Home About us Contact
|
Home About us Contact | ||
|
|
||
Rostral
Terms modified by Rostral Selected AbstractsDifferential expression of RAR, isoforms in the mouse striatum during development: A gradient of RAR,2 expression along the rostrocaudal axisDEVELOPMENTAL DYNAMICS, Issue 2 2005Wen-Lin Liao Abstract The retinoic acid receptor RAR, is highly expressed in the striatum of the ventral telencephalon. We studied the expression pattern of different RAR, isoforms in the developing mouse striatum by in situ hybridization. We found a differential ontogeny of RAR,2 and RAR,1/3 in embryonic day (E) 13.5 lateral ganglionic eminence (striatal primordium). RAR,2 mRNA was detected primarily in the rostral and ventromedial domains, whereas RAR,1/3 mRNAs were enriched in the caudal and dorsolateral domains. Notably, by E16.5, a prominent decreasing gradient of RAR,2 mRNA was present in the developing striatum along the rostrocaudal axis, i.e., RAR,2 was expressed at higher levels in the rostral than the caudal striatum. No such gradient was found for RAR,1/3 and RAR,3 mRNAs. The rostrocaudal RAR,2 gradient gradually disappeared postnatally and was absent in the adult striatum. The differential expression pattern of RAR, isoforms in the developing striatum may provide an anatomical basis for differential gene regulation by RAR, signaling. Developmental Dynamics 233:584,594, 2005. © 2005 Wiley-Liss, Inc. [source] Glutamate drives the touch response through a rostral loop in the spinal cord of zebrafish embryosDEVELOPMENTAL NEUROBIOLOGY, Issue 12 2009Thomas Pietri Abstract Characterizing connectivity in the spinal cord of zebrafish embryos is not only prerequisite to understanding the development of locomotion, but is also necessary for maximizing the potential of genetic studies of circuit formation in this model system. During their first day of development, zebrafish embryos show two simple motor behaviors. First, they coil their trunks spontaneously, and a few hours later they start responding to touch with contralateral coils. These behaviors are contemporaneous until spontaneous coils become infrequent by 30 h. Glutamatergic neurons are distributed throughout the embryonic spinal cord, but their contribution to these early motor behaviors in immature zebrafish is still unclear. We demonstrate that the kinetics of spontaneous coiling and touch-evoked responses show distinct developmental time courses and that the touch response is dependent on AMPA-type glutamate receptor activation. Transection experiments suggest that the circuits required for touch-evoked responses are confined to the spinal cord and that only the most rostral part of the spinal cord is sufficient for triggering the full response. This rostral sensory connection is presumably established via CoPA interneurons, as they project to the rostral spinal cord. Electrophysiological analysis demonstrates that these neurons receive short latency AMPA-type glutamatergic inputs in response to ipsilateral tactile stimuli. We conclude that touch responses in early embryonic zebrafish arise only after glutamatergic synapses connect sensory neurons and interneurons to the contralateral motor network via a rostral loop. This helps define an elementary circuit that is modified by the addition of sensory inputs, resulting in behavioral transformation. © 2009 Wiley Periodicals, Inc. Develop Neurobiol 2009 [source] Phenotypic plasticity, polymorphism and phylogeny within placodermsACTA ZOOLOGICA, Issue 2009K. Trinajstic Abstract Intraspecies variation, polymorphism and asymmetric traits are observed within two families of Arthrodira, the Incisoscutidae and Camuropiscidae, from the Gogo Formation in northern Western Australia. Individual plates of the head and trunk shield show considerable variation between individuals. Plates that show the greatest degree polymorphic traits are the rostral (R), marginal (M), submarginal (SM), preorbital (PrO), anterior dorsolateral, anterior median ventral (AMV) and posterior ventrolateral (PVL) plates. The paths of the sensory line canals are the most variable feature and the dermal plates of the cheek show the greatest asymmetry. It is apparent that if anatomical data in arthrodires are to be interpreted with greater precision, detailed knowledge of intraspecies variation, polymorphic and asymmetric traits is essential. How these variables are treated in cladistic analysis is also critical. Here multistate characters were coded differently in five discrete analyses, each analysis yielding a different number of trees and relationships. It was concluded that including and coding for multistate characters gave the most robust tree. In addition, further morphological characters from a new specimen of Gogosteus sarahae Long (1994) indicates many of the characters used to separate this genus from Incisoscutum are inconsistent and so it is here considered that the genus Gogosteus is a junior synonym of Incisoscutum. [source] Light and scanning microscopic studies of integument differentiation in the grass snake Natrix natrix L. (Lepidosauria, Serpentes) during embryogenesisACTA ZOOLOGICA, Issue 1 2009Elwira Swad Abstract We analysed the differentiation of body cover in the grass snake (Natrix natrix L.) over the full length of the embryo's body at each developmental stage. Based on investigations using both light and scanning electron microscopes, we divided the embryonic development of the grass snake integument into four phases. The shape of the epidermal cells changes first on the caudal and ventral parts of the embryo, then gradually towards the rostral and dorsal areas. In stage V on the ventral side of the embryo the gastrosteges are formed from single primordia, but on the dorsal side the epidermis forms the scale primordia in stage VII. This indicates that scalation begins on the ventral body surface, and spreads dorsally. The appearance of melanocytes between the cells of the stratum germinativum in stage VII coincides with changes in embryo colouration. The first dermal melanocytes were detected in stage XI so in this stage the definitive skin pattern is formed. In the same stage the epidermis forms the first embryonic shedding complex and the periderm layer begins to detach in small, individual flakes. This process coincides with rapid growth of the embryos. [source] Development of equine upper airway fluid mechanics model for Thoroughbred racehorsesEQUINE VETERINARY JOURNAL, Issue 3 2008V. RAKESH Summary Reason for performing study: Computational fluid dynamics (CFD) models provide the means to evaluate airflow in the upper airways without requiring in vivo experiments. Hypothesis: The physiological conditions of a Thoroughbred racehorse's upper airway during exercise could be simulated. Methods: Computed tomography scanned images of a 3-year-old intact male Thoroughbred racehorse cadaver were used to simulate in vivo geometry. Airway pressure traces from a live Thoroughbred horse, during exercise was used to set the boundary condition. Fluid-flow equations were solved for turbulent flow in the airway during inspiratory and expiratory phases. The wall pressure turbulent kinetic energy and velocity distributions were studied at different cross-sections along the airway. This provided insight into the general flow pattern and helped identify regions susceptible to dynamic collapse. Results: The airflow velocity and static tracheal pressure were comparable to data of horses exercising on a high-speed treadmill reported in recent literature. The cross-sectional area of the fully dilated rima glottidis was 7% greater than the trachea. During inspiration, the area of highest turbulence (i.e. kinetic energy) was in the larynx, the rostral aspect of the nasopharynx was subjected to the most negative wall pressure and the highest airflow velocity is more caudal on the ventral aspect of the nasopharynx (i.e. the soft palate). During exhalation, the area of highest turbulence was in the rostral and mid-nasopharynx, the maximum positive pressure was observed at the caudal aspect of the soft palate and the highest airflow velocity at the front of the nasopharynx. Conclusions and clinical relevance: In the equine upper airway collapsible area, the floor of the rostral aspect of the nasopharynx is subjected to the most significant collapsing pressure with high average turbulent kinetic during inhalation, which may lead to palatal instability and explain the high prevalence of dorsal displacement of the soft palate (DDSP) in racehorses. Maximal abduction of the arytenoid cartilage may not be needed for optimal performance, since the trachea cross-sectional area is 7% smaller than the rima glottidis. [source] Equine dental disease Part 4: a long-term study of 400 cases: apical infections of cheek teethEQUINE VETERINARY JOURNAL, Issue 3 2000P. M. Dixon Summary Of 400 horses referred because of equine dental disease, 162 suffered from primary apical infections of their cheek teeth (CT), including 92 with maxillary CT infections and 70 with mandibular CT infections. Maxillary swellings and sinus tracts were more common (82 and 26% incidence, respectively) with infections of the rostral 3 maxillary CT, than with infections of the caudal 3 maxillary CT(39 and 5% incidence, respectively). Nasal discharge was more commonly present with caudal (95%) than rostral (23%) maxillary CT infections. Mandibular CT apical infections commonly had mandibular swellings (91%) and mandibular sinus tracts (59%) and these infections were closely related to eruption of the affected CT. A variety of treatments, including medical treatment, apical curettage, repulsion and oral extraction of affected teeth were utilised in these cases, with oral extraction appearing to be most satisfactory. Infections of caudal maxillary CT with a secondary paranasal sinusitis were most refractory to treatment, with a complete response to the initial treatment achieved in just 33% of these cases. Most other cases responded fully to their initial treatment. The long-term response to treatment was good in most cases. [source] Dissociable effects of cocaine-seeking behavior following D1 receptor activation and blockade within the caudal and rostral basolateral amygdala in ratsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2009Yasmin Mashhoon Abstract Research with dopamine D1 receptor antagonists or neuronal inactivating agents suggests that there is dissociable regulation of cocaine-seeking behavior by the rostral and caudal basolateral amygdala. In the present study, discrete infusions of the D1 receptor agonist SKF 81297 (0.0,0.8 ,g per side) were compared with those of the D1 receptor antagonist SCH 23390 (0.0,2.0 ,g per side) to demonstrate directly the importance of D1 receptor mechanisms within the rostral and caudal basolateral amygdala for their functional heterogeneity in regulating cocaine-seeking behavior. Under a second-order schedule, cocaine-seeking behavior was studied during maintenance (cocaine and cocaine cues present) and reinstatement (only cocaine cues present). Food-maintained responding was used to examine the specificity of maximal behaviorally effective doses of SKF 81297 and SCH 23390. The results demonstrated that the D1 agonist (0.4 or 0.8 ,g) increased and the D1 antagonist (1.0 ,g) decreased cocaine-seeking behavior during maintenance when infused into the caudal but not the rostral basolateral amygdala. Cocaine intake was not affected by the agonist, and was decreased by the antagonist. During reinstatement, the D1 agonist (0.4 ,g) increased and the D1 antagonist (1.0 ,g) decreased cocaine-seeking behavior when infused into the rostral but not the caudal basolateral amygdala. In tests for behavioral specificity, the above effective doses of SKF 81297 and SCH 23390 used in self-administration experiments did not alter food-maintained responding. However, the 2.0-,g dose of SCH 23390 suppressed drug-maintained and food-maintained responding after infusion into both subregions. Collectively, these findings indicate dissociable sensitivity to D1 receptor ligands within the caudal and rostral basolateral amygdala for altering cocaine-seeking behavior under different conditions that model phases of addiction. [source] Differential modulation by monoamine membrane receptor agonists of reticulospinal input to lamina VIII feline spinal commissural interneuronsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 5 2007Ingela Hammar Abstract Noradrenaline and serotonin have previously been demonstrated to facilitate the transmission between descending reticulospinal tracts fibres and commissural interneurons coordinating left,right hindlimb muscle activity. The aim of the present study was to investigate the contribution of subclasses of monoaminergic membrane receptors to this facilitation. The neurons were located in Rexed lamina VIII in midlumbar segments and identified by their projections to the contralateral gastrocnemius,soleus motor nuclei and by lack of projections rostral to the lumbosacral enlargement. The effects of ionophoretically applied membrane receptor agonists [phenylephrine (noradrenergic ,1), clonidine (noradrenergic ,2), 8-OH-DPAT (5-HT1A, 5-HT7), 2-me-5-HT (5-HT3), 5-me-5-HT (5-HT2) and ,-me-5-HT (5-HT2)] were examined on extracellularly recorded spikes evoked monosynaptically by electric stimulation of descending reticulospinal fibres in the medial longitudinal fascicle. Application of ,1 and 5-HT2 agonists resulted in a facilitation of responses in all investigated neurons while application of ,2, 5-HT1A/7 and 5-HT3 agonists resulted in a depression. These opposite modulatory effects of different agonists suggest that the facilitatory actions of noradrenaline and serotonin on responses of commissural interneurons reported previously following ionophoretic application are the net outcome of the activation of different subclasses of monoaminergic membrane receptors. As these receptors may be distributed predominantly, or even selectively, at either pre- or postsynaptic sites their differential modulatory actions could be compatible with a presynaptically induced depression and a postsynaptically evoked enhancement of synaptic transmission between reticulospinal neurons and commissural interneurons. [source] Neuroanatomical specificity in the expression of the immediate early gene c-fos following expression of appetitive and consummatory male sexual behaviour in Japanese quailEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 7 2006M. Taziaux Abstract We investigated the neural sites related to the occurrence of appetitive (ASB) and consummatory (CSB) aspects of male sexual behaviour in Japanese quail. Castrated males treated with testosterone were exposed for 5 min to one of four experimental conditions: (i) free interaction with a female (CSB group); (ii) expression of rhythmic cloacal sphincter movements in response to the visual presentation of a female (ASB-F group); (iii) or a male (ASB-M group), and (iv) handling as a control manipulation. Brains were collected 90 min after the start of behavioural tests and stained by immunocytochemistry for the FOS protein. An increase in FOS expression was observed throughout the rostro-caudal extent of the medial preoptic nucleus (POM) in CSB males, whereas the view of a female (ASB-F) induced an increased FOS expression in the rostral POM only. In the CSB group, there was also an increase in FOS expression in the bed nucleus striae terminalis, and both the CSB and ASB-F groups exhibited increased FOS expression in aspects of the ventro-lateral thalamus (VLT) related to visual processing. Moreover, both the CSB and ASB-M groups showed increased FOS expression in the lateral septum. These data provide additional support to the idea that there is a partial anatomical dissociation between structures involved in the control of both aspects of male sexual behaviour and independently provide data consistent with a previous lesion study that indicated that the rostral and caudal POM differentially control the expression of ASB and CSB in quail. [source] Eph/ephrin expression in the adult rat visual system following localized retinal lesions: localized and transneuronal up-regulation in the retina and superior colliculusEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2005J. Rodger Abstract Following unilateral optic nerve section in adult PVG hooded rat, the axon guidance cue ephrin-A2 is up-regulated in caudal but not rostral superior colliculus (SC) and the EphA5 receptor is down-regulated in axotomised retinal ganglion cells (RGCs). Changes occur bilaterally despite the retino-collicular projection being mostly crossed. Here we investigate the dynamics of Eph/ephrin expression using in situ hybridization and semi-quantitative immunohistochemistry after localized retinal lesions. Unilateral krypton laser lesions to dorso-nasal retina ablated contralaterally projecting RGCs (DN group); ventro-temporal lesions ablated contralaterally and ipsilaterally projecting RGCs (VT group). Lesions of the entire retina served as controls (Total group). Results are compared to normal animals in which tectal ephrin-A2 and retinal EphA5 are expressed, respectively, as shallow ascending rostro-caudal and naso-temporal gradients. In both SCs of DN and Total groups, tectal ephrin-A2 was up-regulated caudally; in the VT group, expression remained normal bilaterally. Unilateral collicular ablation indicated that bilateral changes in ephrin-A2 expression are mediated via intercollicular pathways. EphA5 expression in the VT group was elevated in the intact nasal region of experimental retinae. For each experimental group, EphA5 expression was also elevated in nasal retina of the opposite eye, resulting in uniform expression across the naso-temporal axis. Up-regulation of ephrin-A2 in caudal, but not rostral, SC suggests the enhancement of developmental positional information as a result of injury. Bilateral increases in retinal EphA5 expression demonstrate that signals for up-regulation operate interocularly. The study demonstrates that signals regulating guidance cue expression are both localized and relayed transneuronally. [source] Odorant specificity of three oscillations and the DC signal in the turtle olfactory bulbEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2003Ying-Wan Lam Abstract The odour-induced population response in the in vivo turtle (Terepene sp.) olfactory bulb consists of three oscillatory components (rostral, middle and caudal) that ride on top of a DC signal. In an initial step to determine the functional role of these four signals, we compared the signals elicited by different odorants. Most experiments compared isoamyl acetate and cineole, odorants which have very different maps of input to olfactory bulb glomeruli in the turtle and a different perceptual quality for humans. We found substantial differences in the response to the two odours in the rise-time of the DC signal and in the latency of the middle oscillation. The rate of rise for cineole was twice as fast as that for isoamyl acetate. Similarly, the latency for the middle oscillation was about twice as long for isoamyl acetate as it was for cineole. On the other hand, a number of characteristics of the signals were not substantially different for the two odorants. These included the latency of the rostral and caudal oscillation, the frequency and envelope of all three oscillations and their locations and spatial extents. A smaller number of experiments were carried out with hexanone and hexanal; the oscillations elicited by these odorants did not appear to be different from those elicited by isoamyl acetate and cineole. Qualitative differences between the oscillations in the turtle and those in two invertebrate phyla suggest that different odour processing strategies may be used. [source] Prefrontal and agranular cingulate projections to the dorsal premotor areas F2 and F7 in the macaque monkeyEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2003Giuseppe Luppino Abstract The superior sector of Brodmann area 6 (dorsal premotor cortex, PMd) of the macaque monkey consists of a rostral and a caudal architectonic area referred to as F7 and F2, respectively. The aim of this study was to define the origin of prefrontal and agranular cingulate afferents to F7 and F2, in the light of functional and hodological evidence showing that these areas do not appear to be functionally homogeneous. Different sectors of F7 and F2 were injected with neural tracers in seven monkeys and the retrograde labelling was qualitatively and quantitatively analysed. The dorsorostral part of F7 (supplementary eye field, F7-SEF) was found to be a target of strong afferents from the frontal eye field (FEF), from the dorsolateral prefrontal regions located dorsally (DLPFd) and ventrally (DLPFv) to the principal sulcus and from cingulate areas 24a, 24b and 24c. In contrast, the remaining part of F7 (F7-non SEF) is only a target of the strong afferents from DLPFd. Finally, the ventrorostral part of F2 (F2vr), but not the F2 sector located around the superior precentral dimple (F2d), receives a minor, but significant, input from DLPFd and a relatively strong input from the cingulate gyrus (areas 24a and 24b) and area 24d. Present data provide strong hodological support in favour of the idea that areas F7 and F2 are formed by two functionally distinct sectors. [source] Deficient long-term synaptic depression in the rostral cerebellum correlated with impaired motor learning in phospholipase C ,4 mutant miceEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 10 2001Mariko Miyata Abstract Long-term depression (LTD) at parallel fibre,Purkinje cell synapse of the cerebellum is thought to be a cellular substrate for motor learning. LTD requires activation of metabotropic glutamate receptor subtype 1 (mGluR1) and its downstream signalling pathways, which invariably involves phospholipase C,s (PLC,s). PLC,s consist of four isoforms (PLC,1,4) among which PLC,4 is the major isoform in most Purkinje cells in the rostral cerebellum (lobule 1 to the rostral half of lobule 6). We studied mutant mice deficient in PLC,4, and found that LTD was deficient in the rostral but not in the caudal cerebellum of the mutant. Basic properties of parallel fibre,Purkinje cell synapses and voltage-gated Ca2+ channel currents appeared normal. The mGluR1-mediated Ca2+ release induced by repetitive parallel fibre stimulation was absent in the rostral cerebellum of the mutant, suggesting that their LTD lesion was due to the defect in the mGluR1-mediated signalling in Purkinje cells. Importantly, the eyeblink conditioning, a simple form of discrete motor learning, was severely impaired in PLC,4 mutant mice. Wild-type mice developed the conditioned eyeblink response, when pairs of the conditioned stimulus (tone) and the unconditioned stimulus (periorbital shock) were repeatedly applied. In contrast, PLC,4 mutant mice could not learn the association between the conditioned and unconditioned stimuli, although their behavioural responses to the tone or to the periorbital shock appeared normal. These results strongly suggest that PLC,4 is essential for LTD in the rostral cerebellum, which may be required for the acuisition of the conditioned eyeblink response. [source] The effect of topically applied salicylic compounds on serotonin-induced scratching behaviour in hairless ratsEXPERIMENTAL DERMATOLOGY, Issue 4 2002J. S. Thomsen Abstract: There is a strong need for antipruritic substances for treating itch in clinical dermatology. In one recent human study, topically applied acetylsalicylic acid has been described to rapidly decrease histamine-induced itch. We have established a model for periferally elicited pruritus by injecting serotonin into the rostral back area (neck) in rats. Using this model, we aimed to investigate the antipruritic potential of four different salicylic compounds, which all possess different skin penetration characteristics. Eighteen rats were studied for 6 weeks. Prior to serotonin injections (2 mg/ml, 50 µl), 10 µl of test substances was applied to a circular area 18 mm in diameter. The four substances were salicylic acid, butyl salicylate, diethylamine salicylate and salicylamide, all solubilized in dimethyl isosorbide to a concentration of 5% w/w. Diethylamine salicylate and salicylamide were previously shown to be slowly absorbed through rat skin in contrast to salicylic acid and butyl salicylate. After serotonin injections, scratching was monitored by video recording for 1.5 h. Compared with the vehicle, a lower number of scratch sequences were seen when diethylamine salicylate (P < 0.001) and salicylamide (P = 0.005) had been applied. The numbers of scratch sequences were lower with diethylamine salicylate and salicylamide than with the vehicle throughout the 1.5-h study period. We conclude that topical application of diethylamine salicylate and salicylamide could suppress serotonin-induced scratching in rats. The antipruritic effect seems to be related to the slow drug release of the two substances. The results may be clinically relevant as serotonin induces itch in humans. [source] Amygdala,prefrontal dissociation of subliminal and supraliminal fearHUMAN BRAIN MAPPING, Issue 8 2006Leanne M. Williams Abstract Facial expressions of fear are universally recognized signals of potential threat. Humans may have evolved specialized neural systems for responding to fear in the absence of conscious stimulus detection. We used functional neuroimaging to establish whether the amygdala and the medial prefrontal regions to which it projects are engaged by subliminal fearful faces and whether responses to subliminal fear are distinguished from those to supraliminal fear. We also examined the time course of amygdala-medial prefrontal responses to supraliminal and subliminal fear. Stimuli were fearful and neutral baseline faces, presented under subliminal (16.7 ms and masked) or supraliminal (500 ms) conditions. Skin conductance responses (SCRs) were recorded simultaneously as an objective index of fear perception. SPM2 was used to undertake search region-of-interest (ROI) analyses for the amygdala and medial prefrontal (including anterior cingulate) cortex, and complementary whole-brain analyses. Time series data were extracted from ROIs to examine activity across early versus late phases of the experiment. SCRs and amygdala activity were enhanced in response to both subliminal and supraliminal fear perception. Time series analysis showed a trend toward greater right amygdala responses to subliminal fear, but left-sided responses to supraliminal fear. Cortically, subliminal fear was distinguished by right ventral anterior cingulate activity and supraliminal fear by dorsal anterior cingulate and medial prefrontal activity. Although subcortical amygdala activity was relatively persistent for subliminal fear, supraliminal fear showed more sustained cortical activity. The findings suggest that preverbal processing of fear may occur via a direct rostral,ventral amygdala pathway without the need for conscious surveillance, whereas elaboration of consciously attended signals of fear may rely on higher-order processing within a dorsal cortico,amygdala pathway. Hum Brain Mapp, 2005. © 2005 Wiley-Liss, Inc. [source] Functional segregation of cortical language areas by sentence repetitionHUMAN BRAIN MAPPING, Issue 5 2006Ghislaine Dehaene-Lambertz Abstract The functional organization of the perisylvian language network was examined using a functional MRI (fMRI) adaptation paradigm with spoken sentences. In Experiment 1, a given sentence was presented every 14.4 s and repeated two, three, or four times in a row. The study of the temporal properties of the BOLD response revealed a temporal gradient along the dorsal,ventral and rostral,caudal directions: From Heschl's gyrus, where the fastest responses were recorded, responses became increasingly slower toward the posterior part of the superior temporal gyrus and toward the temporal poles and the left inferior frontal gyrus, where the slowest responses were observed. Repetition induced a decrease in amplitude and a speeding up of the BOLD response in the superior temporal sulcus (STS), while the most superior temporal regions were not affected. In Experiment 2, small blocks of six sentences were presented in which either the speaker voice or the linguistic content of the sentence, or both, were repeated. Data analyses revealed a clear asymmetry: While two clusters in the left superior temporal sulcus showed identical repetition suppression whether the sentences were produced by the same speaker or different speakers, the homologous right regions were sensitive to sentence repetition only when the speaker voice remained constant. Thus, hemispheric left regions encode linguistic content while homologous right regions encode more details about extralinguistic features like speaker voice. The results demonstrate the feasibility of using sentence-level adaptation to probe the functional organization of cortical language areas. Hum Brain Mapp, 2006. © 2006 Wiley-Liss, Inc. [source] A comparison of label-based review and ALE meta-analysis in the Stroop taskHUMAN BRAIN MAPPING, Issue 1 2005Angela R. Laird Abstract Meta-analysis is an important tool for interpreting results of functional neuroimaging studies and is highly influential in predicting and testing new outcomes. Although traditional label-based review can be used to search for agreement across multiple studies, a new function-location meta-analysis technique called activation likelihood estimation (ALE) offers great improvements over conventional methods. In ALE, reported foci are modeled as Gaussian functions and pooled to create a statistical whole-brain image. ALE meta-analysis and the label-based review were used to investigate the Stroop task in normal subjects, a paradigm known for its effect of producing conflict and response inhibition due to subjects' tendency to perform word reading as opposed to color naming. Both methods yielded similar activation patterns that were dominated by response in the anterior cingulate and the inferior frontal gyrus. ALE showed greater involvement of the anterior cingulate as compared to that in the label-based technique; however, this was likely due to the increased spatial level of distinction allowed with the ALE method. With ALE, further analysis of the anterior cingulate revealed evidence for somatotopic mapping within the rostral and caudal cingulate zones, an issue that has been the source of some conflict in previous reviews of the anterior cingulate cortex. Hum Brain Mapp 25:6,21, 2005. © 2005 Wiley-Liss, Inc. [source] Connections of the zona incerta to the reticular nucleus of the thalamus in the ratJOURNAL OF ANATOMY, Issue 2 2006Safiye Çavdar Abstract This study demonstrated that there is a pathway from the zona incerta to the thalamic reticular nucleus. Injections of horseradish peroxidase or Fluorogold were made, using stereotaxic coordinates, into the rostral, intermediate or caudal regions of the thalamic reticular nucleus of adult Sprague,Dawley rats. The results show that the different regions of the thalamic reticular nucleus have distinct patterns of connections with the sectors of the zona incerta. In terms of the relative strength of the connections, injections made into the rostral regions of the thalamic reticular nucleus showed the highest number of labelled cells within the rostral and ventral sectors of the zona incerta; injections made into the intermediate regions of the thalamic reticular nucleus showed labelled cells in the dorsal and ventral sectors; while injections to the caudal regions of the thalamic reticular nucleus showed only a few labelled cells in the caudal sector of the zona incerta. Previous studies have shown that the zona incerta projects to the higher order thalamic nuclei but not first order thalamic nuclei. The labelling observed in the present study may represent collaterals of zona incerta to higher order thalamic nuclei projections. [source] Ontogenetic allometries and shape changes in the suckermouth armoured catfish Ancistruscf.triradiatus Eigenmann (Loricariidae, Siluriformes), related to suckermouth attachment and yolk-sac sizeJOURNAL OF FISH BIOLOGY, Issue 4 2008T. Geerinckx Early life-history stages of the loricariid catfish Ancistruscf.triradiatus are described, from pre-hatch embryos to juveniles. The descriptions, as well as metric characters, indicate that the free-swimming embryonic stage is followed directly by the juvenile stage, without a true larval stage or metamorphosis. Intense, but gradual ontogenetic head-shape changes are present during the embryonic and free-living embryonic stages: the suckermouth gradually shifts from an almost rostral to a ventral position. The external and internal transformations related to this shape change are considered an adaptation to both the loricariid algae-scraping feeding mode and the need of suckermouth functioning from the moment of hatching, when a ventrally situated suckermouth would be disadvantageous, as a large yolk sac is present. [source] Medullary motor neurones associated with drinking behaviour of Japanese eelsJOURNAL OF FISH BIOLOGY, Issue 1 2003T. Mukuda A fluorescent dye, Evans blue (EB), was injected into the following seven drinking-associated muscles of the Japanese eel Anguilla japonica: the sternohyoid, third branchial, fourth branchial, opercular, pharyngeal, upper oesophageal sphincter and oesophageal body muscles. The sternohyoid muscle promotes ,ingestion', and the remaining muscles contribute to ,swallowing'. All neurones stained by EB were located ipsilaterally in the caudal medulla oblongata (MO) of the Japanese eel. Neurones projecting into the sternohyoid muscle were identified as those in the spino-occipital motor nucleus (NSO), and neurones projecting into the remaining muscles as those in the glossopharyngeal,vagal motor complex (GVC). Within the GVC, the neuronal arrangement was topological, and hence, ,swallowing' will be completed if the GVC neurones ,fire' progressively from rostral to caudal. These neurones in the NSO and GVC may use acetylcholine (ACh) as a neurotransmitter, as the EB-positive neurones in both nuclei were immunoreactive against anticholine acetyltransferase (anti-ChAT) antibody. Besides the MO, some somata in a ganglion of the vagal nerve were also stained by EB injected into the pharyngeal, the upper oesophageal sphincter and the oesophageal body muscles. The localization and the shape of the somata suggest that they are sensory neurones. These sensory neurones were not ChAT-immunoreactive. Combining these results, based on a model for ,swallowing' in mammals, a plausible model for central organization of ,drinking' in the Japanese eel is proposed, which suggests that ,drinking' in the fishes is regulated by the neuronal circuit for ,swallowing' in mammals. [source] Activity of Hypothalamic Dopaminergic Neurones During the Day of Oestrus: Involvement in Prolactin SecretionJOURNAL OF NEUROENDOCRINOLOGY, Issue 10 2010C. M. Leite A secretory surge of prolactin occurs on the afternoon of oestrus in cycling rats. Pituitary prolactin is inhibited by dopamine. We evaluated the activity of the neuroendocrine dopaminergic neurones during oestrus and dioestrus, as determined by dopaminergic activity in the median eminence and neurointermediate lobe of the pituitary, as well as Fos-related antigen expression in tyrosine hydroxylase (TH)-immunoreactive (ir) neurones of the arcuate nucleus (ARC) and periventricular nucleus (Pe). During oestrus, the 4-dihydroxyphenylacetic acid/dopamine ratio in the median eminence decreased at 16.00 h, coinciding with the increase in plasma prolactin levels. Similarly, the expression of Fos-related antigen in TH-ir neurones of Pe and rostral-, dorsomedial- and caudal-ARC also decreased at 16.00 h. On dioestrus, 4-dihydroxyphenylacetic acid/dopamine ratio in the median eminence and Fos-related antigen expression in TH-ir neurones of Pe and rostral-ARC decreased at 18.00 h, whereas prolactin levels were unaltered. No variation in dopaminergic activity was found in the neurointermediate lobe of the pituitary on either oestrus or dioestrus. The number of TH-ir neurones in the ARC and parameters of dopaminergic activity were found to be generally lower on oestrus compared to dioestrus. The transitory decrease in the activity of neuroendocrine dopaminergic neurones temporally associated with the prolactin surge on the afternoon of oestrus suggests a role for dopamine in the generation of the oestrous prolactin surge. [source] Increased Caloric Intake on a Fat-Rich Diet: Role of Ovarian Steroids and Galanin in the Medial Preoptic and Paraventricular Nuclei and Anterior Pituitary of Female RatsJOURNAL OF NEUROENDOCRINOLOGY, Issue 10 2007S. F. Leibowitz Previous studies in male rats have demonstrated that the orexigenic peptide galanin (GAL), in neurones of the anterior parvocellular region of the paraventricular nucleus (aPVN) projecting to the median eminence (ME), is stimulated by consumption of a high-fat diet and may have a role in the hyperphagia induced by fat. In addition to confirming this relationship in female rats and distinguishing the aPVN-ME from other hypothalamic areas, the present study identified two additional extra-hypothalamic sites where GAL is stimulated by dietary fat in females but not males. These sites were the medial preoptic nucleus (MPN), located immediately rostral to the aPVN, and the anterior pituitary (AP). The involvement of ovarian steroids, oestradiol (E2) and progesterone (PROG), in this phenomenon was suggested by an observed increase in circulating levels of these hormones and GAL in MPN and AP with fat consumption and an attenuation of this effect on GAL in ovariectomised (OVX) rats. Furthermore, in the same four areas affected by dietary fat, levels of GAL mRNA and peptide immunoreactivity were stimulated by E2 and further by PROG replacement in E2 -primed OVX rats and were higher in females compared to males. Because both GAL and PROG stimulate feeding, their increase on a fat-rich diet may have functional consequences in females, possibly contributing to the increased caloric intake induced by dietary fat. This is supported by the findings that PROG administration in E2 -primed OVX rats reverses the inhibitory effect of E2 on total caloric intake while increasing voluntary fat ingestion, and that female rats with higher GAL exhibit increased preference for fat compared to males. Thus, ovarian steroids may function together with GAL in a neurocircuit, involving the MPN, aPVN, ME and AP, which coordinate feeding behaviour with reproductive function to promote consumption of a fat-rich diet at times of increased energy demand. [source] Postinjury estrogen treatment of chronic spinal cord injury improves locomotor function in ratsJOURNAL OF NEUROSCIENCE RESEARCH, Issue 8 2010Eric A. Sribnick Abstract Spinal cord injury (SCI) causes loss of neurological function and, depending on serverity, may cause paralysis. The only recommended pharmacotherapy for the treatment of SCI is high-dose methylprednisolone, and its use is controversial. We have previously shown that estrogen treatment attenuated cell death, axonal and myelin damage, calpain and caspase activities, and inflammation in acute SCI. The aim of this study was to examine whether posttreatment of SCI with estrogen would improve locomotor function by protecting cells and axons and reducing inflammation during the chronic phase following injury. Moderately severe injury (40 g · cm force) was induced in male Sprague-Dawley rats following laminectomy at T10. Three groups of animals were used: sham (laminectomy only), vehicle (dimethyl sulfoxide; DMSO)-treated injury group, and estrogen-treated injury group. Animals were treated with 4 mg/kg estrogen at 15 min and 24 hr postnjury, followed by 2 mg/kg estrogen daily for the next 5 days. After treatment, animals were sacrificed at the end of 6 weeks following injury, and 1-cm segments of spinal cord (lesion, rostral to lesion, and caudal to lesion) were removed for biochemical analyses. Estrogen treatment reduced COX-2 activity, blocked nuclear factor-,B translocation, prevented glial reactivity, attenuated neuron death, inhibited activation and activity of calpain and caspase-3, decreased axonal damage, reduced myelin loss in the lesion and penumbra, and improved locomotor function compared with vehicle-treated animals. These findings suggest that estrogen may be useful as a promising therapeutic agent for prevention of damage and improvement of locomotor function in chronic SCI. © 2010 Wiley-Liss, Inc. [source] Promoting directional axon growth from neural progenitors grafted into the injured spinal cordJOURNAL OF NEUROSCIENCE RESEARCH, Issue 6 2010Joseph F. Bonner Abstract Spinal cord injury (SCI) is a devastating condition characterized by disruption of axonal connections, failure of axonal regeneration, and loss of motor and sensory function. The therapeutic promise of neural stem cells has been focused on cell replacement, but many obstacles remain in obtaining neuronal integration following transplantation into the injured CNS. This study investigated the neurotransmitter identity and axonal growth potential of neural progenitors following grafting into adult rats with a dorsal column lesion. We found that using a combination of neuronal and glial restricted progenitors (NRP and GRP) produced graft-derived glutamatergic and GABAergic neurons within the injury site, with minimal axonal extension. Administration of brain-derived neurotrophic factor (BDNF) with the graft promoted modest axonal growth from grafted cells. In contrast, injecting a lentiviral vector expressing BDNF rostral into the injured area generated a neurotrophin gradient and promoted directional growth of axons for up to 9 mm. Animals injected with BDNF lentivirus (at 2.5 and 5.0 mm) showed significantly more axons and significantly longer axons than control animals injected with GFP lentivirus. However, only the 5.0-mm-BDNF group showed a preference for extension in the rostral direction. We concluded that NRP/GRP grafts can be used to produce excitatory and inhibitory neurons, and neurotrophin gradients can guide axonal growth from graft-derived neurons toward putative targets. Together they can serve as a building block for neuronal cell replacement of local circuits and formation of neuronal relays. © 2009 Wiley-Liss, Inc. [source] Blockade of the 5-HT3 receptor for days causes sustained relief from mechanical allodynia following spinal cord injuryJOURNAL OF NEUROSCIENCE RESEARCH, Issue 2 2009Yuhua Chen Abstract Chronic neuropathic pain is a frequent, serious outcome of spinal cord injury (SCI) that is highly refractory to treatment. Serotonin can contribute to neuropathic pain after SCI, as suggested by our previous observation that transient blockade of the 5-HT3 receptor by intrathecal injections of the antagonist ondansetron reduces mechanical allodynia after SCI in rats. The current study determined whether intrathecal or intravenous infusion of ondansetron for 3 or 7 days, respectively, could cause sustained blockade of mechanical allodynia at and below the level of a twelfth thoracic clip compression injury in rats. Intrathecal 3-day infusion of ondansetron (2.0 ,g/hr), targeted to the cord rostral to the SCI and commencing at 28 days after SCI, decreased at-level mechanical allodynia by 40% and below-level allodynia by 60% compared with saline-treated rats (controls). This reduction was sustained throughout drug delivery and for 1 day afterward. During the next 3 days, allodynia gradually returned toward the values of saline-treated rats. An initial experiment showed that bolus intravenous injections of ondansetron (20,100 ,g) at 28 days after SCI decreased both at- and below-level allodynia for 90,120 min. Intravenous 7-day infusions (20 ,g/hr), commencing at 28 days after SCI, significantly decreased at-level allodynia by 48% and below-level allodynia by 51% compared with controls. This reduction of allodynia lasted throughout the infusion and for 1,3 days afterward while pain responses gradually approached those of controls. These findings suggest a potential role of 5-HT3 receptor antagonism in the relief of neuropathic pain after SCI in humans. © 2008 Wiley-Liss, Inc. [source] Temporal and spatial profiles of cell loss after spinal cord injury: Reduction by a metalloporphyrinJOURNAL OF NEUROSCIENCE RESEARCH, Issue 10 2007Xiang Ling Abstract This study presents quantitative temporal and spatial profiles of neuronal loss and apoptosis following a contusion spinal cord injury (50 g · cm). The profiles were evaluated by counting the cresol violet,stained surviving cells and the total number of TUNEL-positive cells and of TUNEL-positive neurons in sections 0, 4 mm from the epicenter and 1, 6, 12, 24, 48, and 72 hr and 1 week postinjury. We demonstrated that neurons continue to disappear over 1 week postinjury and that neuronal loss shifts to areas longer distances from the epicenter over time. TUNEL-positive cells in both gray and white matter appeared after 6 hr, gradually increased to a peak level after 48 hr, and declined by 72 hr postinjury. TUNEL-positive neurons peaked earlier and were present for 1 week, although the total number of neurons was reduced significantly by the end of the week. The neuronal loss and apoptosis were partially prevented by a metalloporphyrin [Mn(III) tetrakis (4-benzoic acid) porphyrin (MnTBAP)]. We demonstrated that MnTBAP (10 and 50 mg/kg, given intraperitoneally) significantly reduced neuronal death in the sections 1,2.5 mm rostral and 1 mm caudal from the epicenter compared with that in the vehicle-treated group, suggesting MnTBAP is more effective in the sections rostral than in those caudal to the epicenter. MnTBAP (10 mg/kg) significantly reduced the number of TUNEL-positive neurons in the sections 1 mm caudal from the epicenter. Our profiles provide a database for pharmacological intervention, and our results on MnTBAP treatment support an important role for antioxidant therapy in spinal cord injury. © 2007 Wiley-Liss, Inc. [source] Brain-derived neurotrophic factor applied to the motor cortex promotes sprouting of corticospinal fibers but not regeneration into a peripheral nerve transplantJOURNAL OF NEUROSCIENCE RESEARCH, Issue 2 2002G.W. Hiebert Abstract Previous experiments from our laboratory have shown that application of brain-derived neurotrophic factor (BDNF) to the red nucleus or the motor cortex stimulates an increase in the expression of regeneration-associated genes in rubrospinal and corticospinal neurons. Furthermore, we have previously shown that BDNF application stimulates regeneration of rubrospinal axons into a peripheral graft after a thoracic injury. The current study investigates whether application of BDNF to the motor cortex will facilitate regeneration of corticospinal neurons into a peripheral nerve graft placed into the thoracic spinal cord. In adult Sprague Dawley rats, the dorsal columns and the corticospinal tract between T9 and T10 were ablated by suction, and a 5-mm-long segment of predegenerated tibial nerve was autograft implanted into the lesion. With an osmotic pump, BDNF was infused directly into the parenchyma of the motor cortex for 14 days. Growth of the corticospinal tract into the nerve graft was then evaluated by transport of an anterograde tracer. Anterogradely labeled corticospinal fibers were not observed in the peripheral nerve graft in animals treated with saline or BDNF. Serotinergic and noradrenergic fibers, as well as peripheral sensory afferents, were observed to penetrate the graft, indicating the viability of the peripheral nerve graft as a permissive growth substrate for these specific fiber types. Although treatment of the corticospinal fibers with BDNF failed to produce regeneration into the graft, there was a distinct increase in the number of axonal sprouts rostral to the injury site. This indicates that treatment of corticospinal neurons with neurotrophins, e.g., BDNF, can be used to enhance sprouting of corticospinal axons within the spinal cord. Whether such sprouting leads to functional recovery after spinal cord injury is currently under investigation. © 2002 Wiley-Liss, Inc. [source] CLINICAL, MRI, AND SKIN BIOPSY FINDINGS IN SENSORY GANGLIONOPATHIESJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 1 2000A. Sghirlanzoni Unlike peripheral motor disorders, sensory disturbances are rarely diagnosed by the probable site of pathology. This approach is useful in the differential diagnosis between chronic sensory axonal neuropathies and ganglionopathies, in which routine clinical and neurophysiological evaluation alone often do not provide definite clues. Methods: Thirty patients with peripheral sensory disturbances were investigated. MRI was performed at cervical level in all cases. Four patients also underwent thoracic and lumbar MRI. Seventeen patients underwent skin biopsy at the proximal thigh and the distal leg. In 4 of them, further skin biopsies were taken at C5 dermatome and at the hand. Density of intra-epidermal nerve fibers (IENF) was quantified. Results: In 22 patients, sensory ganglionopathy was suspected. Disease was idiopathic in 7 cases; paraneoplastic in 3 cases; and associated with Sjögren, AIDS, autoimmune chronic hepatitis, and cisplatin neurotoxicity in 4 cases. One patient had a hereditary sensory autonomic neuropathy. Four patients had vitamin E deficiency and 3 patients a spinocerebellar syndrome. In 8 patients, sensory axonal neuropathy related to diabetes, alcoholism, and AIDS on antiretroviral treatment, and monoclonal gammopathy of undetermined significance was diagnosed. MRI findings: All ganglionopathy patients showed posterior columns hyperintensity on T2-weighted MRI. Conversely, MRI was negative in all axonal sensory neuropathy patients. Skin biopsy findings: In neuropathies, IENF density was significantly lower at the distal leg than at the proximal thigh, while ganglionopathies did not show any change with respect to the rostral:caudal orientation. A similar pattern of epidermal denervation was observed in the arm. Discussion: The degeneration of both central and peripheral sensory pathway in a fashion that is not length-dependent localizes the disease to T-shaped sensory neurons Early ataxia and cutaneous sensory symptoms involving the proximal regions of the body reflect this pattern of denervation and should prompt the diagnosis of ganglionopathy. This can be confirmed by T2-weighted hyperintensity in the posterior columns and a distinct pattern of IENF loss. [source] Case studies in novel narial anatomy: 2.JOURNAL OF ZOOLOGY, Issue 4 2004The enigmatic nose of moose (Artiodactyla: Cervidae: Alces alces) Abstract The facial region of moose Alces alces is highly divergent relative to other cervids and other ruminants. In particular, the narial region forms an expanded muzzle or proboscis that overhangs the mouth. The nose of moose provides a case study in the evolution of narial novelty within a phylogenetically well-resolved group (Cervidae). The function of the nasal apparatus of moose remains enigmatic, and new hypotheses are proposed based on our anatomical findings. Head specimens of moose and outgroup taxa were subjected to medical imaging (CT scanning), vascular injection, gross anatomical dissection, gross sectioning, and skeletonization. Moose noses are characterized by highly enlarged nostrils accompanied by specialized musculature, expanded nasal cartilages, and an increase in the connective-tissue pad serving as the termination of the alar fold. The nostrils are widely separated, and the rhinarium that encircles both nostrils in outgroups is reduced to a tiny central patch in moose. The dorsal lateral nasal cartilage is modified to form a pulley mechanism associated with the levator muscle of the upper lip. The lateral accessory nasal cartilage is enlarged and serves as an attachment site for musculature controlling the aperture of the nostril, particularly the lateralis nasi, the apical dilatators, and the rectus nasi. Bony support for narial structures is reduced. Moose show greatly enlarged nasal cartilages, and the entire osseocartilaginous apparatus is relatively much larger than in outgroups. The nasal vestibule of moose is very large and houses a system of three recesses: one rostral and one caudal to the nostrils, and one associated with the enlarged fibrofatty alar fold. As a result of the expanded nasal vestibule, osseous support for the nasal conchae (i.e. turbinates) has retracted caudally along with the bony nasal aperture. The nasoturbinate and its mucosal counterparts (dorsal nasal concha and rectal fold) are reduced. The upturned maxilloturbinate, however, is associated with an enlarged ventral nasal concha and alar fold. Moose are the only species of cervid with these particular characteristics, indicating that this anatomical configuration is indeed novel. Although functional hypotheses await testing, our anatomical findings and published behavioural observations suggest that the novel narial apparatus of moose probably has less to do with respiratory physiology than with functions pertaining specifically to the nostrils. The widely separated and laterally facing nostrils may enhance stereolfaction (i.e. extracting directional cues from gradients of odorant molecules in the environment), but other attributes of narial architecture (enlarged cartilages, specialized musculature, recesses, fibrofatty pads) suggest that this function may not have been the evolutionary driving force. Rather, these attributes suggest a mechanical function, namely, an elaborated nostril-closing system. [source] The internal cranial anatomy of the Plesiosauria (Reptilia, Sauropterygia): evidence for a functional secondary palateLETHAIA, Issue 4 2006Marie-Céline Buchy In the late 19th Century, the choanae (or internal nares) of the Plesiosauria were identified as a pair of palatal openings located rostral to the external nares, implying a rostrally directed respiratory duct and air path inside the rostrum. Despite obvious functional shortcomings, this idea was firmly established in the scientific literature by the first decade of the 20th Century. The functional consequences of this morphology were only re-examined by the end of the 20th Century, leading to the conclusion that the choanae were not involved in respiration but instead in underwater olfaction, the animals supposedly breathing with the mouth agape. Re-evaluation of the palatal and internal cranial anatomy of the Plesiosauria reveals that the traditional identification of the choanae as a pair of fenestrae situated rostral to the external nares appears erroneous. These openings more likely represent the bony apertures of ducts that lead to internal salt glands situated inside the maxillary rostrum. The ,real' functional choanae (or caudal interpterygoid vacuities), are situated at the caudal end of the bony palate between the sub-temporal fossae, as was suggested in the mid-19th Century. The existence of a functional secondary palate in the Plesiosauria is therefore strongly supported, and the anatomical, physiological, and evolutionary implications of such a structure are discussed. [source] | |||||||||||||||||||||||||||||||