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Response Patterns (response + pattern)
Selected AbstractsThe effects of salinity on aquatic plant germination and zooplankton hatching from two wetland sedimentsFRESHWATER BIOLOGY, Issue 12 2003Daryl L. Nielsen Summary 1. The effect of increasing salinity on the emergence of zooplankton eggs and the germination of aquatic plant seeds from the sediment of two wetlands was examined. Salinity was found to cause reductions in species richness and abundance of aquatic plants and zooplankton at salinities between 1000 and 5000 mg L,1. Aquatic plants also had an associated decrease in above ground biomass. 2. Individual taxa showed different responses to salinity, and four response patterns were identified: (i) increased number of organisms emerging at 1000 mg L,1; (ii) decreased number of organisms emerging above 1000 mg L,1; (iii) decreased number of organisms emerging between 300 and 1000 mg L,1; (iv) no difference in number of organisms emerging across the range of salinities. Response patterns (iii) and (iv) were common to both plants and zooplankton, whereas response patterns (i) and (ii) were only identified for zooplankton. 3. Results indicate that there is potential for the increasing salinity in Australian rivers and wetlands to decrease the species richness of aquatic communities resulting in loss of wetland biodiversity. [source] Naturalistic stimulus trains evoke reproducible subicular responses both within and between animals in vivoHIPPOCAMPUS, Issue 2 2010Beth Tunstall Abstract Previous investigation of CA1-evoked subicular responses has used either single low-frequency pulses (LF), paired-pulses (PP), or high-frequency bursts. Here we test for the first time how subiculum responds to naturalistic stimulation trains (NSTs). We recorded CA1-evoked field potentials from dorsal rat subiculum in response to LF, PP, and two NST patterns. The latter were derived from CA1 place cell activity; NST1 contained bursts of stimuli presented in two main episodes, while the burst-patterned stimuli in NST2 were spaced more evenly. NSTs generated significantly greater field responses compared with LF or PP patterns. Response patterns to either NST were significantly correlated across trial repeats in 9 out of 10 rats, supporting a robust postsynaptic encoding of CA1 input by subiculum. Correlations between NST responses were also observed across experiments; however, these were more variable than those within experiments. The relationship between response magnitude and activation history revealed a strong correlation between magnitude and NST instantaneous frequency for NST1 but was weaker for NST2. In addition, the number of stimuli within a prior 500 ms window was a determining factor for response magnitude for both NSTs. Overall, the robust reproducibility in subicular responses within rats suggests that information within NSTs is faithfully transmitted through the CA1-subiculum axis. However, variation in response sequences across rats suggests that encoding patterns to the same input differ across the subiculum. Changes in the ratio of target bursting and regularly spiking neurons along the subicular proximodistal axis may account for this variation. The activation history of this connection also appears to be a strong determining factor for response magnitude. © 2009 Wiley-Liss, Inc. [source] Differences in cognitive factors between "true drug" versus "placebo pattern" response to fluoxetine as defined by pattern analysisHUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 4 2006Amy H. Farabaugh Abstract Objective Pattern analysis has identified two types of response patterns to antidepressants: "true drug" response (TDR) and "placebo pattern" response (PPR). This study examines the relationship between cognitive factors and TDR and PPR to fluoxetine. Methods We assessed 310 outpatients meeting DSM-III-R criteria for major depressive disorder (MDD) who were enrolled in an 8-week open trial of fluoxetine 20,mg/day. Response patterns were determined using the clinical global impressions-improvement (CGI-I). We administered the following self-rated scales to all patients at the baseline visit and at endpoint: perceived stress scale (PSS), cognitions questionnaire (CQ), Beck hopelessness scale (BHS) and dysfunctional attitudes scale (DAS). Results One hundred and thirty-four patients had TDR, 66 patients had PPR, and 110 patients were non-responders (NR). Demographic variables and severity of depression at baseline (HAMD-17) were not significantly different between the two response pattern groups. We compared cognitive factors before and after treatment across patients with TDR and PPR, and there were no significant differences at baseline in CQ, PSS, BHS, and DAS scores. At endpoint, outpatients with PPR had significantly lower scores on the PSS (p,<,0.001) compared to the patients with TDR, even after adjusting for multiple comparisons and severity of depression at endpoint. Conclusions Significant differences in cognitive/psychological factors, specifically lower post-treatment perceived stress, accompany "placebo" pattern of response to antidepressant treatment and differentiate it from "true drug" response pattern, as defined by pattern analysis. Copyright © 2006 John Wiley & Sons, Ltd. [source] Patterns of growth of juvenile pink abalone Haliotis corrugata fed re-hydrated natural feeds at a laboratory and a hatcheryAQUACULTURE NUTRITION, Issue 3 2009E. SERVIERE-ZARAGOZA Abstract The feasibility of obtaining a similar growth response from juvenile pink abalone Haliotis corrugata at a research laboratory and a hatchery, when using natural feeds was evaluated. Four macroalgae, Egregia menziesii, Eisenia arborea, Macrocystis pyrifera, Gracilaria sp., and the surfgrass Phyllospadix torreyi were used as feeds. Response patterns of abalone were very similar at both facilities in terms of final length, weight, and survival, varying from 13.0 to 15.50 mm, 0.31 to 0.52 g, and 60.0% to 78.6%, respectively. Better growth was obtained when E. menziesii, M. pyrifera, and Gracilaria sp. were offered. Poor results were obtained with surfgrass. The feed conversion ratio was determined at the laboratory and did not vary significantly, ranging from 42.3 to 199.0; although a significant inverse correlation was observed with growth rate. Growth in length and weight and survival rates varied within 1.6,20.2 ,m day,1, 0.123,1.664 mgday,1, 0.4,0.64%day,1, respectively. Mean growth rate in length (14.7,m day,1) and weight (1.18 mg day,1) at the hatchery were significantly higher than that obtained at the laboratory (9.4 ,m day,1 and 0.77 mg day,1), which is most likely a consequence of more suitable water temperature at the hatchery. Mean survival rate was significantly higher at the laboratory (53.1%day,1) than at the hatchery (46.1%day,1). [source] To generalize or not to generalize: spatial categories are influenced by physical attributes and languageDEVELOPMENTAL SCIENCE, Issue 1 2009Susan J. Hespos The current work explored the conditions under which infants generalize spatial relationships from one event to another. English-learning 5-month-olds habituated to a tight- or loose-fit covering event dishabituated to a change in fit during a containment test event, but infants habituated to a visually similar occlusion event did not. Thus, infants' responses appeared to be driven by the physical nature of the fit rather than visual similarity. This response pattern was replicated with Korean-speaking adults, but English-speaking adults showed no sensitivity to change in fit for either event. These findings suggest that language development links linguistic forms to universal, pre-existing representations of meaning, and that linguistic experience can shape sensitivity to distinctions that are marked in one's native language. [source] Soil erosion assessment using geomorphological remote sensing techniques: an example from southern ItalyEARTH SURFACE PROCESSES AND LANDFORMS, Issue 3 2010Sergio Lo Curzio Abstract The aim of this study is to assess of the distribution and map the geomorphological effects of soil erosion at the basin scale identifying newly-formed erosional landsurfaces (NeFELs), by means of an integration of Landsat ETM 7+ remotely sensed data and field-surveyed geomorphological data. The study was performed on a 228·6,km2 -wide area, located in southern Italy. The study area was first characterized from a lithological, pedological, land-use and morpho-topographic point of view and thematic maps were created. Then, the georeferenced Landsat ETM 7+ satellite imagery was processed using the RSI ENVI 4.0 software. The processing consisted of contrast stretching, principal component analysis (PCA), decorrelation stretching and RGB false colour compositing. A field survey was conducted to characterize the features detected on the imagery. Particular attention was given to the NeFELs, which were located using a global positioning system (GPS). We then delimited the Regions of Interest (ROI) on the Landsat ETM 7+ imagery, i.e. polygons representing the ,ground-truth', discriminating the NeFELs from the other features occurring in the imagery. A simple statistical analysis was conducted on the digital number (DN) values of the pixels enclosed in the ROI of the NeFELs, with the aim to determine the spectral response pattern of such landsurfaces. The NeFELs were then classified in the entire image using a maximum likelihood classification algorithm. The results of the classification process were checked in the field. Finally, a spatial analysis was performed by converting the detected landsurfaces into vectorial format and importing them into the ESRI ArcViewGIS 9.0 software. Application of these procedures, together with the results of the field survey, highlighted that some ,objects' in the classified imagery, even if displaying the same spectral response of NeFELs, were not landsurfaces subject to intense soil erosion, thus confirming the strategic importance of the field-checking for the automatically produced data. During the production of the map of the NeFELs, which is the final result of the study, these ,objects' were eliminated by means of simple, geomorphologically-coherent intersection procedures in a geographic information system (GIS) environment. The overall surface of the NeFELs had an area of 22·9,km2, which was 10% of the total. The spatial analysis showed that the highest frequency of the NeFELs occurred on both south-facing and southwest-facing slopes, cut on clayey-marly deposits, on which fine-textured and carbonate-rich Inceptisols were present and displaying slope angle values ranging from 12° to 20°. The comparison of two satellite imageries of different periods highlighted that the NeFELs were most clearly evident immediately after summer tillage operations and not so evident before them, suggesting that these practices could have played an important role in inducing the erosional processes. Copyright © 2009 John Wiley & Sons, Ltd. [source] Toxicity assessment of reference and natural freshwater sediments with the LuminoTox assayENVIRONMENTAL TOXICOLOGY, Issue 4 2006P. M. Dellamatrice Abstract We examined the possibility of adapting the LuminoTox, a recently-commercialized bioanalytical testing procedure initially developed for aqueous samples, to assess the toxic potential of sediments. This portable fluorescent biosensor uses photosynthetic enzyme complexes (PECs) to rapidly measure photosynthetic efficiency. LuminoTox testing of 14 CRM (Certified Reference Material) sediments was first undertaken with (1) a "solid phase assay" (Lum-SPA) in which PECs are in intimate contact with sediment slurries for a 15 min exposure period and (2) an elutriate assay (Lum-ELU) in which PECs are exposed for 15 min to sediment water elutriates. CRM sediment toxicity data were then compared with those generated with the Microtox Solid Phase Assay (Mic-SPA). A significant correlation (P < 0.05) was shown to exist between Lum-SPA and Mic-SPA, indicating that both tests display a similar toxicity response pattern for CRM sediments having differing contaminant profiles. The sediment elutriate Lum-ELU assay displayed toxicity responses (i.e. measurable IC20s) for eight of the 14 CRM sediments, suggesting that it is capable of determining the presence of sediment contaminants that are readily soluble in an aqueous elutriate. Lum-SPA and Mic-SPA bioassays were further conducted on 12 natural freshwater sediments and their toxicity responses were more weakly, yet significantly, correlated. Finally, Lum-SPA testing undertaken with increasing mixtures of kaolin clay confirmed that its toxicity responses, in a manner similar to those reported for the Mic-SPA assay, are also subject to the influence of grain size. While further studies will be required to more fully understand the relationship between Lum-SPA assay responses and the physicochemical makeup of sediments (e.g., grain size, combined presence of natural and anthropogenic contaminants), these preliminary results suggest that LuminoTox testing could be a useful screen to assess the toxic potential of solid media. © 2006 Wiley Periodicals, Inc. Environ Toxicol 21: 395,402, 2006. [source] Effects of pulp and paper mill effluent on fish: A temporal assessment of fish health across sampling cyclesENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2010Timothy J. Barrett Abstract The Canadian environmental effects monitoring (EEM) program is a regulated, cyclical, industry-funded program designed to determine whether receiving water impacts exist when a mill is in compliance with its discharge limits. The results from three cycles of the fish monitoring program (1992 to 2004) are available from over 200 surveys of fish compared between sites located upstream and downstream of pulp and paper mill effluent outfalls. Previous meta-analyses have shown a national average response pattern across cycles characterized by an increase in endpoints measuring energy storage and growth and a decrease in a reproductive endpoint, consistent with a response of nutrient enrichment in combination with some form of metabolic disruption. Although the national average pattern of effects was temporally consistent, there was some variability in the magnitude of effects among cycles. Questions were raised as to whether the intercycle variability was due to changes in effluent quality or due, at least in part, to other factors. The present study compares responses over the first three cycles, and shows that the choice of sentinel species is likely to be a major contributing factor to the variability in observed effects. Subset analyses using studies from mills that used the same sentinel species across cycles reveal fairly uniform responses and little evidence of significant improvements in overall fish health from cycles one to three. However, a meta-analysis using 1991 data collected from 10 mills before the implementation of the EEM program and data from the same mills collected during cycles one to three of the program reveal significantly reduced effects on relative liver weight and potential improvements in other endpoints. Environ. Toxicol. Chem. 2010;29:440,452. © 2009 SETAC [source] Use of paired fathead minnow (Pimephales promelas) reproductive test.ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 7 2006Part 1: Assessing biological effects of final bleached kraft pulp mill effluent using a mobile bioassay trailer system Abstract Reproductive effects have been recorded in wild fish in waters receiving pulp mill effluent (PME) since the mid to late 1980s. Laboratory assays with fathead minnow (FHM; Pimephales promelas) have been developed to better understand fish responses to PME. However, observations from laboratory studies have been variable, making it difficult to establish cause/effect relationships. A lack of environmental relevance in these laboratory studies may have contributed to the variability observed. The objectives of the present study were, first, to determine the effects of bleached kraft PME (BKME) on FHM under environmentally realistic conditions (i.e., ambient water and effluent quality) and, second, to determine the suitability of pair-breeding FHM to better link BKME-induced changes in indicators at the biochemical, individual, and population levels. A mobile bioassay trailer was situated on-site at a bleached kraft mill for 60 d, allowing supply of both ambient water (Lake Superior, Canada) and final BKME. The reproductive output of FHM was initially assessed for 21 d to obtain baseline data pre-exposure. At the end of the pre-exposure period, selected breeding pairs were exposed to final BKME (100% v/v and 1% v/v) for 21 d. Results demonstrated a stimulatory response pattern at 1% BKME (e.g., increased egg production) compared to control. In the 100% treatment, spawning events were reduced and fewer eggs were produced during the first two weeks of exposure. Exposure to 100% (v/v) BKME also resulted in ovipositor development in males and development of male secondary sex characteristics in females. Obtaining pre-exposure data and use of pair-breeding FHM in this assay gave a sensitive indication of effluent effects and allowed accurate comparisons of endpoints to be made. [source] Developmental changes in the BDNF-induced modulation of inhibitory synaptic transmission in the Kölliker,Fuse nucleus of ratEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 12 2007Miriam Kron Abstract The Kölliker,Fuse nucleus (KF), part of the pontine respiratory group, is involved in the control of respiratory phase duration, and receives both excitatory and inhibitory afferent input from various other brain regions. There is evidence for developmental changes in the modulation of excitatory inputs to the KF by the neurotrophin brain-derived neurotrophic factor (BDNF). In the present study we investigated if BDNF exerts developmental effects on inhibitory synaptic transmission in the KF. Recordings of inhibitory postsynaptic currents (IPSCs) in KF neurons in a pontine slice preparation revealed general developmental changes. Recording of spontaneous and evoked IPSCs (sIPSCs, eIPSCS) revealed that neonatally the ,-aminobutyric acid (GABA)ergic fraction of IPSCs was predominant, while in later developmental stages glycinergic neurotransmission significantly increased. Bath-application of BDNF significantly reduced sIPSC frequency in all developmental stages, while BDNF-mediated modulation on eIPSCs showed developmental differences. The eIPSCs mean amplitude was uniformly and significantly reduced following BDNF application only in neurons from rats younger than postnatal day 10. At later postnatal stages the response pattern became heterogeneous, and both augmentations and reductions of eIPSC amplitudes occurred. All BDNF effects on eIPSCs and sIPSCs were reversed with the tyrosine kinase receptor-B inhibitor K252a. We conclude that developmental changes in inhibitory neurotransmission, including the BDNF-mediated modulation of eIPSCs, relate to the postnatal maturation of the KF. The changes in BDNF-mediated modulation of IPSCs in the KF may have strong implications for developmental changes in synaptic plasticity and the adaptation of the breathing pattern to afferent inputs. [source] Modulation of the bacterial response to spectral solar radiation by algae and limiting nutrientsFRESHWATER BIOLOGY, Issue 11 2002J. M. Medina-Sánchez SUMMARY 1. The response of bacterial production (measured as [3H]TdR incorporation rate) to spectral solar radiation was quantified experimentally in an oligotrophic high-mountain lake over 2 years. Bacterial responses were consistent: ultraviolet-B (UVB) was harmful, whereas ultraviolet-A (UVA) + photosynthetically active radiation (PAR) and PAR enhanced bacterial activity. Full sunlight exerted a net stimulatory effect on bacterial activity in mid-summer but a net inhibitory effect towards the end of the ice-free period. 2. Experiments were undertaken to examine whether the bacterial response pattern depended on the presence of algae and/or was modulated by the availability of a limiting inorganic nutrient (phosphorus, P). In the absence of algae, [3H]TdR incorporation rates were significantly lower than when algae were present under all light treatments, and the consistent bacterial response was lost. This suggests that the bacterial response to spectral solar radiation depends on fresh-C released from algae, which determines the net stimulatory outcome of damage and repair in mid-summer. 3. In the absence of algae, UVB radiation inhibited bacteria when they were strongly P-deficient (mean values of N : P ratio: 46.1), whereas it exerted no direct effect on bacterial activity when they were not P-limited. 4. P-enrichment of lake water markedly altered the response of bacteria to spectral solar radiation at the end of ice-free period, when bacteria were strongly P-deficient. Phosphorus enrichment suppressed the inhibitory effect of full sunlight that was observed in October, both in whole lake water (i.e. including algae) and in the absence of algae. This indicates that the bacterial P-deficiency, measured as the cellular N : P ratio, was partly responsible for the net inhibitory effect of full sunlight, implying a high bacterial vulnerability to UVB. [source] Liver cell proliferation requires methionine adenosyltransferase 2A mRNA up-regulationHEPATOLOGY, Issue 6 2002Covadonga Pañeda Regulation of liver cell proliferation is a key event to control organ size during development and liver regeneration. Methionine adenosyltransferase (MAT) 2A is expressed in proliferating liver, whereas MAT1A is the form expressed in adult quiescent hepatocytes. Here we show that, in H35 hepatoma cells, growth factors such as hepatocyte growth factor (HGF) and insulin up-regulated MAT2A expression. HGF actions were time- and dose-response dependent and required transcriptional activity. Mitogen-activated protein (MAP) kinase and phosphatidylinositol 3-phosphate kinase (PI 3-K) pathways were required for both HGF-induced cell proliferation and MAT2A up-regulation. Furthermore, in H35 cells treated with HGF, the inhibition of these pathways was associated with the switch from the expression of fetal liver MAT2A to the adult liver MAT1A isoform. Fetal liver hepatocytes exhibited an identical response pattern. Treatment of H35 hepatoma cells with MAT2A antisense oligonucleotides decreased cell proliferation induced by HGF; this decrease correlated with the decay in MAT2A messenger RNA (mRNA) levels. Finally, growth inhibitors such as transforming growth factor (TGF) , blocked HGF-induced MAT2A up-regulation while increasing MAT1A mRNA levels in H35 cells. In conclusion, our results show that MAT2A expression not only correlates with liver cell proliferation but is required for this process. [source] Altered representation of expected value in the orbitofrontal cortex in maniaHUMAN BRAIN MAPPING, Issue 7 2010Felix Bermpohl Abstract Objective: Increased responsiveness to appetitive and reduced responsiveness to aversive anticipatory cues may be associated with dysfunction of the brain reward system in mania. Here we studied neural correlates of gain and loss expectation in mania using functional magnetic resonance imaging (fMRI). Method: Fifteen manic patients and 26 matched healthy control individuals performed a monetary incentive delay task, during which subjects anticipated to win or lose a varying amount of money. Varying both magnitude and valence (win, loss) of anticipatory cues allowed us to isolate the effects of magnitude, valence and expected value (magnitude-by-valence interaction). Results: Response times and total gain amount did not differ significantly between groups. FMRI data indicated that the ventral striatum responded according to cued incentive magnitude in both groups, and this effect did not significantly differ between groups. However, a significant group difference was observed for expected value representation in the left lateral orbitofrontal cortex (OFC; BA 11 and 47). In this region, patients showed increasing BOLD responses during expectation of increasing gain and decreasing responses during expectation of increasing loss, while healthy subjects tended to show the inverse effect. In seven patients retested after remission OFC responses adapted to the response pattern of healthy controls. Conclusions: The observed alterations are consistent with a state-related affective processing bias during the expectation of gains and losses which may contribute to clinical features of mania, such as the enhanced motivation for seeking rewards and the underestimation of risks and potential punishments. Hum Brain Mapp, 2010. © 2009 Wiley-Liss, Inc. [source] Covariations among fMRI, skin conductance, and behavioral data during processing of concealed informationHUMAN BRAIN MAPPING, Issue 12 2007Matthias Gamer Abstract Imaging techniques have been used to elucidate the neural correlates that underlie deception. The scientifically best understood paradigm for the detection of deception, however, the guilty knowledge test (GKT), was rarely used in imaging studies. By transferring a GKT-paradigm to a functional magnetic resonance imaging (fMRI) study, while additionally quantifying reaction times and skin conductance responses (SCRs), this study aimed at identifying the neural correlates of the behavioral and electrodermal response pattern typically found in GKT examinations. Prior to MR scanning, subjects viewed two specific items (probes) and were instructed to hide their knowledge of these. Two other specific items were designated as targets and required a different behavioral response during the experiment and eight items served as irrelevant stimuli. Reaction times and SCR amplitudes differed significantly between all three item types. The neuroimaging data revealed that right inferior frontal and mid-cingulate regions were more active for probe and target trials compared to irrelevants. Moreover, the differential activation in the right inferior frontal region was modulated by stimulus conflicts. These results were interpreted as an increased top-down influence on the stimulus-response-mapping for concealed and task-relevant items. Additionally, the influence of working memory and retrieval processes on this activation pattern is discussed. Using parametric analyses, reaction times and SCR amplitudes were found to be linearly related to activity in the cerebellum, the right inferior frontal cortex, and the supplementary motor area. This result provides a first link between behavioral measures, sympathetic arousal, and neural activation patterns during a GKT examination. Hum Brain Mapp 2007. © 2007 Wiley-Liss, Inc. [source] Self-Report and Psychophysiological Responses to Fear AppealsHUMAN COMMUNICATION RESEARCH, Issue 2 2009Juan R. Ordoñana This study was designed to assess the relationship between self-report and psychophysiological responses to fear appeals and behavioral changes elicited by these. Ninety-two subjects watched one of four messages that varied in level of threat (high vs. low) and efficacy (high vs. low). Concomitantly, psychophysiological measures (heart rate and skin conductance) were registered. Perceived threat and efficacy varied according to the characteristics of the message. High-threat messages elicited significantly different levels of autonomic arousal than low-threat messages. Following of behavioral recommendation was higher among subjects who were exposed to the high threat / high efficacy stimulus, those who reported high perceived threat, and for those who showed an autonomic response pattern related to the facilitation of attentional processes. Résumé Les auto-évaluations et les réactions psychophysiologiques aux messages véhiculant des peurs Cette étude fut réalisée afin d'évaluer la relation entre les auto-évaluations et les réactions psychophysiologiques à des messages véhiculant des peurs ainsi que les changements suscités par ceux-ci. 92 sujets ont visionné un de quatre messages variant en niveau de danger (élevé ou faible) et d,efficacité (forte ou faible). En même temps, des mesures psychophysiologiques (le rythme cardiaque et la conduction cutanée) furent enregistrées. La perception de danger et d'efficacité variait suivant les caractéristiques du message. Les messages à danger élevé suscitaient des niveaux d,éveil autonome sensiblement différents des messages à faible danger. Le suivi de recommandations comportementales était plus élevé chez les sujets ayant été exposés au stimulus à danger élevé et à forte efficacité, chez ceux ayant déclaré une perception de danger élevé ainsi que chez ceux ayant présenté un schéma de réaction autonome liéà la facilitation des processus attentionnels. Abstract Selbstauskünfte zu und psychophysiologische Reaktionen auf Furchtappelle Ziel dieser Studie war es, die Beziehung zwischen den Aussagen zu und den psychophysiologischen Reaktionen auf Furchtappelle und Verhaltensänderungen zu untersuchen. 92 Teilnehmer sahen eine von vier Botschaften, die nach dem Grad der Gefahr (hoch vs. niedrig) und der Selbstwirksamkeit (hoch vs. niedrig) variierten. Begleitend wurden psychophysiologische Messungen (Herzfrequenz, Hautleitwiderstand) durchgeführt. Die wahrgenommene Bedrohung und Selbstwirksamkeit variierte nach den Charakteristika der Botschaft. Bei Botschaften mit hoher Gefahr zeigten die Teilnehmer einen anderen Grad an autonomer Erregung als bei Botschaften mit geringer Gefahr. Teilnehmer, die den Stimulus mit hoher Gefahr und hoher Selbstwirksamkeit rezipiert hatten, folgten den Verhaltensempfehlungen häufiger als diejenigen, die eine hohe wahrgenommene Gefahr berichteten und jene, die ein autonomes Reaktionsmuster zeigten, welches im Zusammenhang mit Zuwendung und Aufmerksamkeit steht. Resumen Los Auto-Reportes y las Respuestas Psico-Fisiológicas a las Apelaciones al Miedo Este estudio fue designado para evaluar la relación entre los auto-reportes y las respuestas psico-fisiológicas a las apelaciones al miedo y los cambios de comportamiento provocados por estos. 92 sujetos observaron 1 de 4 mensajes que variaron en su nivel de amenaza (alto o bajo) y la eficacia (alta o baja). Concomitantemente, las medidas psico-fisiológicas (pulso cardíaco y conductor de la piel) fueron registradas. La amenaza percibida y la eficacia variaron de acuerdo a las características del mensaje. Los mensajes de amenaza alta provocaron diferentes niveles significativos de excitación nerviosa que los mensajes de amenaza baja. Siguiendo la recomendación de comportamiento fue más alta entre los sujetos que fueron expuestos a la amenaza alta/ eficacia de estímulo alta, aquellos que reportaron una amenaza percibida alta, y para los que mostraron pautas de respuesta nerviosas relacionadas con la facilitación de los procesos de atención. ZhaiYao Yo yak [source] Differences in cognitive factors between "true drug" versus "placebo pattern" response to fluoxetine as defined by pattern analysisHUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 4 2006Amy H. Farabaugh Abstract Objective Pattern analysis has identified two types of response patterns to antidepressants: "true drug" response (TDR) and "placebo pattern" response (PPR). This study examines the relationship between cognitive factors and TDR and PPR to fluoxetine. Methods We assessed 310 outpatients meeting DSM-III-R criteria for major depressive disorder (MDD) who were enrolled in an 8-week open trial of fluoxetine 20,mg/day. Response patterns were determined using the clinical global impressions-improvement (CGI-I). We administered the following self-rated scales to all patients at the baseline visit and at endpoint: perceived stress scale (PSS), cognitions questionnaire (CQ), Beck hopelessness scale (BHS) and dysfunctional attitudes scale (DAS). Results One hundred and thirty-four patients had TDR, 66 patients had PPR, and 110 patients were non-responders (NR). Demographic variables and severity of depression at baseline (HAMD-17) were not significantly different between the two response pattern groups. We compared cognitive factors before and after treatment across patients with TDR and PPR, and there were no significant differences at baseline in CQ, PSS, BHS, and DAS scores. At endpoint, outpatients with PPR had significantly lower scores on the PSS (p,<,0.001) compared to the patients with TDR, even after adjusting for multiple comparisons and severity of depression at endpoint. Conclusions Significant differences in cognitive/psychological factors, specifically lower post-treatment perceived stress, accompany "placebo" pattern of response to antidepressant treatment and differentiate it from "true drug" response pattern, as defined by pattern analysis. Copyright © 2006 John Wiley & Sons, Ltd. [source] Effect of Chronic Amiodarone Therapy on Excitable Gap During Typical Human Atrial FlutterJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 12 2004PHILIPPE MAURY M.D. Introduction: Class I antiarrhythmic drugs increase duration of the excitable gap (EG) during typical atrial flutter whereas intravenous class III drugs decrease the EG. The effect of chronic oral amiodarone therapy on the EG is unknown. Methods and Results: EG was prospectively determined by introducing a premature stimulus and analyzing the response pattern during typical atrial flutter in 30 patients without antiarrhythmic drugs and in 20 patients under chronic oral amiodarone therapy. EG was calculated by the difference between the longest coupling interval leading to resetting and the effective atrial refractory period (EARP). A fully EG was defined by the portion of EG where the response curve of the return cycles was flat. A partially EG was defined by the portion of EG where the return cycle increases while coupling interval decreases. A resetting response curve was constructed by plotting the duration of the return cycle against the value of the coupling interval. Cycle length (CL; 222 ± 17 vs 267 ± 20 msec, P < 0.0001), EARP (128 ± 16 vs 152 ± 18 msec, P < 0.0001), and EG (54 ± 19 vs 70 ± 21 msec, P = 0.01) were significantly longer in patients taking amiodarone than in controls. Compared to CL, the relative part of the EARP (57 ± 7 vs 57 ± 6%, P = 0.96) and EG (24 ± 7 vs 26 ± 8%, P = 0.41) were comparable in both groups. The fully EG was larger in patients under chronic amiodarone therapy than in controls (39 ± 21 vs 26 ± 20 msec, P = 0.03). Neither duration of the partially EG (28 ± 15 vs 31 ± 15 msec, P = 0.42) nor slope of the ascending portion of the resetting response curve (1.15 ± 0.5 vs 1.13 ± 0.4 msec/msec, P = 0.71) differed between the two groups. Conclusion: EG in patients under chronic amiodarone therapy is significantly larger than in controls, mainly because of a longer fully EG. This observation may be explained by opposite effects on conduction velocity and refractoriness. [source] Monte Carlo Based Null Distribution for an Alternative Goodness-of-Fit Test Statistic in IRT ModelsJOURNAL OF EDUCATIONAL MEASUREMENT, Issue 1 2000Clement A. Stone Assessing the correspondence between model predictions and observed data is a recommended procedure for justifying the application of an IRT model. However, with shorter tests, current goodness-of-fit procedures that assume precise point estimates of ability, are inappropriate. The present paper describes a goodness-of-fit statistic that considers the imprecision with which ability is estimated and involves constructing item fit tables based on each examinee's posterior distribution of ability, given the likelihood of their response pattern and an assumed marginal ability distribution. However, the posterior expectations that are computed are dependent and the distribution of the goodness-of-fit statistic is unknown. The present paper also describes a Monte Carlo resampling procedure that can be used to assess the significance of the fit statistic and compares this method with a previously used method. The results indicate that the method described herein is an effective and reasonably simple procedure for assessing the validity of applying IRT models when ability estimates are imprecise. [source] Disparity Between Tonic and Phasic Ethanol-Induced Dopamine Increases in the Nucleus Accumbens of RatsALCOHOLISM, Issue 7 2009Donita L. Robinson Background:, Dopamine concentrations in the nucleus accumbens fluctuate on phasic (subsecond) and tonic (over minutes) timescales in awake rats. Acute ethanol increases tonic concentrations of dopamine, but its effect on subsecond dopamine transients has not been fully explored. Methods:, We measured tonic and phasic dopamine fluctuations in the nucleus accumbens of rats in response to ethanol (within-subject cumulative dosing, 0.125 to 2 g/kg, i.v.). Results:, Microdialysis samples yielded significant tonic increases in dopamine concentrations at 1 to 2 g/kg ethanol in each rat, while repeated saline infusions had no effect. When monitored with fast scan cyclic voltammetry, ethanol increased the frequency of dopamine transients in 6 of 16 recording sites, in contrast to the uniform effect of ethanol as measured with microdialysis. In the remaining 10 recording sites that were unresponsive to ethanol, dopamine transients either decreased in frequency or were unaffected by cumulative ethanol infusions, patterns also observed during repeated saline infusions. The responsiveness of particular recording sites to ethanol was not correlated with either core versus shell placement of the electrodes or the basal rate of dopamine transients. Importantly, the phasic response pattern to a single dose of ethanol at a particular site was qualitatively reproduced when a second dose of ethanol was administered, suggesting that the variable between-site effects reflected specific pharmacology at that recording site. Conclusions:, These data demonstrate that the relatively uniform dopamine concentrations obtained with microdialysis can mask a dramatic heterogeneity of phasic dopamine release within the accumbens. [source] Serotonergic Agents and Alcoholism Treatment: A SimulationALCOHOLISM, Issue 12 2003Scott F. Stoltenberg Background: Those with early-onset alcoholism may better respond to ondansetron (a 5-HT3 receptor antagonist) than to selective serotonin reuptake inhibitor (SSRI) treatment, whereas those with late-onset alcoholism may present the reverse response pattern. Johnson and colleagues proposed a model that attempts to explain the observed treatment response patterns of those with early and late alcoholism onset by focusing on the influence of a common genetic variant in the serotonin transporter regulatory region (5-HTTLPR) on serotonin (5-HT) and dopamine (DA) system function. Methods: The present study formalizes and extends Johnson's descriptive model into a computer simulation consisting of differential equations. For each of 16 conditions defined by genotype, drinking status, diagnostic status, and drug treatment, data were generated by 100 simulation runs. Results: In every condition, the S/_ genotype (S/S and S/L) had higher extracellular 5-HT levels than did the L/L genotype. The S/_ genotype also had higher rates of postsynaptic DA firing than did the L/L genotype with the exception of the SSRI treatment condition, where the firing rates were similar. Drinking generally increased levels of extracellular 5-HT, reduced rates of presynaptic 5-HT firing, and increased rates of postsynaptic DA firing. Drinking produced increases in DA activation that were greater for the L/L genotype in the SSRI treatment condition and for the S/_ genotype in the ondansetron treatment condition. Conclusions: Genotype at 5-HTTLPR may influence relative reward of drinking alcohol while a person is under pharmacological treatment for alcoholism. Alternatively, 5-HTTLPR genotype may influence pathways of alcohol craving. Clinical studies should examine these hypotheses. [source] Bicuculline-induced brain activation in mice detected by functional magnetic resonance imagingMAGNETIC RESONANCE IN MEDICINE, Issue 2 2001Thomas Mueggler Abstract Dynamic measurements of local changes in relative cerebral blood volume (CBVrel) during a pharmacological stimulation paradigm were performed in mice. Using magnetite nanoparticles as an intravascular contrast agent, high-resolution CBVrel maps were obtained. Intravenous administration of the GABAA antagonist bicuculline prompted increases in local CBVrel as assessed by MRI with a high spatial resolution of 0.2 × 0.2 mm2 and a temporal resolution of 21 s. Signal changes occurred 20,30 s after the onset of drug infusion in the somatosensory and motor cortex, followed by other cortical and subcortical structures. The magnitudes of the CBVrel increases were 18% ± 4%, 46% ± 14%, and 67% ± 7%, as compared to prestimulation values for the cortex, and 9% ± 3%, 25% ± 4%, and 36% ± 7% for the caudate putamen for bicuculline doses of 0.6, 1.25, and 1.5 mg/kg, respectively. On-line monitoring of transcutaneous carbon dioxide tension PtcCO2 reflecting arterial PaCO2 did not show any alteration during the stimulation paradigm. One of five of the mice receiving the highest bicuculline dose, and three of seven receiving the intermediate dose displayed a different cortical response pattern. After a CBVrel increase of 40% lasting for approximately 1 min, significant CBVrelreductions by 80% have been observed. Subcortical structures did not display this behavior. The present study suggests that this noninvasive approach of functional MRI (fMRI) can be applied to study drug-induced brain activation by central nervous system (CNS) drugs in mice under normal and pathological situations. Magn Reson Med 46:292,298, 2001. © 2001 Wiley-Liss, Inc. [source] Protein microarray analysis as a tool for monitoring cellular autoreactivity in type 1 diabetes patients and their relativesPEDIATRIC DIABETES, Issue 5 2007Zuzana Vrabelova Background:, Autoreactive T cells have a crucial role in type 1 diabetes (T1D) pathogenesis. Objectives:, The aim of our study was to monitor the in vitro production of cytokines by peripheral blood mononuclear cells (PBMCs) after stimulation with diabetogenic autoantigens. Subjects:, Ten T1D patients (tested at the time of diagnosis and 6 and 12 months later), 10 first-degree relatives of the T1D patients, and 10 controls underwent the study. Methods:, PBMCs were stimulated with glutamic acid decarboxylase 65 (GAD65) amino acids (a.a.) 247,279, 509,528, and 524,543; proinsulin a.a. 9,23; and tyrosine phosphatase (islet antigen-2)/R2 a.a. 853,872. Interleukin (IL)-2, IL-4, IL-5, IL-6, IL-10, IL-13, interferon (IFN)-,, tumor necrosis factor ,, transforming growth factor ,1, and granulocyte colony-stimulating factor (GCSF) were analyzed by protein microarray. Results:, Differences in cytokine(s) poststimulatory and mainly in basal production were observed in all groups. The most prominent findings were in controls, the higher basal levels of IL-2, IL-4, IL-5, IL-13, and GCSF were observed when compared with relatives (p < 0.05, for all). After stimulation in controls, there was a significant decrease in IL-2, IL-13, GCSF, and IFN-, (p < 0.05, for all). The group of relatives was the most variable in poststimulatory production. A strong correlation between cytokines production was found but groups differed in this aspect. Conclusion:, By multiplex analysis, it may be possible, for example, to define the risk immunological response pattern among relatives or to monitor the immune response in patients on immune modulation therapy. [source] Sex differences in the hemodynamic responses to mental stress: Effect of caffeine consumptionPSYCHOPHYSIOLOGY, Issue 4 2006Noha H. Farag Abstract The effect of caffeine on stress responses was compared in 25 men and 22 women in a 2-week placebo-controlled, double-blind, randomized crossover trial. On each week, participants abstained from all dietary sources of caffeine before undergoing a 6-h laboratory protocol under placebo or caffeine exposure followed by a 30-min mental stressor with blood pressure (BP) and cardiovascular hemodynamic assessments. On the placebo session, men and women showed a significant BP increase to stress, although women had significant cardiac responses whereas men had vascular responses. Caffeine ingestion before stress caused both men and women to have enhanced hemodynamic responses to the stressor associated with an increase in cardiac index and a drop in the peripheral resistance index. Caffeine enhances the cardiovascular fight-or-flight response pattern to stress in men and women. [source] Pericranial muscular, respiratory, and heart rate components of the orienting responsePSYCHOPHYSIOLOGY, Issue 6 2002J.J. Stekelenburg We have earlier found that voluntary attention to weak auditory stimuli induces inhibition of respiration, heart rate, and electromyographic (EMG) activity of masticatory and lower facial muscles and that these responses lower the auditory threshold for low-frequency sounds. In the current study, we examined whether this inhibitory response pattern also occurs during involuntary orienting to novel, nonsignal sounds. Environmental sounds of low intensity were presented unexpectedly during the performance of a reading task. Orienting responses (ORs) were elicited as indicated by heart rate deceleration and skin conductance responses. Inhibitory respiratory and pericranial EMG responses appeared to be intrinsic components of the OR. Together with the autonomic responses, they habituated when a nonsignal auditory stimulus was repeatedly presented. Our results also suggest that eye and pinna movements occurred toward the sound source. The results of the current study are consistent with the hypothesis of Sokolov (1963) that the primary function of the OR is enhancement of sensory sensitivity. [source] The impact of semantic memory organization and sentence context information on spoken language processing by younger and older adults: An ERP studyPSYCHOPHYSIOLOGY, Issue 2 2002Kara D. Federmeier To examine changes in semantic memory organization and use during aging, we recorded event-related potentials as younger and older adults listened to sentences ending with the expected word, an unexpected word from the same semantic category, or an unexpected word from a different category. Half of the contexts were highly constraining. In both groups, expected words elicited less negativity 300,500 ms (N400) than unexpected ones, and unexpected words elicited smaller N400s when these were categorically related. Whereas younger adults showed the greatest N400 reduction to unexpected but related words in high constraint contexts, older adults showed the opposite tendency. Thus, unlike younger adults, older adults as a group do not seem to be using context predictively. Older adults with higher verbal fluency and larger vocabularies, however, showed the younger response pattern, suggesting resource availability may offset certain age-related changes. [source] Response properties of isolated mouse olfactory receptor cellsTHE JOURNAL OF PHYSIOLOGY, Issue 1 2001Johannes Reisert 1Response properties of isolated mouse olfactory receptor cells were investigated using the suction pipette technique. Cells were exposed to the odour cineole or to solutions of modified ionic content by rapidly changing the solution superfusing the cilia. All experiments were performed at 37°C. 2Mouse olfactory receptor cells displayed a steep dependence of action potential frequency on stimulus concentration, a 3-fold increase in stimulus concentration often saturating the firing frequency at 200-300 Hz. The receptor current increased more gradually with increasing cineole concentration and did not saturate within the 100-fold range of cineole concentrations applied. 3When stimulated for 30 s with a low odour concentration, cells responded with sporadic spike firing. Higher concentrations led to the generation of a large receptor current at the onset of stimulation which returned to baseline levels within a few seconds, accompanied during its rising phase by a short burst of action potentials. Thereafter an oscillating response pattern was observed during the remainder of the stimulus, consisting of repetitive increases in receptor current of around 1 s duration accompanied by short bursts of action potentials. 4Olfactory adaptation was studied by comparing the responses to two closely spaced odour stimuli. The response to the second odour stimulus recovered to 80% of its original magnitude when the cell was superfused with Ringer solution during the 5 s interval between odour exposures. In contrast, exposure to a choline-substituted low Na+ solution between odour stimuli had two effects. First, the receptor current response to the first odour stimulus did not terminate as quickly as in the presence of Na+, suggesting the presence of a Na+ -Ca2+ exchanger. Second, the response to the second stimulus only recovered to 55% of its original magnitude, demonstrating the involvement of Na+ -Ca2+ exchange in the recovery of sensitivity in mouse olfactory receptor cells following stimulation. [source] Does modified interpretation bias influence automatic avoidance behaviour?APPLIED COGNITIVE PSYCHOLOGY, Issue 3 2010Wolf-Gero Lange Cognitive bias modification (CBM) studies suggest a causal role of interpretation biases in the aetiology and maintenance of Social Anxiety Disorder. However, it is unknown if the effects of induced biases transfer to behaviour. In two analogue studies, behavioural changes in response to aversive and positive stimuli were measured after the induction of positive and negative interpretation biases in ,averagely anxious' participants. Responses to emotional multi-facial displays (,crowds') were measured using an indirect Approach,Avoidance Task (AAT). The crowds comprised different ratios of either neutral and angry faces or happy and angry faces. In Experiment 1, negatively trained participants (NETs) showed a faster avoidance response for the neutral,angry crowds when the number of angry pictures in the crowd increased. This response pattern resembles the one previously found in socially anxious individuals. Experiment 2 replicated the effect of the cognitive bias manipulation on conceptually comparable material, but did not show transfer to the behavioural task. These studies add to the body of knowledge regarding successful modification of interpretive bias and generalizability to a behavioural task. Copyright © 2010 John Wiley & Sons, Ltd. [source] Influence of salinity, diurnal rhythm and daylength on feeding in Laternula marilina ReeveAQUACULTURE RESEARCH, Issue 2 2005Shuhong Zhuang Abstract A nature-simulating culture system was used to explore the influence of salinity, the diurnal cycle and daylength on ingestion rate (IR) and assimilation efficiency (AE) of Laternula marilina. The clams used in the experiments were grouped into three sizes: large, medium and small according to shell length and dry fresh weight. The clams in all size groups demonstrated a common response pattern in IR and AE under salinities ranging from 18 to 34 g L,1. The clams achieved the greatest IR within the salinity range 27,30 g L,1. There was a marked reduction in IR outside this range. Of the salinities tested 18 g L,1 was the harshest stress to the feeding of L. marilina. Between the salinities of 24 and 34 g L,1, the AE of the clam responded in an inverse way to that of IR, suggesting that L. marilina is able to compensate for the loss of IR by an increase in AE. Although the differences between clam size groups were not statistically different, those between different salinities were except those between 27 and 34 g L,1 (IR) and 23 and 34 g L,1 (AE). All sizes of clam showed a two-phase diurnal feeding pattern, a high ingestion phase from 00:00 to 08:00 hours and a low ingestion phase from 12:00 to 20:00 hours. The response of feeding (as measured by IR) to daylength comprised high and constant feeding at daylengths from 0 to 16 h and declining and unstable feeding as daylength increased from 16 to 24 h. All sizes of clams demonstrated an inverse adaptation to AE compared with IR, indicating that the clam is able to achieve a stable feeding physiology by compensating for daylength-induced variations in IR by changing AE. [source] Smoking and pregnancy-related pelvic painBJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 8 2010K Biering Please cite this paper as: Biering K, Aagaard Nohr E, Olsen J, Hjollund N, Nybo Andersen A-M, Juhl M. Smoking and pregnancy-related pelvic pain. BJOG 2010;117:1019,1026. Objective, To investigate possible associations between smoking and pregnancy-related pelvic pain. Design, Nested case,control study. Setting, Denmark 2000,2001. Population, The Danish National Birth Cohort. Methods, The women were interviewed twice in pregnancy and twice after childbirth. The first pregnancy interview provided information on smoking and possible confounding factors, whereas the first interview after birth addressed case identification. Cases (n = 2302) were defined on the basis of self-reported pelvic pain, and controls were selected among women who did not report pelvic pain (n = 2692). Logistic regression analysis was used to estimate associations between smoking and pelvic pain. Main outcome mreasue, Pregnancy-related pelvic pain. Results, Compared with non-smokers, women who smoked during pregnancy had an adjusted odds ratio of 1.2 (1.0,1.4) for overall pelvic pain, similar to women who stopped smoking in early pregnancy 1.3 (1.1,1.7). The equivalent adjusted odds ratio for severe pelvic pain was 1.2 (1.0,1.5) for smokers, and 1.5 (1.2,1.9) for women who stopped smoking. Smoking intensity, measured as number of cigarettes smoked per day, was associated with pelvic pain in a dose,response pattern. Information about smoking was collected prospectively, which makes it unlikely that differential recall alone explains the results. Conclusions, Smoking was associated with pregnancy-related pelvic pain, with a dose,response pattern between reported smoking intensity and pelvic pain. These findings suggest a possible new risk factor for a common ailment during pregnancy. [source] Vagal Reactivity and Affective Adjustment in Infants during Interaction ChallengesCHILD DEVELOPMENT, Issue 5 2001Olga V. Bazhenova Respiratory sinus arrhythmia (RSA) and heart period were evaluated in 5-month-old infants (N= 40) during interaction challenges requiring affective adjustment. The paradigm consisted of four 2-min experimental conditions designed to elicit behavioral and autonomic responses to object-mediated (Picture Attention and Toy Attention) and person-mediated (Still Face and Social Interaction) engagement. The data demonstrated that autonomic state systematically changed during engagement and disengagement with the environment. During the object-mediated challenge, increases in RSA were uniquely related to positive engagement. During the person-mediated challenge, there was a more complex integration of autonomic and behavioral responses characterized by concordant increases and decreases in RSA, heart period, positive engagement, negative affect, and motor activity. When participants were partitioned into two groups, based on their RSA response pattern during the person-mediated challenge, only participants who exhibited a pattern of RSA decrease from Toy Attention to Still Face followed by a rapid recovery during Social Interaction demonstrated regulation of behavioral activity, including concordant recovery from stress. These findings provide additional empirical support for the role of vagal regulation of the heart in the modulation of affective adjustment and engagement behavior. [source] | ||||||||||||||||||||||||||||||||||||||||