bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effects of selective amygdala, orbital frontal cortex or hippocampal formation lesions on reward assessment in nonhuman primates
Authors: Machado Christopher J. , Bachevalier Jocelyne 
Published: June 2007

AbstractWe examined the effects of bilateral amygdaloid, hippocampal or orbital frontal cortex lesions on reward assessment in rhesus monkeys (Macaca mulatta). In Experiment 1, basic preferences for foods and inedible nonfoods were measured pre‐ and postsurgery. None of the lesions produced changes in animals' preferences for palatable foods or raw meat relative to presurgery, although amygdaloid or hippocampal lesions yielded increased preference for inedible nonfoods postsurgery. When the reinforcement value of each animal's highest‐preferred food was decreased by selective satiation, only animals with neurotoxic orbital frontal cortex lesions continued to select the sated food. Experiment 2 measured the impact of each lesion on learning 60 concurrent discrimination problems and, then, on flexibly avoiding objects associated with sated foods in favour of objects associated with nonsated foods. None of the lesions affected concurrent discrimination learning, but animals with neurotoxic amygdala or aspiration orbital frontal lesions could not refrain from displacing items covering devalued foods. Only animals with orbital lesions also selected the devalued food beneath the object. The results indicate a functional dissociation for the amygdala and orbital frontal cortex in reward assessment, depending on the type of the reinforcer available (objects vs. food). Finally, this is the first study indicating that the hippocampal formation is involved in the assessment of familiar nonfoods, but not in judging the current value of unconditioned and conditioned reinforcers.
Differential c‐fos expression in the brain of male Japanese quail following exposure to stimuli that predict or do not predict the arrival of a female
Authors: Taziaux M. , Lopez J. , Cornil C. A. , Balthazart J. , Holloway K. S. 
Published: June 2007

AbstractWe investigated the effects of presenting a sexual conditioned stimulus on the expression of c‐fos in male Japanese quail. Eight brain sites were selected for analysis based on previous reports of c‐fos expression in these areas correlated with sexual behaviour or learning. Males received either paired or explicitly unpaired presentations of an arbitrary stimulus and visual access to a female. Nine conditioning trials were conducted, one per day, for each subject. On the day following the ninth trial, subjects were exposed to the conditional stimulus (CS) for 5 min. Conditioning was confirmed by analysis of rhythmic cloacal sphincter movements (RCSM), an appetitive sexual behaviour, made in response to the CS presentation. Subjects in the paired condition performed significantly more RCSM than subjects in the unpaired group. Brains were collected 90 min following the stimulus exposure and stained by immunohistochemistry for the FOS protein. Significant group differences in the number of FOS‐immunoreactive (FOS‐ir) cells were found in two brain regions, the nucleus taeniae of the amygdala (TnA) and the hippocampus (Hp). Subjects in the paired condition had fewer FOS‐ir cells in both areas than subjects in the unpaired condition. These data provide additional support to the hypothesis that TnA is implicated in the expression of appetitive sexual behaviours in male quail and corroborate numerous previous reports of the involvement of the hippocampus in conditioning. Further, these data suggest that conditioned and unconditioned sexual stimuli activate different brain regions but have similar behavioural consequences.
Serotonin increases the excitability of the hypothalamic paraventricular nucleus magnocellular neurons
Authors: Ho Sara S. N. , Chow Billy K. C. , Yung Wing‐Ho 
Published: June 2007

AbstractRecent evidence that 5‐hydroxytryptamine (5‐HT or serotonin) enhances the release and the gene expression of vasopressin and oxytocin in the hypothalamic paraventricular nucleus (PVN) suggests that 5‐HT can excite the PVN magnocellular neurons. The objective of this study was to examine the underlying mechanisms for such excitatory action in the electrophysiologically identified hypothalamic PVN magnocellular neurons in rats using whole‐cell patch‐clamp. We found that 5‐HT weakly depolarizes 33.3% of PVN magnocellular neurons in the presence of tetrodotoxin. A minuscule inward current was produced by 5‐HT in 48% of the cells, which was attenuated when the 5‐HT4 antagonist GR113808 or the 5‐HT7 antagonist SB269970 was added. In addition, 5‐HT reduced the frequency of miniature inhibitory postsynaptic currents in a dose‐dependent manner. This inhibition was mimicked by the 5‐HT1B agonist CP93129, and reversed in the presence of 5‐HT1B antagonists cyanopindolol and SB224289. Besides, 5‐HT induced a biphasic effect on the frequency of miniature excitatory postsynaptic currents, comprising a transient inhibition and a delayed concentration‐dependent excitation (onset latency ∼ 5 min). The facilitation was mimicked by the 5‐HT2A/2C agonist DOI and abolished in the presence of the 5‐HT2C antagonist RS102221. Our findings reveal that 5‐HT directly increases the excitability of the PVN magnocellular neurons via multiple receptor subtypes and mechanisms. This may help understanding the regulation of 5‐HT‐induced hormone release and feeding behavior in the PVN.
Development of structural and functional connectivity in the thalamocortical somatosensory pathway in the wallaby
Authors: Leamey C. A. , Flett D. L. , Ho S. M. , Marotte L. R. 
Published: June 2007

AbstractNeuronal activity is implicated as a driving force in the development of sensory systems. In order for it to play a developmental role, however, the pathways involved must be capable of transmitting this activity. The relationship between afferent arrival, synapse formation and the onset of chemical neurotransmission has been examined using the advantageous model of a marsupial mammal, the wallaby (Macropus eugenii), to determine at what stage activity has the capacity to influence cortical development. It is known that thalamocortical afferents arrive in the somatosensory cortex on postnatal day (P)15 and that their growth cones reach to the base of the compact cell zone of the cortical plate. However, electronmicroscopy showed that thalamocortical synapses were absent at this stage. Glutamatergic responses were recorded in the cortex following stimulation of the thalamus in slices at this time but only in magnesium‐free conditions. The responses were mediated entirely by N‐methyl‐d‐aspartate (NMDA) receptors. From P28, responses could be recorded in normal magnesium and comprised a dominant NMDA‐mediated component and a non‐NMDA mediated component. At this time thalamocortical synapses were first identified and they were in the cortical plate. By P63 the non‐NMDA‐mediated component had increased relative to the NMDA‐mediated component, and by P70 layer IV began to emerge and contained thalamocortical synapses. By P76 a fast non‐NMDA‐mediated peak dominated the response. This coincides with the appearance of cortical whisker‐related patches and the onset in vivo of responses to peripheral stimulation of the whiskers.
Auditory evoked fields differentially encode speech features: an MEG investigation of the P50m and N100m time courses during syllable processing
Authors: Tavabi Kambiz , Obleser Jonas , Dobel Christian , Pantev Christo 
Published: June 2007

AbstractThe functional organization of speech sound processing in the human brain and its unfolding over time are still not well understood. While the N100/N100m is a comparatively well‐studied, and quite late, component of the auditory evoked field elicited by speech, earlier processes such as those reflected in the P50m remain to be resolved. Using magnetoencephalography, the present study follows up on previous reports of N100m‐centred spatiotemporal encoding of phonological features and coarticulatory processes in the auditory cortex during consonant–vowel syllable perception. Our results indicate that the time course and response strength of the P50m and N100m components of evoked magnetic fields are differentially influenced by mutually exclusive place‐of‐articulation features of a syllable's stop consonant and vowel segments. Topographical differences in P50m generators were driven by place contrasts between consonants in syllables, with spatial gradients orthogonal to the ones previously reported for N100m. Peak latency results replicated previous findings for the N100m and revealed a reverse pattern for the earlier P50m (shorter latencies depending on the presence of a back vowel [o]). Our findings allow attribution of a role in basic feature extraction to the comparatively early P50m time window. Moreover, the observations substantiate the assumption that the N100m response reflects a more abstract phonological representational stage during speech perception.
Simulation of robustness against lesions of cortical networks
Authors: Kaiser Marcus , Martin Robert , Andras Peter , Young Malcolm P. 
Published: June 2007

AbstractStructure entails function, and thus a structural description of the brain will help to understand its function and may provide insights into many properties of brain systems, from their robustness and recovery from damage to their dynamics and even their evolution. Advances in the analysis of complex networks provide useful new approaches to understanding structural and functional properties of brain networks. Structural properties of networks recently described allow their characterization as small‐world, random (exponential) and scale‐free. They complement the set of other properties that have been explored in the context of brain connectivity, such as topology, hodology, clustering and hierarchical organization. Here we apply new network analysis methods to cortical interareal connectivity networks for the cat and macaque brains. We compare these corticocortical fibre networks to benchmark rewired, small‐world, scale‐free and random networks using two analysis strategies, in which we measure the effects of the removal of nodes and connections on the structural properties of the cortical networks. The structural decay of the brain networks is in most respects similar to that of scale‐free networks. The results implicate highly connected hub‐nodes and bottleneck connections as a structural basis for some of the conditional robustness of brain systems. This informs the understanding of the development of connectivity of the brain networks.
Inhibition of spinal constitutive NOS‐2 by 1400W attenuates tissue injury and inflammation‐induced hyperalgesia and spinal p38 activation
Authors: Tang Qingbo , Svensson Camilla I. , Fitzsimmons Bethany , Webb Michael , Yaksh Tony L. , Hua Xiao‐Ying 
Published: June 2007

AbstractNitric oxide (NO) and its synthesizing enzymes, including NO synthase‐2 (NOS‐2, also called inducible NOS, iNOS), have been implicated in spinal nociception. 1400W is a highly selective NOS‐2 inhibitor, as compared with either NOS‐1 (neuronal NOS, nNOS) or NOS‐3 (endothelial NOS). Here we examined the anti‐nociceptive effects of intrathecal (IT) administration of 1400W in two experimental models of hyperalgesia (formalin and carrageenan models), in addition to the effect of 1400W on stimulation‐induced activation of spinal p38 mitogen‐activated protein kinase (p38). IT treatment of rats with 1400W produced a dose‐dependent inhibition of paw formalin‐induced phase II flinches, and attenuated carrageenan‐induced thermal hyperalgesia. In contrast, IT injection of a selective inhibitor of NOS‐1, nNOS inhibitor‐I, had no effect in either model. Furthermore, 1400W at a dose that suppressed formalin‐induced flinching behavior also blocked formalin‐evoked p38 phosphorylation (activation) in the spinal cord, while nNOS inhibitor‐I displayed no activity. The prompt effects of IT 1400W suggest involvement of constitutively expressed NOS‐2 in spinal nociception. The NOS‐2 protein in rat spinal cords was undetectable by Western blotting. However, when the protein was immunoprecipitated prior to Western blotting, NOS‐2‐immunoreactive bands were detected in the tissues, including naïve spinal cords. The presence of constitutive spinal NOS‐2 was further confirmed by reverse transcriptase‐polymerase chain reaction. Taken together, the present studies suggest that constitutively expressed spinal NOS‐2 mediates tissue injury and inflammation‐induced hyperalgesia, and that activation of p38 is one of the downstream factors in NO‐mediated signaling in the initial processing of spinal nociception.
Experimental clipping of sagebrush inhibits seed germination of neighbours
Authors: Karban Richard 
Published: June 2007

AbstractCurrent views of plant communities emphasize the importance of competition for resources and colonization ability in determining seedling establishment and plant distributions. Many desert shrubs are surrounded by bare zones that lack other plants or have different suites of species beneath them compared with the open desert surrounding them. Releases of biochemicals as volatiles from leaves, leachates from litter, or exudates from roots have been proposed as mechanisms for this pattern, but such phytotoxicity has been controversial. I tested the hypothesis that experimental clipping of sagebrush foliage enhances its effect as a germination inhibitor. Germination of native forbs and grasses was reduced in association with clipped, compared with unclipped, sagebrush foliage in lath house and field experiments. Sagebrush seeds were not significantly affected. Air contact was required for this inhibition of germination. Soil contact and leaf litter were not required and added little inhibition of germination. These results suggest a potentially large, indirect, and previously overlooked role for interactions between herbivory and germination that could affect plant community structure.
The impact of computer‐mediated interaction on distance learning
Authors: Godwin Stephen J. , Thorpe Mary S. , Richardson John T. E. 
Published: June 2007

AbstractDistance‐learning courses were classified with regard to their use of computer‐mediated interaction and the degree to which such interaction was integrated into the curriculum and the assessment regime. This produced four groups of courses varying according to their use of interaction and integration. The impact of interaction and integration was investigated in terms of their effects on students' performance, their perceptions of academic quality and their approaches to studying. In all three respects, variations within the groups of courses proved to be more important than variations between the groups. Interpretation of these results suggests that the adoption of interactive environments within computer‐mediated learning may not be enough in itself to lead to positive learning outcomes. We found no evidence for this assumption in terms of students' completion rates, pass rates, grades, perceptions of the quality of their courses or approaches to studying. Large variations in the measured indicators were found between courses, and these appeared to be largely independent of the effects of interaction and integration. Courses may differ markedly with regard to how they make use of computer‐mediated interaction and how this is integrated into the curriculum and the assessment regime. A case study approach is suggested as being more likely to identify the impact of specific designs based on computer‐mediated interaction and to bring together the diverse student responses arising from the use of such interaction in their studies.
SECOND HOMES AND COMPACT CITIES IN SPAIN: TWO ELEMENTS OF THE SAME SYSTEM?
Authors: MÓDENES JUAN‐ANTONIO , LÓPEZ‐COLÁS JULIÁN 
Published: June 2007

ABSTRACTThe aim of this paper is to connect two processes that have been analysed independently to date and that have characterised the housing experience of the Spanish population. On the one hand, the consequences induced by the high density of Spanish urban spaces on other spatial spheres of people's lives and on the other hand, the traditional presence and the recent expansion of second home possession. In this context, we will demonstrate that, in Spain, a strong statistical relationship has been established between the location of main dwellings in a very dense urban context and a greater probability of having second homes. This relationship is better known in the scientific literature as the ‘compensation hypothesis’.
INTERNATIONAL CO‐OPERATION OF POLISH MUNICIPALITIES: DIRECTIONS and EFFECTS
Authors: FURMANKIEWICZ MAREK 
Published: June 2007

ABSTRACTThe paper describes and discusses the outcomes of the cross‐border and international co‐operation (CIC) of Polish local governments in the years 1990–2004 (before Polish accession to the European Union), indicated by local government officers in a questionnaire survey, and finally it gives some general conclusions as to future CIC support policy. In 2004, nearly half of all existing 2,500 Polish municipalities participated in CIC. They achieved most frequently non‐material local effects of co‐operation in euroregions and in town‐twinning (citizen and professional exchange, etc.). The economic effects such as investments, equipment purchases, innovative management, etc. were achieved to a lower degree, but they were important in improving local public services in dozens of urban municipalities. In general, CIC enhanced mainly European integration in creating links between communities and helping to overcome negative national prejudices, but to a lesser degree integration interpreted as levelling economic differences.
Economic Progress, Social Regress?
Authors: FARMER AMY , KALI RAJA 
Published: June 2007

AbstractA central issue in the debate regarding the relevance of social capital is whether the decline in social embeddedness that has attended modernization over the last 40 years in the United States is as harmful as Putnam, among others, claim it to be. Critics of Putnam's thesis argue that various arms‐length institutions fulfil the roles performed by social capital thereby mitigating the negative impact of its recent decline. We develop a framework that provides insight into when such institutions may be adequate and when they might not. We find that if market (economic) and non‐market (social) interactions differ in their payoffs but are interlinked through the modernization of the economy, the optimal level of modernization in market interactions will be higher than that in non‐market interactions. Further, market supporting institutions are likely to increase the divergence between economic and social interactions since analogs for market institutions that constrain opportunistic behavior are usually nonexistent in social contexts. In this sense, economic progress may be accompanied by social regress.
Mutant SOD1G93A microglia are more neurotoxic relative to wild‐type microglia
Authors: Xiao Qin , Zhao Weihua , Beers David R. , Yen Albert A. , Xie Wenjie , Henkel Jenny S. , Appel Stanley H. 
Published: June 2007

AbstractRecent studies suggest that microglia over‐expressing mutant human superoxide dismutase (mSOD1G93A) may contribute to motoneuron death in a transgenic mouse model of familial amyotrophic lateral sclerosis. To further assess the relative neurotoxicity of wild‐type microglia, mSOD1G93A microglia, and microglia over‐expressing wild‐type human SOD1, we used primary cultures of microglia and motoneurons in the presence and absence of lipopolysaccharide stimulation. Following activation with lipopolysaccharide, mSOD1G93A microglia released more nitric oxide, more superoxide, and less insulin‐like growth factor‐1 than wild‐type microglia. In microglia/motoneuron co‐cultures, mSOD1G93A microglia induced more motoneuron death and decreased neurite numbers and length compared with wild‐type microglia. Mutant SOD1G93A microglia also induced more motoneuron injury than microglia over‐expressing wild‐type human SOD1 in microglia/motoneuron co‐cultures. Motoneuron survival was inversely correlated with nitrate + nitrite concentrations in mSOD1G93A co‐cultures, suggesting the important role of nitric oxide in microglia‐induced motoneuron injury. Thus, relative to wild‐type microglia, mSOD1G93A microglia were more neurotoxic and induced more motoneuron injury than similarly treated wild‐type microglia.
Apoptotic action of E2F1 requires glycogen synthase kinase 3‐β activity in PC12 cells
Authors: Espada Lilia , Udapudi Basavaraj , Podlesniy Petar , Fabregat Isabel , Espinet Carme , Tauler Albert 
Published: June 2007

AbstractBoth E2F1 and GSK3β have been described as essential targets in neuronal apoptosis. Previous studies have demonstrated that GSK3β binds to E2F1 in vivo. We wanted to investigate whether these proteins could share a common apoptotic signal pathway in neuronal cells. With this intention, we developed a PC12 ER‐E2F1 stable cell line in which E2F1 activity was dependent on the presence of 4‐hydroxitamoxifen. E2F1 activation produced apoptosis in naive and post‐mitotic cells; serum and nerve growth factor respectively protected them from E2F1 apoptotic stimuli. The presence of specific GSK3β inhibitors SB216763 and LiCl completely protected cells from apoptosis induced by E2F1 activation. In addition, knocked down GSK3β experiments by small interference RNAs have demonstrated that a reduction of GSK3β protein levels can lower the apoptotic effect of E2F1. Finally, we demonstrated that the apoptotic effect of E2F1 is not due to the regulation of GSK3β activity, and that the inhibitory effect of GSK3β inhibitor SB216763 on E2F1 induced apoptosis could be due to an alteration in the E2F1‐regulated transcription gene pattern. In summary, we have demonstrated that the apoptotic action of E2F1 requires GSK3β activity.
champuru 1.0: a computer software for unraveling mixtures of two DNA sequences of unequal lengths
Authors: FLOT JEAN‐FRANÇOIS 
Published: June 2007

Abstract champuru is an interactive, user‐friendly web software that facilitates the deconvolution of mixed chromatograms obtained when sequencing directly mixtures of two DNA templates of unequal lengths. The program takes as input two strings of characters describing the forward and reverse chromatograms as obtained by direct sequencing and returns, most often after several iterations aimed at correcting basecalling errors, the sequences of the two templates present in the mixture. champuru was written in perl, with a web interface accessible online at http://134.157.186.185/champuru/champuru.htm.