target groups of neurites to synaptic layers in this vertebrate visual system.

Topographic and functional neuroanatomical study of GABAergic disinhibitory striatum-nigral inputs and inhibitory nigrocollicular pathways: neural hodology recruiting the substantia nigra, pars reticulata, for the modulation of the neural activity in the inferior colliculus involved with panic-like emotions.

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Castellan-Baldan, Lissandra; da Costa Kawasaki, Mateus; Ribeiro, Sandro José; Calvo, Fabrício; Corrêa, Vani Maria Alves; Coimbra, Norberto Cysne

2006-08-01

Considering the influence of the substantia nigra on mesencephalic neurons involved with fear-induced reactions organized in rostral aspects of the dorsal midbrain, the present work investigated the topographical and functional neuroanatomy of similar influence on caudal division of the corpora quadrigemina, addressing: (a) the neural hodology connecting the neostriatum, the substantia nigra, periaqueductal gray matter and inferior colliculus (IC) neural networks; (b) the influence of the inhibitory neostriatonigral-nigrocollicular GABAergic links on the control of the defensive behavior organized in the IC. The effects of the increase or decrease of activity of nigrocollicular inputs on defensive responses elicited by either electrical or chemical stimulation of the IC were also determined. Electrolytic or chemical lesions of the substantia nigra, pars reticulata (SNpr), decreased the freezing and escape behaviors thresholds elicited by electrical stimulation of the IC, and increased the behavioral responses evoked by the GABAA blockade in the same sites of the mesencephalic tectum (MT) electrically stimulated. These findings were corroborated by similar effects caused by microinjections of the GABAA-receptor agonist muscimol in the SNpr, followed by electrical and chemical stimulations of the IC. The GABAA blockade in the SNpr caused a significant increase in the defensive behavior thresholds elicited by electrical stimulation of the IC and a decrease in the mean incidence of panic-like responses induced by microinjections of bicuculline in the mesencephalic tectum (inferior colliculus). These findings suggest that the substantia nigra receives GABAergic inputs that modulate local and also inhibitory GABAergic outputs toward the IC. In fact, neurotracing experiments with fast blue and iontophoretic microinjections of biotinylated dextran amine either into the inferior colliculus or in the reticular division of the substantia nigra demonstrated a neural link

Entrained rhythmic activities of neuronal ensembles as perceptual memory of time interval.

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Sumbre, Germán; Muto, Akira; Baier, Herwig; Poo, Mu-ming

2008-11-06

The ability to process temporal information is fundamental to sensory perception, cognitive processing and motor behaviour of all living organisms, from amoebae to humans. Neural circuit mechanisms based on neuronal and synaptic properties have been shown to process temporal information over the range of tens of microseconds to hundreds of milliseconds. How neural circuits process temporal information in the range of seconds to minutes is much less understood. Studies of working memory in monkeys and rats have shown that neurons in the prefrontal cortex, the parietal cortex and the thalamus exhibit ramping activities that linearly correlate with the lapse of time until the end of a specific time interval of several seconds that the animal is trained to memorize. Many organisms can also memorize the time interval of rhythmic sensory stimuli in the timescale of seconds and can coordinate motor behaviour accordingly, for example, by keeping the rhythm after exposure to the beat of music. Here we report a form of rhythmic activity among specific neuronal ensembles in the zebrafish optic tectum, which retains the memory of the time interval (in the order of seconds) of repetitive sensory stimuli for a duration of up to approximately 20 s. After repetitive visual conditioning stimulation (CS) of zebrafish larvae, we observed rhythmic post-CS activities among specific tectal neuronal ensembles, with a regular interval that closely matched the CS. Visuomotor behaviour of the zebrafish larvae also showed regular post-CS repetitions at the entrained time interval that correlated with rhythmic neuronal ensemble activities in the tectum. Thus, rhythmic activities among specific neuronal ensembles may act as an adjustable 'metronome' for time intervals in the order of seconds, and serve as a mechanism for the short-term perceptual memory of rhythmic sensory experience.

Inorganic mercury accumulation in brain following waterborne exposure elicits a deficit on the number of brain cells and impairs swimming behavior in fish (white seabream-Diplodus sargus).

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Pereira, Patrícia; Puga, Sónia; Cardoso, Vera; Pinto-Ribeiro, Filipa; Raimundo, Joana; Barata, Marisa; Pousão-Ferreira, Pedro; Pacheco, Mário; Almeida, Armando

2016-01-01

The current study contributes to fill the knowledge gap on the neurotoxicity of inorganic mercury (iHg) in fish through the implementation of a combined evaluation of brain morphometric alterations (volume and total number of neurons plus glial cells in specific regions of the brain) and swimming behavior (endpoints related with the motor activity and mood/anxiety-like status). White seabream (Diplodus sargus) was exposed to realistic levels of iHg in water (2μgL(-1)) during 7 (E7) and 14 days (E14). After that, fish were allowed to recover for 28 days (PE28) in order to evaluate brain regeneration and reversibility of behavioral syndromes. A significant reduction in the number of cells in hypothalamus, optic tectum and cerebellum was found at E7, accompanied by relevant changes on swimming behavior. Moreover, the decrease in the number of neurons and glia in the molecular layer of the cerebellum was followed by a contraction of its volume. This is the first time that a deficit on the number of cells is reported in fish brain after iHg exposure. Interestingly, a recovery of hypothalamus and cerebellum occurred at E14, as evidenced by the identical number of cells found in exposed and control fish, and volume of cerebellum, which might be associated with an adaptive phenomenon. After 28 days post-exposure, the optic tectum continued to show a decrease in the number of cells, pointing out a higher vulnerability of this region. These morphometric alterations coincided with numerous changes on swimming behavior, related both with fish motor function and mood/anxiety-like status. Overall, current data pointed out the iHg potential to induce brain morphometric alterations, emphasizing a long-lasting neurobehavioral hazard. Copyright © 2015 Elsevier B.V. All rights reserved.

Quantitative pharmacological analysis of 2-125I-iodomelatonin binding sites in discrete areas of the chicken brain

International Nuclear Information System (INIS)

Siuciak, J.A.; Krause, D.N.; Dubocovich, M.L.

1991-01-01

The authors have localized and characterized 2-125I-iodomelatonin binding sites in the chicken brain using in vitro quantitative autoradiography. Binding sites were widely distributed throughout the chicken brain, predominantly in regions associated with the visual system. The specific binding of 2-125I-iodomelatonin to discrete chicken brain areas was found to be saturable, reversible, and of high affinity. The specific binding of 2-125I-iodomelatonin (75 pm) was quantitated for 40 identifiable brain regions. Eight brain regions were chosen for binding characterization and pharmacological analysis: optic tectum, Edinger-Westphal nucleus, oculomotor nucleus, nucleus rotundus, ventral supraoptic decussation, ventrolateral geniculate nucleus, neostriatum, and ectostriatum. These regions showed no rostral-caudal gradient in 2-125I-iodomelatonin specific binding, and saturation analysis revealed a single class of high-affinity sites with KD values in the range of 33-48 pM and receptor site density (Bmax) ranging from 31 to 58 fmol/mg protein. Competition experiments carried out with various indoles revealed a similar order of pharmacological affinities in these areas: melatonin greater than 6-chloromelatonin greater than methoxyluzindole greater than N-acetylserotonin greater than luzindole much greater than 5-HT greater than 5-methoxytryptamine. The affinity constants determined by quantitative autoradiography for these compounds to compete for 2-125I-iodomelatonin binding in the optic tectum correlated well with the affinities in chicken brain membranes at 25 degrees C (r = 0.966; slope = 0.845; n = 7) and 0 degree C (r = 0.946; slope = 0.379; n = 7), chicken retinal membranes (r = 0.973; slope = 0.759; n = 7), and the potency or affinity of these compounds to affect the calcium-dependent release of 3H-dopamine from the rabbit retina (r = 0.902; slope = 0.506; n = 6)

Bacterial infection of the lower respiratory tract in 34 horses.

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Racklyeft, D J; Love, D N

2000-08-01

To investigate associations between the bacteriology and aspects of history, clinical presentation, outcome and pathology of lower respiratory tract disease of 34 horses. Detailed aerobic and anaerobic bacteriological investigations were performed on clinical specimens from horses with pneumonia, lung abscessation and necrotic pneumonia with or without pleurisy in an attempt to identify those bacteria that might contribute to the initiation and progression of infection. Bacteria were cultured from 33 of the 34 horses. In ten cases, only aerobic/facultatively anaerobic isolates were cultured while aerobic/facultatively anaerobic bacteria and obligately anaerobic bacteria were isolated in the other 23 cases. Moderate to large numbers of anaerobic bacteria were isolated only when the estimated duration of illness was at least five days. Bacteria were not cultured from 12 of the pleural fluid samples but were always cultured from pulmonary samples (either transtracheal aspirates from live horses or pulmonary lesions at necropsy). Streptococcus equi subsp zooepidemicus was isolated in the three cases where only one bacterial species was cultured. In the other 30 cases, multiple species were isolated. These included most often and in greatest numbers, Streptococcus equi subsp zooepidemicus, Pasteurellaceae, Escherichia coli, anaerobic cocci, Eubacterium fossor, Bacteroides tectum, Prevotella heparinolytica, Fusobacterium spp, and pigmented members of the genera Prevotella and Porphyromonas. Aerobic/facultatively anaerobic organisms were isolated from 97% of horses, while obligately anaerobic organisms were cultured from 68% of horses. There was no association between the isolation of any specific bacterium and the outcome of disease. However, obligately anaerobic bacteria (such as anaerobic cocci, Bacteroides tectum, P heparinolytica and Fusobacterium spp) and the facultatively anaerobic species Escherichia coli, were recovered more commonly from horses that died or were

The Ontogeny and Brain Distribution Dynamics of the Appetite Regulators NPY, CART and pOX in Larval Atlantic Cod (Gadus morhua L.).

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Le, Hoang T M D; Angotzi, Anna Rita; Ebbesson, Lars O E; Karlsen, Ørjan; Rønnestad, Ivar

2016-01-01

Similar to many marine teleost species, Atlantic cod undergo remarkable physiological changes during the early life stages with concurrent and profound changes in feeding biology and ecology. In contrast to the digestive system, very little is known about the ontogeny and the localization of the centers that control appetite and feed ingestion in the developing brain of fish. We examined the expression patterns of three appetite regulating factors (orexigenic: neuropeptide Y, NPY; prepro-orexin, pOX and anorexigenic: cocaine- and amphetamine-regulated transcript, CART) in discrete brain regions of developing Atlantic cod using chromogenic and double fluorescent in situ hybridization. Differential temporal and spatial expression patterns for each appetite regulator were found from first feeding (4 days post hatch; dph) to juvenile stage (76 dph). Neurons expressing NPY mRNA were detected in the telencephalon (highest expression), diencephalon, and optic tectum from 4 dph onward. CART mRNA expression had a wider distribution along the anterior-posterior brain axis, including both telencephalon and diencephalon from 4 dph. From 46 dph, CART transcripts were also detected in the olfactory bulb, region of the nucleus of medial longitudinal fascicle, optic tectum and midbrain tegmentum. At 4 and 20 dph, pOX mRNA expression was exclusively found in the preoptic region, but extended to the hypothalamus at 46 and 76 dph. Co-expression of both CART and pOX genes were also observed in several hypothalamic neurons throughout larval development. Our results show that both orexigenic and anorexigenic factors are present in the telencephalon, diencephalon and mesencephalon in cod larvae. The telencephalon mostly contains key factors of hunger control (NPY), while the diencephalon, and particularly the hypothalamus may have a more complex role in modulating the multifunctional control of appetite in this species. As the larvae develop, the overall progression in temporal and

GFAP-immunopositive structures in spiny dogfish, Squalus acanthias, and little skate, Raia erinacea, brains: differences have evolutionary implications.

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Kálmán, M; Gould, R M

2001-07-01

GFAP expression patterns were compared between the brains of a spiny dogfish (Squalus acanthias) and a little skate (Raia erinacea). After anesthesia, the animals were perfused with paraformaldehyde. Serial vibratome sections were immunostained against GFAP using the avidin-biotin method. Spiny dogfish brain contained mainly uniformly-distributed, radially arranged ependymoglia. From GFAP distribution, the layered organization in both the telencephalon and the tectum were visible. In the cerebellum, the molecular and granular layers displayed conspicuously different glial structures; in the former a Bergmann glia-like population was found. No true astrocytes (i.e., stellate-shaped cells) were found. Radial glial endfeet lined all meningeal surfaces. Radial fibers also seemed to form endfeet and en passant contacts on the vessels. Plexuses of fine perivascular glial fibers also contributed to the perivascular glia. Compared with spiny dogfish brain, GFAP expression in the little skate brain was confined. Radial glia were limited to a few areas, e.g., segments of the ventricular surface of the telencephalon, and the midline of the diencephalon and mesencephalon. Scarce astrocytes occurred in every brain part, but only the optic chiasm, and the junction of the tegmentum and optic tectum contained large numbers of astrocytes. Astrocytes formed the meningeal glia limitans and the perivascular glia. No GFAP-immunopositive Bergmann glia-like structure was found. Astrocytes seen in the little skate were clearly different from the mammalian and avian ones; they had a different process system - extra large forms were frequently seen, and the meningeal and perivascular cells were spread along the surface instead of forming endfeet by processes. The differences between Squalus and Raia astroglia were much like those found between reptiles versus mammals and birds. It suggests independent and parallel glial evolutionary processes in amniotes and chondrichthyans, seemingly

Lipoma of the midbrain: post-mortem finding in a patient with breast cancer

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Verônica Maia Gouvea

1989-09-01

Full Text Available Intracranial lipomas are rare, usually do not have clinical expression and are located mare frequently in the corpus callosum. Other locations include the spinal cord, midbrain tectum, superior vermis, tuber cinereum, infundibulum and more rarely cerebellopontine angle, hypothalamus, superior medullary velum and insula. We report the case of a lipoma of the left inferior colliculus which was a post-mortem finding in a woman who died of breast cancer. Although there are reports of intracranial lipomas in patients with malignant tumors there is no explanation for the co-existence of the two tumors. The present tumor also includes a segment of a nerve which is not uncommon, but a less common finding was the presence of nests of Schwann cells within it, shown by immunohistochemistry.

Pollen morphology of the family crassulaceae from pakistan and kashmir and its taxonomic implications

International Nuclear Information System (INIS)

Qasir, M.; Perveen, A.; Sarwar, G.R.

2015-01-01

Pollen morphology of 28 species representing 9 genera viz., Bryophyllum, Kalanchoe, Pseudosedum, Rhodiola, Rosularia, Hylotelephium, Sedum, Tillaea and Orostachys of the family Crassulaceae from Pakistan has been studied by light and scanning electron microscope. Pollen grains are usually free, radially symmetrical, isopolar, sub-oblate to oblate-spheroidal, or prolate-spheroidal to subprolate often prolate and tricolporate. Tectum mostly striate-rugulate or sub-psilate rarely reticulate-rugulate. Significant variation is found in shape and exine ornamentation and on the basis these characters family has been divided into three pollen types' viz., Rhodiola sinuata-type, Rosularia viguieri-type and Sedum hispanicum-type. Numerical analysis of based on pollen characters of 28 species was also carried out to determine the phylogenetic relationships of various genera and the species of the family Crassulaceae. (author)

Pollen flora of pakistan-lxxi. rosaceae

International Nuclear Information System (INIS)

Perveen, A.; Qaiser, M.

2014-01-01

Pollen morphology of 50 species representing 17 genera of the family Rosaceae i.e., Alchemilla, Argimonia, Cotoneaster, Crataegus, Duchesnea, Fragaria, Eriybotyra, Filipandula, Geum, Malus, Prunus, Potentilla, Pyrus , Rosa, Sibbaldia, Sorbaria and Sorbus has been studied from Pakistan by light and scanning electron microscope. Pollen grains are usually free, radially symmetrical, isopolar, prolate-spheroidal to subprolate or oblate-spheroidal rarely perprolate, tricolporate rarely tricolpate. Tectum mostly coarsely-finely striate, rarely striate-rugulate, scabrate or spinulose often reticulate. Rosaceae is more or less eurypalynous family. Significant variation is found in P/E ratio, shape and exine ornamentation and on the basis of these characters family has been divided into seven pollen types viz., Agrimonia eupatoria-type, Alchemilla ypsilotoma-type, Cotoneaster affinis-type, Fragaria nubicola-type, Geum roylei-type, Malus pumila-type, Potentilla pamirica-type. Pollen data is useful at specific and generic level. (author)

Anna-Caterina Walk: Das Andere im Tatort. Migration und Integration im Fernsehkrimi. Marburg: Tectum Wissenschaftsverlag 2011.

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Patricia Piberger

2012-08-01

Full Text Available Aus medien- und kulturwissenschaftlicher Perspektive widmet sich Anna-Caterina Walk in ihrer knappen Publikation der TV-Krimireihe ‚Tatort‘. Anhand von drei konkreten Folgen analysiert sie, wie das Andere in dieser Serie medial repräsentiert und konstruiert wird. Ihr Ziel ist es, die konkreten Darstellungen und deren Bedeutungen in ihrer Selbstverständlichkeit zu hinterfragen. Dabei sucht sie vor allem nach nicht-stereotypen oder destabilisierenden Bildern und fordert zugleich einen kritischeren Umgang mit Differenzkonstruktionen der Identität innerhalb der einzelnen ‚Tatort‘-Folgen. Zumal der Fokus der Autorin auf kulturellen Andersartigkeiten liegt, kommen Betrachtungen des_der geschlechtlich Anderen eine marginale Position zu und bleiben prinzipiell eher oberflächlich.In her concise publication, Anna-Caterina Walk dedicates herself to the TV crime series Tatort using a media studies and cultural studies perspective. Based on three specific episodes, she analyzes how the ‘other’ is medially represented and constructed in the series. She aims at questioning the self-evidence of specific representations and their meanings. In doing so, she searches, above all, for non-stereotypical or destabilizing images and, at the same time, demands a more critical approach to constructions of difference regarding identity within the individual Tatort episodes. Considerations of the gendered ‘other/s’ are treated only marginally and generally remain superficial, particularly since the author focuses on cultural otherness.

Neurons Responsive to Global Visual Motion Have Unique Tuning Properties in Hummingbirds.

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Gaede, Andrea H; Goller, Benjamin; Lam, Jessica P M; Wylie, Douglas R; Altshuler, Douglas L

2017-01-23

Neurons in animal visual systems that respond to global optic flow exhibit selectivity for motion direction and/or velocity. The avian lentiformis mesencephali (LM), known in mammals as the nucleus of the optic tract (NOT), is a key nucleus for global motion processing [1-4]. In all animals tested, it has been found that the majority of LM and NOT neurons are tuned to temporo-nasal (back-to-front) motion [4-11]. Moreover, the monocular gain of the optokinetic response is higher in this direction, compared to naso-temporal (front-to-back) motion [12, 13]. Hummingbirds are sensitive to small visual perturbations while hovering, and they drift to compensate for optic flow in all directions [14]. Interestingly, the LM, but not other visual nuclei, is hypertrophied in hummingbirds relative to other birds [15], which suggests enhanced perception of global visual motion. Using extracellular recording techniques, we found that there is a uniform distribution of preferred directions in the LM in Anna's hummingbirds, whereas zebra finch and pigeon LM populations, as in other tetrapods, show a strong bias toward temporo-nasal motion. Furthermore, LM and NOT neurons are generally classified as tuned to "fast" or "slow" motion [10, 16, 17], and we predicted that most neurons would be tuned to slow visual motion as an adaptation for slow hovering. However, we found the opposite result: most hummingbird LM neurons are tuned to fast pattern velocities, compared to zebra finches and pigeons. Collectively, these results suggest a role in rapid responses during hovering, as well as in velocity control and collision avoidance during forward flight of hummingbirds. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Ontogeny and Brain Distribution Dynamics of the Appetite Regulators NPY, CART and pOX in Larval Atlantic Cod (Gadus morhua L..

Directory of Open Access Journals (Sweden)

Hoang T M D Le

Full Text Available Similar to many marine teleost species, Atlantic cod undergo remarkable physiological changes during the early life stages with concurrent and profound changes in feeding biology and ecology. In contrast to the digestive system, very little is known about the ontogeny and the localization of the centers that control appetite and feed ingestion in the developing brain of fish. We examined the expression patterns of three appetite regulating factors (orexigenic: neuropeptide Y, NPY; prepro-orexin, pOX and anorexigenic: cocaine- and amphetamine-regulated transcript, CART in discrete brain regions of developing Atlantic cod using chromogenic and double fluorescent in situ hybridization. Differential temporal and spatial expression patterns for each appetite regulator were found from first feeding (4 days post hatch; dph to juvenile stage (76 dph. Neurons expressing NPY mRNA were detected in the telencephalon (highest expression, diencephalon, and optic tectum from 4 dph onward. CART mRNA expression had a wider distribution along the anterior-posterior brain axis, including both telencephalon and diencephalon from 4 dph. From 46 dph, CART transcripts were also detected in the olfactory bulb, region of the nucleus of medial longitudinal fascicle, optic tectum and midbrain tegmentum. At 4 and 20 dph, pOX mRNA expression was exclusively found in the preoptic region, but extended to the hypothalamus at 46 and 76 dph. Co-expression of both CART and pOX genes were also observed in several hypothalamic neurons throughout larval development. Our results show that both orexigenic and anorexigenic factors are present in the telencephalon, diencephalon and mesencephalon in cod larvae. The telencephalon mostly contains key factors of hunger control (NPY, while the diencephalon, and particularly the hypothalamus may have a more complex role in modulating the multifunctional control of appetite in this species. As the larvae develop, the overall progression in

Neuropeptide Y (NPY), cocaine- and amphetamine-regulated transcript (CART) and cholecystokinin (CCK) in winter skate (Raja ocellata): cDNA cloning, tissue distribution and mRNA expression responses to fasting.

Science.gov (United States)

MacDonald, Erin; Volkoff, Hélène

2009-04-01

cDNAs encoding for neuropeptide Y (NPY), cocaine- and amphetamine-regulated transcript (CART) and cholecystokinin (CCK) were cloned in an elasmobranch fish, the winter skate. mRNA tissue distribution was examined for the three peptides as well as the effects of two weeks of fasting on their expression. Skate NPY, CART and CCK sequences display similarities with sequences for teleost fish but in general the degree of identity is relatively low (50%). All three peptides are present in brain and in several peripheral tissues, including gut and gonads. Within the brain, the three peptides are expressed in the hypothalamus, telencephalon, optic tectum and cerebellum. Two weeks of fasting induced an increase in telencephalon NPY and an increase in CCK in the gut but had no effects on hypothalamic NPY, CART and CCK, or on telencephalon CART. Our results provide basis for further investigation into the regulation of feeding in winter skate.

Xenopus laevis Retinal Ganglion Cell Dendritic Arbors Develop Independently of Visual Stimulation

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Barbara Lom

2004-01-01

Full Text Available Newly formed neurons must locate their appropriate target cells and then form synaptic connections with these targets in order to establish a functional nervous system. In the vertebrate retina, retinal ganglion cell (RGC dendrites extend from the cell body and form synapses with nearby amacrine and bipolar cells. RGC axons, however, exit the retina and synapse with the dendrites of midbrain neurons in the optic tectum. We examined how visual stimulation influenced Xenopus RGC dendritic arborization. Neuronal activity is known to be an important factor in shaping dendritic and axonal arborization. Thus, we reared tadpoles in dark and light environments then used rhodamine dextran retrograde labeling to identify RGCs in the retina. When we compared RGC dendritic arbors from tadpoles reared in dark and light environments, we found no morphological differences, suggesting that physiological visual activity did not contribute to the morphological development of Xenopus RGC dendritic arbors.

A three-dimensional stereotaxic MRI brain atlas of the cichlid fish Oreochromis mossambicus.

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Simões, José M; Teles, Magda C; Oliveira, Rui F; Van der Linden, Annemie; Verhoye, Marleen

2012-01-01

The African cichlid Oreochromis mossambicus (Mozambique tilapia) has been used as a model system in a wide range of behavioural and neurobiological studies. The increasing number of genetic tools available for this species, together with the emerging interest in its use for neurobiological studies, increased the need for an accurate hodological mapping of the tilapia brain to supplement the available histological data. The goal of our study was to elaborate a three-dimensional, high-resolution digital atlas using magnetic resonance imaging, supported by Nissl staining. Resulting images were viewed and analysed in all orientations (transverse, sagittal, and horizontal) and manually labelled to reveal structures in the olfactory bulb, telencephalon, diencephalon, optic tectum, and cerebellum. This high resolution tilapia brain atlas is expected to become a very useful tool for neuroscientists using this fish model and will certainly expand their use in future studies regarding the central nervous system.

Brain MRI findings of welders : high signal intensity in T1WI secondary to manganese exposure

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Kim, K. W.; Lim, M. A.; Shon, M. Y.; Lee, S. H.; Ha, D. G.; Kwon, K. R.; Kim, S. S.; Hong, Y. S.; Lee, Y. H. [Sunlin Presbyterian Hospital, Pohang (Korea, Republic of); Cheong, H. K. [Dongguk University, Seoul (Korea, Republic of)

1998-03-01

To evaluate the clinical and brain MRI findings of welders and to determine the utility of MRI in the assessment of occupational manganese exposure. All welders complained of fatigue, headache, anorexia, and decreased libido. The palmomental reflex was positive in five (28%), Myerson`s sign in four (22%), and intention tremor in three (17%). Mean blood Mn was 5.18 (range, 1.77-9.34) {mu}g/dl, mean urine Mn was 5.84 (range, 1.07 -22) {mu}g/l, serum Fe was elevated in one welder, and serum Cd in two. T1WI of brain MRI revealed high signal intensities in the globus pallidus, the putamen, the substantia nigra, the tectum, the caudate nucleus, the subthalamic nucleus, the hypothalamus and the pituitary gland. These intensities correlated closely with blood Mn levels, suggesting their potential role in estimating the accumulation of Mn in the brain. (author). 25 refs., 2 tabs., 5 figs.

Tributyltin exposure causes brain damage in Sebastiscus marmoratus.

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Zhang, Jiliang; Zuo, Zhenghong; Chen, Rong; Chen, Yixin; Wang, Chonggang

2008-09-01

Tributyltin (TBT) is a ubiquitous marine environmental contaminant characterized primarily by its reproductive toxicity. However, the neurotoxic effect of TBT has not been extensively described, especially in fishes which have a high number of species in the marine environment. This study was conducted to investigate the neurotoxic effects of TBT at environmental levels (1, 10, and 100ngl(-1)) on female Sebastiscus marmoratus. The results showed that TBT exposure induced apoptosis in brain cells of three regions including the pallial areas of the telencephalon, the granular layer of the optic tectum, and the cerebellum. In addition, the increase of reactive oxygen species and nitric oxide levels, and the decrease of Na+/K+-ATPase activity were found in the brain. The results strongly indicated neurotoxicity of TBT to fishes. According to the regions in which apoptosis was found in the brain, TBT exposure might influence the schooling, sensory and motorial functions of fishes.

Calsyntenins Are Expressed in a Dynamic and Partially Overlapping Manner during Neural Development

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Gemma de Ramon Francàs

2017-08-01

Full Text Available Calsyntenins form a family of linker proteins between distinct populations of vesicles and kinesin motors for axonal transport. They were implicated in synapse formation and synaptic plasticity by findings in worms, mice and humans. These findings were in accordance with the postsynaptic localization of the Calsyntenins in the adult brain. However, they also affect the formation of neural circuits, as loss of Calsyntenin-1 (Clstn1 was shown to interfere with axonal branching and axon guidance. Despite the fact that Calsyntenins were discovered originally in embryonic chicken motoneurons, their distribution in the developing nervous system has not been analyzed in detail so far. Here, we summarize our analysis of the temporal and spatial expression patterns of the cargo-docking proteins Clstn1, Clstn2 and Clstn3 during neural development by comparing the dynamic distribution of their mRNAs by in situ hybridization in the spinal cord, the cerebellum, the retina and the tectum, as well as in the dorsal root ganglia (DRG.

Circuits for Action and Cognition: A View from the Superior Colliculus.

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Basso, Michele A; May, Paul J

2017-09-15

The superior colliculus is one of the most well-studied structures in the brain, and with each new report, its proposed role in behavior seems to increase in complexity. Forty years of evidence show that the colliculus is critical for reorienting an organism toward objects of interest. In monkeys, this involves saccadic eye movements. Recent work in the monkey colliculus and in the homologous optic tectum of the bird extends our understanding of the role of the colliculus in higher mental functions, such as attention and decision making. In this review, we highlight some of these recent results, as well as those capitalizing on circuit-based methodologies using transgenic mice models, to understand the contribution of the colliculus to attention and decision making. The wealth of information we have about the colliculus, together with new tools, provides a unique opportunity to obtain a detailed accounting of the neurons, circuits, and computations that underlie complex behavior.

Inhibition of non-neuronal cell proliferation in the goldfish visual pathway affects the regenerative capacity of the retina

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Neuman, D.; Yerushalmi, A.; Schwartz, M.

1983-01-01

Proliferating cells associated with the visual pathway were found in the present study of affect the regenerative capacity of the goldfish retina following optic nerve injury. The contribution of these cells to the process of regeneration was investigated in the goldfish visual system by reducing their proliferation in the optic tract and tecta, using X-irradiation. The regenerative ability of the retina was then evaluated by the following parameters: sprouting from retinal explants, protein synthesis in the retina and accumulation of radiolabeled transported components in the tectum. X-irradiation of the visual system at an early stage of the regeneration process had a promoting effect whereas irradiation at a later stage resulted in a reduced capacity to regenerate. The results are discussed with respect to the possibility that proliferating cells, possibly glia, exert two contradictory contributions: an inhibitory effect at the site of injury, whereas distal to it, a supportive, perhaps trophic effect. (Auth.)

Inhibition of non-neuronal cell proliferation in the goldfish visual pathway affects the regenerative capacity of the retina

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Neuman, D.; Yerushalmi, A.; Schwartz, M. (Weizmann Inst. of Science, Rehovoth (Israel))

1983-08-08

Proliferating cells associated with the visual pathway were found in the present study of affect the regenerative capacity of the goldfish retina following optic nerve injury. The contribution of these cells to the process of regeneration was investigated in the goldfish visual system by reducing their proliferation in the optic tract and tecta, using X-irradiation. The regenerative ability of the retina was then evaluated by the following parameters: sprouting from retinal explants, protein synthesis in the retina and accumulation of radiolabeled transported components in the tectum. X-irradiation of the visual system at an early stage of the regeneration process had a promoting effect whereas irradiation at a later stage resulted in a reduced capacity to regenerate. The results are discussed with respect to the possibility that proliferating cells, possibly glia, exert two contradictory contributions: an inhibitory effect at the site of injury, whereas distal to it, a supportive, perhaps trophic effect.

Neurodevelopmental effects of chronic exposure to elevated levels of pro-inflammatory cytokines in a developing visual system

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Ruthazer Edward S

2010-01-01

Full Text Available Abstract Background Imbalances in the regulation of pro-inflammatory cytokines have been increasingly correlated with a number of severe and prevalent neurodevelopmental disorders, including autism spectrum disorder, schizophrenia and Down syndrome. Although several studies have shown that cytokines have potent effects on neural function, their role in neural development is still poorly understood. In this study, we investigated the link between abnormal cytokine levels and neural development using the Xenopus laevis tadpole visual system, a model frequently used to examine the anatomical and functional development of neural circuits. Results Using a test for a visually guided behavior that requires normal visual system development, we examined the long-term effects of prolonged developmental exposure to three pro-inflammatory cytokines with known neural functions: interleukin (IL-1β, IL-6 and tumor necrosis factor (TNF-α. We found that all cytokines affected the development of normal visually guided behavior. Neuroanatomical imaging of the visual projection showed that none of the cytokines caused any gross abnormalities in the anatomical organization of this projection, suggesting that they may be acting at the level of neuronal microcircuits. We further tested the effects of TNF-α on the electrophysiological properties of the retinotectal circuit and found that long-term developmental exposure to TNF-α resulted in enhanced spontaneous excitatory synaptic transmission in tectal neurons, increased AMPA/NMDA ratios of retinotectal synapses, and a decrease in the number of immature synapses containing only NMDA receptors, consistent with premature maturation and stabilization of these synapses. Local interconnectivity within the tectum also appeared to remain widespread, as shown by increased recurrent polysynaptic activity, and was similar to what is seen in more immature, less refined tectal circuits. TNF-α treatment also enhanced the

Analysis of protein profile and pollen morphology of guaiacum officinale linn

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Zeb, S.

2017-01-01

Asthma and allergic rhinitis is triggered by the pollen of trees, grasses and weeds. Guaiacum officinale L. tree is widely cultivated along with the road side. This species was selected to check its allergenic role.Pollen morphology of Guaiacum officinale was examined by Light microsco4pe (LM) and Scanning electron microscope (SEM). Pollen grains of Guaiacum officinale were prolate shape, having tricolpate aperture, and rugulate tectum. Pollen protein concentration of G. officinale was determined by Bradford's assay and qualitative protein analysis of pollen was done by SDS-PAGE(Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis).Total protein content in the pollen extract was 24.28mg/g of pollen. The SDS-PAGE pollen grains protein analysis showed 07 different protein bands. The molecular weight of separated proteins ranged from 25 to 65kDa. Biochemical analysis of G. officinale pollen grains revealed the presence of low molecular weight proteins therefore it is strongly suggested that this species must be considered as a potent allergy causing species. This research would help for the proper diagnosis and treatment of the bronchial allergy suffering patients. (author)

MRI characteristics of midbrain tumours

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Sun, B.; Wang, C.C.; Wang, J.

1999-01-01

We diagnosed 60 cases of midbrain tumours by MRI between 1993 to 1997. There were 39 males and 21 females, aged 2-64 years, mean 25.6 years. We found 38 patients with true intramedullary midbrain tumours, 11 predominantly in the tectum, 20 in the tegmentum and 7 with a downward extension to the pons; there were 7 within the cerebral aqueduct. There were 22 patients with infiltrating midbrain tumours extending from adjacent structures, 11 cases each from the thalamus and pineal region. All patients received surgical treatment. Gross total resection was achieved in 42 cases, subtotal (> 75 %) resection in 18. Pathological diagnoses included 16 low-grade and 15 high-grade astrocytomas; 5 oligodendroastrocytomas; 2 ependymomas; 11 glioblastomas; and 11 pineal parenchymal or germ-cell tumours. Midbrain tumours are a heterogeneous group of neoplasms, with wide variation in clinical and MRI features, related to the site and type of tumour. MRI not only allows precise analysis of their growth pattern, but also can lead to a correct preoperative diagnosis in the majority of cases. (orig.) (orig.)

Intermediate filament immunohistochemistry of astroglial cells in the leopard gecko, Eublepharis macularius.

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Lazzari, Maurizio; Franceschini, Valeria

2005-11-01

The distribution of intermediate filament molecular markers, glial fibrillary acidic protein (GFAP) and vimentin, has been studied in the central nervous system (CNS) of the adult leopard gecko, Eublepharis macularius. This immunohistochemical study points out the presence of different astroglial cell types. The main pattern is constituted by ependymal radial glia, which have their cell bodies located in the ependymal layer throughout the brain ventricular system. Radial glia proper or radial astrocytes show their cell bodies displaced from the ependymal layer into a periependymal zone and are observed only in the spinal cord. Star-shaped astrocytes are scarce. They are detected in the ventral and lateral regions of the diencephalon and mesencephalon, in the superficial layer of the optic tectum, in the ventral medulla oblongata, and in the ventral and lateral spinal cord. In the different regions of the CNS, the staining intensity appears not to be identical even in the same cellular type. The results reported in the present study show an heterogeneous feature of the astroglial pattern in E. macularius.

Axon-Axon Interactions Regulate Topographic Optic Tract Sorting via CYFIP2-Dependent WAVE Complex Function.

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Cioni, Jean-Michel; Wong, Hovy Ho-Wai; Bressan, Dario; Kodama, Lay; Harris, William A; Holt, Christine E

2018-03-07

The axons of retinal ganglion cells (RGCs) are topographically sorted before they arrive at the optic tectum. This pre-target sorting, typical of axon tracts throughout the brain, is poorly understood. Here, we show that cytoplasmic FMR1-interacting proteins (CYFIPs) fulfill non-redundant functions in RGCs, with CYFIP1 mediating axon growth and CYFIP2 specifically involved in axon sorting. We find that CYFIP2 mediates homotypic and heterotypic contact-triggered fasciculation and repulsion responses between dorsal and ventral axons. CYFIP2 associates with transporting ribonucleoprotein particles in axons and regulates translation. Axon-axon contact stimulates CYFIP2 to move into growth cones where it joins the actin nucleating WAVE regulatory complex (WRC) in the periphery and regulates actin remodeling and filopodial dynamics. CYFIP2's function in axon sorting is mediated by its binding to the WRC but not its translational regulation. Together, these findings uncover CYFIP2 as a key regulatory link between axon-axon interactions, filopodial dynamics, and optic tract sorting. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

GABAergic transmission and chloride equilibrium potential are not modulated by pyruvate in the developing optic tectum of Xenopus laevis tadpoles.

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Arseny S Khakhalin

Full Text Available In the developing mammalian brain, gamma-aminobutyric acid (GABA is thought to play an excitatory rather than an inhibitory role due to high levels of intracellular Cl(- in immature neurons. This idea, however, has been questioned by recent studies which suggest that glucose-based artificial cerebrospinal fluid (ACSF may be inadequate for experiments on immature and developing brains. These studies suggest that immature neurons may require alternative energy sources, such as lactate or pyruvate. Lack of these other energy sources is thought to result in artificially high intracellular Cl(- concentrations, and therefore a more depolarized GABA receptor (GABAR reversal potential. Since glucose metabolism can vary widely among different species, it is important to test the effects of these alternative energy sources on different experimental preparations. We tested whether pyruvate affects GABAergic transmission in isolated brains of developing wild type Xenopus tadpoles in vitro by recording the responsiveness of tectal neurons to optic nerve stimulation, and by measuring currents evoked by local GABA application in a gramicidin perforated patch configuration. We found that, in contrast with previously reported results, the reversal potential for GABAR-mediated currents does not change significantly between developmental stages 45 and 49. Partial substitution of glucose by pyruvate had only minor effects on both the GABA reversal potential, and the responsiveness of tectal neurons at stages 45 and 49. Total depletion of energy sources from the ACSF did not affect neural responsiveness. We also report a strong spatial gradient in GABA reversal potential, with immature cells adjacent to the lateral and caudal proliferative zones having more positive reversal potentials. We conclude that in this experimental preparation standard glucose-based ACSF is an appropriate extracellular media for in vitro experiments.

Venous anomalies and abnormalities of the posterior fossa

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Goulao, A.; Alvarez, H.; Garcia Monaco, R.; Pruvost, P.; Lasjaunias, P.

1990-01-01

The authors report a series of 16 patients with venous anomalies or abnormalities of the posterior fossa studied by angiography, CT and/or MRI. We believe that so-called 'venous angioma' are extreme anatomic variants that drain normal territories, and we prefer to call them developmental venous anomalies (DVA). Posterior fossa DVA, like the supra-tentorial ones are classified according to their drainage into deep and superficial type. They are exclusively located in the cerebellum or tectum. In 4 cases DVA was an incidental finding, in 3 an associated cerebral venous malformation (CVM) was found and felt to be the cause of the symptoms and only in one (Trigeminal pain) was a link between both suspected. Cavernous venous malformation (CVM) were found in frequent association with DVA (27%). 4 cases were single and 2 multiple. 5 CVM were located in the brain stem and 3 in the cerebellum. The clinical and radiological files were reviewed and a direct relationship between symptoms and localization was found in all patients with CVM. In 2 cases venous dysplasia was found: 1 Sturge-Weber and 1 First branchial arch syndrome. Both posterior fossa venous abnormalities were incidental findings. (orig.)

Discrepancy between species borders at morphological and molecular levels in the genus Cochliopodium (Amoebozoa, Himatismenida), with the description of Cochliopodium plurinucleolum n. sp.

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Geisen, Stefan; Kudryavtsev, Alexander; Bonkowski, Michael; Smirnov, Alexey

2014-05-01

Amoebae of the genus Cochliopodium are characterized by a tectum that is a layer of scales covering the dorsal surface of the cell. A combination of scale structure, morphological features and, nowadays, molecular information allows species discrimination. Here we describe a soil species Cochliopodium plurinucleolum n. sp. that besides strong genetic divergence from all currently described species of Cochliopodium differs morphologically by the presence of several peripheral nucleoli in the nucleus. Further, we unambiguously show that the Golgi attachment associated with a dictyosome in Cochliopodium is a cytoplasmic microtubule organizing center (MTOC). Last, we provide detailed morphological and molecular information on the sister clade of C. plurinucleolum, containing C. minus, C. minutoidum, C. pentatrifurcatum and C. megatetrastylus. These species share nearly identical sequences of both, small subunit ribosomal RNA and partial Cox1 genes, and nearly identical structure of the scales. Scales of C. pentatrifurcatum differ, however, strongly from scales of the others while sequences of C. pentatrifurcatum and C. minus are nearly identical. These discrepancies urge for future sampling efforts to disentangle species characteristics within Cochliopdium and to investigate morphological and molecular patterns that allow reliable species differentiation. Copyright © 2014 Elsevier GmbH. All rights reserved.

Pollen morphology of Amygdalus L. (Rosaceae in Iran

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Mahnaz Vafadar

2011-01-01

Full Text Available Pollen grain of 16 species and three hybrids of the genus Amygdalus L., representing two subgenera and two sections distributed in Iran were examined by light and scanning electron microscopy. All pollen grains are tricolporate. The shape of grains varies from subprolate through prolate. Regarding outline, in polar view, pollen grains are triangular-circular and in equatorial view, elliptic. Regarding sculpturing of exine, the frequent type like many members of family Rosaceae is striate with or without perforations that can be subdivided into three subtypes: type I (A-B, type II (A-B and type V. In three species, A. trichamygdalus, A. spinosissima and A. orientalis, exine sculpture type is completely different. In the first species is rugulate, in the second species is reticulate and in A. orientalis, it is gemmate-perforate. Ornamentation of ridges (muri in the striate sculpture is parallel to ectocolpus. Number of perforations in tectum, diameter of them, striae intervals and the thickness of ridges varies among studied taxa. The striae have different depth and slope. Results showed that among pollen grain characters, shape is useful character solely for separating of taxonomic ranks in Iranian Amygdalus specially in subgeneric or section level.

Region specific changes in nonapeptide levels during client fish interactions with allopatric and sympatric cleaner fish.

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Soares, Marta C; Cardoso, Sónia C; Mazzei, Renata; André, Gonçalo I; Morais, Marta; Gozdowska, Magdalena; Kalamarz-Kubiak, Hanna; Kulczykowska, Ewa

2017-01-01

Social relationships are crucially dependent on individual ability to learn and remember ecologically relevant cues. However, the way animals recognize cues before engaging in any social interaction and how their response is regulated by brain neuromodulators remains unclear. We examined the putative involvement of arginine vasotocin (AVT) and isotocin (IT), acting at different brain regions, during fish decision-making in the context of cooperation, by trying to identify how fish distinguish and recognize the value of other social partners or species. We hypothesized that the behavioural responses of cleaner fish clients to different social contexts would be underlain by changes in brain AVT and IT levels. We have found that changes in AVT at the level of forebrain and optic tectum are linked with a response to allopatric cleaners (novel or unfamiliar stimuli) while those at cerebellum are associated with the willingness to be cleaned (in response to sympatric cleaners). On the other hand, higher brain IT levels that were solely found in the diencephalon, also in response to allopatric cleaners. Our results are the first to implicate these nonapeptides, AVT in particular, in the assessment of social cues which enable fish to engage in mutualistic activities.

Rana computatrix to human language: towards a computational neuroethology of language evolution.

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Arbib, Michael A

2003-10-15

Walter's Machina speculatrix inspired the name Rana computatrix for a family of models of visuomotor coordination in the frog, which contributed to the development of computational neuroethology. We offer here an 'evolutionary' perspective on models in the same tradition for rat, monkey and human. For rat, we show how the frog-like taxon affordance model provides a basis for the spatial navigation mechanisms that involve the hippocampus and other brain regions. For monkey, we recall two models of neural mechanisms for visuomotor coordination. The first, for saccades, shows how interactions between the parietal and frontal cortex augment superior colliculus seen as the homologue of frog tectum. The second, for grasping, continues the theme of parieto-frontal interactions, linking parietal affordances to motor schemas in premotor cortex. It further emphasizes the mirror system for grasping, in which neurons are active both when the monkey executes a specific grasp and when it observes a similar grasp executed by others. The model of human-brain mechanisms is based on the mirror-system hypothesis of the evolution of the language-ready brain, which sees the human Broca's area as an evolved extension of the mirror system for grasping.

Increase in telencephalic dopamine and cerebellar norepinephrine contents by hydrostatic pressure in goldfish: the possible involvement in hydrostatic pressure-related locomotion.

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Ikegami, Taro; Takemura, Akihiro; Choi, Eunjung; Suda, Atsushi; Tomonaga, Shozo; Badruzzaman, Muhammad; Furuse, Mitsuhiro

2015-10-01

Fish are faced with a wide range of hydrostatic pressure (HP) in their natural habitats. Additionally, freshwater fish are occasionally exposed to rapid changes in HP due to heavy rainfall, flood and/or dam release. Accordingly, variations in HP are one of the most important environmental cues for fish. However, little information is available on how HP information is perceived and transmitted in the central nervous system of fish. The present study examined the effect of HP (water depth of 1.3 m) on the quantities of monoamines and their metabolites in the telencephalon, optic tectum, diencephalon, cerebellum (including partial mesencephalon) and vagal lobe (including medulla oblongata) of the goldfish, Carassius auratus, using high-performance liquid chromatography. HP affected monoamine and metabolite contents in restricted brain regions, including the telencephalon, cerebellum and vagal lobe. In particular, HP significantly increased the levels of dopamine (DA) in the telencephalon at 15 min and that of norepinephrine (NE) in the cerebellum at 30 min. In addition, HP also significantly increased locomotor activity at 15 and 30 min after HP treatment. It is possible that HP indirectly induces locomotion in goldfish via telencephalic DA and cerebellar NE neuronal activity.

Expression of RPRM/rprm in the Olfactory System of Embryonic Zebrafish (Danio rerio)

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Stanic, Karen; Quiroz, Alonso; Lemus, Carmen G.; Wichmann, Ignacio A.; Corvalán, Alejandro H.; Owen, Gareth I.; Opazo, Juan C.; Concha, Miguel L.; Amigo, Julio D.

2018-01-01

The Reprimo (RPRM) family is composed of highly conserved single-exon genes. The expression pattern of this gene family has been recently described during zebrafish (Danio rerio) embryogenesis, and primarily locates in the nervous system. Its most characterized member, RPRM, which duplicated to give rise rprma and rprmb in the fish lineage, is known to act as a tumor-suppressor gene in mammalian models. Here, we describe in detail the spatiotemporal expression of three rprm genes (rprma, rprmb, and rprml) within distinct anatomical structures in the developing peripheral and central nervous system. In the zebrafish, rprma mRNA is expressed in the olfactory placodes (OP) and olfactory epithelium (OE), rprmb is observed in the tectum opticum (TeO) and trigeminal ganglion (Tg), whereas rprml is found primarily in the telencephalon (Tel). At protein level, RPRM is present in a subset of cells in the OP, and neurons in the OE, TeO, hindbrain and sensory peripheral structures. Most importantly, the expression of RPRM has been conserved between teleosts and mammals. Thus, we provide a reference dataset describing the expression patterns of RPRM gene products during zebrafish and mouse development as a first step to approach the physiological role of the RPRM gene family. PMID:29636669

MR findings of wernicke encephalopathy

International Nuclear Information System (INIS)

Yoon, Hyun Ki; Chang, Kee Hyun; Lee, Goo; Han, Moon Hee; Park, Sung Ho; Na, Duk Yull; Song, Chi Sung

1991-01-01

Seven patients (33 to 58 years old) with clinical diagnoses of Wernicke encephalopathy were examined with MR on either a 2.0T (5 cases) or a 0.5T scanner (2 cases) using spin-echo pulse sequences. In 2 patients, follow-up MR studies were performed 1 and 5 weeks after thiamine (vitamine B1) treatment. Five patients (4 chronic alcoholics and 1 with hyperemesis gravidarum) showed atrophy of both mamillary bodies, along with patchy lesions around the third ventricle, medial thalami, tectum of the midbrain, and periaqueductal gray matter. Another patient with hyperemesis of gravidrum demonstrated only slightly atrophic mamillary bodies, and the last patient with severe vomiting after gastrojejunostomy showed only diencephaic/mesencephalic lesions with apparently normal mamillary bodies. A follow-up MR showed a decrease in previously-noted diencephalic/-/mesencephalic lesions but no change in the size of the mamillary bodies. Diencephalic/mesencephalic lesions were well seen as a high-signal intensity on proton-and T2-weighted axial images, while atrophy of the mamillary bodies was seen best on T1-weighted sagittal images. MR imaging is very useful in demonstrating the characteristic lesions of Wernicke encephalopathy and in evaluating the result of treatment on follow-up study

Distribution of glycogen phosphorylase and cytochrome oxidase in the central nervous system of the turtle Trachemys dorbigni.

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Partata, W A; Krepsky, A M; Xavier, L L; Marques, M; Achaval, M

1999-10-01

Glycogen phosphorylase (GP) and cytochrome oxidase (CO) activities were mapped histochemically in the brain of the turtle Trachemys dorbigni. In the telencephalon, both activities occurred in the olfactory bulb, in all cortical areas, in the dorsal ventricular ridge, striatum, primordium hippocampi and olfactory tubercle. In the diencephalon, they were identified in some areas of the hypothalamus, and in rotundus and geniculate nuclei. Both reactions were detected in the oculomotor, trochlear, mesencephalic trigeminal nuclei, the nucleus of the posterior commissure, torus semicircularis, substantia nigra and ruber and isthmic nuclei of the mesencephalon. In all layers of the optic tectum GP activity was found, but CO only labelled the stratum griseum centrale. In the medulla oblonga both enzymes appear in the reticular, raphe and vestibular nuclei, locus coeruleus and nuclei of cranial nerves. In the cerebellum, the granular and molecular layers, and the deep cerebellar nuclei were positive for both enzymes. The Purkinje cells were only reactive for CO. In the spinal cord, motor and commissural neurones exhibited a positive reaction for the two enzymes. However, CO also occurred in the marginal nucleus and in the lateral funiculus. These results may be useful as a basis for subsequent studies on turtle brain metabolism.

Tracing of single fibers of the nervus terminalis in the goldfish brain.

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von Bartheld, C S; Meyer, D L

1986-01-01

Central projections of the nervus terminalis (n.t.) in the goldfish were investigated using cobalt- and horseradish peroxidase-tracing techniques. Single n.t. fibers were identified after unilateral application of cobalt chloride-lysine to the rostral olfactory bulb. The central course and branching patterns of individual n.t. fibers were studied in serial sections. Eight types of n.t. fibers are differentiated according to pathways and projection patterns. Projection areas of the n.t. include the contralateral olfactory bulb, the ipsilateral periventricular preoptic nucleus, both retinae, the caudal zone of the periventricular hypothalamus bilaterally, and the rostral optic tectum bilaterally. N.t. fibers cross to contralateral targets in the anterior commissure, the optic chiasma, the horizontal commissure, the posterior commissure, and possibly the habenular commissure. We propose criteria that differentiate central n.t. fibers from those of the classical secondary olfactory projections. Branching patterns of eight n.t. fiber types are described. Mesencephalic projections of the n.t. and of secondary olfactory fibers are compared and discussed with regard to prior reports on the olfactory system of teleosts. Further fiber types for which the association with the n.t. could not be established with certainty were traced to the torus longitudinalis, the torus semicircularis, and to the superior reticular nucleus on the ipsilateral side.

Glycolysis-induced discordance between glucose metabolic rates measured with radiolabeled fluorodeoxyglucose and glucose

International Nuclear Information System (INIS)

Ackermann, R.F.; Lear, J.L.

1989-01-01

We have developed an autoradiographic method for estimating the oxidative and glycolytic components of local CMRglc (LCMRglc), using sequentially administered [ 18 F]fluorodeoxyglucose (FDG) and [ 14 C]-6-glucose (GLC). FDG-6-phosphate accumulation is proportional to the rate of glucose phosphorylation, which occurs before the divergence of glycolytic (GMg) and oxidative (GMo) glucose metabolism and is therefore related to total cerebral glucose metabolism GMt: GMg + GMo = GMt. With oxidative metabolism, the 14 C label of GLC is temporarily retained in Krebs cycle-related substrate pools. We hypothesize that with glycolytic metabolism, however, a significant fraction of the 14 C label is lost from the brain via lactate production and efflux from the brain. Thus, cerebral GLC metabolite concentration may be more closely related to GMo than to GMt. If true, the glycolytic metabolic rate will be related to the difference between FDG- and GLC-derived LCMRglc. Thus far, we have studied normal awake rats, rats with limbic activation induced by kainic acid (KA), and rats visually stimulated with 16-Hz flashes. In KA-treated rats, significant discordance between FDG and GLC accumulation, which we attribute to glycolysis, occurred only in activated limbic structures. In visually stimulated rats, significant discordance occurred only in the optic tectum

Expression of RPRM/rprm in the Olfactory System of Embryonic Zebrafish (Danio rerio

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Karen Stanic

2018-03-01

Full Text Available The Reprimo (RPRM family is composed of highly conserved single-exon genes. The expression pattern of this gene family has been recently described during zebrafish (Danio rerio embryogenesis, and primarily locates in the nervous system. Its most characterized member, RPRM, which duplicated to give rise rprma and rprmb in the fish lineage, is known to act as a tumor-suppressor gene in mammalian models. Here, we describe in detail the spatiotemporal expression of three rprm genes (rprma, rprmb, and rprml within distinct anatomical structures in the developing peripheral and central nervous system. In the zebrafish, rprma mRNA is expressed in the olfactory placodes (OP and olfactory epithelium (OE, rprmb is observed in the tectum opticum (TeO and trigeminal ganglion (Tg, whereas rprml is found primarily in the telencephalon (Tel. At protein level, RPRM is present in a subset of cells in the OP, and neurons in the OE, TeO, hindbrain and sensory peripheral structures. Most importantly, the expression of RPRM has been conserved between teleosts and mammals. Thus, we provide a reference dataset describing the expression patterns of RPRM gene products during zebrafish and mouse development as a first step to approach the physiological role of the RPRM gene family.

GABAergic influences on ORX receptor-dependent abnormal motor behaviors and neurodegenerative events in fish

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Facciolo, Rosa Maria; Crudo, Michele; Giusi, Giuseppina; Canonaco, Marcello

2010-01-01

At date the major neuroreceptors i.e. γ-aminobutyric acid A (GABA A R) and orexin (ORXR) systems are beginning to be linked to homeostasis, neuroendocrine and emotional states. In this study, intraperitoneal treatment of the marine teleost Thalassoma pavo with the highly selective GABA A R agonist (muscimol, MUS; 0,1 μg/g body weight) and/or its antagonist bicuculline (BIC; 1 μg/g body weight) have corroborated a GABA A ergic role on motor behaviors. In particular, MUS induced moderate (p A R was very likely responsible for very strong and strong ORXR mRNA reductions in cerebellum valvula and torus longitudinalis, respectively. Moreover these effects were linked to evident ultra-structural changes such as shrunken cell membranes and loss of cytoplasmic architecture. In contrast, MUS supplied a very low, if any, argyrophilic reaction in hypothalamic and mesencephalic regions plus a scarce level of ultra-structural damages. Interestingly, combined administrations of MUS + BIC were not related to consistent damages, aside mild neuronal alterations in motor-related areas such as optic tectum. Overall it is tempting to suggest, for the first time, a neuroprotective role of GABA A R inhibitory actions against the overexcitatory ORXR-dependent neurodegeneration and consequently abnormal swimming events in fish.

Biologically inspired collision avoidance system for unmanned vehicles

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Ortiz, Fernando E.; Graham, Brett; Spagnoli, Kyle; Kelmelis, Eric J.

2009-05-01

In this project, we collaborate with researchers in the neuroscience department at the University of Delaware to develop an Field Programmable Gate Array (FPGA)-based embedded computer, inspired by the brains of small vertebrates (fish). The mechanisms of object detection and avoidance in fish have been extensively studied by our Delaware collaborators. The midbrain optic tectum is a biological multimodal navigation controller capable of processing input from all senses that convey spatial information, including vision, audition, touch, and lateral-line (water current sensing in fish). Unfortunately, computational complexity makes these models too slow for use in real-time applications. These simulations are run offline on state-of-the-art desktop computers, presenting a gap between the application and the target platform: a low-power embedded device. EM Photonics has expertise in developing of high-performance computers based on commodity platforms such as graphic cards (GPUs) and FPGAs. FPGAs offer (1) high computational power, low power consumption and small footprint (in line with typical autonomous vehicle constraints), and (2) the ability to implement massively-parallel computational architectures, which can be leveraged to closely emulate biological systems. Combining UD's brain modeling algorithms and the power of FPGAs, this computer enables autonomous navigation in complex environments, and further types of onboard neural processing in future applications.

Warionia (Asteraceae: a relict genus of Cichorieae?

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Katinas, Liliana

2008-12-01

Full Text Available The genus Warionia, with its only species W. saharae, is endemic to the northwestern edge of the African Sahara desert. This is a somewhat thistle-like aromatic plant, with white latex, and fleshy, pinnately- partite leaves. Warionia is in many respects so different from any other genus of Asteraceae, that it has been tentatively placed in the tribes Cardueae, Cichorieae, Gundelieae, and Mutisieae. Until now, a comprehensive study of Warionia to have a complete context for discussing its taxonomic position is lacking. The general morphology, anatomy, palynology and chromosome number of W. saharae are investigated here, and the species is described and illustrated. Laticifers in leaves and stems indicate a relationship with Cichorieae, and are associated with the phloem, in contact with it or with the surrounding sclerenchyma sheath. The pollen features indicate a strong relation with Cardueae, namely the structure with Anthemoid pattern where the columellae are joined to the foot layer, the ectosexine with thin columellae, the endosexine with stout and ramified columellae, the conspicuous spines with globose bases and conspicuous apical channels, and the tectum surface very perforate. Chromosomal counts resulted in 2n = 34. The morphological and palynological evidence positions Warionia between the tribes Cardueae and Cichorieae suggesting that it could be a remnant of the ancestral stock that gave rise to both tribes.El género Warionia, y su única especie, W. saharae, es endémico del noroeste del desierto africano del Sahara. Es una planta semejante a un cardo, aromática, con látex blanco y hojas carnosas, pinnatipartidas. Warionia es tan diferente de otros géneros de Asteraceae que fue ubicada en las tribus Cardueae, Cichorieae, Gundelieae y Mutisieae. Hasta ahora, no existía un estudio global de Warionia como contexto para discutir su posición taxonómica. Se ha investigado aquí su morfología, anatomía, palinología y n

Optimization of a GCaMP calcium indicator for neural activity imaging.

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Akerboom, Jasper; Chen, Tsai-Wen; Wardill, Trevor J; Tian, Lin; Marvin, Jonathan S; Mutlu, Sevinç; Calderón, Nicole Carreras; Esposti, Federico; Borghuis, Bart G; Sun, Xiaonan Richard; Gordus, Andrew; Orger, Michael B; Portugues, Ruben; Engert, Florian; Macklin, John J; Filosa, Alessandro; Aggarwal, Aman; Kerr, Rex A; Takagi, Ryousuke; Kracun, Sebastian; Shigetomi, Eiji; Khakh, Baljit S; Baier, Herwig; Lagnado, Leon; Wang, Samuel S-H; Bargmann, Cornelia I; Kimmel, Bruce E; Jayaraman, Vivek; Svoboda, Karel; Kim, Douglas S; Schreiter, Eric R; Looger, Loren L

2012-10-03

Genetically encoded calcium indicators (GECIs) are powerful tools for systems neuroscience. Recent efforts in protein engineering have significantly increased the performance of GECIs. The state-of-the art single-wavelength GECI, GCaMP3, has been deployed in a number of model organisms and can reliably detect three or more action potentials in short bursts in several systems in vivo. Through protein structure determination, targeted mutagenesis, high-throughput screening, and a battery of in vitro assays, we have increased the dynamic range of GCaMP3 by severalfold, creating a family of "GCaMP5" sensors. We tested GCaMP5s in several systems: cultured neurons and astrocytes, mouse retina, and in vivo in Caenorhabditis chemosensory neurons, Drosophila larval neuromuscular junction and adult antennal lobe, zebrafish retina and tectum, and mouse visual cortex. Signal-to-noise ratio was improved by at least 2- to 3-fold. In the visual cortex, two GCaMP5 variants detected twice as many visual stimulus-responsive cells as GCaMP3. By combining in vivo imaging with electrophysiology we show that GCaMP5 fluorescence provides a more reliable measure of neuronal activity than its predecessor GCaMP3. GCaMP5 allows more sensitive detection of neural activity in vivo and may find widespread applications for cellular imaging in general.

Mammal-like organization of the avian midbrain central gray and a reappraisal of the intercollicular nucleus.

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Marcy A Kingsbury

Full Text Available In mammals, rostrocaudal columns of the midbrain periaqueductal gray (PAG regulate diverse behavioral and physiological functions, including sexual and fight-or-flight behavior, but homologous columns have not been identified in non-mammalian species. In contrast to mammals, in which the PAG lies ventral to the superior colliculus and surrounds the cerebral aqueduct, birds exhibit a hypertrophied tectum that is displaced laterally, and thus the midbrain central gray (CG extends mediolaterally rather than dorsoventrally as in mammals. We therefore hypothesized that the avian CG is organized much like a folded open PAG. To address this hypothesis, we conducted immunohistochemical comparisons of the midbrains of mice and finches, as well as Fos studies of aggressive dominance, subordinance, non-social defense and sexual behavior in territorial and gregarious finch species. We obtained excellent support for our predictions based on the folded open model of the PAG and further showed that birds possess functional and anatomical zones that form longitudinal columns similar to those in mammals. However, distinguishing characteristics of the dorsal/dorsolateral PAG, such as a dense peptidergic innervation, a longitudinal column of neuronal nitric oxide synthase neurons, and aggression-induced Fos responses, do not lie within the classical avian CG, but in the laterally adjacent intercollicular nucleus (ICo, suggesting that much of the ICo is homologous to the dorsal PAG.

A dominance hierarchy of auditory spatial cues in barn owls.

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Ilana B Witten

2010-04-01

Full Text Available Barn owls integrate spatial information across frequency channels to localize sounds in space.We presented barn owls with synchronous sounds that contained different bands of frequencies (3-5 kHz and 7-9 kHz from different locations in space. When the owls were confronted with the conflicting localization cues from two synchronous sounds of equal level, their orienting responses were dominated by one of the sounds: they oriented toward the location of the low frequency sound when the sources were separated in azimuth; in contrast, they oriented toward the location of the high frequency sound when the sources were separated in elevation. We identified neural correlates of this behavioral effect in the optic tectum (OT, superior colliculus in mammals, which contains a map of auditory space and is involved in generating orienting movements to sounds. We found that low frequency cues dominate the representation of sound azimuth in the OT space map, whereas high frequency cues dominate the representation of sound elevation.We argue that the dominance hierarchy of localization cues reflects several factors: 1 the relative amplitude of the sound providing the cue, 2 the resolution with which the auditory system measures the value of a cue, and 3 the spatial ambiguity in interpreting the cue. These same factors may contribute to the relative weighting of sound localization cues in other species, including humans.

Quantitative Analysis of Axonal Branch Dynamics in the Developing Nervous System.

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Kelsey Chalmers

2016-03-01

Full Text Available Branching is an important mechanism by which axons navigate to their targets during neural development. For instance, in the developing zebrafish retinotectal system, selective branching plays a critical role during both initial pathfinding and subsequent arborisation once the target zone has been reached. Here we show how quantitative methods can help extract new information from time-lapse imaging about the nature of the underlying branch dynamics. First, we introduce Dynamic Time Warping to this domain as a method for automatically matching branches between frames, replacing the effort required for manual matching. Second, we model branch dynamics as a birth-death process, i.e. a special case of a continuous-time Markov process. This reveals that the birth rate for branches from zebrafish retinotectal axons, as they navigate across the tectum, increased over time. We observed no significant change in the death rate for branches over this time period. However, blocking neuronal activity with TTX slightly increased the death rate, without a detectable change in the birth rate. Third, we show how the extraction of these rates allows computational simulations of branch dynamics whose statistics closely match the data. Together these results reveal new aspects of the biology of retinotectal pathfinding, and introduce computational techniques which are applicable to the study of axon branching more generally.

ALDH1A3 loss of function causes bilateral anophthalmia/microphthalmia and hypoplasia of the optic nerve and optic chiasm.

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Yahyavi, Mani; Abouzeid, Hana; Gawdat, Ghada; de Preux, Anne-Sophie; Xiao, Tong; Bardakjian, Tanya; Schneider, Adele; Choi, Alex; Jorgenson, Eric; Baier, Herwig; El Sada, Mohamad; Schorderet, Daniel F; Slavotinek, Anne M

2013-08-15

The major active retinoid, all-trans retinoic acid, has long been recognized as critical for the development of several organs, including the eye. Mutations in STRA6, the gene encoding the cellular receptor for vitamin A, in patients with Matthew-Wood syndrome and anophthalmia/microphthalmia (A/M), have previously demonstrated the importance of retinol metabolism in human eye disease. We used homozygosity mapping combined with next-generation sequencing to interrogate patients with anophthalmia and microphthalmia for new causative genes. We used whole-exome and whole-genome sequencing to study a family with two affected brothers with bilateral A/M and a simplex case with bilateral anophthalmia and hypoplasia of the optic nerve and optic chiasm. Analysis of novel sequence variants revealed homozygosity for two nonsense mutations in ALDH1A3, c.568A>G, predicting p.Lys190*, in the familial cases, and c.1165A>T, predicting p.Lys389*, in the simplex case. Both mutations predict nonsense-mediated decay and complete loss of function. We performed antisense morpholino (MO) studies in Danio rerio to characterize the developmental effects of loss of Aldh1a3 function. MO-injected larvae showed a significant reduction in eye size, and aberrant axonal projections to the tectum were noted. We conclude that ALDH1A3 loss of function causes anophthalmia and aberrant eye development in humans and in animal model systems.

Targeted knock-in of CreER T2 in zebrafish using CRISPR/Cas9.

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Kesavan, Gokul; Hammer, Juliane; Hans, Stefan; Brand, Michael

2018-04-01

New genome-editing approaches, such as the CRISPR/Cas system, have opened up great opportunities to insert or delete genes at targeted loci and have revolutionized genetics in model organisms like the zebrafish. The Cre-loxp recombination system is widely used to activate or inactivate genes with high spatial and temporal specificity. Using a CRISPR/Cas9-mediated knock-in strategy, we inserted a zebrafish codon-optimized CreER T2 transgene at the otx2 gene locus to generate a conditional Cre-driver line. We chose otx2 as it is a patterning gene of the anterior neural plate that is expressed during early development. By knocking in CreER T2 upstream of the endogenous ATG of otx2, we utilized this gene's native promoter and enhancer elements to perfectly match CreER T2 and endogenous otx2 expression patterns. Next, by combining this novel driver line with a Cre-dependent reporter line, we show that only in the presence of tamoxifen can efficient Cre-loxp-mediated recombination be achieved in the anterior neural plate-derived tissues like the telencephalon, the eye and the optic tectum. Our results imply that the otx2:CreER T2 transgenic fish will be a valuable tool for lineage tracing and conditional mutant studies in larval and adult zebrafish.

Sporoderm development in Acer tataricum (Aceraceae): an interpretation.

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Gabarayeva, Nina I; Grigorjeva, Valentina V; Rowley, John R

2010-11-01

For the first time, the developmental events in the course of complicated exine structure establishment have been traced in detail with transmission electron microscope in the representative of Acer. A new look at unfolding events is suggested using the knowledge of a boundary field, colloid science. Our purpose was to find out whether the sequence of sporoderm developmental events represents, in essence, the sequence of self-assembling micellar mesophases, initiated by genomically given physicochemical parameters and induced by surfactant glycoproteins at increasing concentration. Indeed, the first units observed in the periplasmic space are globular ones (=spherical micelles) which become arranged into rod-like units (=cylindrical micelles). Then, twisted clusters of rodlets form a layer of procolumellae (middle micellar mesophase). The tectum emerges as an untwisting and merging of distal ends of procolumellae (distal untwist of micelle clusters). In the end of tetrad period, when a hydrophilic-hydrophobic switch occurs in the periplasmic space, the contrast reversal of the columellae corresponds to the change of normal micelles to reverse ones. The initiation of the foot layer and the endexine lamellae, with their typical central "white lines", corresponds to the next-"neat"-mesophase, with its typical central gaps between layers. Aperture sites during development show all the main micellar mesophases and their transitional forms. The data received have supported our previous hypothesis.

Cadmium affects retinogenesis during zebrafish embryonic development

International Nuclear Information System (INIS)

Hen Chow, Elly Suk; Yu Hui, Michelle Nga; Cheng, Chi Wa; Cheng, Shuk Han

2009-01-01

Ocular malformations are commonly observed in embryos of aquatic species after exposure to toxicants. Using zebrafish embryos as the model organism, we showed that cadmium exposure from sphere stage (4 hpf) to end of segmentation stage (24 hpf) induced microphthalmia in cadmium-treated embryos. Embryos with eye defects were then assessed for visual abilities. Cadmium-exposed embryos were behaviorally blind, showing hyperpigmentation and loss of camouflage response to light. We investigated the cellular basis of the formation of the small eyes phenotype and the induction of blindness by studying retina development and retinotectal projections. Retinal progenitors were found in cadmium-treated embryos albeit in smaller numbers. The number of retinal ganglion cells (RGC), the first class of retinal cells to differentiate during retinogenesis, was reduced, while photoreceptor cells, the last batch of retinal neurons to differentiate, were absent. Cadmium also affected the propagation of neurons in neurogenic waves. The neurons remained in the ventronasal area and failed to spread across the retina. Drastically reduced RGC axons and disrupted optic stalk showed that the optic nerves did not extend from the retina beyond the chiasm into the tectum. Our data suggested that impairment in neuronal differentiation of the retina, disruption in RGC axon formation and absence of cone photoreceptors were the causes of microphthalmia and visual impairment in cadmium-treated embryos

Functional morphology of the brain of the African giant pouched rat (Cricetomys gambianus Waterhouse, 1840

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Chikera S. Ibe

2014-03-01

Full Text Available A gross morphological study of the brain of the African giant pouched rat (Cricetomys gambianus Waterhouse, 1840 was undertaken in order to document its normal features and assess the structure-function paradigm. The study was conducted by direct observation of 29 adult African giant pouched rats’ brains. In the telencephalon, the cerebral cortex was devoid of prominent gyri and sulci, but the large olfactory bulb and tract relaying impulses to the olfactory cortex were very prominent. The large size of the olfactory bulb correlated with the established sharp olfactory acuity of the rodent. In the mesencephalic tectum, the caudal colliculi were bigger than the rostral colliculi, indicating a more acute sense of hearing than sight. In the metencephalon, the cerebellar vermis, the flocculus and the paraflocculus were highly coiled and, thus, well developed. The myelencephalon revealed a better organised ventral surface than dorsal surface; the cuneate fascicle, the intermediate sulcus and the lateral sulcus were not evident on the dorsal surface, but there were clearly visible pyramids and olivary prominence on the ventral surface. In conclusion, the highly coiled cerebellar vermis, flocculus and paraflocculus, as well as the conspicuous pyramids and olivary prominence are indicative of a good motor coordination and balance in the African giant pouched rat.

Vasoactive intestinal peptide binding sites and fibers in the brain of the pigeon Columba livia: An autoradiographic and immunohistochemical study

International Nuclear Information System (INIS)

Hof, P.R.; Dietl, M.M.; Charnay, Y.; Martin, J.L.; Bouras, C.; Palacios, J.M.; Magistretti, P.J.

1991-01-01

The distribution of vasoactive intestinal peptide (VIP) binding sites in the pigeon brain was examined by in vitro autoradiography on slide-mounted sections. A fully characterized monoiodinated form of VIP, which maintains the biological activity of the native peptide, was used throughout this study. The highest densities of binding sites were observed in the hyperstriatum dorsale, archistriatum, auditory field L of neostriatum, area corticoidea dorsolateralis and temporo-parieto-occipitalis, area parahippocampalis, tectum opticum, nucleus dorsomedialis anterior thalami, and in the periventricular area of the hypothalamus. Lower densities of specific binding occurred in the neostriatum, hyperstriatum ventrale and nucleus septi lateralis, dorsolateral area of the thalamus, and lateral and posteromedial hypothalamus. Very low to background levels of VIP binding were detected in the ectostriatum, paleostriatum primitivum, paleostriatum augmentatum, lobus parolfactorius, nucleus accumbens, most of the brainstem, and the cerebellum. The distribution of VIP-containing fibers and terminals was examined by indirect immunofluorescence using a polyclonal antibody against porcine VIP. Fibers and terminals were observed in the area corticoidea dorsolateralis, area parahippocampalis, hippocampus, hyperstriatum accessorium, hyperstriatum dorsale, archistriatum, tuberculum olfactorium, nuclei dorsolateralis and dorsomedialis of the thalamus, and throughout the hypothalamus and the median eminence. Long projecting fibers were visualized in the tractus septohippocampalis. In the brainstem VIP immunoreactive fibers and terminals were observed mainly in the substantia grisea centralis, fasciculus longitudinalis medialis, lemniscus lateralis, and in the area surrounding the nuclei of the 7th, 9th, and 10th cranial nerves

Contralateral Supracerebellar-Infratentorial Approach for Resection of Thalamic Cavernous Malformations.

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Mascitelli, Justin; Burkhardt, Jan-Karl; Gandhi, Sirin; Lawton, Michael T

2018-02-26

Surgical resection of cavernous malformations (CM) in the posterior thalamus, pineal region, and midbrain tectum is technically challenging owing to the presence of adjacent eloquent cortex and critical neurovascular structures. Various supracerebellar infratentorial (SCIT) approaches have been used in the surgical armamentarium targeting lesions in this region, including the median, paramedian, and extreme lateral variants. Surgical view of a posterior thalamic CM from the traditional ipsilateral vantage point may be obscured by occipital lobe and tentorium. To describe a novel surgical approach via a contralateral SCIT (cSCIT) trajectory for resecting posterior thalamic CMs. From 1997 to 2017, 75 patients underwent the SCIT approach for cerebrovascular/oncologic pathology by the senior author. Of these, 30 patients underwent the SCIT approach for CM resection, and 3 patients underwent the cSCIT approach. Historical patient data, radiographic features, surgical technique, and postoperative neurological outcomes were evaluated in each patient. All 3 patients presented with symptomatic CMs within the right posterior thalamus with radiographic evidence of hemorrhage. All surgeries were performed in the sitting position. There were no intraoperative complications. Neuroimaging demonstrated complete CM resection in all cases. There were no new or worsening neurological deficits or evidence of rebleeding/recurrence noted postoperatively. This study establishes the surgical feasibility of a contralateral SCIT approach in resection of symptomatic thalamic CMs It demonstrates the application for this procedure in extending the surgical trajectory superiorly and laterally and maximizing safe resectability of these deep CMs with gravity-assisted brain retraction.

Sense and antisense transcripts of the developmentally regulated murine hsp70.2 gene are expressed in distinct and only partially overlapping areas in the adult brain

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Murashov, A. K.; Wolgemuth, D. J.

1996-01-01

We have examined the spatial pattern of expression of a member of the hsp70 gene family, hsp70.2, in the mouse central nervous system. Surprisingly, RNA blot analysis and in situ hybridization revealed abundant expression of an 'antisense' hsp70.2 transcript in several areas of adult mouse brain. Two different transcripts recognized by sense and antisense riboprobes for the hsp70.2 gene were expressed in distinct and only partially overlapping neuronal populations. RNA blot analysis revealed low levels of the 2.7 kb transcript of hsp70.2 in several areas of the brain, with highest signal in the hippocampus. Abundant expression of a slightly larger (approximately 2.8 kb) 'antisense' transcript was detected in several brain regions, notably in the brainstem, cerebellum, mesencephalic tectum, thalamus, cortex, and hippocampus. In situ hybridization revealed that the sense and antisense transcripts were both predominantly neuronal and localized to the same cell types in the granular layer of the cerebellum, trapezoid nucleus of the superior olivary complex, locus coeruleus and hippocampus. The hsp70.2 antisense transcripts were particularly abundant in the frontal cortex, dentate gyrus, subthalamic nucleus, zona incerta, superior and inferior colliculi, central gray, brainstem, and cerebellar Purkinje cells. Our findings have revealed a distinct cellular and spatial localization of both sense and antisense transcripts, demonstrating a new level of complexity in the function of the heat shock genes.

Distribution of AMPA-type glutamate receptor subunits in the chick visual system

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Pires R.S.

1997-01-01

Full Text Available Several glutamate receptor (GluR subunits have been characterized during the past few years. In the present study, subunit-specific antisera were used to determine the distribution of the AMPA-type glutamate receptor subunits GluR1-4 in retinorecipient areas of the chick brain. Six white leghorn chicks (Gallus gallus, 7-15 days old, unknown sex were deeply anesthetized and perfused with 4% buffered paraformaldehyde and brain sections were stained using immunoperoxidase techniques. The AMPA-type glutamate receptor subunits GluR1, GluR2/3 and GluR4 were present in several retinorecipient areas, with varying degrees of colocalization. For example, perikarya in layers 2, 3, and 5 of the optic tectum contained GluR1, whereas GluR2/3 subunits appeared mainly in neurons of layer 13. The GluR4 subunit was only detected in a few cells of the tectal layer 13. GluR1 and GluR2/3 were observed in neurons of the nucleus geniculatus lateralis ventralis, whereas GluR4 was only present in its neuropil. Somata in the accessory optic nucleus appeared to contain GluR2/3 and GluR4, whereas GluR1 was the dominant subunit in the neuropil of this nucleus. These results suggest that different subpopulations of visual neurons might express different combinations of AMPA-type GluR subunits, which in turn might generate different synaptic responses to glutamate derived from retinal ganglion cell axons

Behavioral and neural lateralization of vision in courtship singing of the zebra finch.

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George, Isabelle; Hara, Erina; Hessler, Neal A

2006-09-01

Along with human speech and language processing, birdsong has been one of the best-characterized model systems for understanding the relationship of lateralization of brain function to behavior. Lateralization of song production has been extensively characterized, and lateralization of song perception has begun to be studied. Here we have begun to examine whether behavior and brain function are lateralized in relation to communicative aspects of singing, as well. In order to monitor central brain function, we assayed the levels of several activity dependent immediate early genes after directed courtship singing. Consistent with a lateralization of visual processing during communication, there were higher levels of expression of both egr-1 and c-fos in the left optic tectum after directed singing. Because input from the eyes to the brain is almost completely contralateral in birds, these results suggest that visual input from the right eye should be favored during normal singing to females. Consistent with this, we further found that males sang more when they could use only their right eye compared to when they could use only their left eye. Normal levels of singing, though, required free use of both eyes to view the female. These results suggest that there is a preference for visual processing by the right eye and left brain hemisphere during courtship singing. This may reflect a proposed specialization of the avian left hemisphere in sustaining attention on stimuli toward which a motor response is planned.

Goldfish Leptin-AI and Leptin-AII: Function and Central Mechanism in Feeding Control

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Ai-Fen Yan

2016-05-01

Full Text Available In mammals, leptin is a peripheral satiety factor that inhibits feeding by regulating a variety of appetite-related hormones in the brain. However, most of the previous studies examining leptin in fish feeding were performed with mammalian leptins, which share very low sequence homologies with fish leptins. To elucidate the function and mechanism of endogenous fish leptins in feeding regulation, recombinant goldfish leptin-AI and leptin-AII were expressed in methylotrophic yeast and purified by immobilized metal ion affinity chromatography (IMAC. By intraperitoneal (IP injection, both leptin-AI and leptin-AII were shown to inhibit the feeding behavior and to reduce the food consumption of goldfish in 2 h. In addition, co-treatment of leptin-AI or leptin-AII could block the feeding behavior and reduce the food consumption induced by neuropeptide Y (NPY injection. High levels of leptin receptor (lepR mRNA were detected in the hypothalamus, telencephalon, optic tectum and cerebellum of the goldfish brain. The appetite inhibitory effects of leptins were mediated by downregulating the mRNA levels of orexigenic NPY, agouti-related peptide (AgRP and orexin and upregulating the mRNA levels of anorexigenic cocaine-amphetamine-regulated transcript (CART, cholecystokinin (CCK, melanin-concentrating hormone (MCH and proopiomelanocortin (POMC in different areas of the goldfish brain. Our study, as a whole, provides new insights into the functions and mechanisms of leptins in appetite control in a fish model.

Evolution of brains and behavior for optimal foraging: A tale of two predators

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Catania, Kenneth C.

2012-01-01

Star-nosed moles and tentacled snakes have exceptional mechanosensory systems that illustrate a number of general features of nervous system organization and evolution. Star-nosed moles use the star for active touch—rapidly scanning the environment with the nasal rays. The star has the densest concentration of mechanoreceptors described for any mammal, with a central tactile fovea magnified in anatomically visible neocortical modules. The somatosensory system parallels visual system organization, illustrating general features of high-resolution sensory representations. Star-nosed moles are the fastest mammalian foragers, able to identify and eat small prey in 120 ms. Optimal foraging theory suggests that the star evolved for profitably exploiting small invertebrates in a competitive wetland environment. The tentacled snake’s facial appendages are superficially similar to the mole’s nasal rays, but they have a very different function. These snakes are fully aquatic and use tentacles for passive detection of nearby fish. Trigeminal afferents respond to water movements and project tentacle information to the tectum in alignment with vision, illustrating a general theme for the integration of different sensory modalities. Tentacled snakes act as rare enemies, taking advantage of fish C-start escape responses by startling fish toward their strike—often aiming for the future location of escaping fish. By turning fish escapes to their advantage, snakes increase strike success and reduce handling time with head-first captures. The latter may, in turn, prevent snakes from becoming prey when feeding. Findings in these two unusual predators emphasize the importance of a multidisciplinary approach for understanding the evolution of brains and behavior. PMID:22723352

Connections of the superior paraolivary nucleus of the rat: II. Reciprocal connections with the tectal longitudinal column

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Antonio eViñuela

2011-02-01

Full Text Available The superior paraolivary nucleus (SPON, a prominent GABAergic center of the mammalian auditory brainstem, projects to the ipsilateral inferior colliculus (IC and sends axons through the commissure of the IC (CoIC. Herein we demonstrate that the SPON is reciprocally connected with the recently discovered tectal longitudinal column (TLC. The TLC is a long and narrow structure that spans nearly the entire midbrain tectum longitudinally, immediately above the periaqueductal gray matter (PAG and very close to the midline.Unilateral injections of biotinylated dextran into the SPON of the rat label abundant terminal fibers in the TLC of both sides, with an ipsilateral predominance. The SPON provides a dense innervation of the entire rostrocaudal extent of the ipsilateral TLC, and a relatively sparser innervation of the caudal and rostral portions of the contralateral TLC. SPON fibers reach the TLC by two routes: as collaterals of axons of the CoIC, and as axons that circumvent the ipsilateral IC before traveling in the deep layers of the superior colliculus.The density of these projections identifies SPON as a significant source of input to the TLC. Other targets of the SPON discovered in this study include the deep layers of the superior colliculus and the PAG. The same experiments reveal numerous labeled cell bodies in the TLC, interspersed among the labeled SPON fibers. This observation suggests that the SPON is a significant target of TLC projections.The discovery of novel reciprocal connections between the SPON and the TLC opens unexpected avenues for investigation of sound processing in mammalian brainstem circuits.

Regenerating reptile retinas: a comparative approach to restoring retinal ganglion cell function.

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Williams, D L

2017-02-01

Transection or damage to the mammalian optic nerve generally results in loss of retinal ganglion cells by apoptosis. This cell death is seen less in fish or amphibians where retinal ganglion cell survival and axon regeneration leads to recovery of sight. Reptiles lie somewhere in the middle of this spectrum of nerve regeneration, and different species have been reported to have a significant variation in their retinal ganglion cell regenerative capacity. The ornate dragon lizard Ctenophoris ornatus exhibits a profound capacity for regeneration, whereas the Tenerife wall lizard Gallotia galloti has a more variable response to optic nerve damage. Some individuals regain visual activity such as the pupillomotor responses, whereas in others axons fail to regenerate sufficiently. Even in Ctenophoris, although the retinal ganglion cell axons regenerate adequately enough to synapse in the tectum, they do not make long-term topographic connections allowing recovery of complex visually motivated behaviour. The question then centres on where these intraspecies differences originate. Is it variation in the innate ability of retinal ganglion cells from different species to regenerate with functional validity? Or is it variances between different species in the substrate within which the nerves regenerate, the extracellular environment of the damaged nerve or the supporting cells surrounding the regenerating axons? Investigations of retinal ganglion cell regeneration between different species of lower vertebrates in vivo may shed light on these questions. Or perhaps more interesting are in vitro studies comparing axon regeneration of retinal ganglion cells from various species placed on differing substrates.

Neurogenesis in the brain stem of the rabbit: an autoradiographic study

International Nuclear Information System (INIS)

Oblinger, M.M.; Das, G.D.

1981-01-01

With the aid of ( 3 H)-thymidine autoradiography, neurogenesis was documented in the nuclear groups of the medulla oblongata, pons, and mid-brain, as well as in the brain stem reticular formation of the rabbit. Following single injections of ( 3 H)-thymidine, counts were taken of intensely labeled neurons within the nuclei of the functional columns related to the cranial nerves, nuclei of several other functional classifications, and nuclei that did not fit into a functional category. In the brain stem as a whole, neurogenesis was found to occur between days 10.0 and 18.5 of gestation: however, the majority of nuclei studied contained intensely neurons only between days 12.0 and 15.0. Only in the pontine nucleus and the tectum were intensely labeled cells observed as late as day 18.5. Directional gradients of histogenesis were often observed within, as well as between, various nuclei. Within the nuclear columns related to the cranial nerves, a clear mediolateral spread of neurogenesis was observable such that nuclei of the motor columns reached a peak in neurogenesis before those in the sensory columns. Likewise, a mediolateral proliferation pattern was seen in the brain stem reticular formation. Other individual directional gradients were discernible; however, in the brain stem as a whole, distinct overall gradients were not observable. In many individual nuclei, gradients in neuron size were observed such that large neurons preferentially arose prior to smaller neurons. Information pertaining to gradients in neurogenesis, as well as to relationships among functionally related nuclei, are discussed

Distribution of FMRFamide-like immunoreactivity in the brain, retina and nervus terminalis of the sockeye salmon parr, Oncorhynchus nerka.

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Ostholm, T; Ekström, P; Ebbesson, S O

1990-09-01

Neurons displaying FMRFamide(Phe - Met - Arg - Phe - NH2)-like immunoreactivity have recently been implicated in neural plasticity in salmon. We now extend these findings by describing the extent of the FMRF-like immunoreactive (FMRF-IR) system in the brain, retina and olfactory system of sockeye salmon parr using the indirect peroxidase anti-peroxidase technique. FMRF-IR perikarya were found in the periventricular hypothalamus, mesencephalic laminar nucleus, nucleus nervi terminalis and retina (presumed amacrine cells), and along the olfactory nerves. FMRF-IR fibers were distributed throughout the brain with highest densities in the ventral area of the telencephalon, in the medial forebrain bundle, and at the borders between layers III/IV and IV/V in the optic tectum. High densities of immunoreactive fibers were also observed in the area around the torus semicircularis, in the medial hypothalamus, median raphe, ventromedial tegmentum, and central gray. In the retina, immunopositive fibers were localized to the inner plexiform layer, but several fiber elements were also found in the outer plexiform layer. The olfactory system displayed FMRF-IR fibers in the epithelium and along the olfactory nerves. These findings differ from those reported in other species as follows: (i) FMRF-IR cells in the retina have not previously been reported in teleosts; (ii) the presence of FMRF-IR fibers in the outer plexiform layer of the retina is a new finding for any species; (iii) the occurrence of immunopositive cells in the mesencephalic laminar nucleus has to our knowledge not been demonstrated previously.

Selective attention without a neocortex.

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Krauzlis, Richard J; Bogadhi, Amarender R; Herman, James P; Bollimunta, Anil

2018-05-01

Selective attention refers to the ability to restrict neural processing and behavioral responses to a relevant subset of available stimuli, while simultaneously excluding other valid stimuli from consideration. In primates and other mammals, descriptions of this ability typically emphasize the neural processing that takes place in the cerebral neocortex. However, non-mammals such as birds, reptiles, amphibians and fish, which completely lack a neocortex, also have the ability to selectively attend. In this article, we survey the behavioral evidence for selective attention in non-mammals, and review the midbrain and forebrain structures that are responsible. The ancestral forms of selective attention are presumably selective orienting behaviors, such as prey-catching and predator avoidance. These behaviors depend critically on a set of subcortical structures, including the optic tectum (OT), thalamus and striatum, that are highly conserved across vertebrate evolution. In contrast, the contributions of different pallial regions in the forebrain to selective attention have been subject to more substantial changes and reorganization. This evolutionary perspective makes plain that selective attention is not a function achieved de novo with the emergence of the neocortex, but instead is implemented by circuits accrued and modified over hundreds of millions of years, beginning well before the forebrain contained a neocortex. Determining how older subcortical circuits interact with the more recently evolved components in the neocortex will likely be crucial for understanding the complex properties of selective attention in primates and other mammals, and for identifying the etiology of attention disorders. Published by Elsevier Ltd.

cDNA cloning of chicken orexin receptor and tissue distribution: sexually dimorphic expression in chicken gonads.

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Ohkubo, T; Tsukada, A; Shamoto, K

2003-12-01

Orexin-A and -B are known to stimulate food intake in mammals. However, the critical roles of orexins in birds are not fully understood, since orexins have no stimulatory effect on food intake in the chicken. To understand the physiological role(s) of orexins in birds, we have cloned chicken orexin receptor (cOXR) cDNA by RT-PCR, and analysed the tIssue distribution of OXR mRNA in the chicken. The cOXR cDNA is 1869 bp long and encodes 501 amino acids. The cloned cDNA for cOXR corresponds to the type 2 OXR in mammals, and shows approximately 80% similarity to those of mammals at the amino acid level. Expression analysis by RNase protection assay revealed OXR mRNA was distributed widely in brain regions, and expression in the cerebrum, hypothalamus and optic tectum were abundant. In peripheral tIssues, OXR mRNA was expressed in the pituitary gland, adrenal gland and testis, but no mRNA expression was observed in other tIssues examined. Furthermore, we found that the amount of cOXR mRNA was different between testis and ovary, while prepro-orexin mRNA is equally expressed in the gonads of both sexes in the chicken. These data indicate that the orexins have neuroendocrine actions in chickens, which are mediated through hypothalamic receptors as has been observed in mammals. In addition, orexin may have specific role(s) in the regulation of gonadal function in which sex-dependent mechanisms could be involved.

Multiple spectral channels in branchiopods. I. Vision in dim light and neural correlates.

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Lessios, Nicolas; Rutowski, Ronald L; Cohen, Jonathan H; Sayre, Marcel E; Strausfeld, Nicholas J

2018-05-22

Animals that have true color vision possess several spectral classes of photoreceptors. Pancrustaceans (Hexapoda+Crustacea) that integrate spectral information about their reconstructed visual world do so from photoreceptor terminals supplying their second optic neuropils, with subsequent participation of the third (lobula) and deeper centers (optic foci). Here, we describe experiments and correlative neural arrangements underlying convergent visual pathways in two species of branchiopod crustaceans that have to cope with a broad range of spectral ambience and illuminance in ephemeral pools, yet possess just two optic neuropils, the lamina and the optic tectum. Electroretinographic recordings and multimodel inference based on modeled spectral absorptance were used to identify the most likely number of spectral photoreceptor classes in their compound eyes. Recordings from the retina provide support for four color channels. Neuroanatomical observations resolve arrangements in their laminas that suggest signal summation at low light intensities, incorporating chromatic channels. Neuroanatomical observations demonstrate that spatial summation in the lamina of the two species are mediated by quite different mechanisms, both of which allow signals from several ommatidia to be pooled at single lamina monopolar cells. We propose that such summation provides sufficient signal for vision at intensities equivalent to those experienced by insects in terrestrial habitats under dim starlight. Our findings suggest that despite the absence of optic lobe neuropils necessary for spectral discrimination utilized by true color vision, four spectral photoreceptor classes have been maintained in Branchiopoda for vision at very low light intensities at variable ambient wavelengths that typify conditions in ephemeral freshwater habitats. © 2018. Published by The Company of Biologists Ltd.

Rapid behavioral and genomic responses to social opportunity.

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Sabrina S Burmeister

2005-11-01

Full Text Available From primates to bees, social status regulates reproduction. In the cichlid fish Astatotilapia (Haplochromis burtoni, subordinate males have reduced fertility and must become dominant to reproduce. This increase in sexual capacity is orchestrated by neurons in the preoptic area, which enlarge in response to dominance and increase expression of gonadotropin-releasing hormone 1 (GnRH1, a peptide critical for reproduction. Using a novel behavioral paradigm, we show for the first time that subordinate males can become dominant within minutes of an opportunity to do so, displaying dramatic changes in body coloration and behavior. We also found that social opportunity induced expression of the immediate-early gene egr-1 in the anterior preoptic area, peaking in regions with high densities of GnRH1 neurons, and not in brain regions that express the related peptides GnRH2 and GnRH3. This genomic response did not occur in stable subordinate or stable dominant males even though stable dominants, like ascending males, displayed dominance behaviors. Moreover, egr-1 in the optic tectum and the cerebellum was similarly induced in all experimental groups, showing that egr-1 induction in the anterior preoptic area of ascending males was specific to this brain region. Because egr-1 codes for a transcription factor important in neural plasticity, induction of egr-1 in the anterior preoptic area by social opportunity could be an early trigger in the molecular cascade that culminates in enhanced fertility and other long-term physiological changes associated with dominance.

Organization of the orexin/hypocretin system in the brain of two basal actinopterygian fishes, the cladistians Polypterus senegalus and Erpetoichthys calabaricus.

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López, Jesús M; Sanz-Morello, Berta; González, Agustín

2014-11-01

Cladistians are primitive actinopterygian fishes mostly neglected in neuroanatomical studies. In the present study, the detailed neuroanatomical distribution of orexin (hypocretin)-like immunoreactive (OX-ir) cell bodies and fibers was analyzed in the brain of two species representative of the two extant genera of cladistians. Antibodies against mammalian orexin-A and orexin-B peptides were used. Simultaneous detection of orexins with neuropeptide Y (NPY), tyrosine hydroxylase (TH), and serotonin (5-HT) was used to establish accurately the topography of the orexin system and to evaluate the possible interactions with NPY and monoaminergic systems. A largely common pattern of OX-ir distribution in the two cladistian species was observed. Most OX-ir cells were located in the suprachiasmatic nucleus and tuberal hypothalamus, whereas scarce cells were observed in the posterior tubercle. In addition, a population of OX-ir cells was found in the preoptic area only in Polypterus and some cells also contained TH. The observed widespread distribution of OX-ir fibers was especially abundant in the retrobulbar area, subpallial areas, preoptic area, suprachiasmatic nucleus, tuberal hypothalamic area, prethalamus, thalamus, pretectum, optic tectum, and tegmentum. Low innervation was found in relation to monoaminergic cell groups, whereas a high NPY innervation was observed in all OX-ir cell groups. These relationships would represent the anatomical substrate for the functional interdependence between these systems. The organization of the orexin system in cladistians revealed a pattern largely consistent with those reported for all studied groups of vertebrates, suggesting that the primitive organization of this peptidergic system occurred in the common ancestor of gnathostome vertebrates. Copyright © 2014 Elsevier Inc. All rights reserved.

Effects of silver nanoparticles on the development and histopathology biomarkers of Japanese medaka (Oryzias latipes) using the partial-life test.

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Wu, Yuan; Zhou, Qunfang; Li, Hongcheng; Liu, Wei; Wang, Thanh; Jiang, Guibin

2010-10-15

Silver nanoparticles (AgNPs) have emerged as an important class of nanomaterials and are currently used in a wide range of industrial and commercial applications. This has caused increasing concern about their effects on the environment and to human health. Using Japanese medaka (Oryzias latipes) at early-life stages as experimental models, the developmental toxicity of silver nanoparticles was investigated following exposure to 100-1000 μg/L homogeneously dispersed AgNPs for 70 days, and developmental endpoints were evaluated by microscopy during embryonic, larval and juvenile stages of development in medaka. Meanwhile, histopathological changes in the larval eye were evaluated. Retarded development and reduced pigmentation were observed in the treated embryos by AgNPs at high concentrations (≥ 400 μg/L). Maximum width of the optic tectum, as an indicator of midbrain development, decreased significantly in a dose-related manner. Furthermore, silver nanoparticles exposure at all concentrations induced a variety of morphological malformations such as edema, spinal abnormalities, finfold abnormalities, heart malformations and eye defects. Histopathological observations also confirmed the occurrence of abnormal eye development induced by AgNPs. The data showed non-linear or U-shaped dose-response patterns for growth retardation at 5 days of postfertilization, as well as the incidence of abnormalities. Preliminary results suggested that the developmental process of medaka may be affected by exposure to silver nanoparticles. Morphological abnormalities in early-life stages of medaka showed the potential developmental toxicities of silver nanoparticles. Further research should be focused on the mechanisms of developmental toxicity in fish exposed to silver nanoparticles. Crown Copyright 2009. Published by Elsevier B.V. All rights reserved.

The mesencephalic GCt-ICo complex and tonic immobility in pigeons (Columba livia): a c-Fos study.

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Melleu, Fernando Falkenburger; Lino-de-Oliveira, C; Marino-Neto, J

2017-04-01

Tonic immobility (TI) is a response to a predator attack, or other inescapable danger, characterized by immobility, analgesia and unresponsiveness to external stimuli. In mammals, the periaqueductal gray (PAG) and deep tectal regions control the expression of TI as well as other defensive behaviors. In birds, little is known about the mesencephalic circuitry involved in the control of TI. Here, adult pigeons (both sex, n = 4/group), randomly assigned to non-handled, handled or TI groups, were killed 90 min after manipulations and the brains processed for detection of c-Fos immunoreactive cells (c-Fos-ir, marker for neural activity) in the mesencephalic central gray (GCt) and the adjacent nucleus intercollicularis (ICo). The NADPH-diaphorase staining delineated the boundaries of the sub nuclei in the ICo-GCt complex. Compared to non-handled, TI (but not handling) induced c-Fos-ir in NADPH-diaphorase-rich and -poor regions. After TI, the number of c-Fos-ir increased in the caudal and intermediate areas of the ICo (but not in the GCt), throughout the rostrocaudal axis of the dorsal stratum griseum periventriculare (SGPd) of the optic tectum and in the n. mesencephalicus lateralis pars dorsalis (MLd), which is part of the ascending auditory pathway. These data suggest that inescapable threatening stimuli such as TI may recruit neurons in discrete areas of ICo-GCt complex, deep tectal layer and in ascending auditory circuits that may control the expression of defensive behaviors in pigeons. Additionally, data indicate that the contiguous deep tectal SCPd (but not GCt) in birds may be functionally comparable to the mammalian dorsal PAG.

Magnetic Resonance Imaging of a Case of Central Neurocytoma.

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Dedushi, Kreshnike; Kabashi, Serbeze; Ugurel, Mehmet Sahin; Ramadani, Naser; Mucaj, Sefedin; Zeqiraj, Kamber

2016-12-01

The purpose of this study is to investigate the MRI features of central neurocytoma. A 45 year old man with 3 months of worsening daily headaches. These headaches were diffuse, lasted for several hours, and mostly occurred in the morning. She was initially diagnosed and treated for migraines but later he had epileptic attack and diplopia and neurolog recomaded MRI. precontrast MRI; TSE/T2Wsequence in axial/coronal planes; 3D-Hi-resolution T1W sagittal; FLAIR/T2W axial; FLAIR/T2W and Flash/T2W oblique coronal plane (perpendicular to temporal lobes) GRE/T2W axial plane for detection of heme products. Post-contrast TSE/T1W sequence in axial, coronal and sagittal planes. Diffusion weighted and ADC mapping MRI images for EPI sequence in axial plane. A 23x12mm heterogeneous mass within aqueductus cerebri, with calcified and hemorrhagic foci and extending downwards till fourth ventricle. It's originating from the right paramedian posterior aqueductal wall (tectum), and also extending to and involving the tegmentum of mesencephalon at its right paramedian aspect. CSF flow obstruction secondary to described aqueductal mass, with resultant triventricular hydrocephalus). Marked transependymal CSF leak can be noted at periventricular white matter, secondary to severe hydrocephalus. After IV injection of contrast media, this mass shows mild-to-moderate heterogenous speckled enhancement. MRI is helpful in defining tumor extension, which is important in preoperative planning. Although IN is a relatively rare lesion, it should be considered in the differential diagnosis of intraventricular lesions in the presence of such typical MR findings. However, a definitive diagnosis requires immunochemical study and electron microscopy.

Intracranial structures of meningomyelocels studied by computed tomography

Energy Technology Data Exchange (ETDEWEB)

Asada, M.; Tamaki, N.; Matsumoto, S. (Kobe Univ. (Japan). School of Medicine)

1980-10-01

We have had experience with forty-two patients with meningomyeloceles; their intracranial structures have been studied and analysed by CT. Six patients (16%) revealed no abnormalities, while thirty-six (82%) had hydrocephalus. All the cases have undergone repair of the meningomyelocele, and thirty-five parties, a shunt operation for hydrocephalus. The CT analysis of the intracranial structures of the meningomyelocele revealed that scaphocephalus was present in 40%, posteriorly dominant ventricular dilatation in the lateral ventricle in 73%, and enlarged massa intermedia in 54%. The following postoperative changes were found: sharp edges of the anterior and posterior horns were found in 81%, prominent dilatation of quadrigeminal and retrothalamic cisterns in 76%, and the interdigitation of the medial cerebral cortex in 69%. In the posterior fossa, a hypoplastic cerebellar tentorium was found in 70% of the cases and a pear-shaped deformity of the upper cerebellum in 62%. The brain stem was enclosed laterally by the anteriorly situated ventral portion of the cerebellum in 74%, and the fourth ventricle was collapsed or narrowed in 76%. An absence of the septum pellucidum was associated in six cases; a quadrigeminal cyst, in two, and a cavum septi pellucidum, in one. CT is a useful and safe apparatus for evaluating the intracranial structures of Arnold-Chiari malformations. Trivial morphological changes, such as the ectopic gray matter, beaking tectum, enlarged accessory commissure, and aqueduct stenosis observed in autopsy cases, are still impossible to demonstrate on CT. It is, however, hoped that with the improvement of the CT image, the sagittal image will become more precise for evaluating the downward displacement of the brain stem and the fourth ventricle.

Intracranial structures of meningomyelocels studied by computed tomography

International Nuclear Information System (INIS)

Asada, Masahiro; Tamaki, Norihiko; Matsumoto, Satoshi

1980-01-01

We have had experience with forty-two patients with meningomyeloceles; their intracranial structures have been studied and analysed by CT. Six patients (16%) revealed no abnormalities, while thirty-six (82%) had hydrocephalus. All the cases have undergone repair of the meningomyelocele, and thirty-five parties, a shunt operation for hydrocephalus. The CT analysis of the intracranial structures of the meningomyelocele revealed that scaphocephalus was present in 40%, posteriorly dominant ventricular dilatation in the lateral ventricle in 73%, and enlarged massa intermedia in 54%. The following postoperative changes were found: sharp edges of the anterior and posterior horns were found in 81%, prominent dilatation of quadrigeminal and retrothalamic cisterns in 76%, and the interdigitation of the medial cerebral cortex in 69%. In the posterior fossa, a hypoplastic cerebellar tentorium was found in 70% of the cases and a pear-shaped deformity of the upper cerebellum in 62%. The brain stem was enclosed laterally by the anteriorly situated ventral portion of the cerebellum in 74%, and the fourth ventricle was collapsed or narrowed in 76%. An absence of the septum pellucidum was associated in six cases; a quadrigeminal cyst, in two, and a cavum septi pellucidum, in one. CT is a useful and safe apparatus for evaluating the intracranial structures of Arnold-Chiari malformations. Trivial morphological changes, such as the ectopic gray matter, beaking tectum, enlarged accessory commissure, and aqueduct stenosis observed in autopsy cases, are still impossible to demonstrate on CT. It is, however, hoped that with the improvement of the CT image, the sagittal image will become more precise for evaluating the downward displacement of the brain stem and the fourth ventricle. (author)

Brain Mapping of Ghrelin O-Acyltransferase in Goldfish (Carassius Auratus): Novel Roles for the Ghrelinergic System in Fish?

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Blanco, Ayelén M; Sánchez-Bretaño, Aída; Delgado, María J; Valenciano, Ana I

2016-06-01

Ghrelin O-acyltransferase (GOAT) is the enzyme responsible for acylation of ghrelin, a gut-brain hormone with important roles in many physiological functions in vertebrates. Many aspects of GOAT remain to be elucidated, especially in fish, and particularly its anatomical distribution within the different brain areas has never been reported to date. The present study aimed to characterize the brain mapping of GOAT using RT-qPCR and immunohistochemistry in a teleost, the goldfish (Carassius auratus). Results show that goat transcripts are expressed in different brain areas of the goldfish, with the highest levels in the vagal lobe. Using immunohistochemistry, we also report the presence of GOAT immunoreactive cells in different encephalic areas, including the telencephalon, some hypothalamic nuclei, pineal gland, optic tectum and cerebellum, although they are especially abundant in the hindbrain. Particularly, an important signal is observed in the vagal lobe and some fiber tracts of the brainstem, such as the medial longitudinal fasciculus, Mauthneri fasciculus, secondary gustatory tract and spinothalamic tract. Most of the forebrain areas where GOAT is detected, particularly the hypothalamic nuclei, also express the ghs-r1a ghrelin receptor and other appetite-regulating hormones (e.g., orexin and NPY), supporting the role of ghrelin as a modulator of food intake and energy balance in fish. Present results are the first report on the presence of GOAT in the brain using imaging techniques. The high presence of GOAT in the hindbrain is a novelty, and point to possible new functions for the ghrelinergic system in fish. Anat Rec, 299:748-758, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

NOGO-A induction and localization during chick brain development indicate a role disparate from neurite outgrowth inhibition

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Liwnicz Boleslaw H

2007-04-01

Full Text Available Abstract Background Nogo-A, a myelin-associated protein, inhibits neurite outgrowth and abates regeneration in the adult vertebrate central nervous system (CNS and may play a role in maintaining neural pathways once established. However, the presence of Nogo-A during early CNS development is counterintuitive and hints at an additional role for Nogo-A beyond neurite inhibition. Results We isolated chicken NOGO-A and determined its sequence. A multiple alignment of the amino acid sequence across divergent species, identified five previously undescribed, Nogo-A specific conserved regions that may be relevant for development. NOGO gene transcripts (NOGO-A, NOGO-B and NOGO-C were differentially expressed in the CNS during development and a second NOGO-A splice variant was identified. We further localized NOGO-A expression during key phases of CNS development by in situ hybridization. CNS-associated NOGO-A was induced coincident with neural plate formation and up-regulated by FGF in the transformation of non-neural ectoderm into neural precursors. NOGO-A expression was diffuse in the neuroectoderm during the early proliferative phase of development, and migration, but localized to large projection neurons of the optic tectum and tectal-associated nuclei during architectural differentiation, lamination and network establishment. Conclusion These data suggest Nogo-A plays a functional role in the determination of neural identity and/or differentiation and also appears to play a later role in the networking of large projection neurons during neurite formation and synaptogenesis. These data indicate that Nogo-A is a multifunctional protein with additional roles during CNS development that are disparate from its later role of neurite outgrowth inhibition in the adult CNS.

Extensive distribution of glial cytoplasmic inclusions in an autopsied case of multiple system atrophy with a prolonged 18-year clinical course.

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Masui, Kenta; Nakata, Yukako; Fujii, Naoki; Iwaki, Toru

2012-02-01

We describe herein an autopsied case of multiple system atrophy (MSA) with prolonged clinical course of 18 years, and evaluate the extent of neurodegeneration and glial cytoplasmic inclusions (GCIs) in the entire brain of this rare case. A 64-year-old woman presented with typical neurological symptoms and imaging features of MSA. Thereafter, she became bedridden, and breathing was assisted through a tracheostomy for 12 years. She died at the age of 82 after 18 years from the initial symptom. Post mortem examination revealed severe neurodegeneration in the inferior olive, pontine nuclei, substantia nigra, locus ceruleus, putamen and cerebellum. Notably, phosphorylated α-synuclein (p-α-syn)-positive GCIs were found in these areas, but their number was very low. In contrast, the density of GCIs was much higher in such regions as the tectum/tegmentum of the brainstem, pyramidal tracts, neocortices and limbic system, which usually contain a small number of GCIs. Another constituent of GCIs, ubiquitin (Ub) and Ub-associated autophagy substrate p62, were also positive in some GCIs, and distribution of Ub/p62 immunoreactivity was proportionate to that of p-α-syn+ GCIs despite the very long duration of the disease. Furthermore, this case had complicated hypoxic encephalopathy, but p-α-syn+ GCIs were also found in the damaged white matter, indicating the contribution of α-syncleinopathy as well as hypoxic effect to the secondary myelin and axonal loss in the white matter. Together, this rare case suggests the contribution of the disease duration to the prevalence of GCIs, and the possible involvement of the limbic system in extensive-stage disease. © 2011 Japanese Society of Neuropathology.

Distribution of mu, delta, and kappa opioid receptor binding sites in the brain of the one-day-old domestic chick (Gallus domesticus): An in vitro quantitative autoradiographic study

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Csillag, A.; Bourne, R.C.; Stewart, M.G. (Open Univ., Milton Keynes (England))

1990-12-15

Three highly specific opioid ligands--(D-Ala2,Gly-ol)-enkephalin (DAGO) for mu (mu) receptor sites, (D-Pen2,D-Pen5)-enkephalin (DPDPE) for delta (delta) sites, and U-69593 for kappa (kappa) sites--were used to determine the regional distribution of the three major subtypes of opioid receptor binding sites in the brains of 1-day-old domestic chicks by the technique of quantitative receptor autoradiography. While there was a degree of heterogeneity in the binding levels of each of the ligands, some notable similarities existed in the binding of the mu and kappa ligands in several forebrain regions, and in the optic tectum of the midbrain where mu and delta binding was very high. In the forebrain there was a high level of binding of mu and kappa ligands in the hyperstriatum, and for the mu ligand there was a very distinct lamination of binding sites in hyperstriatum accessorium, intercalatum supremum, dorsale and ventrale. Levels of binding of the mu and kappa ligands were also high in nucleus basalis, and (for mu only) in the neostriatum. The distribution of binding of the delta specific ligand in the forebrain showed marked differences to that of mu and kappa, being particularly low in the hyperstriatum and neostriatum. Very high levels of labelling of delta binding sites were, however, found in the nucleus rotundus. Binding of the three ligands was generally low or absent in the cerebellum and medulla, apart from a distinct labelling of the granule cell layer by the mu-ligand. A kinetic analysis was made of the binding of the three ligands to whole forebrain sections using scintillation counting methods.

Localization of rem2 in the central nervous system of the adult rainbow trout (Oncorhynchus mykiss).

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Downs, Anna G; Scholles, Katie R; Hollis, David M

2016-12-01

Rem2 is member of the RGK (Rem, Rad, and Gem/Kir) subfamily of the Ras superfamily of GTP binding proteins known to influence Ca 2+ entry into the cell. In addition, Rem2, which is found at high levels in the vertebrate brain, is also implicated in cell proliferation and synapse formation. Though the specific, regional localization of Rem2 in the adult mammalian central nervous system has been well-described, such information is lacking in other vertebrates. Rem2 is involved in neuronal processes where the capacities between adults of different vertebrate classes vary. Thus, we sought to localize the rem2 gene in the central nervous system of an adult anamniotic vertebrate, the rainbow trout (Oncorhynchus mykiss). In situ hybridization using a digoxigenin (DIG)-labeled RNA probe was used to identify the regional distribution of rem2 expression throughout the trout central nervous system, while real-time polymerase chain reaction (rtPCR) further supported these findings. Based on in situ hybridization, the regional distribution of rem2 occurred within each major subdivision of the brain and included large populations of rem2 expressing cells in the dorsal telencephalon of the cerebrum, the internal cellular layer of the olfactory bulb, and the optic tectum of the midbrain. In contrast, no rem2 expressing cells were resolved within the cerebellum. These results were corroborated by rtPCR, where differential rem2 expression occurred between the major subdivisions assayed with the highest levels being found in the cerebrum, while it was nearly absent in the cerebellum. These data indicate that rem2 gene expression is broadly distributed and likely influences diverse functions in the adult fish central nervous system. Copyright © 2016 Elsevier B.V. All rights reserved.

Anatomical specializations for nocturnality in a critically endangered parrot, the Kakapo (Strigops habroptilus.

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Jeremy R Corfield

Full Text Available The shift from a diurnal to nocturnal lifestyle in vertebrates is generally associated with either enhanced visual sensitivity or a decreased reliance on vision. Within birds, most studies have focused on differences in the visual system across all birds with respect to nocturnality-diurnality. The critically endangered Kakapo (Strigops habroptilus, a parrot endemic to New Zealand, is an example of a species that has evolved a nocturnal lifestyle in an otherwise diurnal lineage, but nothing is known about its' visual system. Here, we provide a detailed morphological analysis of the orbits, brain, eye, and retina of the Kakapo and comparisons with other birds. Morphometric analyses revealed that the Kakapo's orbits are significantly more convergent than other parrots, suggesting an increased binocular overlap in the visual field. The Kakapo exhibits an eye shape that is consistent with other nocturnal birds, including owls and nightjars, but is also within the range of the diurnal parrots. With respect to the brain, the Kakapo has a significantly smaller optic nerve and tectofugal visual pathway. Specifically, the optic tectum, nucleus rotundus and entopallium were significantly reduced in relative size compared to other parrots. There was no apparent reduction to the thalamofugal visual pathway. Finally, the retinal morphology of the Kakapo is similar to that of both diurnal and nocturnal birds, suggesting a retina that is specialised for a crepuscular niche. Overall, this suggests that the Kakapo has enhanced light sensitivity, poor visual acuity and a larger binocular field than other parrots. We conclude that the Kakapo possesses a visual system unlike that of either strictly nocturnal or diurnal birds and therefore does not adhere to the traditional view of the evolution of nocturnality in birds.

A new saurichthyiform (Actinopterygii with a crushing feeding mechanism from the Middle Triassic of Guizhou (China.

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Feixiang Wu

Full Text Available Equipped with an effective predatory feeding mechanism enhanced by large and sharp teeth, pointed snout and elongate body, saurichthyiform fishes are considered common fish-eaters in the early Mesozoic aquatic ecosystems. Additionally, because of the similar body plan across species, saurichthyiforms are also regarded evolutionally conservative, with few morphological and ecological changes during their long history. However, their phylogenetic affinity remains unclear as to whether they are chondrostean, neopterygian or stem-actinopteran, and likewise the intrarelationships of the group have rarely been explored.Here we report a new saurichthyiform from the Middle Triassic of Guizhou, China, based on the well-preserved specimens including a 3-D braincase. The new taxon, Yelangichthys macrocephalus gen. et sp. nov., is unique among saurichthyiforms in having a peculiar neurocranium with a broad orbital tectum, paired posterior myodomes, a deep, transverse fossa in the posterodorsal part of the orbit, and a feeding mechanism structured for durophagy. Phylogenetic analysis places Yelangichthys gen. nov. at the most basal position in the Saurichthyiformes as the sister to Saurichthyidae, and a new family Yelangichthyidae is erected to include only Y. macrocephalus gen. et sp. nov. The monophyly of the Chondrostei comprising [Saurichthyiformes + Acipenseriformes] Birgeriiformes is supported, but not the monophyly of Saurichthys, the type genus of Saurichthyidae. With its outstanding osteological details, Yelangichthys gen. nov. greatly increases the neurocranial variations in saurichthyiforms, and its novel feeding structure suggests the consumption of hard-preys instead of fishes.Our findings highlight the detailed osteology of a saurichthyiform braincase and its feeding design. We suggest that saurichthyiforms are closely allied to the Acipenseriformes. Saurichthyiforms were very diverse in the cranial osteology and they might have undergone a

A New Saurichthyiform (Actinopterygii) with a Crushing Feeding Mechanism from the Middle Triassic of Guizhou (China)

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Wu, Feixiang; Chang, Mee-mann; Sun, Yuanlin; Xu, Guanghui

2013-01-01

Background Equipped with an effective predatory feeding mechanism enhanced by large and sharp teeth, pointed snout and elongate body, saurichthyiform fishes are considered common fish-eaters in the early Mesozoic aquatic ecosystems. Additionally, because of the similar body plan across species, saurichthyiforms are also regarded evolutionally conservative, with few morphological and ecological changes during their long history. However, their phylogenetic affinity remains unclear as to whether they are chondrostean, neopterygian or stem-actinopteran, and likewise the intrarelationships of the group have rarely been explored. Methodology/Principal Findings Here we report a new saurichthyiform from the Middle Triassic of Guizhou, China, based on the well-preserved specimens including a 3-D braincase. The new taxon, Yelangichthys macrocephalus gen. et sp. nov., is unique among saurichthyiforms in having a peculiar neurocranium with a broad orbital tectum, paired posterior myodomes, a deep, transverse fossa in the posterodorsal part of the orbit, and a feeding mechanism structured for durophagy. Phylogenetic analysis places Yelangichthys gen. nov. at the most basal position in the Saurichthyiformes as the sister to Saurichthyidae, and a new family Yelangichthyidae is erected to include only Y. macrocephalus gen. et sp. nov. The monophyly of the Chondrostei comprising [Saurichthyiformes + Acipenseriformes] Birgeriiformes is supported, but not the monophyly of Saurichthys, the type genus of Saurichthyidae. With its outstanding osteological details, Yelangichthys gen. nov. greatly increases the neurocranial variations in saurichthyiforms, and its novel feeding structure suggests the consumption of hard-preys instead of fishes. Conclusions/Significance Our findings highlight the detailed osteology of a saurichthyiform braincase and its feeding design. We suggest that saurichthyiforms are closely allied to the Acipenseriformes. Saurichthyiforms were very diverse in the

Fragile X Mental Retardation Protein Is Required to Maintain Visual Conditioning-Induced Behavioral Plasticity by Limiting Local Protein Synthesis.

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Liu, Han-Hsuan; Cline, Hollis T

2016-07-06

Fragile X mental retardation protein (FMRP) is thought to regulate neuronal plasticity by limiting dendritic protein synthesis, but direct demonstration of a requirement for FMRP control of local protein synthesis during behavioral plasticity is lacking. Here we tested whether FMRP knockdown in Xenopus optic tectum affects local protein synthesis in vivo and whether FMRP knockdown affects protein synthesis-dependent visual avoidance behavioral plasticity. We tagged newly synthesized proteins by incorporation of the noncanonical amino acid azidohomoalanine and visualized them with fluorescent noncanonical amino acid tagging (FUNCAT). Visual conditioning and FMRP knockdown produce similar increases in FUNCAT in tectal neuropil. Induction of visual conditioning-dependent behavioral plasticity occurs normally in FMRP knockdown animals, but plasticity degrades over 24 h. These results indicate that FMRP affects visual conditioning-induced local protein synthesis and is required to maintain the visual conditioning-induced behavioral plasticity. Fragile X syndrome (FXS) is the most common form of inherited intellectual disability. Exaggerated dendritic protein synthesis resulting from loss of fragile X mental retardation protein (FMRP) is thought to underlie cognitive deficits in FXS, but no direct evidence has demonstrated that FMRP-regulated dendritic protein synthesis affects behavioral plasticity in intact animals. Xenopus tadpoles exhibit a visual avoidance behavior that improves with visual conditioning in a protein synthesis-dependent manner. We showed that FMRP knockdown and visual conditioning dramatically increase protein synthesis in neuronal processes. Furthermore, induction of visual conditioning-dependent behavioral plasticity occurs normally after FMRP knockdown, but performance rapidly deteriorated in the absence of FMRP. These studies show that FMRP negatively regulates local protein synthesis and is required to maintain visual conditioning

Magnetic resonance imaging in neuro-Behcet's disease

International Nuclear Information System (INIS)

Kojima, Shigeyuki; Fukutake, Toshio; Hirayama, Keizo; Iwamoto, Itsuo

1987-01-01

In four patients with neuro-Behcet's disease, the findings of magnetic resonance imaging (MRI) were evaluated in comparison with the results of X-ray computed tomography (CT), especially for brainstem lesions. MRI was able to reveal brainstem lesions in three patients, in addition to lesions of basal ganglia, internal capsule and thalamus in the same patients. In contrast, X-ray CT demonstrated lesions of basal ganglia and internal capsule in only one patient, and it did not detect any brainstem lesions. Non-specific findings, including cerebral and brainstem atrophy, were revealed more clearly in inversion recovery images than in X-ray CT. Spin echo images were superior to inversion recovery images for detecting the lesions of demyelination, necrosis, gliosis and so on in neuro-Behcet's disease. The brainstem lesions visualized by MRI were situated in the regions of the basis pontis, cerebral peduncle and tectum of the midbrain. In neuro-Behcet's disease, the main pathological lesions are known occur in the ventral parts of the brainstem, but X-ray CT cannot always reveale these brainstem lesions because it produces bone artifacts. For this reason, the X-ray CT findings of neuro-Behcet's disease reported previously have been nonspecific cerebral or brainstem atrophy and decreased attenuations in the basal ganglia or subcortical white matter. Thus it is generally difficult to differentiate neuro-Behcet's disease from other intracranial lesions on the basis of the supratentorial X-ray CT findings. However, the above mentioned brainstem lesions visualized by MRI are consistent with the pathologically preferential site in neuro-Behcet's disease, and MRI can assist in the clinical diagnosis of neuro-Behcet's disease by demonstrating the brainstem lesions clearly, even when neurological involvement precedes the typical dermatologic and ophthalmologic manifestations. (author)

Notch receptor expression in neurogenic regions of the adult zebrafish brain.

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Vanessa de Oliveira-Carlos

Full Text Available The adult zebrash brain has a remarkable constitutive neurogenic capacity. The regulation and maintenance of its adult neurogenic niches are poorly understood. In mammals, Notch signaling is involved in stem cell maintenance both in embryonic and adult CNS. To better understand how Notch signaling is involved in stem cell maintenance during adult neurogenesis in zebrafish we analysed Notch receptor expression in five neurogenic zones of the adult zebrafish brain. Combining proliferation and glial markers we identified several subsets of Notch receptor expressing cells. We found that 90 [Formula: see text] of proliferating radial glia express notch1a, notch1b and notch3. In contrast, the proliferating non-glial populations of the dorsal telencephalon and hypothalamus rarely express notch3 and about half express notch1a/1b. In the non-proliferating radial glia notch3 is the predominant receptor throughout the brain. In the ventral telencephalon and in the mitotic area of the optic tectum, where cells have neuroepithelial properties, notch1a/1b/3 are expressed in most proliferating cells. However, in the cerebellar niche, although progenitors also have neuroepithelial properties, only notch1a/1b are expressed in a high number of PCNA [Formula: see text] cells. In this region notch3 expression is mostly in Bergmann glia and at low levels in few PCNA [Formula: see text] cells. Additionally, we found that in the proliferation zone of the ventral telencephalon, Notch receptors display an apical high to basal low gradient of expression. Notch receptors are also expressed in subpopulations of oligodendrocytes, neurons and endothelial cells. We suggest that the partial regional heterogeneity observed for Notch expression in progenitor cells might be related to the cellular diversity present in each of these neurogenic niches.

LPXRFa peptide system in the European sea bass: A molecular and immunohistochemical approach.

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Paullada-Salmerón, José A; Cowan, Mairi; Aliaga-Guerrero, María; Gómez, Ana; Zanuy, Silvia; Mañanos, Evaristo; Muñoz-Cueto, José A

2016-01-01

Gonadotropin-inhibitory hormone (GnIH) is a neuropeptide that suppresses reproduction in birds and mammals by inhibiting GnRH and gonadotropin secretion. GnIH orthologs with a C-terminal LPXRFamide (LPXRFa) motif have been identified in teleost fish. Although recent work also suggests its role in fish reproduction, studies are scarce and controversial, and have mainly focused on cyprinids. In this work we cloned a full-length cDNA encoding an LPXRFa precursor in the European sea bass, Dicentrarchus labrax. In contrast to other teleosts, the sea bass LPXRFa precursor contains only two putative RFamide peptides, termed sbLPXRFa1 and sbLPXRFa2. sblpxrfa transcripts were expressed predominantly in the olfactory bulbs/telencephalon, diencephalon, midbrain tegmentum, retina, and gonads. We also developed a specific antiserum against sbLPXRFa2, which revealed sbLPXRFa-immunoreactive (ir) perikarya in the olfactory bulbs-terminal nerve, ventral telencephalon, caudal preoptic area, dorsal mesencephalic tegmentum, and rostral rhombencephalon. These sbLPXRFa-ir cells profusely innervated the preoptic area, hypothalamus, optic tectum, semicircular torus, and caudal midbrain tegmentum, but conspicuous projections also reached the olfactory bulbs, ventral/dorsal telencephalon, habenula, ventral thalamus, pretectum, rostral midbrain tegmentum, posterior tuberculum, reticular formation, and viscerosensory lobe. The retina, pineal, vascular sac, and pituitary were also targets of sbLPXRFa-ir cells. In the pituitary, this innervation was observed close to follicle-stimulating hormone (FSH), luteinizing hormone (LH) and growth hormone (GH) cells. Tract-tracing retrograde labeling suggests that telencephalic and preoptic sbLPXRFa cells might represent the source of pituitary innervation. The immunohistochemical distribution of sbLPXRFa cells and fibers suggest that LPXRFa peptides might be involved in some functions as well as reproduction, such as feeding, growth, and behavior. �

Magnetic Resonance Imaging of a Case of Central Neurocytoma

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Dedushi, Kreshnike; Kabashi, Serbeze; Ugurel, Mehmet Sahin; Ramadani, Naser; Mucaj, Sefedin; Zeqiraj, Kamber

2016-01-01

Background: The purpose of this study is to investigate the MRI features of central neurocytoma. Case report: A 45 year old man with 3 months of worsening daily headaches. These headaches were diffuse, lasted for several hours, and mostly occurred in the morning. She was initially diagnosed and treated for migraines but later he had epileptic attack and diplopia and neurolog recomaded MRI. Methods: precontrast MRI; TSE/T2Wsequence in axial/coronal planes; 3D–Hi-resolution T1W sagittal; FLAIR/T2W axial; FLAIR/T2W and Flash/T2W oblique coronal plane (perpendicular to temporal lobes) GRE/T2W axial plane for detection of heme products. Post-contrast TSE/T1W sequence in axial, coronal and sagittal planes. Diffusion weighted and ADC mapping MRI images for EPI sequence in axial plane. Results: A 23x12mm heterogeneous mass within aqueductus cerebri, with calcified and hemorrhagic foci and extending downwards till fourth ventricle. It’s originating from the right paramedian posterior aqueductal wall (tectum), and also extending to and involving the tegmentum of mesencephalon at its right paramedian aspect. CSF flow obstruction secondary to described aqueductal mass, with resultant triventricular hydrocephalus). Marked transependymal CSF leak can be noted at periventricular white matter, secondary to severe hydrocephalus. After IV injection of contrast media, this mass shows mild-to-moderate heterogenous speckled enhancement. Conclusion: MRI is helpful in defining tumor extension, which is important in preoperative planning. Although IN is a relatively rare lesion, it should be considered in the differential diagnosis of intraventricular lesions in the presence of such typical MR findings. However, a definitive diagnosis requires immunochemical study and electron microscopy. PMID:28077908

Tamaño relativo encefálico e índices cerebrales en Vanellus c. chilensis (Aves: Charadriidae Relative encephalic size and cerebral indices of Vanellus c. chilensis (Aves: Charadriidae

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ESTELA PISTONE

2002-09-01

Full Text Available Se analizó la composición cuantitativa encefálica y se estimaron índices cerebrales en Vanellus c. chilensis (tero o queltehue. Se estimó el volumen porcentual e índices cerebrales del encéfalo total y de siete de sus componentes, como así también los núcleos de relevo de las vías trigeminal, visual y acústica. El telencéfalo es el componente de mayor volumen relativo, siendo el neoestriado la estructura telencefálica de tamaño superior. El desarrollo del estriado propiamente dicho, tecto óptico y los núcleos de relevo de las vías visual y trigeminal concuerdan con la dieta carnívora de Vanellus c. chilensis. El tamaño relativo del Wulst y de los núcleos de la vía acústica se asocia a las complicadas tácticas que utiliza esta especie en la defensa del nido. Los índices cerebrales de las estructuras encefálicas analizadas indican que Vanellus c. chilensis es un ave progresivaThe quantitative encephalic composition and cerebral indices of Vanellus c. chilensis (southern lapwing were analyzed. The percentual volumes and cerebral indices for the whole encephalon and for seven components were calculated as well as relevous nuclei of the trigeminal, visual and acoustic pathways. The component of greater relative volume is the telencephalon. The neostriatum is the most developed encephalic structure. Developing of bulbus olfactorius, striatum, tectum opticum and relevous nuclei of visual and trigeminal pathways are according with the carnivorous diet of Vanellus c. chilensis. The relative size of Wulst and relevous nuclei of acoustic pathway appears associated with the complex tactics used by this species in the defense of nest. Cerebral indices of all the analyzed structures suggest that Vanellus c. chilensis is a progresive bird

The cytoarchitecture of the torus semicircularis in the Tegu lizard, Tupinambis nigropunctatus.

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Browner, R H; Rubinson, K

1977-12-15

The torus semicircularis (TS) of the Tegu lizard extends from the superficial caudal mesencephalon, dorsal to the exiting trochlear nerve, to a position ventral to the middle part of the optic tectum and its ventricle. It has an oblique orientation with the caudal pole abutting the midline while the rostal end is lateral and slightly ventral. The TS consists of a central nucleus and several adjacent cell groups. The central nucleus and the laminar nucleus, situated medially, extend the entire length of the TS while the cortical nucleus, situated dorsally and laterally, is present only in the caudal superficial portion. The central nucleus is composed of ovoid neurons with branched, radiating dendrites. The dendrites are directed medially and laterally with spines on the distal portion of the dendritic tree. The laminar nucleus consists of three to five neuronal layers. It is mainly composed of fusiform neurons with one dendritic trunk from each extremity of the soma. There is little branching and few dendritic spines. The cortical nucleus is a laminated region consisting of alternating layers of neurons and lateral lemniscal fibers. The neurons of the superficial layers are fusiform with their long axis perpendicular to the long axis of the brainstem. They possess two main dendritic trunks which parallel the laminae and are covered with dendritic spines. The deeper layers consist of pyramidal neurons with three dendritic trunks, secondary branches, and few spines. The long axis of these neurons extends from the center of the TS to the periphery. Two dendritic trunks extend dorsally or laterally towards the surface, while the third extends towards the central nucleus. The dendrites, thus, extend across the laminae. In addition, a cell-free lateral zone is described.

MR imaging of pineal cysts

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Ahn, Yong Sik; Yu, Hyeon; Kim, Wan Tae; Bae, Jin Woo; Moon, Hee Jung; Shin, Hyun Ja

1999-01-01

To evaluate the incidence and characteristic findings of pineal cyst incidentally detected on magnetic resonance (MR) imaging. Brain MR images obtained in 2432 patients were retrospectively reviewed to determine the incidence and MR findings of pineal cysts, which were evaluated according to their size, shape, location, signal intensity, interval change, contrast enhancement and mass effect on adjacent structures. Cysts were encountered in 107(4.4 %) of 2432 patients evaluated. their size ranged from 1 X 1 X 1 to 15 X 8 X 9 (mean, 5.97 X 3.82 X 4.82)mm. All were spherical (n=53) or oval (n=54) in shape. Their margin was smooth and they were homogeneous in nature. On T1-weighted images, the cysts were seen to be hyperintense (n=57) or isointense (n=50) to cerebrospinal fluid, but less so than brain parenchyma. T2-weighted images showed them to be isointense (n=51)or hyperintense (n=56) to cerebrospinal fluid. The cysts were centrally located in 65 cases and eccentrically in 42. Compression of the superior colliculi of the tectum was demonstrated in 17 cases (15.9 %). NO patients presented clinical symptoms or signs related to either pineal or tectal lesions. Peripheral enhancement around the cyst after Gd-DTPA injection was demonstrated in 51 cases(100 %). Follow-up examinations in 19 cases demonstrated no interval change. The incidence of pineal cysts was 4.4 %. The MR characteristics of simple pineal cysts include: (1) an oval or spherical shape, (2) a smooth outer margin and homogeneous nature, (3) isosignal or slightly high signal intensity to cerebrospinal fluid on whole pulse sequences, (4) ring enhancement after contrast injection, (5) an absence of interval change, as seen during follow up MR study. These MR appearances of pineal cysts might be helpful for differentiating them from pineal tumors

Oral associated bacterial infection in horses: studies on the normal anaerobic flora from the pharyngeal tonsillar surface and its association with lower respiratory tract and paraoral infections.

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Bailey, G D; Love, D N

1991-02-15

Two hundred and seventy bacterial isolates were obtained from the pharyngeal tonsillar surface of 12 normal horses and 98 obligatory anaerobic bacteria were characterised. Of these, 57 isolates belonging to 7 genera (Peptostreptococcus (1); Eubacterium (9); Clostridium (6); Veillonella (6); Megasphera (1); Bacteroides (28); Fusobacterium (6)) were identified, and 16 of these were identified to species level (P. anaerobius (1); E. fossor (9); C. villosum (1); B. fragilis (1); B. tectum (2); B. heparinolyticus (2)). Three hundred and twenty isolates were obtained from 23 samples from horses with lower respiratory tract (LRT) or paraoral (PO) bacterial infections. Of the 143 bacteria selected for detailed characterisation, obligate anaerobes accounted for 100 isolates, facultative anaerobes for 42 isolates and obligate aerobes for one isolate. Phenotypic characterisation separated 99 of the isolates into 14 genera. Among the obligately anaerobic species, Gram-positive cocci including P. anaerobius comprised 25% of isolates, E. fossor 11% and other Gram-positive rods (excluding Clostridium sp.) 18% of isolates. The Gram-negative rods comprised B. fragilis 5%, B. heparinolyticus 5%, asaccharolytic pigmented Bacteroides 3% and other Bacteroides 13%, while a so-far unnamed species of Fusobacterium (7%), and Gram-negative corroding rods (3%) were isolated. Among the facultatively anaerobic isolates, S. equi subsp. zooepidemicus accounted for 31% of isolates, followed by Pasteurella spp. 19%, Escherichia coli 17%, Actinomyces spp. 9%, Streptococcus spp. 9%. Incidental facultative isolates were Enterococcus spp. 2%, Enterobacter cloaceae 2%, Actinobacillus spp. 2% and Gram-negative corroding rods 5%. On the basis of the similarities (as determined by DNA hybridization data and/or phenotypic characteristics) of some of the bacterial species (e.g. E. fossor and B. heparinolyticus) isolated from both the normal pharyngeal tonsillar surfaces and LRT and PO diseases of horses, it

Time course Analysis of Gene expression patterns in ZebrafIsh Eye during Optic Nerve Regeneration

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Amy T. Mccurley

2010-01-01

Full Text Available It is well-established that neurons in the adult mammalian central nervous system (CNS are terminally differentiated and, if injured, will be unable to regenerate their connections. In contrast to mammals, zebrafish and other teleosts display a robust neuroregenerative response. Following optic nerve crush (ONX, retinal ganglion cells (RGC regrow their axons to synapse with topographically correct targets in the optic tectum, such that vision is restored in ~21 days. What accounts for these differences between teleostean and mammalian responses to neural injury is not fully understood. A time course analysis of global gene expression patterns in the zebrafish eye after ONX can help to elucidate cellular and molecular mechanisms that contribute to a successful neuroregeneration. To define different phases of regeneration after ONX, alpha tubulin 1 ( tuba1 and growth-associated protein 43 ( gap43 , markers previously shown to correspond to morphophological events, were measured by real time quantitative PCR (qPCR. Microarray analysis was then performed at defined intervals (6 hours, 1, 4, 12, and 21 days post-ONX and compared to SHAM. Results show that optic nerve damage induces multiple, phase-related transcriptional programs, with the maximum number of genes changed and highest fold-change occurring at 4 days. Several functional groups affected by optic nerve regeneration, including cell adhesion, apoptosis, cell cycle, energy metabolism, ion channel activity, and calcium signaling, were identified. Utilizing the whole eye allowed us to identify signaling contributions from the vitreous, immune and glial cells as well as the neural cells of the retina. Comparisons between our dataset and transcriptional profiles from other models of regeneration in zebrafish retina, heart and fin revealed a subset of commonly regulated transcripts, indicating shared mechanisms in different regenerating tissues. Knowledge of gene expression patterns in all

Efferent projections of the ectostriatum in the pigeon (Columba livia)

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Husband, S. A.; Shimizu, T.

1999-01-01

The ectostriatum is a major visual component of the avian telencephalon. The core region of the ectostriatum (Ec) receives visual input from the optic tectum through thalamic nuclei. In the present study, the efferent projections of the ectostriatum were investigated by using the anterograde tracers Phaseolus vulgaris leucoagglutinin and biotinylated dextran amine. Projection patterns resulting from these tracers were confirmed by the retrograde tracer cholera toxin subunit B. When anterograde tracers were injected in Ec, primary projections were seen traveling dorsolaterally to the belt region of the ectostriatum (Ep) and the neostriatal area immediately surrounding Ep (Ep2). Neurons in Ep sent projections primarily to the overlying Ep2. The efferents of Ep2 traveled dorsolaterally to terminate in three telencephalic regions, from anterior to posterior: (1) neostriatum frontale, pars lateralis (NFL), (2) area temporo-parieto-occipitalis (TPO), and (3) neostriatum intermedium, pars lateralis (NIL). A part of the archistriatum intermedium and the lateral part of the neostriatum caudale also received somewhat minor projections. In addition, some neurons in Ec were also the source of direct, but minor, projections to the NFL, TPO, NIL, and archistriatum intermedium. The topographical relationship among the primary (Ec), secondary (Ep and Ep2), and tertiary (NFL, TPO, NIL) areas indicate that the neural populations for visual processing are organized along the rostral-caudal axis. Thus, the anterior Ec sent efferents to the anterior Ep, which in turn sent projections to anterior Ep2. Neurons in the anterior Ep2 sent projections to NFL and the anterior TPO. Similarly, the intermediate and posterior Ec sent projections to corresponding parts of Ep, whose efferents projected to intermediate and posterior Ep2, respectively. The intermediate Ep2 gave rise to major projections to TPO, whereas posterior Ep2 neurons sent efferents primarily to NIL. The organization of this

Visual-auditory integration for visual search: a behavioral study in barn owls

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Yael eHazan

2015-02-01

Full Text Available Barn owls are nocturnal predators that rely on both vision and hearing for survival. The optic tectum of barn owls, a midbrain structure involved in selective attention, has been used as a model for studying visual- auditory integration at the neuronal level. However, behavioral data on visual- auditory integration in barn owls are lacking. The goal of this study was to examine if the integration of visual and auditory signals contributes to the process of guiding attention towards salient stimuli. We attached miniature wireless video cameras on barn owls' heads (OwlCam to track their target of gaze. We first provide evidence that the area centralis (a retinal area with a maximal density of photoreceptors is used as a functional fovea in barn owls. Thus, by mapping the projection of the area centralis on the OwlCam's video frame, it is possible to extract the target of gaze. For the experiment, owls were positioned on a high perch and four food items were scattered in a large arena on the floor. In addition, a hidden loudspeaker was positioned in the arena. The positions of the food items and speaker were changed every session. Video sequences from the OwlCam were saved for offline analysis while the owls spontaneously scanned the room and the food items with abrupt gaze shifts (head saccades. From time to time during the experiment, a brief sound was emitted from the speaker. The fixation points immediately following the sounds were extracted and the distances between the gaze position and the nearest items and loudspeaker were measured. The head saccades were rarely towards the location of the sound source but to salient visual features in the room, such as the door knob or the food items. However, among the food items, the one closest to the loudspeaker had the highest probability of attracting a gaze shift. This result supports the notion that auditory signals are integrated with visual information for the selection of the next visual search

Differential tissue distribution, developmental programming, estrogen regulation and promoter characteristics of cyp19 genes in teleost fish.

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Callard, G V; Tchoudakova, A V; Kishida, M; Wood, E

2001-12-01

Teleost fish are characterized by exceptionally high levels of brain estrogen biosynthesis when compared to the brains of other vertebrates or to the ovaries of the same fish. Goldfish (Carassius auratus) and zebrafish (Danio rerio) have utility as complementary models for understanding the molecular basis and functional significance of exaggerated neural estrogen biosynthesis. Multiple cytochrome P450 aromatase (P450arom) cDNAs that derive from separate gene loci (cyp19a and cyp19b) are differentially expressed in brain (P450aromB>A) and ovary (P450aromA>B) and have a different developmental program (B>A) and response to estrogen upregulation (B only). As measured by increased P450aromB mRNA, a functional estrogen response system is first detected 24-48 h post-fertilization (hpf), consistent with the onset of estrogen receptor (ER) expression (alpha, beta, and gamma). The 5'-flanking region of the cyp19b gene has a TATA box, two estrogen response elements (EREs), an ERE half-site (ERE1/2), a nerve growth factor inducible-B protein (NGFI-B)/Nur77 responsive element (NBRE) binding site, and a sequence identical to the zebrafish GATA-2 gene neural specific enhancer. The cyp19a promoter region has TATA and CAAT boxes, a steroidogenic factor-1 (SF-1) binding site, and two aryl hydrocarbon receptor (AhR)/AhR nuclear translocator factor (ARNT) binding motifs. Both genes have multiple potential SRY/SOX binding sites (16 and 8 in cyp19b and cyp19a, respectively). Luciferase reporters have basal promoter activity in GH3 cells, but differences (a>b) are opposite to fish pituitary (b>a). When microinjected into fertilized zebrafish eggs, a cyp19b promoter-driven green fluorescent protein (GFP) reporter (but not cyp19a) is expressed in neurons of 30-48 hpf embryos, most prominently in retinal ganglion cells (RGCs) and their projections to optic tectum. Further studies are required to identify functionally relevant cis-elements and cellular factors, and to determine the

Epizootic vacuolar myelinopathy of the central nervous system of bald eagles (Haliaeetus leucocephalus) and American coots (Fulica americana)

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Thomas, N.J.; Meteyer, C.U.; Sileo, L.

1998-01-01

Unprecedented mortality occurred in bald eagles (Haliaeetus leucocephalus) at DeGray Lake, Arkansas, during the winters of 1994-1995 and 1996-1997. The first eagles were found dead during November, soon after arrival from fall migration, and deaths continued into January during both episodes. In total, 29 eagles died at or near DeGray Lake in the winter of 1994-1995 and 26 died in the winter of 1996-1997; no eagle mortality was noted during the same months of the intervening winter or in the earlier history of the lake. During the mortality events, sick eagles were observed overflying perches or colliding with rock walls. Signs of incoordination and limb paresis were also observed in American coots (Fulica americana) during the episodes of eagle mortality, but mortality in coots was minimal. No consistent abnormalities were seen on gross necropsy of either species. No microscopic findings in organs other than the central nervous system (CNS) could explain the cause of death. By light microscopy, all 26 eagles examined and 62/77 (81%) coots had striking, diffuse, spongy degeneration of the white matter of the CNS. Vacuolation occurred in all myelinated CNS tissue, including the cerebellar folia and medulla oblongata, but was most prominent in the optic tectum. In the spinal cord, vacuoles were concentrated near the gray matter, and occasional swollen axons were seen. Vacuoles were uniformly present in optic nerves but were not evident in the retina or peripheral or autonomic nerves. Cellular inflammatory response to the lesion was distinctly lacking. Vacuoles were 8-50 microns in diameter and occurred individually, in clusters, or in rows. In sections stained by luxol fast blue/periodic acid-Schiff stain, the vacuoles were delimited and transected by myelin strands. Transmission electron microscopy revealed intramyelinic vacuoles formed in the myelin sheaths by splitting of one or more myelin lamellae at the intraperiodic line. This lesion is characteristic of

Cell Proliferation, Migration, and Neurogenesis in the Adult Brain of the Pulse Type Weakly Electric Fish, Gymnotus omarorum

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Valentina Olivera-Pasilio

2017-08-01

Full Text Available Adult neurogenesis, an essential mechanism of brain plasticity, enables brain development along postnatal life, constant addition of new neurons, neuronal turnover, and/or regeneration. It is amply distributed but negatively modulated during development and along evolution. Widespread cell proliferation, high neurogenic, and regenerative capacities are considered characteristics of teleost brains during adulthood. These anamniotes are promising models to depict factors that modulate cell proliferation, migration, and neurogenesis, and might be intervened to promote brain plasticity in mammals. Nevertheless, the migration path of derived cells to their final destination was not studied in various teleosts, including most weakly electric fish. In this group adult brain morphology is attributed to sensory specialization, involving the concerted evolution of peripheral electroreceptors and electric organs, encompassed by the evolution of neural networks involved in electrosensory information processing. In wave type gymnotids adult brain morphology is proposed to result from lifelong region specific cell proliferation and neurogenesis. Consistently, pulse type weakly electric gymnotids and mormyrids show widespread distribution of proliferation zones that persists in adulthood, but their neurogenic potential is still unknown. Here we studied the migration process and differentiation of newborn cells into the neuronal phenotype in the pulse type gymnotid Gymnotus omarorum. Pulse labeling of S-phase cells with 5-Chloro-2′-deoxyuridine thymidine followed by 1 to 180 day survivals evidenced long distance migration of newborn cells from the rostralmost telencephalic ventricle to the olfactory bulb, and between layers of all cerebellar divisions. Shorter migration appeared in the tectum opticum and torus semicircularis. In many brain regions, derived cells expressed early neuronal markers doublecortin (chase: 1–30 days and HuC/HuD (chase: 7–180 days

Promoter characteristics of two cyp19 genes differentially expressed in the brain and ovary of teleost fish.

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Tchoudakova, A; Kishida, M; Wood, E; Callard, G V

2001-11-01

prominently in retinal ganglion cells (RGC) and axon-like projections to the optic tectum. Expression of a cyp19a/GFP reporter was not detectable up to 72 hpf. Tandem analysis of cyp19a and cyp19b promoters in living zebrafish embryos can be a useful approach for identifying cis-elements and cellular factors involved in the correct tissue-specific, spatial, temporal and estrogen regulated expression of aromatase genes during CNS and gonadal development.