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Sample records for aversive competition influence

  1. Aversive Learning and Trait Aggression Influence Retaliatory Behavior.

    PubMed

    Molapour, Tanaz; Lindström, Björn; Olsson, Andreas

    2016-01-01

    In two experiments (n = 35, n = 34), we used a modified fear-conditioning paradigm to investigate the role of aversive learning in retaliatory behavior in social context. Participants first completed an initial aversive learning phase in which the pairing of a neutral conditioned stimulus (CS; i.e., neutral face) with a naturally aversive unconditioned stimulus (US; electric shock) was learned. Then they were given an opportunity to interact (i.e., administer 0-2 shocks) with the same faces again, during a Test phase. In Experiment 2, we used the same paradigm with the addition of online trial-by-trial ratings (e.g., US expectancy and anger) to examine the role of aversive learning, anger, and the learned expectancy of receiving punishment more closely. Our results indicate that learned aversions influenced future retaliation in a social context. In both experiments, participants showed largest skin conductance responses (SCRs) to the faces paired with one or two shocks, demonstrating successful aversive learning. Importantly, participants administered more shocks to the faces paired with the most number of shocks when the opportunity was given during test. Also, our results revealed that aggressive traits (Buss and Perry Aggression scale) were associated with retaliation only toward CSs associated with aversive experiences. These two experiments show that aggressive traits, when paired with aversive learning experiences enhance the likelihood to act anti-socially toward others. PMID:27375520

  2. Aversive Learning and Trait Aggression Influence Retaliatory Behavior

    PubMed Central

    Molapour, Tanaz; Lindström, Björn; Olsson, Andreas

    2016-01-01

    In two experiments (n = 35, n = 34), we used a modified fear-conditioning paradigm to investigate the role of aversive learning in retaliatory behavior in social context. Participants first completed an initial aversive learning phase in which the pairing of a neutral conditioned stimulus (CS; i.e., neutral face) with a naturally aversive unconditioned stimulus (US; electric shock) was learned. Then they were given an opportunity to interact (i.e., administer 0–2 shocks) with the same faces again, during a Test phase. In Experiment 2, we used the same paradigm with the addition of online trial-by-trial ratings (e.g., US expectancy and anger) to examine the role of aversive learning, anger, and the learned expectancy of receiving punishment more closely. Our results indicate that learned aversions influenced future retaliation in a social context. In both experiments, participants showed largest skin conductance responses (SCRs) to the faces paired with one or two shocks, demonstrating successful aversive learning. Importantly, participants administered more shocks to the faces paired with the most number of shocks when the opportunity was given during test. Also, our results revealed that aggressive traits (Buss and Perry Aggression scale) were associated with retaliation only toward CSs associated with aversive experiences. These two experiments show that aggressive traits, when paired with aversive learning experiences enhance the likelihood to act anti-socially toward others. PMID:27375520

  3. Does ambiguity aversion influence the framing effect during decision making?

    PubMed

    Osmont, Anaïs; Cassotti, Mathieu; Agogué, Marine; Houdé, Olivier; Moutier, Sylvain

    2015-04-01

    Decision-makers present a systematic tendency to avoid ambiguous options for which the level of risk is unknown. This ambiguity aversion is one of the most striking decision-making biases. Given that human choices strongly depend on the options' presentation, the purpose of the present study was to examine whether ambiguity aversion influences the framing effect during decision making. We designed a new financial decision-making task involving the manipulation of both frame and uncertainty levels. Thirty-seven participants had to choose between a sure option and a gamble depicting either clear or ambiguous probabilities. The results revealed a clear preference for the sure option in the ambiguity condition regardless of frame. However, participants presented a framing effect in both the risk and ambiguity conditions. Indeed, the framing effect was bidirectional in the risk condition and unidirectional in the ambiguity condition given that it did not involve preference reversal but only a more extreme choice tendency. PMID:25030206

  4. The Influence of Loss Aversion on Mountain Bikers' Behavioral Intentions

    NASA Astrophysics Data System (ADS)

    Purrington, Andrew; Zinn, Harry

    2011-09-01

    Public involvement in management decision making has received increased attention from researchers in recent years. These studies, however, have rarely considered differences in behavior resulting from gains and losses, despite ample evidence that individuals' behavior is not the same across situations. Individuals are often more sensitive to losses than gains, which research suggests is related to ownership (real or perceived) of the item lost. We present evidence from a within-subjects quasi-experimental design to test whether mountain bikers' reported intentions differ between gain based and loss based conditions. These data were analyzed using a multi-step repeated measures analysis of variance and repeated measures analysis of covariance. The results suggest that losses are more powerful than gains in motivating public engagement in management decision making. Further, the type of action was also shown to influence behavioral intentions. Additional analyses provide support to the claim that, centrality, used as a proximate measure of ownership, moderates the contextual effects on behavioral intentions. Thus, loss aversion, moderated by ownership, is a plausible explanation of stakeholder involvement.

  5. Genotypic influence on aversive conditioning in honeybees, using a novel thermal reinforcement procedure.

    PubMed

    Junca, Pierre; Carcaud, Julie; Moulin, Sibyle; Garnery, Lionel; Sandoz, Jean-Christophe

    2014-01-01

    In Pavlovian conditioning, animals learn to associate initially neutral stimuli with positive or negative outcomes, leading to appetitive and aversive learning respectively. The honeybee (Apis mellifera) is a prominent invertebrate model for studying both versions of olfactory learning and for unraveling the influence of genotype. As a queen bee mates with about 15 males, her worker offspring belong to as many, genetically-different patrilines. While the genetic dependency of appetitive learning is well established in bees, it is not the case for aversive learning, as a robust protocol was only developed recently. In the original conditioning of the sting extension response (SER), bees learn to associate an odor (conditioned stimulus - CS) with an electric shock (unconditioned stimulus - US). This US is however not a natural stimulus for bees, which may represent a potential caveat for dissecting the genetics underlying aversive learning. We thus first tested heat as a potential new US for SER conditioning. We show that thermal stimulation of several sensory structures on the bee's body triggers the SER, in a temperature-dependent manner. Moreover, heat applied to the antennae, mouthparts or legs is an efficient US for SER conditioning. Then, using microsatellite analysis, we analyzed heat sensitivity and aversive learning performances in ten worker patrilines issued from a naturally inseminated queen. We demonstrate a strong influence of genotype on aversive learning, possibly indicating the existence of a genetic determinism of this capacity. Such determinism could be instrumental for efficient task partitioning within the hive. PMID:24828422

  6. Genotypic Influence on Aversive Conditioning in Honeybees, Using a Novel Thermal Reinforcement Procedure

    PubMed Central

    Junca, Pierre; Carcaud, Julie; Moulin, Sibyle; Garnery, Lionel; Sandoz, Jean-Christophe

    2014-01-01

    In Pavlovian conditioning, animals learn to associate initially neutral stimuli with positive or negative outcomes, leading to appetitive and aversive learning respectively. The honeybee (Apis mellifera) is a prominent invertebrate model for studying both versions of olfactory learning and for unraveling the influence of genotype. As a queen bee mates with about 15 males, her worker offspring belong to as many, genetically-different patrilines. While the genetic dependency of appetitive learning is well established in bees, it is not the case for aversive learning, as a robust protocol was only developed recently. In the original conditioning of the sting extension response (SER), bees learn to associate an odor (conditioned stimulus - CS) with an electric shock (unconditioned stimulus - US). This US is however not a natural stimulus for bees, which may represent a potential caveat for dissecting the genetics underlying aversive learning. We thus first tested heat as a potential new US for SER conditioning. We show that thermal stimulation of several sensory structures on the bee’s body triggers the SER, in a temperature-dependent manner. Moreover, heat applied to the antennae, mouthparts or legs is an efficient US for SER conditioning. Then, using microsatellite analysis, we analyzed heat sensitivity and aversive learning performances in ten worker patrilines issued from a naturally inseminated queen. We demonstrate a strong influence of genotype on aversive learning, possibly indicating the existence of a genetic determinism of this capacity. Such determinism could be instrumental for efficient task partitioning within the hive. PMID:24828422

  7. Myopic Loss Aversion: Demystifying the Key Factors Influencing Decision Problem Framing

    ERIC Educational Resources Information Center

    Hardin, Andrew M.; Looney, Clayton Arlen

    2012-01-01

    Advancement of myopic loss aversion theory has been hamstrung by conflicting results, methodological inconsistencies, and a piecemeal approach toward understanding the key factors influencing decision problem framing. A series of controlled experiments provides a more holistic view of the variables promoting myopia. Extending the information…

  8. Once failed, twice shy: How group-based competition influences risk preference in young children.

    PubMed

    Zhu, Yi; Wang, Jiajie; Lv, Xiaofeng; Li, Yansong

    2016-04-01

    Recent developmental research demonstrates that young children tend to be risk-seeking. However, very little is known about the extent to which such a capacity varies with children's group-based experience. Given that between-group competition is a central feature of human social life, this study aimed at examining the influence of group-based competition over risk preference in young children. In total, 234 children from 3 age groups (2-4-year-olds, 5-6-year-olds, and 8-9-year-olds) engaged in an intergroup competition manipulation, which was followed by a prosocial game assessing children's ingroup egalitarianism and a gambling task measuring children's risk preference. We found that children in the intergroup competition condition tended to be risk-averse compared with those who were in the nonintergroup competition condition. Furthermore, we found that an aversion to risk in the intergroup competition condition was driven by such an aversion observed in children from the losing group. In addition, we found a positive relationship between ingroup egalitarianism and risk preference in children from the winning group rather than those from the losing group. Together, our results contribute to the understanding of the effects of group-based experience on children's risk preference and may have important implications for understanding individuals' risky decisions. PMID:26974207

  9. ADHD and Delay Aversion: The Influence of Non-Temporal Stimulation on Choice for Delayed Rewards

    ERIC Educational Resources Information Center

    Antrop, Inge; Stock, Pieter; Verte, Sylvie; Wiersema, Jan Roelt; Baeyens, Dieter; Roeyers, Herbert

    2006-01-01

    Background: Delay aversion, the motivation to escape or avoid delay, results in preference for small immediate over large delayed rewards. Delay aversion has been proposed as one distinctive psychological process that may underlie the behavioural symptoms and cognitive deficits of attention deficit/hyperactivity disorder (ADHD). Furthermore, the…

  10. Serotonin selectively influences moral judgment and behavior through effects on harm aversion.

    PubMed

    Crockett, Molly J; Clark, Luke; Hauser, Marc D; Robbins, Trevor W

    2010-10-01

    Aversive emotional reactions to real or imagined social harms infuse moral judgment and motivate prosocial behavior. Here, we show that the neurotransmitter serotonin directly alters both moral judgment and behavior through increasing subjects' aversion to personally harming others. We enhanced serotonin in healthy volunteers with citalopram (a selective serotonin reuptake inhibitor) and contrasted its effects with both a pharmacological control treatment and a placebo on tests of moral judgment and behavior. We measured the drugs' effects on moral judgment in a set of moral 'dilemmas' pitting utilitarian outcomes (e.g., saving five lives) against highly aversive harmful actions (e.g., killing an innocent person). Enhancing serotonin made subjects more likely to judge harmful actions as forbidden, but only in cases where harms were emotionally salient. This harm-avoidant bias after citalopram was also evident in behavior during the ultimatum game, in which subjects decide to accept or reject fair or unfair monetary offers from another player. Rejecting unfair offers enforces a fairness norm but also harms the other player financially. Enhancing serotonin made subjects less likely to reject unfair offers. Furthermore, the prosocial effects of citalopram varied as a function of trait empathy. Individuals high in trait empathy showed stronger effects of citalopram on moral judgment and behavior than individuals low in trait empathy. Together, these findings provide unique evidence that serotonin could promote prosocial behavior by enhancing harm aversion, a prosocial sentiment that directly affects both moral judgment and moral behavior. PMID:20876101

  11. Nutrient environment influences competition among Aspergillus flavus genotypes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Structures of Aspergillus flavus populations, shaped by intraspecific competition, influence the incidences and severities of crop aflatoxin contamination. Competition for nutrients may be one factor modulating intraspecific interactions, but influences of specific types and concentrations of nutrie...

  12. Substitutive Competition: Virtual Pets as Competitive Buffers to Alleviate Possible Negative Influence on Pupils

    ERIC Educational Resources Information Center

    Chen, Zhi-Hong; Chou, Chih-Yueh; Biswas, Gautam; Chan, Tak-Wai

    2012-01-01

    Although competition is regarded as a powerful motivator in game-based learning, it might have a negative influence, such as damage to confidence, on students who lose the competition. In this paper, we propose an indirect approach, substitutive competition, to alleviate such negative influences. The approach is used to develop a My-Pet v3 system,…

  13. Pontine and Thalamic Influences on Fluid Rewards: II. Sucrose and Corn Oil Conditioned Aversions

    PubMed Central

    Liang, Nu-Chu; Grigson, Patricia S.; Norgren, Ralph

    2011-01-01

    In this study conditioned aversions were produced in sham feeding rats to limit postingestive feedback from the oral stimulus. All control rats learned an aversion to either 100% corn oil or 0.3M sucrose when ingestion of these stimuli was followed by an injection of lithium chloride (LiCl). Rats with lesions of the ventroposteromedial thalamus also learned to avoid either corn oil or sucrose. After 3 trials, rats with damage to the parabrachial nuclei (PBN) learned to avoid 100% corn oil, but failed to do so when the stimulus was 0.3M sucrose. These results support our hypothesis that the PBN is necessary to appropriately respond to a taste, but not an oil cue as a function of experience (i.e., pairings with LiCl). The results also are consistent with our results from operant tasks demonstrating that the trigeminal thalamus, the ventroposteromedial nucleus, is not required for responding to the rewarding properties of sucrose, oil, or for modifying the response to these stimuli as a function of experience. PMID:21699909

  14. COMPETITIVE ABILITY IN MALE HOUSE MICE (Mus musculus): GENETIC INFLUENCES

    PubMed Central

    Cunningham, Christopher B.; Ruff, James S.; Chase, Kevin; Potts, Wayne K.; Carrier, David R.

    2013-01-01

    Conspecifics of many animal species physically compete to gain reproductive resources and thus fitness. Despite the importance of competitive ability across the animal kingdom, specific traits that influence or underpin competitive ability are poorly characterized. Here, we investigate whether there are genetic influences on competitive ability within male house mice. Additionally, we examined if litter demographics (litter size and litter sex ratio) influence competitive ability. We phenotyped two generations for a male s ability to possess a reproductive resource--a prime nesting site--using semi-natural enclosures with mixed sex groupings. We used the animal model coupled with an extensive pedigree to estimate several genetic parameters. Competitive ability was found to be highly heritable, but only displayed a moderate genetic correlation to body mass. Interestingly, litter sex ratio had a weak negative influence on competitive ability. Litter size had no significant influence on competitive ability. Our study also highlights how much remians unknown about the proximal causes of competitive ability. PMID:23291957

  15. Alcohol reduces aversion to ambiguity

    PubMed Central

    Tyszka, Tadeusz; Macko, Anna; Stańczak, Maciej

    2015-01-01

    Several years ago, Cohen et al. (1958) demonstrated that under the influence of alcohol drivers became more risk prone, although their risk perception remained unchanged. Research shows that ambiguity aversion is to some extent positively correlated with risk aversion, though not very highly (Camerer and Weber, 1992). The question addressed by the present research is whether alcohol reduces ambiguity aversion. Our research was conducted in a natural setting (a restaurant bar), where customers with differing levels of alcohol intoxication were offered a choice between a risky and an ambiguous lottery. We found that alcohol reduced ambiguity aversion and that the effect occurred in men but not women. We interpret these findings in terms of the risk-as-value hypothesis, according to which, people in Western culture tend to value risk, and suggest that alcohol consumption triggers adherence to socially and culturally valued patterns of conduct different for men and women. PMID:25642202

  16. Unpleasant odors increase aversion to monetary losses.

    PubMed

    Stancak, Andrej; Xie, Yuxin; Fallon, Nicholas; Bulsing, Patricia; Giesbrecht, Timo; Thomas, Anna; Pantelous, Athanasios A

    2015-04-01

    Loss aversion is the tendency to prefer avoiding losses over acquiring gains of equal nominal values. Unpleasant odors not only influence affective state but have also been shown to activate brain regions similar to those mediating loss aversion. Therefore, we hypothesized a stronger loss aversion in a monetary gamble task if gambles were associated with an unpleasant as opposed to pleasant odor. In thirty human subjects, unpleasant (methylmercaptan), pleasant (jasmine), and neutral (clean air) odors were presented for 4 s. At the same time, uncertain gambles offering an equal chance of gain or loss of a variable amount of money, or a prospect of an assured win were displayed. One hundred different gambles were presented three times, each time paired with a different odor. Loss aversion, risk aversion, and logit sensitivity were evaluated using non-linear fitting of individual gamble decisions. Loss aversion was larger when prospects were displayed in the presence of methylmercaptan compared to jasmine or clean air. Moreover, individual differences in changes in loss aversion to the unpleasant as compared to pleasant odor correlated with odor pleasantness but not with odor intensity. Skin conductance responses to losses during the outcome period were larger when gambles were associated with methylmercaptan compared to jasmine. Increased loss aversion while perceiving an unpleasant odor suggests a dynamic adjustment of loss aversion toward greater sensitivity to losses. Given that odors are biological signals of hazards, such adjustment of loss aversion may have adaptive value in situations entailing threat or danger. PMID:25711689

  17. Food-chain competition influences gene's size

    NASA Astrophysics Data System (ADS)

    Dembska, Marta; Dudek, Mirosław R.; Stauffer, Dietrich

    2006-11-01

    We have analyzed an effect of the Bak-Sneppen predator-prey food-chain self-organization on nucleotide content of evolving species. In our model, genomes of the species under consideration have been represented by their nucleotide genomic fraction and we have applied two-parameter Kimura model of substitutions to include the changes of the fraction in time. The initial nucleotide fraction and substitution rates were decided with the help of random number generator. Deviation of the genomic nucleotide fraction from its equilibrium value was playing the role of the fitness parameter, B, in Bak-Sneppen model. Our finding is, that the higher is the value of the threshold fitness, during the evolution course, the more frequent are large fluctuations in number of species with strongly differentiated nucleotide content; and it is more often the case that the oldest species, which survive the food-chain competition, might have specific nucleotide fraction making possible generating long genes.

  18. Incidental fear cues increase monetary loss aversion.

    PubMed

    Schulreich, Stefan; Gerhardt, Holger; Heekeren, Hauke R

    2016-04-01

    In many everyday decisions, people exhibit loss aversion-a greater sensitivity to losses relative to gains of equal size. Loss aversion is thought to be (at least partly) mediated by emotional--in particular, fear-related--processes. Decision research has shown that even incidental emotions, which are unrelated to the decision at hand, can influence decision making. The effect of incidental fear on loss aversion, however, is thus far unclear. In two studies, we experimentally investigated how incidental fear cues, presented during (Study 1) or before (Study 2) choices to accept or reject mixed gambles over real monetary stakes, influence monetary loss aversion. We find that the presentation of fearful faces, relative to the presentation of neutral faces, increased risk aversion-an effect that could be attributed to increased loss aversion. The size of this effect was moderated by psychopathic personality: Fearless dominance, in particular its interpersonal facet, but not self-centered impulsivity, attenuated the effect of incidental fear cues on loss aversion, consistent with reduced fear reactivity. Together, these results highlight the sensitivity of loss aversion to the affective context. PMID:26595436

  19. Interpersonal touch suppresses visual processing of aversive stimuli

    PubMed Central

    Kawamichi, Hiroaki; Kitada, Ryo; Yoshihara, Kazufumi; Takahashi, Haruka K.; Sadato, Norihiro

    2015-01-01

    Social contact is essential for survival in human society. A previous study demonstrated that interpersonal contact alleviates pain-related distress by suppressing the activity of its underlying neural network. One explanation for this is that attention is shifted from the cause of distress to interpersonal contact. To test this hypothesis, we conducted a functional MRI (fMRI) study wherein eight pairs of close female friends rated the aversiveness of aversive and non-aversive visual stimuli under two conditions: joining hands either with a rubber model (rubber-hand condition) or with a close friend (human-hand condition). Subsequently, participants rated the overall comfortableness of each condition. The rating result after fMRI indicated that participants experienced greater comfortableness during the human-hand compared to the rubber-hand condition, whereas aversiveness ratings during fMRI were comparable across conditions. The fMRI results showed that the two conditions commonly produced aversive-related activation in both sides of the visual cortex (including V1, V2, and V5). An interaction between aversiveness and hand type showed rubber-hand-specific activation for (aversive > non-aversive) in other visual areas (including V1, V2, V3, and V4v). The effect of interpersonal contact on the processing of aversive stimuli was negatively correlated with the increment of attentional focus to aversiveness measured by a pain-catastrophizing scale. These results suggest that interpersonal touch suppresses the processing of aversive visual stimuli in the occipital cortex. This effect covaried with aversiveness-insensitivity, such that aversive-insensitive individuals might require a lesser degree of attentional capture to aversive-stimulus processing. As joining hands did not influence the subjective ratings of aversiveness, interpersonal touch may operate by redirecting excessive attention away from aversive characteristics of the stimuli. PMID:25904856

  20. Competition strength influences individual preferences in an auction game

    PubMed Central

    Toelch, Ulf; Jubera-Garcia, Esperanza; Kurth-Nelson, Zeb; Dolan, Raymond J.

    2014-01-01

    Competitive interactions between individuals are ubiquitous in human societies. Auctions represent an institutionalized context for these interactions, a context where individuals frequently make non-optimal decisions. In particular, competition in auctions can lead to overbidding, resulting in the so-called winner’s curse, often explained by invoking emotional arousal. In this study, we investigated an alternative possibility, namely that competitors’ bids are construed as a source of information about the good’s common value thereby influencing an individuals’ private value estimate. We tested this hypothesis by asking participants to bid in a repeated all-pay auction game for five different real items. Crucially, participants had to rank the auction items for their preference before and after the experiment. We observed a clear relation between auction dynamics and preference change. We found that low competition reduced preference while high competition increased preference. Our findings support a view that competitors’ bids in auction games are perceived as valid social signal for the common value of an item. We suggest that this influence of social information constitutes a major cause for the frequently observed deviations from optimality in auctions. PMID:25168161

  1. Coping With Aversive Feelings.

    ERIC Educational Resources Information Center

    Saarni, Carolyn

    This study focused on how school-age children develop and refine their strategies for dealing with aversive emotions, defined as fear, shame, anger, sadness, and hurt feelings. Two groups of children were used, one from a public school, serving a working class neighborhood, and the other from a sexual abuse treatment agency. The aversive emotions…

  2. Competition between engrams influences fear memory formation and recall.

    PubMed

    Rashid, Asim J; Yan, Chen; Mercaldo, Valentina; Hsiang, Hwa-Lin Liz; Park, Sungmo; Cole, Christina J; De Cristofaro, Antonietta; Yu, Julia; Ramakrishnan, Charu; Lee, Soo Yeun; Deisseroth, Karl; Frankland, Paul W; Josselyn, Sheena A

    2016-07-22

    Collections of cells called engrams are thought to represent memories. Although there has been progress in identifying and manipulating single engrams, little is known about how multiple engrams interact to influence memory. In lateral amygdala (LA), neurons with increased excitability during training outcompete their neighbors for allocation to an engram. We examined whether competition based on neuronal excitability also governs the interaction between engrams. Mice received two distinct fear conditioning events separated by different intervals. LA neuron excitability was optogenetically manipulated and revealed a transient competitive process that integrates memories for events occurring closely in time (coallocating overlapping populations of neurons to both engrams) and separates memories for events occurring at distal times (disallocating nonoverlapping populations to each engram). PMID:27463673

  3. Reception of Aversive Taste.

    PubMed

    Lunceford, Blair E; Kubanek, Julia

    2015-09-01

    Many organisms encounter noxious or unpalatable compounds in their diets. Thus, a robust reception-system for aversive taste is necessary for an individual's survival; however, mechanisms for perceiving aversive taste vary among organisms. Possession of a system sensitive to aversive taste allows for recognition of a vast array of noxious molecules via membrane-bound receptors, co-receptors, and ion channels. These receptor-ligand interactions trigger signal transduction pathways resulting in activation of nerves and in neural processing, which in turn dictates behavior, including rejection of the noxious item. The impacts of these molecular processes on behavior differ among species, and these differences have impacts at the ecosystem level by driving feeding-behavior, organization of communities, and ultimately, speciation. For example, when comparing mammalian carnivores and herbivores, it is not surprising that herbivores that encounter a variety of toxic plants in their diets express a larger number of aversive taste receptors than carnivores. Comparing the molecular mechanisms and ecological consequences of aversive-taste reception among organisms in a variety of types of ecosystems and ecological niches will illuminate the role of taste in ecology and evolution. PMID:26025470

  4. The Influence of Collective Behavior on Pacing in Endurance Competitions

    PubMed Central

    Renfree, Andrew; Crivoi do Carmo, Everton; Martin, Louise; Peters, Derek M.

    2015-01-01

    A number of theoretical models have been proposed in recent years to explain pacing strategies observed in individual competitive endurance events. These have typically related to the internal regulatory processes that inform the making of decisions relating to muscular work rate. Despite a substantial body of research which has investigated the influence of collective group dynamics on individual behaviors in various animal species, this issue has not been comprehensively studied in individual athletic events. This is somewhat surprising given that athletes often directly compete in close proximity to one another, and that collective behavior has also been observed in other human environments including pedestrian interactions and financial market trading. Whilst the reasons for adopting collective behavior are not fully understood, collective behavior is thought to result from individual agents following simple local rules that result in seemingly complex large systems that act to confer some biological advantage to the collective as a whole. Although such collective behaviors may generally be beneficial, competitive endurance events are complicated by the fact that increasing levels of physiological disruption as activity progresses may compromise the ability of some individuals to continue to interact with other group members. This could result in early fatigue and relative underperformance due to suboptimal utilization of physiological resources by some athletes. Alternatively, engagement with a collective behavior may benefit all due to a reduction in the complexity of decisions to be made and a subsequent reduction in cognitive loading and mental fatigue. This paper seeks evidence for collective behavior in previously published analyses of pacing behavior and proposes mechanisms through which it could potentially be either beneficial, or detrimental to individual performance. It concludes with suggestions for future research to enhance understanding of this

  5. Competition.

    PubMed

    Chambers, D W

    1997-01-01

    Our ambivalence toward competition can be traced to an unspoken preference for certain types of competition which give us an advantage over the types we value less. Four types are defined (a) pure (same rules, same objectives), (b) collaborative (same rules, shared objective), (c) market share (different rules, same objectives), and (d) market growth (different rules, value added orientation). The defining characteristics of the four types of competition are respectively: needing a referee, arguing over the spoils, differentiation and substitutability, and customer focus. Dentistry has features of all four types of competition, thus making it difficult to have a meaningful discussion or frame a coherent policy on this topic. PMID:9270222

  6. Intraspecific competition during infection by Aspergillus flavus is influenced by plant host species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Communities of Aspergillus flavus are composed of diverse genotypes that collectively influence incidence and severity of crop aflatoxin contamination. Isolates vary in competitive ability on maize, but empirical data on the extent to which host-specific influences determine outcomes of competition ...

  7. Competitive Speech and Debate: How Play Influenced American Educational Practice

    ERIC Educational Resources Information Center

    Bartanen, Michael D.; Littlefield, Robert S.

    2015-01-01

    The authors identify competitive speech and debate as a form of play that helped democratize American citizenship for the poor, who used what they learned through the practice to advance their personal social and economic goals. In addition, this competitive activity led to the development of speech communication as an academic discipline and…

  8. Dual-axis hormonal covariation in adolescence and the moderating influence of prior trauma and aversive maternal parenting.

    PubMed

    Simmons, Julian G; Byrne, Michelle L; Schwartz, Orli S; Whittle, Sarah L; Sheeber, Lisa; Kaess, Michael; Youssef, George J; Allen, Nicholas B

    2015-09-01

    Adversity early in life can disrupt the functioning of the hypothalamic-pituitary-adrenal and hypothalamic-pituitary-gonadal axes and increase risk for negative health outcomes. The interplay between these axes and the environment is complex, and understanding needs to be advanced by the investigation of the multiple hormonal relationships underlying these processes. The current study examined basal hormonal associations between morning levels of cortisol, testosterone, and dehydroepiandrosterone in a cohort of adolescents (mean age 15.56 years). The moderating influence of childhood adversity was also examined, as indexed by self-reported trauma (at mean age 14.91), and observed maternal aggressive parenting (at mean age 12.41). Between-person regressions revealed significant associations between hormones that were moderated by both measures of adversity. In females, all hormones positively covaried, but also interacted with adversity, such that positive covariation was typically only present when levels of trauma and/or aggressive parenting were low. In males, hormonal associations and interactions were less evident; however, interactions were detected for cortisol-testosterone - positively covarying at high levels of aggressive parenting but negatively covarying at low levels - and DHEA-cortisol - similarly positively covarying at high levels of parental aggression. These results demonstrate associations between adrenal and gonadal hormones and the moderating role of adversity, which is likely driven by feedback mechanisms, or cross-talk, between the axes. These findings suggest that hormonal changes may be the pathway through which early life adversity alters physiology and increases health risks, but does so differentially in the sexes; however further study is necessary to establish causation. PMID:25754696

  9. The Influence of Prior Handling on the Effective CS-US Interval in Long-Trace Taste-Aversion Conditioning in Rats

    ERIC Educational Resources Information Center

    Hinderliter, Charles F.; Andrews, Amy; Misanin, James R.

    2012-01-01

    In conditioned taste aversion (CTA), a taste, the conditioned stimulus (CS), is paired with an illness-inducing stimulus, the unconditioned stimulus (US), to produce CS-US associations at very long (hours) intervals, a result that appears to violate the law of contiguity. The specific length of the maximum effective trace interval that has been…

  10. Competitiveness

    NASA Astrophysics Data System (ADS)

    Minihan, Charles E.

    1991-03-01

    Competition is defined as a spirited, sometimes ruthless, engagement of rivals such as in a race, a match, or an effort by one person to sell goods or services to customers in the marketplace of another. Sound familiar? If you will bear with me for a few minutes, I would like to examine competitiveness on a more global basis with emphasis on the rules of the game. You may be thinking that more often than not the competitive arena is relatively small and far from global, and its consequences are singularly influential on a trivial document called the P & L. However, with the newly established freedom of a major segment of the world population and with the industrial capability formerly known as Communist moving into what has heretofore been "our" limited arena, the competition could get very brisk. Brisk, and perhaps ruthless, unless we work together to try to establish an international industrial policy that is truly based on equality of competitive opportunity for all.

  11. Population density influences male-male competition in guppies.

    PubMed

    Jirotkul

    1999-12-01

    This study tested the general prediction that population density affects male-male competition, female mate choice and the opportunity for sexual selection. By manipulating the density of guppies, Poecilia reticulata, while keeping the sex ratio constant, I found that male mating tactics were phenotypically plastic with respect to density. As density increased, males decreased their courtship displays. Male-male competition and mate searching were highest at intermediate densities. Population density had no significant effect on the total number of copulations, copulatory tactics or the percentage of postcopulatory guarding. Female preference for males with a higher percentage of orange coloration was similar at all density levels. The 'opportunity for sexual selection', which estimates the upper limit to which a selected trait can shift if directional selection is operating and was calculated as the variance in number of copulations per male divided by the square of the mean number of copulations, was negatively associated with population density. This may be due to the decrease in male-male competition at high density rather than female preference which was similar across density treatments. Copyright 1999 The Association for the Study of Animal Behaviour. PMID:10600137

  12. The ontogeny of ethanol aversion.

    PubMed

    Saalfield, Jessica; Spear, Linda

    2016-03-15

    Recent work has suggested separate developmental periods within the broader framework of adolescence, with data suggesting distinct alterations and vulnerabilities within these intervals. While previous research has suggested reduced sensitivity to the aversive effects of alcohol in adolescence relative to adults, a more detailed ontogeny of this effect has yet to be conducted. The adolescent brain undergoes significant transitions throughout adolescence, including in regions linked with drug reward and aversion. The current study aimed to determine the ontogeny of ethanol aversion by utilizing a conditioned taste aversion procedure at six different ages to test the hypothesis that the transitions into, through, and out of adolescence are associated with ontogenetic alterations in sensitivity to the aversive properties of ethanol. Non-deprived animals given Boost® as the conditioned stimulus (CS) were used in Experiment 1, whereas Experiment 2 used water-restricted animals provided with a saccharin/sucrose solution as the CS. In both experiments, an attenuated sensitivity to the aversive properties of ethanol was evident in adolescents compared to adults, although more age differences were apparent in water deprived animals than when a highly palatable CS was given to ad libitum animals. Overall, the data suggest an attenuated sensitivity to the aversive properties of ethanol that is most pronounced during pre- and early adolescence, declining thereafter to reach the enhanced aversive sensitivity of adults. PMID:26774181

  13. Opinion dynamics on interacting networks: media competition and social influence

    NASA Astrophysics Data System (ADS)

    Quattrociocchi, Walter; Caldarelli, Guido; Scala, Antonio

    2014-05-01

    The inner dynamics of the multiple actors of the informations systems - i.e, T.V., newspapers, blogs, social network platforms, - play a fundamental role on the evolution of the public opinion. Coherently with the recent history of the information system (from few main stream media to the massive diffusion of socio-technical system), in this work we investigate how main stream media signed interaction might shape the opinion space. In particular we focus on how different size (in the number of media) and interaction patterns of the information system may affect collective debates and thus the opinions' distribution. We introduce a sophisticated computational model of opinion dynamics which accounts for the coexistence of media and gossip as separated mechanisms and for their feedback loops. The model accounts also for the effect of the media communication patterns by considering both the simple case where each medium mimics the behavior of the most successful one (to maximize the audience) and the case where there is polarization and thus competition among media memes. We show that plurality and competition within information sources lead to stable configurations where several and distant cultures coexist.

  14. Opinion dynamics on interacting networks: media competition and social influence.

    PubMed

    Quattrociocchi, Walter; Caldarelli, Guido; Scala, Antonio

    2014-01-01

    The inner dynamics of the multiple actors of the informations systems - i.e, T.V., newspapers, blogs, social network platforms, - play a fundamental role on the evolution of the public opinion. Coherently with the recent history of the information system (from few main stream media to the massive diffusion of socio-technical system), in this work we investigate how main stream media signed interaction might shape the opinion space. In particular we focus on how different size (in the number of media) and interaction patterns of the information system may affect collective debates and thus the opinions' distribution. We introduce a sophisticated computational model of opinion dynamics which accounts for the coexistence of media and gossip as separated mechanisms and for their feedback loops. The model accounts also for the effect of the media communication patterns by considering both the simple case where each medium mimics the behavior of the most successful one (to maximize the audience) and the case where there is polarization and thus competition among media memes. We show that plurality and competition within information sources lead to stable configurations where several and distant cultures coexist. PMID:24861995

  15. Opinion dynamics on interacting networks: media competition and social influence

    PubMed Central

    Quattrociocchi, Walter; Caldarelli, Guido; Scala, Antonio

    2014-01-01

    The inner dynamics of the multiple actors of the informations systems – i.e, T.V., newspapers, blogs, social network platforms, – play a fundamental role on the evolution of the public opinion. Coherently with the recent history of the information system (from few main stream media to the massive diffusion of socio-technical system), in this work we investigate how main stream media signed interaction might shape the opinion space. In particular we focus on how different size (in the number of media) and interaction patterns of the information system may affect collective debates and thus the opinions' distribution. We introduce a sophisticated computational model of opinion dynamics which accounts for the coexistence of media and gossip as separated mechanisms and for their feedback loops. The model accounts also for the effect of the media communication patterns by considering both the simple case where each medium mimics the behavior of the most successful one (to maximize the audience) and the case where there is polarization and thus competition among media memes. We show that plurality and competition within information sources lead to stable configurations where several and distant cultures coexist. PMID:24861995

  16. Role of hypothermia in ethanol-induced conditioned taste aversion.

    PubMed

    Cunningham, C L; Hawks, D M; Niehus, D R

    1988-01-01

    Two experiments examined the effect of ambient temperature during ethanol exposure on development of conditioned taste aversion to saccharin. In both studies, male albino rats receiving saccharin-ethanol (1.5 g/kg, IP) pairings followed by 6-h exposure to a 32 degrees C environment developed a weaker saccharin aversion than did rats experiencing ethanol at room temperature. Exposure to the warm environment reduced ethanol-induced hypothermia, but enhanced ethanol's motor-impairing effect. The influence of ambient temperature on ethanol-induced taste aversion may be due to changes in body temperature, neural sensitivity, or elimination rate. Although alternative accounts cannot be entirely dismissed, this outcome suggests that ethanol-induced hypothermia plays a role in determining strength of conditioned taste aversion and thus may be involved in the regulation of oral ethanol intake in rats. PMID:3137617

  17. Parents influence asymmetric sibling competition: experimental evidence with partially dependent young.

    PubMed

    Smiseth, Per T; Ward, Richard J S; Moore, Allen J

    2007-12-01

    Asymmetric sibling competition, which occurs when some siblings hatch as stronger competitors than others, is an important component of avian reproductive strategies. Here, we report two experiments on the burying beetle Nicrophorus vespilloides investigating how parents might influence the outcome of asymmetric sibling competition. In this species, as in altricial birds, different-aged offspring compete for resources provided by the parents. However, unlike altricial birds, offspring depend only partially on their parents for resources, and parents adjust the brood size directly through filial cannibalism. In the first experiment, we compared the growth and survivorship of different-aged offspring when parents could and could not influence asymmetric sibling competition. In the second experiment, we recorded behavioral interactions between different-aged offspring and parents. We found that senior offspring (early-hatched) grew faster than juniors (late-hatched) when parents were present and could influence the outcome of sibling competition, whereas seniors and juniors grew at similar rates when parents were removed. Thus, seniors benefited more than did juniors when the offspring could obtain resources by begging from the female parent. There was no difference in the survivorship of seniors and juniors. We also found that seniors and juniors spent a similar amount of time feeding from female parents, but juniors spent more time begging and were less effective at begging than seniors. Interestingly, juniors spent more time begging only as long as seniors also begged, suggesting that juniors adjusted their begging effort in response to direct competition against seniors for resources provided by parents. Our study provides novel insights into the ecological significance of asymmetric sibling competition by showing that asymmetric sibling competition took place when parents were present and offspring could obtain resources by begging. In contrast, we found no

  18. Thinking like a trader selectively reduces individuals' loss aversion

    PubMed Central

    Sokol-Hessner, Peter; Hsu, Ming; Curley, Nina G.; Delgado, Mauricio R.; Camerer, Colin F.; Phelps, Elizabeth A.

    2009-01-01

    Research on emotion regulation has focused upon observers' ability to regulate their emotional reaction to stimuli such as affective pictures, but many other aspects of our affective experience are also potentially amenable to intentional cognitive regulation. In the domain of decision-making, recent work has demonstrated a role for emotions in choice, although such work has generally remained agnostic about the specific role of emotion. Combining psychologically-derived cognitive strategies, physiological measurements of arousal, and an economic model of behavior, this study examined changes in choices (specifically, loss aversion) and physiological correlates of behavior as the result of an intentional cognitive regulation strategy. Participants were on average more aroused per dollar to losses relative to gains, as measured with skin conductance response, and the difference in arousal to losses versus gains correlated with behavioral loss aversion across subjects. These results suggest a specific role for arousal responses in loss aversion. Most importantly, the intentional cognitive regulation strategy, which emphasized “perspective-taking,” uniquely reduced both behavioral loss aversion and arousal to losses relative to gains, largely by influencing arousal to losses. Our results confirm previous research demonstrating loss aversion while providing new evidence characterizing individual differences and arousal correlates and illustrating the effectiveness of intentional regulation strategies in reducing loss aversion both behaviorally and physiologically. PMID:19289824

  19. The origin of risk aversion

    PubMed Central

    Zhang, Ruixun; Brennan, Thomas J.; Lo, Andrew W.

    2014-01-01

    Risk aversion is one of the most basic assumptions of economic behavior, but few studies have addressed the question of where risk preferences come from and why they differ from one individual to the next. Here, we propose an evolutionary explanation for the origin of risk aversion. In the context of a simple binary-choice model, we show that risk aversion emerges by natural selection if reproductive risk is systematic (i.e., correlated across individuals in a given generation). In contrast, risk neutrality emerges if reproductive risk is idiosyncratic (i.e., uncorrelated across each given generation). More generally, our framework implies that the degree of risk aversion is determined by the stochastic nature of reproductive rates, and we show that different statistical properties lead to different utility functions. The simplicity and generality of our model suggest that these implications are primitive and cut across species, physiology, and genetic origins. PMID:25453072

  20. The origin of risk aversion.

    PubMed

    Zhang, Ruixun; Brennan, Thomas J; Lo, Andrew W

    2014-12-16

    Risk aversion is one of the most basic assumptions of economic behavior, but few studies have addressed the question of where risk preferences come from and why they differ from one individual to the next. Here, we propose an evolutionary explanation for the origin of risk aversion. In the context of a simple binary-choice model, we show that risk aversion emerges by natural selection if reproductive risk is systematic (i.e., correlated across individuals in a given generation). In contrast, risk neutrality emerges if reproductive risk is idiosyncratic (i.e., uncorrelated across each given generation). More generally, our framework implies that the degree of risk aversion is determined by the stochastic nature of reproductive rates, and we show that different statistical properties lead to different utility functions. The simplicity and generality of our model suggest that these implications are primitive and cut across species, physiology, and genetic origins. PMID:25453072

  1. Instructions of cooperation and competition influence the neural responses to others' pain: An ERP study.

    PubMed

    Cui, Fang; Zhu, Xiangru; Duan, Feiyan; Luo, Yuejia

    2016-01-01

    Neural activities triggered by viewing other's in pain have been previously reported to be modulated by various factors. How instructions of cooperation and competition can influence these activities has not been explored yet. In the current study, participants were instructed to play a game cooperatively or competitively with a partner. During the game, pictures showing an anonymous individual's hand or foot in painful or non-painful situations were randomly presented in an oddball style. The event-related potentials (ERPs) when the participants passively observed these pictures under different instructions were compared. We found a significant interaction of Instruction × Picture on the P3 component, where only under competitive instruction did the painful pictures elicit significantly larger amplitudes than the non-painful pictures, but not under the cooperative instruction. This result indicates that the participants were more responsive to other's pain in a competitive context than in a cooperative context. PMID:26226618

  2. Competitive Strategy and Influences on E-Learning in Entrepreneur-Led SMEs

    ERIC Educational Resources Information Center

    Roffe, Ian

    2007-01-01

    Purpose: To explore the influence of competitive strategy in entrepreneur-led SMEs and the effects on e-learning HRD. Design/methodology/approach: Performance consulting company reviews provide holistic information on nine case studies on small and medium sized enterprises drawn from the printing, agri-foods and media industries. Findings:…

  3. Preexposure to Salty and Sour Taste Enhances Conditioned Taste Aversion to Novel Sucrose

    ERIC Educational Resources Information Center

    Flores, Veronica L.; Moran, Anan; Bernstein, Max; Katz, Donald B.

    2016-01-01

    Conditioned taste aversion (CTA) is an intensively studied single-trial learning paradigm whereby animals are trained to avoid a taste that has been paired with malaise. Many factors influence the strength of aversion learning; prominently studied among these is taste novelty--the fact that preexposure to the taste conditioned stimulus (CS)…

  4. The Influence of Hospital Market Competition on Patient Mortality and Total Performance Score.

    PubMed

    Haley, Donald Robert; Zhao, Mei; Spaulding, Aaron; Hamadi, Hanadi; Xu, Jing; Yeomans, Katelyn

    2016-01-01

    The Affordable Care Act of 2010 launch of Medicare Value-Based Purchasing has become the platform for payment reform. It is a mechanism by which buyers of health care services hold providers accountable for high-quality and cost-effective care. The objective of the study was to examine the relationship between quality of hospital care and hospital competition using the quality-quantity behavioral model of hospital behavior. The quality-quantity behavioral model of hospital behavior was used as the conceptual framework for this study. Data from the American Hospital Association database, the Hospital Compare database, and the Area Health Resources Files database were used. Multivariate regression analysis was used to examine the effect of hospital competition on patient mortality. Hospital market competition was significantly and negatively related to the 3 mortality rates. Consistent with the literature, hospitals located in more competitive markets had lower mortality rates for patients with acute myocardial infarction, heart failure, and pneumonia. The results suggest that hospitals may be more readily to compete on quality of care and patient outcomes. The findings are important because policies that seek to control and negatively influence a competitive hospital environment, such as Certificate of Need legislation, may negatively affect patient mortality rates. Therefore, policymakers should encourage the development of policies that facilitate a more competitive and transparent health care marketplace to potentially and significantly improve patient mortality. PMID:27455368

  5. Competitive advantage in the ERP system's value-chain and its influence on future development

    NASA Astrophysics Data System (ADS)

    Johansson, Björn; Newman, Mike

    2010-02-01

    Using the resource-based view, we present a set of propositions related to enterprise resource planning (ERP) development, reflections on competitive advantage and the different roles that stakeholders play in the value-chain. This has the goal of building a foundation for future research on ERPs and how stakeholders' desire to achieve competitive advantage influence ERP development, especially when it comes to development of a more standardised or pre-customised ERP system. The propositions also act as a foundation for increasing our knowledge concerning the difficulty in developing improved ERP systems.

  6. The Influence of Information Acquisition on the Complex Dynamics of Market Competition

    NASA Astrophysics Data System (ADS)

    Guo, Zhanbing; Ma, Junhai

    In this paper, we build a dynamical game model with three bounded rational players (firms) to study the influence of information on the complex dynamics of market competition, where useful information is about rival’s real decision. In this dynamical game model, one information-sharing team is composed of two firms, they acquire and share the information about their common competitor, however, they make their own decisions separately, where the amount of information acquired by this information-sharing team will determine the estimation accuracy about the rival’s real decision. Based on this dynamical game model and some creative 3D diagrams, the influence of the amount of information on the complex dynamics of market competition such as local dynamics, global dynamics and profits is studied. These results have significant theoretical and practical values to realize the influence of information.

  7. Aversion and attraction through olfaction

    PubMed Central

    Li, Qian; Liberles, Stephen D.

    2015-01-01

    Sensory cues that predict reward or punishment are fundamental drivers of animal behavior. For example, attractive odors of palatable food or a potential mate predict reward while aversive odors of pathogen-laced food or a predator predict punishment. Aversive and attractive odors can be detected by intermingled sensory neurons that express highly related olfactory receptors and display similar central projections. These findings raise basic questions of how innate odor valence is extracted from olfactory circuits, how such circuits are developmentally endowed and modulated by state, and the relationship between innate and learned odor responses. Here, we review odors, receptors, and neural circuits associated with stimulus valence, discussing salient principles derived from studies on nematodes, insects, and vertebrates. Understanding the organization of neural circuitry that mediates odor aversion and attraction will provide key insights into how the brain functions. PMID:25649823

  8. Influence of competition in minimal systems with discontinuous absorbing phase transitions

    NASA Astrophysics Data System (ADS)

    Pianegonda, Salete; Fiore, Carlos E.

    2016-06-01

    Contact processes (CP's) with particle creation requiring a minimal neighborhood (restrictive or threshold CP's) present a novel sort of discontinuous absorbing transitions, that revealed itself robust under the inclusion of different ingredients, such as distinct lattice topologies, particle annihilations and diffusion. Here, we tackle on the influence of competition between restrictive and standard dynamics (that describes the usual CP and a continuous DP transition is presented). Systems have been studied via mean-field theory (MFT) and numerical simulations. Results show partial contrast between MFT and numerical results. While the former predicts that considerable competition rates are required to shift the phase transition, the latter reveals the change occurs for rather limited (small) fractions. Thus, unlike previous ingredients (such as diffusion and others), limited competitive rates suppress the phase coexistence.

  9. Interspecific Competition Influences Fitness Benefits of Assortative Mating for Territorial Aggression in Eastern Bluebirds (Sialia sialis)

    PubMed Central

    Harris, Morgan R.; Siefferman, Lynn

    2014-01-01

    Territorial aggression influences fitness and, in monogamous pairs, the behavior of both individuals could impact reproductive success. Moreover, territorial aggression is particularly important in the context of interspecific competition. Tree swallows and eastern bluebirds are highly aggressive, secondary cavity-nesting birds that compete for limited nesting sites. We studied eastern bluebirds at a field site in the southern Appalachian Mountains that has been recently colonized (<40 yr) by tree swallows undergoing a natural range expansion. The field site is composed of distinct areas where bluebirds compete regularly with tree swallows and areas where there is little interaction between the two species. Once birds had settled, we measured how interspecific competition affects the relationship between assortative mating (paired individuals that behave similarly) and reproductive success in eastern bluebirds. We found a strong tendency toward assortative mating throughout the field site. In areas of high interspecific competition, pairs that behaved the most similarly and displayed either extremely aggressive or extremely non-aggressive phenotypes experienced higher reproductive success. Our data suggest that interspecific competition with tree swallows may select for bluebirds that express similar behavior to that of their mate. Furthermore, animal personality may be an important factor influencing the outcome of interactions between native and aggressive, invasive species. PMID:24516672

  10. 'Competitive' food and beverage policies: are they influencing childhood overweight trends?

    PubMed

    Sanchez-Vaznaugh, Emma V; Sánchez, Brisa N; Baek, Jonggyu; Crawford, Patricia B

    2010-01-01

    We examined whether new policies restricting sales in schools of so-called competitive foods and beverages-those that fall outside of what is served through federally reimbursed school meal programs-influenced increasing rates of overweight children in the Los Angeles Unified School District and the rest of California. After these policies, which set stricter nutrition standards for certain food and beverages sold to students, took effect, the rate of increase in overweight children significantly diminished among fifth graders in Los Angeles and among fifth-grade boys and seventh graders in the rest of California. The extent to which the new nutritional policies contributed to the change is unclear. This is one of the first studies examining the postulated population-level influence of recently implemented policies aimed at sales of competitive foods and beverages in schools. PMID:20194985

  11. Conditioned suppression, punishment, and aversion

    NASA Technical Reports Server (NTRS)

    Orme-Johnson, D. W.; Yarczower, M.

    1974-01-01

    The aversive action of visual stimuli was studied in two groups of pigeons which received response-contingent or noncontingent electric shocks in cages with translucent response keys. Presentation of grain for 3 sec, contingent on key pecking, was the visual stimulus associated with conditioned punishment or suppression. The responses of the pigeons in three different experiments are compared.

  12. Influence of interspecific competition and landscape structure on spatial homogenization of avian assemblages.

    PubMed

    Robertson, Oliver J; McAlpine, Clive; House, Alan; Maron, Martine

    2013-01-01

    Human-induced biotic homogenization resulting from landscape change and increased competition from widespread generalists or 'winners', is widely recognized as a global threat to biodiversity. However, it remains unclear what aspects of landscape structure influence homogenization. This paper tests the importance of interspecific competition and landscape structure, for the spatial homogeneity of avian assemblages within a fragmented agricultural landscape of eastern Australia. We used field observations of the density of 128 diurnal bird species to calculate taxonomic and functional similarity among assemblages. We then examined whether taxonomic and functional similarity varied with patch type, the extent of woodland habitat, land-use intensity, habitat subdivision, and the presence of Manorina colonies (a competitive genus of honeyeaters). We found the presence of a Manorina colony was the most significant factor positively influencing both taxonomic and functional similarity of bird assemblages. Competition from members of this widespread genus of native honeyeater, rather than landscape structure, was the main cause of both taxonomic and functional homogenization. These species have not recently expanded their range, but rather have increased in density in response to agricultural landscape change. The negative impacts of Manorina honeyeaters on assemblage similarity were most pronounced in landscapes of moderate land-use intensity. We conclude that in these human-modified landscapes, increased competition from dominant native species, or 'winners', can result in homogeneous avian assemblages and the loss of specialist species. These interacting processes make biotic homogenization resulting from land-use change a global threat to biodiversity in modified agro-ecosystems. PMID:23724136

  13. Influence of Interspecific Competition and Landscape Structure on Spatial Homogenization of Avian Assemblages

    PubMed Central

    Robertson, Oliver J.; McAlpine, Clive; House, Alan; Maron, Martine

    2013-01-01

    Human-induced biotic homogenization resulting from landscape change and increased competition from widespread generalists or ‘winners’, is widely recognized as a global threat to biodiversity. However, it remains unclear what aspects of landscape structure influence homogenization. This paper tests the importance of interspecific competition and landscape structure, for the spatial homogeneity of avian assemblages within a fragmented agricultural landscape of eastern Australia. We used field observations of the density of 128 diurnal bird species to calculate taxonomic and functional similarity among assemblages. We then examined whether taxonomic and functional similarity varied with patch type, the extent of woodland habitat, land-use intensity, habitat subdivision, and the presence of Manorina colonies (a competitive genus of honeyeaters). We found the presence of a Manorina colony was the most significant factor positively influencing both taxonomic and functional similarity of bird assemblages. Competition from members of this widespread genus of native honeyeater, rather than landscape structure, was the main cause of both taxonomic and functional homogenization. These species have not recently expanded their range, but rather have increased in density in response to agricultural landscape change. The negative impacts of Manorina honeyeaters on assemblage similarity were most pronounced in landscapes of moderate land-use intensity. We conclude that in these human-modified landscapes, increased competition from dominant native species, or ‘winners’, can result in homogeneous avian assemblages and the loss of specialist species. These interacting processes make biotic homogenization resulting from land-use change a global threat to biodiversity in modified agro-ecosystems. PMID:23724136

  14. Distributional preferences and competitive behavior☆

    PubMed Central

    Balafoutas, Loukas; Kerschbamer, Rudolf; Sutter, Matthias

    2012-01-01

    We study experimentally the relationship between distributional preferences and competitive behavior. We find that spiteful subjects react strongest to competitive pressure and win in a tournament significantly more often than efficiency-minded and inequality averse subjects. However, when given the choice between a tournament and a piece rate scheme, efficiency-minded subjects choose the tournament most often, while spiteful and inequality averse subjects avoid it. When controlling for distributional preferences, risk attitudes and past performance, the gender gap in the willingness to compete is no longer significant, indicating that gender-related variables explain why twice as many men as women self-select into competition. PMID:23576829

  15. Transactional Influences of Infants' Orienting Ability and Maternal Cooperation on Competition in Three-Year-Old Children.

    ERIC Educational Resources Information Center

    Lutkenhaus, Paul; And Others

    1985-01-01

    Describes how three-year-olds regulate their effort during competition and compares their facial expressions after failure and success, demonstrating the operation of a display rule in competition. Explores the cross-situational stability of subjects' regulation of behavior, as well as the relationship between factors influencing mother-child…

  16. The Betrayal Aversion Elicitation Task: An Individual Level Betrayal Aversion Measure

    PubMed Central

    Aimone, Jason; Ball, Sheryl; King-Casas, Brooks

    2015-01-01

    Research on betrayal aversion shows that individuals’ response to risk depends not only on probabilities and payoffs, but also on whether the risk includes a betrayal of trust. While previous studies focus on measuring aggregate levels of betrayal aversion, the connection between an individual’s own betrayal aversion and other individually varying factors, including risk preferences, are currently unexplored. This paper develops a new task to elicit an individual’s level of betrayal aversion that can then be compared to individual characteristics. We demonstrate the feasibility of our new task and show that our aggregate individual results are consistent with previous studies. We then use this classification to ask whether betrayal aversion is correlated with risk aversion. While we find risk aversion and betrayal aversion have no significant relationship, we do observe that risk aversion is correlated with non-social risk preferences, but not the social, betrayal related, risk component of the new task. PMID:26331944

  17. The influence of relationship status, mate seeking, and sex on intrasexual competition.

    PubMed

    Fisher, Maryanne L; Tran, Ulrich S; Voracek, Martin

    2008-08-01

    Researchers have little explored individuals' perceptions of same-sex attractiveness in terms of the influence of relationship status. By using intrasexual competition as a conceptual framework, the authors predicted that romantically involved individuals would protect their relationship by derogating competitors. Although previous researchers have strongly predicted this result, in the present study the relationship status had a negligible impact on competition, for which relationship commitment, sociosexual orientation, and self-monitoring did not account. Also, among uninvolved individuals, the authors expected those individuals seeking mates would use competitor derogation more than would those individuals not seeking mates, but there was no significant difference. Finally, because the vehicle for this investigation was attractiveness, an area in which women compete, the authors proposed that women would derogate more fiercely than would men. However, the results did not support this hypothesis either. The authors discuss future directions for research. PMID:18807423

  18. Tree growth and competition in an old-growth Picea abies forest of boreal Sweden: influence of tree spatial patterning

    USGS Publications Warehouse

    Fraver, Shawn; D'Amato, Anthony W.; Bradford, John B.; Jonsson, Bengt Gunnar; Jönsson, Mari; Esseen, Per-Anders

    2013-01-01

    Question: What factors best characterize tree competitive environments in this structurally diverse old-growth forest, and do these factors vary spatially within and among stands? Location: Old-growth Picea abies forest of boreal Sweden. Methods: Using long-term, mapped permanent plot data augmented with dendrochronological analyses, we evaluated the effect of neighbourhood competition on focal tree growth by means of standard competition indices, each modified to include various metrics of trees size, neighbour mortality weighting (for neighbours that died during the inventory period), and within-neighbourhood tree clustering. Candidate models were evaluated using mixed-model linear regression analyses, with mean basal area increment as the response variable. We then analysed stand-level spatial patterns of competition indices and growth rates (via kriging) to determine if the relationship between these patterns could further elucidate factors influencing tree growth. Results: Inter-tree competition clearly affected growth rates, with crown volume being the size metric most strongly influencing the neighbourhood competitive environment. Including neighbour tree mortality weightings in models only slightly improved descriptions of competitive interactions. Although the within-neighbourhood clustering index did not improve model predictions, competition intensity was influenced by the underlying stand-level tree spatial arrangement: stand-level clustering locally intensified competition and reduced tree growth, whereas in the absence of such clustering, inter-tree competition played a lesser role in constraining tree growth. Conclusions: Our findings demonstrate that competition continues to influence forest processes and structures in an old-growth system that has not experienced major disturbances for at least two centuries. The finding that the underlying tree spatial pattern influenced the competitive environment suggests caution in interpreting traditional tree

  19. Solution aversion: On the relation between ideology and motivated disbelief.

    PubMed

    Campbell, Troy H; Kay, Aaron C

    2014-11-01

    There is often a curious distinction between what the scientific community and the general population believe to be true of dire scientific issues, and this skepticism tends to vary markedly across groups. For instance, in the case of climate change, Republicans (conservatives) are especially skeptical of the relevant science, particularly when they are compared with Democrats (liberals). What causes such radical group differences? We suggest, as have previous accounts, that this phenomenon is often motivated. However, the source of this motivation is not necessarily an aversion to the problem, per se, but an aversion to the solutions associated with the problem. This difference in underlying process holds important implications for understanding, predicting, and influencing motivated skepticism. In 4 studies, we tested this solution aversion explanation for why people are often so divided over evidence and why this divide often occurs so saliently across political party lines. Studies 1, 2, and 3-using correlational and experimental methodologies-demonstrated that Republicans' increased skepticism toward environmental sciences may be partly attributable to a conflict between specific ideological values and the most popularly discussed environmental solutions. Study 4 found that, in a different domain (crime), those holding a more liberal ideology (support for gun control) also show skepticism motivated by solution aversion. PMID:25347128

  20. Influence of corallivory, competition, and habitat structure on coral community shifts.

    PubMed

    Lenihan, Hunter S; Holbrook, Sally J; Schmitt, Russell J; Brooks, Andrew J

    2011-10-01

    The species composition of coral communities has shifted in many areas worldwide through the relative loss of important ecosystem engineers such as highly branched corals, which are integral in maintaining reef biodiversity. We assessed the degree to which the performance of recently recruited branching corals was influenced by corallivory, competition, sedimentation, and the interactions between these factors. We also explored whether the species-specific influence of these biotic and abiotic constraints helps to explain recent shifts in the coral community in lagoons of Moorea, French Polynesia. Population surveys revealed evidence of a community shift away from a historically acroporid-dominated community to a pocilloporid- and poritid-dominated community, but also showed that the distribution and abundance of coral taxa varied predictably with location in the lagoon. At the microhabitat scale, branching corals grew mainly on dead or partially dead massive Porites ("bommies"), promontories with enhanced current velocities and reduced sedimentation. A demographic study revealed that growth and survival of juvenile Pocillopora verrucosa and Acropora retusa, the two most common branching species of each taxon, were affected by predation and competition with vermetid gastropods. By 24 months of age, 20-60% of juvenile corals suffered partial predation by corallivorous fishes, and injured corals experienced reduced growth and survival. A field experiment confirmed that partial predation by corallivorous fishes is an important, but habitat-modulated, constraint for branching corals. Competition with vermetid gastropods reduced growth of both branching species but unexpectedly also provided an associational defense against corallivory. Overall, the impact of abiotic constraints was habitat-specific and similar for Acropora and Pocillopora, but biotic interactions, especially corallivory, had a greater negative effect on Acropora than Pocillopora, which may explain the

  1. The Relative Influence of Competition and Prey Defenses on the Phenotypic Structure of Insectivorous Bat Ensembles in Southern Africa

    PubMed Central

    Schoeman, M. Corrie; Jacobs, David S.

    2008-01-01

    Deterministic filters such as competition and prey defences should have a strong influence on the community structure of animals such as insectivorous bats that have life histories characterized by low fecundity, low predation risk, long life expectancy, and stable populations. We investigated the relative influence of these two deterministic filters on the phenotypic structure of insectivorous bat ensembles in southern Africa. We used null models to simulate the random phenotypic patterns expected in the absence of competition or prey defences and analysed the deviations of the observed phenotypic pattern from these expected random patterns. The phenotypic structure at local scales exhibited non-random patterns consistent with both competition and prey defense hypotheses. There was evidence that competition influenced body size distribution across ensembles. Competition also influenced wing and echolocation patterns in ensembles and in functional foraging groups with high species richness or abundance. At the same time, prey defense filters influenced echolocation patterns in two species-poor ensembles. Non-random patterns remained evident even after we removed the influence of body size from wing morphology and echolocation parameters taking phylogeny into account. However, abiotic filters such as geographic distribution ranges of small and large-bodied species, extinction risk, and the physics of flight and sound probably also interacted with biotic filters at local and/or regional scales to influence the community structure of sympatric bats in southern Africa. Future studies should investigate alternative parameters that define bat community structure such as diet and abundance to better determine the influence of competition and prey defences on the structure of insectivorous bat ensembles in southern Africa. PMID:19005563

  2. The influence of operational sex ratio on the intensity of competition for mates.

    PubMed

    Weir, Laura K; Grant, James W A; Hutchings, Jeffrey A

    2011-02-01

    The evolution and maintenance of secondary sexual characteristics and behavior are heavily influenced by the variance in mating success among individuals in a population. The operational sex ratio (OSR) is often used as a predictor of the intensity of competition for mates, as it describes the relative number of males and females who are ready to mate. We investigate changes in aggression, courtship, mate guarding, and sperm release as a function of changes in the OSR using meta-analytic techniques. As the OSR becomes increasingly biased, aggression increases as competitors attempt to defend mates, but this aggression begins to decrease at an OSR of 1.99, presumably due to the increased costs of competition as rivals become more numerous. Sperm release follows a similar but not significant trend. By contrast, courtship rate decreases as the OSR becomes increasingly biased, whereas mate guarding and copulation duration increase. Overall, predictable behavioral changes occur in response to OSR, although the nature of the change is dependent on the type of mating behavior. These results suggest considerable flexibility of mating system structure within species, which can be predicted by OSR and likely results in variation in the strength of sexual selection. PMID:21460553

  3. Influence of recruit condition on food competition and predation risk in a coral reef fish.

    PubMed

    Booth, David J; Beretta, Giglia A

    2004-07-01

    Settlement rate is considered to be a major determinant of the population structure of coral reef fishes. In this study, the effects of larval physiological condition on survival, predation risk and competitive ability are assessed for a small damselfish, Pomacentrus moluccensis. New settlers were collected and fed for 5 days to produce high and low condition (measured as lipid) treatment fish. In a field experiment, pairs (one high and one low condition fish) were transplanted to corals. Persistence over 2 weeks was much higher (100% vs. 25%) in high condition fish. In mixed groups in the laboratory, high condition fish were both aggressively dominant and consumed more of a limiting prey source than low condition fish. In addition, low condition fish were shown to be at much higher risk of predation. All of the low condition fish but only 33% of high condition fish in mixed groups were consumed by fish predators, and in a separate experiment, 73% of feeding strikes by predators were directed at low condition fish. Quality of new settlers can have an important influence on subsequent juvenile survival. The mechanisms for this effect are likely to include a combination of effects of condition on food competition and predation risk. PMID:15179583

  4. Ambient temperature effects on taste aversion conditioned by ethanol: contribution of ethanol-induced hypothermia.

    PubMed

    Cunningham, C L; Niehus, J S; Bachtold, J F

    1992-12-01

    Six experiments examined the effects of low (5-10 degrees C), normal (21 degrees C), or high (32 degrees) ambient temperature on conditioned taste aversion and body temperature changes produced by ethanol, lithium chloride, or morphine sulfate. Fluid-deprived rats received five to seven taste conditioning trials at 48-hr intervals. On each trial, access to saccharin at normal ambient temperature was followed by injection of drug or saline and placement for 6 hr into a temperature-controlled enclosure. Exposure to low ambient temperature facilitated, whereas exposure to high ambient temperature retarded acquisition of ethanol-induced conditioned taste aversion. The ability of an alteration in ambient temperature to influence conditioned taste aversion varied as a function of ethanol dose and was related to ambient temperature's effect on ethanol-induced hypothermia. More specifically, strength of conditioned taste aversion was negatively correlated with core body temperature after ethanol injection. Alterations in ambient temperature alone did not affect ingestion of a paired flavor solution in the absence of drug. Moreover, alterations in ambient temperature did not appear to influence conditioned taste aversion by changing ethanol pharmacokinetics. Finally, high and low ambient temperature did not affect development of taste aversion conditioned by lithium chloride or morphine sulfate. The overall pattern of data presented by these experiments supports the hypothesis that ambient-temperature influences strength of ethanol-induced conditioned taste aversion by altering the hypothermic response to ethanol. More generally, these data support the suggestion that body temperature change induced by ethanol is related to ethanol's aversive motivational effects and may be involved in modulating ethanol intake. PMID:1471766

  5. COMPETITIVE INFLUENCE OF PHOSPHORUS AND CALCIUM ON PB IN-VITRO BIOAVAILABILITY

    EPA Science Inventory

    The bioavailability of a metal is heavily related to the speciation of the particular metal. Further, the complexity of examining metal bioavailability is compounded by the presence of competitive ions. Thus, equally contaminated soils with varying concentrations of competitive e...

  6. Health Security and Risk Aversion.

    PubMed

    Herington, Jonathan

    2016-09-01

    Health security has become a popular way of justifying efforts to control catastrophic threats to public health. Unfortunately, there has been little analysis of the concept of health security, nor the relationship between health security and other potential aims of public health policy. In this paper I develop an account of health security as an aversion to risky policy options. I explore three reasons for thinking risk avoidance is a distinctly worthwhile aim of public health policy: (i) that security is intrinsically valuable, (ii) that it is necessary for social planning and (iii) that it is an appropriate response to decision-making in contexts of very limited information. Striking the right balance between securing and maximizing population health thus requires a substantive, and hitherto unrecognized, value judgment. Finally, I critically evaluate the current health security agenda in light of this new account of the concept and its relationship to the other aims of public health policy. PMID:26990349

  7. Competitive exclusion within the predator community influences the distribution of a threatened prey species.

    PubMed

    Byholm, Patrik; Burgas, Daniel; Virtanen, Tarmo; Valkama, Jari

    2012-08-01

    While much effort has been made to quantify how landscape composition influences the distribution of species, the possibility that geographical differences in species interactions might affect species distributions has received less attention. Investigating a predator-prey setting in a boreal forest ecosystem, we empirically show that large-scale differences in the predator community structure and small-scale competitive exclusion among predators affect the local distribution of a threatened forest specialist more than does landscape composition. Consequently, even though the landscape parameters affecting Siberian flying squirrel (Pteromys volans) distribution (prey) did not differ between nest sites of the predators Northern Goshawks (Accipiter gentilis) and Ural Owls (Strix uralensis), flying squirrels were heterospecifically attracted by goshawks in a region where both predator species were present. No such effect was found in another region where Ural Owls were absent. These results provide evidence that differences in species interactions over large spatial scales may be a major force influencing the distribution and abundance patterns of species. On the basis of these findings, we suspect that subtle species interactions might be a central reason why landscape models constructed to predict species distributions often fail when applied to wider geographical scales. PMID:22928409

  8. Responses to Forces Influencing Cohesion as a Function of Player Status and Level of Male Varsity Basketball Competition.

    ERIC Educational Resources Information Center

    Gruber, Joseph J.; Gray, Gary R.

    1982-01-01

    A study analyzed team cohesion perceptions of 515 male varsity basketball players (10 to 22 years of age) to determine if factors influencing team cohesion were a function of competitive intensity or of the importance of individual players to their team. Players with the most game playing time were more satisfied than those with less playing time.…

  9. The influence of competition and host plant resistance on selection of Phytophthora infestans populations in Michigan State and Northern Ireland

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The current investigation used multiple cultivars of potato and genotypes of Phytophthora infestans to study the P. infestans genotype x cultivar interaction, and investigate the potential influence of competition and level of field resistance on selection of the surrounding population of P. infesta...

  10. Distinct traces for appetitive versus aversive olfactory memories in DPM neurons of Drosophila.

    PubMed

    Cervantes-Sandoval, Isaac; Davis, Ronald L

    2012-07-10

    The global logic used by the brain for differentially encoding positive and negative experiences remains unknown along with how such experiences are represented by collections of memory traces at the cellular level. Here we contrast the cellular memory traces that form in the dorsal paired medial (DPM) neurons of Drosophila after conditioning flies with odors associated with aversive or appetitive unconditioned stimuli (US). Our results show that the appetitive DPM neuron trace is distinguished from the aversive in three fundamental ways: (1) The DPM neurons do not respond to an appetitive US of sucrose by itself, in contrast to their robust response to an aversive US. (2) The appetitive trace persists for twice as long as the aversive trace. (3) The appetitive trace is expressed in both neurite branches of the neuron, rather than being confined to a single branch like the aversive trace. In addition, we demonstrate that training flies with nonnutritive sugars that elicit a behavioral memory that decays within 24 hr generates, like aversive conditioning, a short-lived and branch-restricted memory trace. These results indicate that the persistence and breadth of the DPM neuron memory trace influences the duration of behavioral memory. PMID:22658595

  11. Fetal Protection : The Roles of Social Learning and Innate Food Aversions in South India.

    PubMed

    Placek, Caitlyn D; Hagen, Edward H

    2015-09-01

    Pregnancy involves puzzling aversions to nutritious foods. Although studies generally support the hypotheses that such aversions are evolved mechanisms to protect the fetus from toxins and/or pathogens, other factors, such as resource scarcity and psychological distress, have not been investigated as often. In addition, many studies have focused on populations with high-quality diets and low infectious disease burden, conditions that diverge from the putative evolutionary environment favoring fetal protection mechanisms. This study tests the fetal protection, resource scarcity, and psychological distress hypotheses of food aversions in a resource-constrained population with high infectious disease burden. The role of culture is also explored. In the first of two studies in Tamil Nadu, India, we investigated cultural explanations of pregnancy diet among non-pregnant women (N = 54). In the second study, we conducted structured interviews with pregnant women (N = 94) to determine their cravings and aversions, resource scarcity, indices of pathogen exposure, immune activation, psychological distress, and emic causes of aversions. Study 1 found that fruits were the most commonly reported food that pregnant women should avoid because of their harmful effects on infants. Study 2 found modest support for the fetal protection hypothesis for food aversions. It also found that pregnant women most commonly avoided fruits as well as "black" and "hot" foods. Aversions were primarily acquired through learning and focused on protecting the infant from harm. Our findings provide modest support for the fetal protection hypothesis and surprisingly strong support for the influence of cultural norms and learning on dietary aversions in pregnancy. PMID:26286435

  12. Prospective and Pavlovian mechanisms in aversive behaviour

    PubMed Central

    Rigoli, Francesco; Pezzulo, Giovanni; Dolan, Raymond J.

    2016-01-01

    Studying aversive behaviour is critical for understanding negative emotions and associated psychopathologies. However a comprehensive picture of the mechanisms underlying aversion is lacking, with associative learning theories focusing on Pavlovian reactions and decision-making theoretic approaches on prospective functions. We propose a computational model of aversion that combines goal-directed and Pavlovian forms of control into a unifying framework in which their relative importance is regulated by factors such as threat distance and controllability. Using simulations, we test whether the model can reproduce available empirical findings and discuss its relevance to understanding factors underlying negative emotions such as fear and anxiety. Furthermore, the specific method used to construct the model permits a natural mapping from its components to brain structure and function. Our model provides a basis for a unifying account of aversion that can guide empirical and interventional study contexts. PMID:26539969

  13. Prospective and Pavlovian mechanisms in aversive behaviour.

    PubMed

    Rigoli, Francesco; Pezzulo, Giovanni; Dolan, Raymond J

    2016-01-01

    Studying aversive behaviour is critical for understanding negative emotions and associated psychopathologies. However a comprehensive picture of the mechanisms underlying aversion is lacking, with associative learning theories focusing on Pavlovian reactions and decision-making theoretic approaches on prospective functions. We propose a computational model of aversion that combines goal-directed and Pavlovian forms of control into a unifying framework in which their relative importance is regulated by factors such as threat distance and controllability. Using simulations, we test whether the model can reproduce available empirical findings and discuss its relevance to understanding factors underlying negative emotions such as fear and anxiety. Furthermore, the specific method used to construct the model permits a natural mapping from its components to brain structure and function. Our model provides a basis for a unifying account of aversion that can guide empirical and interventional study contexts. PMID:26539969

  14. On loss aversion in capuchin monkeys.

    PubMed

    Silberberg, Alan; Roma, Peter G; Huntsberry, Mary E; Warren-Boulton, Frederick R; Sakagami, Takayuki; Ruggiero, Angela M; Suomi, Stephen J

    2008-03-01

    Chen, Lakshminarayanan, and Santos (2006) claim to show in three choice experiments that monkeys react rationally to price and wealth shocks, but, when faced with gambles, display hallmark, human-like biases that include loss aversion. We present three experiments with monkeys and humans consistent with a reinterpretation of their data that attributes their results not to loss aversion, but to differences between choice alternatives in delay of reinforcement. PMID:18422015

  15. The Influence of Flood Disturbances on Interspecific Competition Between Stream Invertebrates

    NASA Astrophysics Data System (ADS)

    Effenberger, M.; Diehl, S.; Matthaei, C. D.

    2005-05-01

    We investigated the influence of repeated abiotic disturbances on interspecific competition between stream invertebrates. Artificial substrates (tiles) were exposed in 2 German streams with different flow regimes (floodprone versus stable). Half the tiles were disturbed (once every 2 weeks) by scrubbing to simulate a bed-moving flood, the other half remained undisturbed. We also manipulated densities of 2 of the most common invertebrate taxa in each stream (floodprone: Baetis and Heptageniidae; stable: Simulium and Brachycentrus montanus). Three invertebrate removal treatments (removal of taxon 1, removal of taxon 2, and unmanipulated controls) were applied, and invertebrates were removed every 3 days. After 2, 4 and 6 weeks each, we sampled 8 tiles from each treatment and determined invertebrate faunal composition, epilithic algal biomass (Chl a) and biofilm biomass (AFDM) for each sample. Both disturbance and invertebrate removal affected the stream biota. Disturbance reduced algal and biofilm biomasses in both streams, and invertebrate density in the floodprone stream. Brachycentrus removal resulted in higher flatworm density. Disturbance and invertebrate removal also interacted with each other. Density of the "non-target" mayfly Baetis in the stable stream was highest in Simulium removal treatments on disturbed tiles, but lowest in Simulium removal treatments on undisturbed tiles.

  16. Influence of dormancy on microbial competition under intermittent substrate supply: insights from model simulations.

    PubMed

    Stolpovsky, Konstantin; Fetzer, Ingo; Van Cappellen, Philippe; Thullner, Martin

    2016-06-01

    Most natural environments are characterized by frequent changes of their abiotic conditions. Microorganisms can respond to such changes by switching their physiological state between activity and dormancy allowing them to endure periods of unfavorable abiotic conditions. As a consequence, the competitiveness of microbial species is not simply determined by their growth performance under favorable conditions but also by their ability and readiness to respond to periods of unfavorable environmental conditions. The present study investigates the relevance of factors controlling the abundance and activity of individual bacterial species competing for an intermittently supplied substrate. For this purpose, numerical experiments were performed addressing the response of microbial systems to regularly applied feeding pulses. Simulation results show that community dynamics may exhibit a non-trivial link to the frequency of the external constraints and that for a certain combination of these environmental conditions coexistence of species is possible. The ecological implication of our results is that even non-dominant, neglected species can have a strong influence on realized species composition of dominant key species, due to their invisible presence enable the coexistence between important key species and by this affecting provided function of the system. PMID:27044984

  17. Myosin Light Chain Kinase (MLCK) Gene Influences Exercise Induced Muscle Damage during a Competitive Marathon.

    PubMed

    Del Coso, Juan; Valero, Marjorie; Lara, Beatriz; Salinero, Juan José; Gallo-Salazar, César; Areces, Francisco

    2016-01-01

    Myosin light chain kinase (MLCK) phosphorylates the regulatory light chain (RLC) of myosin producing increases in force development during skeletal muscle contraction. It has been suggested that MLCK gene polymorphisms might alter RLC phosphorylation thereby decreasing the ability to produce force and to resist strain during voluntary muscle contractions. Thus, the genetic variations in the MLCK gene might predispose some individuals to higher values of muscle damage during exercise, especially during endurance competitions. The aim of this investigation was to determine the influence of MLCK genetic variants on exercise-induced muscle damage produced during a marathon. Sixty-seven experienced runners competed in a marathon race. The MLCK genotype (C37885A) of these marathoners was determined. Before and after the race, a sample of venous blood was obtained to assess changes in serum myoglobin concentrations and leg muscle power changes were measured during a countermovement jump. Self-reported leg muscle pain and fatigue were determined by questionnaires. A total of 59 marathoners (88.1%) were CC homozygotes and 8 marathoners (11.9%) were CA heterozygotes. The two groups of participants completed the race with a similar time (228 ± 33 vs 234 ± 39 min; P = 0.30) and similar self-reported values for fatigue (15 ± 2 vs 16 ± 2 A.U.; P = 0.21) and lower-limb muscle pain (6.2 ± 1.7 vs 6.6 ± 1.8 cm; P = 0.29). However, CC marathoners presented higher serum myoglobin concentrations (739 ± 792 vs 348 ± 144 μg·mL-1; P = 0.03) and greater pre-to-post- race leg muscle power reduction (-32.7 ± 15.7 vs -21.2 ± 21.6%; P = 0.05) than CA marathoners. CA heterozygotes for MLCK C37885A might present higher exercise-induced muscle damage after a marathon competition than CC counterparts. PMID:27483374

  18. Myosin Light Chain Kinase (MLCK) Gene Influences Exercise Induced Muscle Damage during a Competitive Marathon

    PubMed Central

    Valero, Marjorie; Lara, Beatriz; Salinero, Juan José; Gallo-Salazar, César; Areces, Francisco

    2016-01-01

    Myosin light chain kinase (MLCK) phosphorylates the regulatory light chain (RLC) of myosin producing increases in force development during skeletal muscle contraction. It has been suggested that MLCK gene polymorphisms might alter RLC phosphorylation thereby decreasing the ability to produce force and to resist strain during voluntary muscle contractions. Thus, the genetic variations in the MLCK gene might predispose some individuals to higher values of muscle damage during exercise, especially during endurance competitions. The aim of this investigation was to determine the influence of MLCK genetic variants on exercise-induced muscle damage produced during a marathon. Sixty-seven experienced runners competed in a marathon race. The MLCK genotype (C37885A) of these marathoners was determined. Before and after the race, a sample of venous blood was obtained to assess changes in serum myoglobin concentrations and leg muscle power changes were measured during a countermovement jump. Self-reported leg muscle pain and fatigue were determined by questionnaires. A total of 59 marathoners (88.1%) were CC homozygotes and 8 marathoners (11.9%) were CA heterozygotes. The two groups of participants completed the race with a similar time (228 ± 33 vs 234 ± 39 min; P = 0.30) and similar self-reported values for fatigue (15 ± 2 vs 16 ± 2 A.U.; P = 0.21) and lower-limb muscle pain (6.2 ± 1.7 vs 6.6 ± 1.8 cm; P = 0.29). However, CC marathoners presented higher serum myoglobin concentrations (739 ± 792 vs 348 ± 144 μg·mL-1; P = 0.03) and greater pre-to-post- race leg muscle power reduction (-32.7 ± 15.7 vs -21.2 ± 21.6%; P = 0.05) than CA marathoners. CA heterozygotes for MLCK C37885A might present higher exercise-induced muscle damage after a marathon competition than CC counterparts. PMID:27483374

  19. Taste Aversions Conditioned by the Aversiveness of Insulin and Formalin: Role of CS Specificity

    ERIC Educational Resources Information Center

    Domjan, Michael; Levy, Carolyn J.

    1977-01-01

    Experimenters in the past have reported that when insulin is used as the unconditioned stimulus (US), rats will learn an aversion to a sodium chloride but not a sucrose solution, whereas with formalin as the US, they will learn an aversion to a sucrose but not a saline solution. The present experiments failed to confirm these findings. (Editor)

  20. Intervention Aversiveness: Educators' Perceptions of the Need for Restrictions on Aversive Interventions.

    ERIC Educational Resources Information Center

    Tobin, Tary J.; Sugai, George

    1993-01-01

    A survey of 158 educators found that respondents tended to consider interventions that use physical pain or discomfort or social humiliation to be very aversive and tended to favor restricting the use of these interventions. Respondents viewed many other decelerative interventions as relatively mild aversives that they should be able to use.…

  1. Illusory correlations between neutral and aversive stimuli can be induced by outcome aversiveness.

    PubMed

    Wiemer, Julian; Mühlberger, Andreas; Pauli, Paul

    2014-01-01

    Anxiety is often characterised by an overestimation of the contingency between concern-relevant and aversive stimuli, and an amplified aversiveness of such aversive stimuli. Here we tested whether outcome aversiveness causally enhances contingency estimates. Twenty-four participants were exposed to neutral visual cues which were followed by startle sounds. The loudness and hence the aversiveness of the cue was determined by the cue colour while the likelihood of the startle sound always remained constant (50%). Results indicated an illusory correlation specifically for the cue followed by the most aversive startle sound as reflected in enhanced on-line and a posteriori covariation estimates. This bias was positively correlated with state and trait anxiety. Physiological arousal measured by pupil diameter was enhanced in response to the most aversive startle sound confirming its distinct processing. In conclusion, these results suggest that aversive outcomes may induce illusory correlations, most likely in anxious persons, and explain previous findings of illusory correlations in anxiety disorders. PMID:23829308

  2. Competition between Visual Events Modulates the Influence of Salience during Free-Viewing of Naturalistic Videos

    PubMed Central

    Nardo, Davide; Console, Paola; Reverberi, Carlo; Macaluso, Emiliano

    2016-01-01

    In daily life the brain is exposed to a large amount of external signals that compete for processing resources. The attentional system can select relevant information based on many possible combinations of goal-directed and stimulus-driven control signals. Here, we investigate the behavioral and physiological effects of competition between distinctive visual events during free-viewing of naturalistic videos. Nineteen healthy subjects underwent functional magnetic resonance imaging (fMRI) while viewing short video-clips of everyday life situations, without any explicit goal-directed task. Each video contained either a single semantically-relevant event on the left or right side (Lat-trials), or multiple distinctive events in both hemifields (Multi-trials). For each video, we computed a salience index to quantify the lateralization bias due to stimulus-driven signals, and a gaze index (based on eye-tracking data) to quantify the efficacy of the stimuli in capturing attention to either side. Behaviorally, our results showed that stimulus-driven salience influenced spatial orienting only in presence of multiple competing events (Multi-trials). fMRI results showed that the processing of competing events engaged the ventral attention network, including the right temporoparietal junction (R TPJ) and the right inferior frontal cortex. Salience was found to modulate activity in the visual cortex, but only in the presence of competing events; while the orienting efficacy of Multi-trials affected activity in both the visual cortex and posterior parietal cortex (PPC). We conclude that in presence of multiple competing events, the ventral attention system detects semantically-relevant events, while regions of the dorsal system make use of saliency signals to select relevant locations and guide spatial orienting. PMID:27445760

  3. The Competitive Influences of Perceptual Load and Working Memory Guidance on Selective Attention.

    PubMed

    Tan, Jinfeng; Zhao, Yuanfang; Wang, Lijun; Tian, Xia; Cui, Yan; Yang, Qian; Pan, Weigang; Zhao, Xiaoyue; Chen, Antao

    2015-01-01

    The perceptual load theory in selective attention literature proposes that the interference from task-irrelevant distractor is eliminated when perceptual capacity is fully consumed by task-relevant information. However, the biased competition model suggests that the contents of working memory (WM) can guide attentional selection automatically, even when this guidance is detrimental to visual search. An intriguing but unsolved question is what will happen when selective attention is influenced by both perceptual load and WM guidance. To study this issue, behavioral performances and event-related potentials (ERPs) were recorded when participants were presented with a cue to either identify or hold in memory and had to perform a visual search task subsequently, under conditions of low or high perceptual load. Behavioural data showed that high perceptual load eliminated the attentional capture by WM. The ERP results revealed an obvious WM guidance effect in P1 component with invalid trials eliciting larger P1 than neutral trials, regardless of the level of perceptual load. The interaction between perceptual load and WM guidance was significant for the posterior N1 component. The memory guidance effect on N1 was eliminated by high perceptual load. Standardized Low Resolution Electrical Tomography Analysis (sLORETA) showed that the WM guidance effect and the perceptual load effect on attention can be localized into the occipital area and parietal lobe, respectively. Merely identifying the cue produced no effect on the P1 or N1 component. These results suggest that in selective attention, the information held in WM could capture attention at the early stage of visual processing in the occipital cortex. Interestingly, this initial capture of attention by WM could be modulated by the level of perceptual load and the parietal lobe mediates target selection at the discrimination stage. PMID:26098079

  4. Anterior insula activity reflects the effects of intentionality on the anticipation of aversive stimulation.

    PubMed

    Liljeholm, Mimi; Dunne, Simon; O'Doherty, John P

    2014-08-20

    If someone causes you harm, your affective reaction to that person might be profoundly influenced by your inferences about the intentionality of their actions. In the present study, we aimed to understand how affective responses to a biologically salient aversive outcome administered by others are modulated by the extent to which a given individual is judged to have deliberately or inadvertently delivered the outcome. Using fMRI, we examined how neural responses to anticipation and receipt of an aversive stimulus are modulated by this fundamental social judgment. We found that affective evaluations about an individual whose actions led to either noxious or neutral consequences for the subject did indeed depend on the perceived intentions of that individual. At the neural level, activity in the anterior insula correlated with the interaction between perceived intentionality and anticipated outcome valence, suggesting that this region reflects the influence of mental state attribution on aversive expectations. PMID:25143614

  5. Influence of competition playing venue on the hormonal responses, state anxiety and perception of effort in elite basketball athletes.

    PubMed

    Arruda, Ademir F S; Aoki, Marcelo S; Freitas, Camila G; Drago, Gustavo; Oliveira, Roney; Crewther, Blair T; Moreira, Alexandre

    2014-05-10

    This study examined the influence of competition playing venue on the hormonal responses, state anxiety and perception of effort in elite basketball players. Eighteen males from two basketball teams were monitored during two competitive matches that were played against each other on a home and away basis. Salivary testosterone (T) and cortisol (C) concentrations were measured before and after each match. The Competitive State Anxiety Inventory-2 (CSAI-2) test was also administrated prior to each match and session ratings of perceived exertion (RPE) were taken post-game. Playing at home was accompanied by elevated pre-match T concentration, as compared to playing away (p<0.05). The matches played at home were also won. Salivary T and C concentrations were similarly elevated across the matches (percent changes from pre to post) played either at home or away. No significant differences in state anxiety and perception of effort were identified between the playing venues. Pre-match T and C concentrations and the percent changes in these hormones were significantly related to somatic anxiety, especially when playing at home (p<0.05). In conclusion, the competition playing venue appeared to influence athlete salivary hormonal responses prior to elite basketball matches. These hormonal responses were associated with player's anxiety state, which might contribute to performance and the eventual match outcomes. PMID:24642001

  6. [Study on restriction factors and countermeasures of influence of China medical devices competitiveness].

    PubMed

    Zhang, Zhijun

    2012-07-01

    Recent years, China medical devices industry has been a sunrise industry with widely-ranged products, high-tech innovation, and booming market demands. But with the globalization of market economy, China industry is still in the inferior position of competition. How to promote the industrial structure transition, increase scientific and technological level, speed up the updating of products, enhance the international competitiveness is one of the major tasks to maintain the healthy development of industry. This article makes a study on current situation of China medical devices industry, analyses the new opportunities, challenges and restriction factors, provides the countermeasures of strengthening industry competitiveness as well. PMID:23189649

  7. Do fish perceive anaesthetics as aversive?

    PubMed

    Readman, Gareth D; Owen, Stewart F; Murrell, Joanna C; Knowles, Toby G

    2013-01-01

    This study addresses a fundamental question in fish welfare: are the anaesthetics used for fish aversive? Despite years of routine general use of many agents, within both scientific research and aquaculture, there is a paucity of information regarding their tolerance and associated behavioural responses by fish. This study examined nine of the most commonly used fish anaesthetic agents, and performed preference tests using adult mixed sex zebrafish (Danio rerio), the most commonly held laboratory fish. Video tracking software quantified swimming behaviour related to aversion for each anaesthetic at 50% of its standard recommended dose compared with clean water in a flow-through chemotaxic choice chamber. Results suggest that several commonly used anaesthetics were aversive, including two of the most commonly recommended and used: MS222 (ethyl 3-aminobenzoate methanesulphate) and benzocaine. For ethical best practice, it is recommended that compounds that are aversive, even at low concentration, should no longer be used routinely for anaesthesia or indeed the first step of humane euthanasia of adult zebrafish. Two agents were found not to induce aversive behavioural responses: etomidate and 2,2,2 tribromoethanol. For the millions of adult zebrafish used in laboratories and breeding worldwide, etomidate appears best suited for future routine humane use. PMID:24086294

  8. Fish Aversion and Attraction to Selected Agrichemicals.

    PubMed

    da Rosa, João Gabriel Santos; de Abreu, Murilo Sander; Giacomini, Ana Cristina Varrone; Koakoski, Gessi; Kalichak, Fabiana; Oliveira, Thiago Acosta; de Alcântara Barcellos, Heloísa Helena; Barreto, Rodrigo Egydio; Barcellos, Leonardo José Gil

    2016-10-01

    In agriculture intensive areas, fishponds and natural water bodies located in close proximity to these fields receive water with variable amounts of agrichemicals. Consequently, toxic compounds reach nontarget organisms. For instance, aquatic organisms can be exposed to tebuconazole-based fungicides (TBF), glyphosate-based herbicides (GBH), and atrazine-based herbicides (ABH) that are potentially dangerous, which motivates the following question: Are these agrichemicals attractant or aversive to fish? To answer this question, adult zebrafish were tested in a chamber that allows fish to escape from or seek a lane of contaminated water. This attraction and aversion paradigm was evaluated with zebrafish in the presence of an acute contamination with these compounds. We showed that only GBH was aversive to fish, whereas ABH and TBF caused neither attraction nor aversion for zebrafish. Thus, these chemicals do not impose an extra toxic risk by being an attractant for fish, although TBF and ABH can be more deleterious, because they induce no aversive response. Because the uptake and bioaccumulation of chemicals in fish seems to be time- and dose-dependent, a fish that remains longer in the presence of these substances tends to absorb higher concentrations than one that escapes from contaminated sites. PMID:27423874

  9. Rivals in the dark: how competition influences search in decisions under uncertainty.

    PubMed

    Phillips, Nathaniel D; Hertwig, Ralph; Kareev, Yaakov; Avrahami, Judith

    2014-10-01

    In choices between uncertain options, information search can increase the chances of distinguishing good from bad options. However, many choices are made in the presence of other choosers who may seize the better option while one is still engaged in search. How long do (and should) people search before choosing between uncertain options in the presence of such competition? To address this question, we introduce a new experimental paradigm called the competitive sampling game. We use both simulation and empirical data to compare search and choice between competitive and solitary environments. Simulation results show that minimal search is adaptive when one expects competitors to choose quickly or is uncertain about how long competitors will search. Descriptively, we observe that competition drastically reduces information search prior to choice. PMID:25010397

  10. Mistletoe Infection in an Oak Forest Is Influenced by Competition and Host Size

    PubMed Central

    Matula, Radim; Svátek, Martin; Pálková, Marcela; Volařík, Daniel; Vrška, Tomáš

    2015-01-01

    Host size and distance from an infected plant have been previously found to affect mistletoe occurrence in woody vegetation but the effect of host plant competition on mistletoe infection has not been empirically tested. For an individual tree, increasing competition from neighbouring trees decreases its resource availability, and resource availability is also known to affect the establishment of mistletoes on host trees. Therefore, competition is likely to affect mistletoe infection but evidence for such a mechanism is lacking. Based on this, we hypothesised that the probability of occurrence as well as the abundance of mistletoes on a tree would increase not only with increasing host size and decreasing distance from an infected tree but also with decreasing competition by neighbouring trees. Our hypothesis was tested using generalized linear models (GLMs) with data on Loranthus europaeus Jacq., one of the two most common mistletoes in Europe, on 1015 potential host stems collected in a large fully mapped plot in the Czech Republic. Because many trees were multi-stemmed, we ran the analyses for both individual stems and whole trees. We found that the probability of mistletoe occurrence on individual stems was affected mostly by stem size, whereas competition had the most important effects on the probability of mistletoe occurrence on whole trees as well as on mistletoe abundance. Therefore, we confirmed our hypothesis that competition among trees has a negative effect on mistletoe occurrence. PMID:25992920

  11. The 18th Annual Intelligent Ground Vehicle Competition: trends and influences for intelligent ground vehicle control

    NASA Astrophysics Data System (ADS)

    Theisen, Bernard L.; Frederick, Philip; Smuda, William

    2011-01-01

    The Intelligent Ground Vehicle Competition (IGVC) is one of four, unmanned systems, student competitions that were founded by the Association for Unmanned Vehicle Systems International (AUVSI). The IGVC is a multidisciplinary exercise in product realization that challenges college engineering student teams to integrate advanced control theory, machine vision, vehicular electronics and mobile platform fundamentals to design and build an unmanned system. Teams from around the world focus on developing a suite of dual-use technologies to equip ground vehicles of the future with intelligent driving capabilities. Over the past 18 years, the competition has challenged undergraduate, graduate and Ph.D. students with real world applications in intelligent transportation systems, the military and manufacturing automation. To date, teams from over 75 universities and colleges have participated. This paper describes some of the applications of the technologies required by this competition and discusses the educational benefits. The primary goal of the IGVC is to advance engineering education in intelligent vehicles and related technologies. The employment and professional networking opportunities created for students and industrial sponsors through a series of technical events over the four-day competition are highlighted. Finally, an assessment of the competition based on participation is presented.

  12. How to make loss aversion disappear and reverse: tests of the decision by sampling origin of loss aversion.

    PubMed

    Walasek, Lukasz; Stewart, Neil

    2015-02-01

    One of the most robust empirical findings in the behavioral sciences is loss aversion--the finding that losses loom larger than gains. We offer a new psychological explanation of the origins of loss aversion in which loss aversion emerges from differences in the distribution of gains and losses people experience. In 4 experiments, we tested this proposition by manipulating the range of gains and losses that individuals saw during the process of eliciting their loss aversion. We were able to find loss aversion, loss neutrality, and even the reverse of loss aversion. PMID:25485606

  13. Metabolic Scope and Interspecific Competition in Sculpins of Greenland Are Influenced by Increased Temperatures Due to Climate Change

    PubMed Central

    Seth, Henrik; Gräns, Albin; Sandblom, Erik; Olsson, Catharina; Wiklander, Kerstin; Johnsson, Jörgen I.; Axelsson, Michael

    2013-01-01

    Ongoing climate change has led to an increase in sea surface temperatures of 2–4°C on the west coast of Greenland. Since fish are ectothermic, metabolic rate increases with ambient temperature. This makes these animals particularly sensitive to changes in temperature; subsequently any change may influence their metabolic scope, i.e. the physiological capacity to undertake aerobically challenging activities. Any temperature increase may thus disrupt species-specific temperature adaptations, at both the molecular level as well as in behavior, and concomitant species differences in the temperature sensitivity may shift the competitive balance among coexisting species. We investigated the influence of temperature on metabolic scope and competitive ability in three species of marine sculpin that coexist in Greenland coastal waters. Since these species have different distribution ranges, we hypothesized that there should be a difference in their physiological response to temperature; hence we compared their metabolic scope at three temperatures (4, 9 and 14°C). Their competitive ability at the ambient temperature of 9°C was also tested in an attempt to link physiological capacity with behaviour. The Arctic staghorn sculpin, the species with the northernmost distribution range, had a lower metabolic scope in the higher temperature range compared to the other two species, which had similar metabolic scope at the three temperatures. The Arctic staghorn sculpin also had reduced competitive ability at 9°C and may thus already be negatively affected by the current ocean warming. Our results suggest that climate change can have effects on fish physiology and interspecific competition, which may alter the species composition of the Arctic fish fauna. PMID:23690960

  14. Influence of species, size and relative abundance on the outcomes of competitive interactions between brook trout and juvenile coho salmon

    USGS Publications Warehouse

    Thornton, Emily J; Duda, Jeff; Quinn, Thomas P

    2016-01-01

    Resource competition between animals is influenced by a number of factors including the species, size and relative abundance of competing individuals. Stream-dwelling animals often experience variably available food resources, and some employ territorial behaviors to increase their access to food. We investigated the factors that affect dominance between resident, non-native brook trout and recolonizing juvenile coho salmon in the Elwha River, WA, USA, to see if brook trout are likely to disrupt coho salmon recolonization via interference competition. During dyadic laboratory feeding trials, we hypothesized that fish size, not species, would determine which individuals consumed the most food items, and that species would have no effect. We found that species, not size, played a significant role in dominance; coho salmon won 95% of trials, even when only 52% the length of their brook trout competitors. As the pairs of competing fish spent more time together during a trial sequence, coho salmon began to consume more food, and brook trout began to lose more, suggesting that the results of early trials influenced fish performance later. In group trials, we hypothesized that group composition and species would not influence fish foraging success. In single species groups, coho salmon consumed more than brook trout, but the ranges overlapped. Brook trout consumption remained constant through all treatments, but coho salmon consumed more food in treatments with fewer coho salmon, suggesting that coho salmon experienced more intra- than inter-specific competition and that brook trout do not pose a substantial challenge. Based on our results, we think it is unlikely that competition from brook trout will disrupt Elwha River recolonization by coho salmon.

  15. Inequality aversion and voting on redistribution☆

    PubMed Central

    Höchtl, Wolfgang; Sausgruber, Rupert; Tyran, Jean-Robert

    2012-01-01

    Some people have a concern for a fair distribution of incomes while others do not. Does such a concern matter for majority voting on redistribution? Fairness preferences are relevant for redistribution outcomes only if fair-minded voters are pivotal. Pivotality, in turn, depends on the structure of income classes. We experimentally study voting on redistribution between two income classes and show that the effect of inequality aversion is asymmetric. Inequality aversion is more likely to matter if the “rich” are in majority. With a “poor” majority, we find that redistribution outcomes look as if all voters were exclusively motivated by self-interest. PMID:23564967

  16. Taste aversion learning: a contemporary perspective.

    PubMed

    Bernstein, I L

    1999-03-01

    Food aversion learning has attracted widespread interest because it is a highly adaptive, powerful type of learning with both practical and theoretical ramifications. It has features that make it unusual and robust when compared with other learning paradigms. It has relevance to human problems in that it is likely to contribute to food choice and appetite problems in certain clinical situations. And the robustness of this learning makes it a promising model for neurobiologists interested in understanding neural mechanisms of plasticity. This review provides a broad overview of these aspects of taste aversion learning and points to areas where questions remain and additional research is needed. PMID:10198919

  17. Heterogeneity in Primary Productivity Influences Competitive Interactions between Red Deer and Alpine Chamois

    PubMed Central

    Anderwald, Pia; Haller, Rudolf M.; Filli, Flurin

    2016-01-01

    Habitat heterogeneity can promote coexistence between herbivores of different body size limited to different extents by resource quantity and quality. Red deer (Cervus elaphus) are known as superior competitors to smaller species with similar diets. We compared competitive interactions and habitat use between red deer and Alpine chamois (Rupicapra rupicapra) in two adjacent valleys in a strictly protected area in the Central Alps. Red deer density was higher in the valley with higher primary productivity. Only here was horn growth in kid and yearling chamois (as a measure for body condition) negatively correlated with red deer population size, suggesting interspecific competition, and chamois selected meadows with steeper slopes and lower productivity than available on average. Conversely, red deer selected meadows of high productivity, particularly in the poorer area. As these were located mainly at lower elevations, this led to strong altitudinal segregation between the two species here. Local differences in interspecific competition thus coincided with differences in habitat preference and–segregation between areas. This suggests that spatial habitat and resource heterogeneity at the scale of adjacent valleys can provide competition refuges for competitively inferior mountain ungulates which differ from their superior competitor in their metabolic requirements. PMID:26824867

  18. Heterogeneity in Primary Productivity Influences Competitive Interactions between Red Deer and Alpine Chamois.

    PubMed

    Anderwald, Pia; Haller, Rudolf M; Filli, Flurin

    2016-01-01

    Habitat heterogeneity can promote coexistence between herbivores of different body size limited to different extents by resource quantity and quality. Red deer (Cervus elaphus) are known as superior competitors to smaller species with similar diets. We compared competitive interactions and habitat use between red deer and Alpine chamois (Rupicapra rupicapra) in two adjacent valleys in a strictly protected area in the Central Alps. Red deer density was higher in the valley with higher primary productivity. Only here was horn growth in kid and yearling chamois (as a measure for body condition) negatively correlated with red deer population size, suggesting interspecific competition, and chamois selected meadows with steeper slopes and lower productivity than available on average. Conversely, red deer selected meadows of high productivity, particularly in the poorer area. As these were located mainly at lower elevations, this led to strong altitudinal segregation between the two species here. Local differences in interspecific competition thus coincided with differences in habitat preference and-segregation between areas. This suggests that spatial habitat and resource heterogeneity at the scale of adjacent valleys can provide competition refuges for competitively inferior mountain ungulates which differ from their superior competitor in their metabolic requirements. PMID:26824867

  19. Effects of aversive stimuli on learning and memory in Arctic ground squirrels.

    PubMed

    Zhao, H; Bucci, D J; Weltzin, M; Drew, K L

    2004-05-01

    The present study was designed to assess effects of aversive stimuli on learning and memory in wild-caught Arctic ground squirrels (AGS, Spermophilus parryii) using an active avoidance learning paradigm. Results indicate that animals trained with low-value aversive stimuli (air puffs and lights) retained the task better than animals trained with high-value aversive stimuli (air puffs, lights, and foot shock). Poor retention could not be explained by learning impairment, fear-induced freezing behavior or the effects of massed versus spaced training trials. Wild-caught AGS readily hibernate under laboratory conditions and provide a model of pronounced adult synaptic plasticity associated with emergence from hibernation. Characterization of learning and retention using active avoidance as well as other learning paradigms is a first step towards developing behavioral paradigms to assess cognitive function in this wild-trapped species. The present study shows that captive AGS are sensitive to aversive stimuli, argues for a direct effect on retention and suggests that high baseline levels of stress in a captive population may influence behavioral measures. The results further suggest that future studies of the effects of hibernation on learning and retention of active avoidance tasks employ low-level aversive stimuli. PMID:15084438

  20. Interspecific competition influences the organization of a diverse sessile insect community

    NASA Astrophysics Data System (ADS)

    Cornelissen, Tatiana; de Carvalho Guimarães, Carla Daniele; Rodrigues Viana, João Paulo; Silva, Bárbara

    2013-10-01

    Interspecific competition has played a major role in determining the effects of species interactions in terrestrial communities and the perception of its role on shaping population dynamics and community structure has changed throughout the years. In this study, we evaluated the existence of interspecific competition in the herbivore community of the dioecious plant Baccharis pseudomyriocephala (Asteraceae), which holds a diverse community of gall-forming insects. Sixty plants were studied and gall richness and abundance among plants were evaluated. To address whether a plant already occupied by a gall species is preferred or avoided by another gall species, null models were used for all 60 plants combined and for male and female plants separately. Our results have shown that the 11 species of gall-formers found on B. pseudomyriocephala co-occur less than expected by chance alone, indicating that interspecific competition might be an important force structuring the insect community in this tropical host plant, regardless of plant gender.

  1. Dopamine Regulates Aversive Contextual Learning and Associated In Vivo Synaptic Plasticity in the Hippocampus.

    PubMed

    Broussard, John I; Yang, Kechun; Levine, Amber T; Tsetsenis, Theodoros; Jenson, Daniel; Cao, Fei; Garcia, Isabella; Arenkiel, Benjamin R; Zhou, Fu-Ming; De Biasi, Mariella; Dani, John A

    2016-03-01

    Dopamine release during reward-driven behaviors influences synaptic plasticity. However, dopamine innervation and release in the hippocampus and its role during aversive behaviors are controversial. Here, we show that in vivo hippocampal synaptic plasticity in the CA3-CA1 circuit underlies contextual learning during inhibitory avoidance (IA) training. Immunohistochemistry and molecular techniques verified sparse dopaminergic innervation of the hippocampus from the midbrain. The long-term synaptic potentiation (LTP) underlying the learning of IA was assessed with a D1-like dopamine receptor agonist or antagonist in ex vivo hippocampal slices and in vivo in freely moving mice. Inhibition of D1-like dopamine receptors impaired memory of the IA task and prevented the training-induced enhancement of both ex vivo and in vivo LTP induction. The results indicate that dopamine-receptor signaling during an aversive contextual task regulates aversive memory retention and regulates associated synaptic mechanisms in the hippocampus that likely underlie learning. PMID:26904943

  2. On the Influence of Quorum Sensing in the Competition Between Bacteria and Immune System of Invertebrates

    NASA Astrophysics Data System (ADS)

    Fergola, Paolo; Zhang, Juan; Cerasuolo, Marianna; Ma, Zhien

    2008-07-01

    The competition between bacteria and innate immune system of invertebrate animals is described by means of ODEs. Two different systems are considered corresponding to the absence or the presence of Quorum Sensing (Q.S.) mechanism. Qualitative properties of the solutions of both systems as well as the stability of their meaningful equilibria are analyzed. By constructing suitable Lyapunov functions, global asymptotic stability results have been proved when the quorum sensing is absent. In order to better illustrate the dynamics of competition, some numerical simulations, obtained by means of MATHEMATICA (Wolfram Research, 1989) are presented.

  3. 21 CFR 882.5235 - Aversive conditioning device.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Aversive conditioning device. 882.5235 Section 882...) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Therapeutic Devices § 882.5235 Aversive conditioning device. (a) Identification. An aversive conditioning device is an instrument used to administer...

  4. Influence of School Environment on Student Lunch Participation and Competitive Food Sales

    ERIC Educational Resources Information Center

    Litchfield, Ruth E.; Wenz, Betsy

    2011-01-01

    Purpose/Objectives: The school nutrition environment includes food policy and practices, advertising, and presence of competitive foods (CF). CF provide schools with revenue; however, CF decrease National School Lunch Program (NSLP) participation and reimbursement as well as the nutrient density of children's diets. Local wellness policies (LWPs)…

  5. Lotka systems with directed dispersal dynamics: Competition and influence of diffusion strategies.

    PubMed

    Braverman, E; Kamrujjaman, Md

    2016-09-01

    We study a Lotka system describing two competing populations, and each of them chooses its diffusion strategy as the tendency to have a distribution proportional to a certain positive prescribed function. For instance, the standard diffusion corresponds to the choice of a uniform distribution. The paper is focused on the interplay of species competition and diffusion strategies. In the case when one of the diffusion strategies is proportional to the carrying capacity, while the other is not, and the competition does not discriminate the former species, we prove the competitive exclusion of the latter one. If the competition favors the latter species, there is still a range of parameters for which there is a coexistence, thanks to the better dispersal strategy chosen by the former species. The dependency on the interaction type, diffusion coefficients and intrinsic growth rates is explored. We prove that in the limit case, higher diffusion coefficients are detrimental while higher growth rates, as well as lower resources sharing, are beneficial for population survival. PMID:27353014

  6. Helping Children Think: Gaze Aversion and Teaching

    ERIC Educational Resources Information Center

    Phelps, Fiona G.; Doherty-Sneddon, Gwyneth; Warnock, Hannah

    2006-01-01

    Looking away from an interlocutor's face during demanding cognitive activity can help adults answer challenging arithmetic and verbal-reasoning questions (Glenberg, Schroeder, & Robertson, 1998). However, such "gaze aversion" (GA) is poorly applied by 5-year-old school children (Doherty-Sneddon, Bruce, Bonner, Longbotham, & Doyle, 2002). In…

  7. On Loss Aversion in Capuchin Monkeys

    ERIC Educational Resources Information Center

    Silberberg, Alan; Roma, Peter G.; Huntsberry, Mary E.; Warren-Boulton, Frederick R.; Sakagami, Takayuki; Ruggiero, Angela M.; Suomi, Stephen J.

    2008-01-01

    Chen, Lakshminarayanan, and Santos (2006) claim to show in three choice experiments that monkeys react rationally to price and wealth shocks, but, when faced with gambles, display hallmark, human-like biases that include loss aversion. We present three experiments with monkeys and humans consistent with a reinterpretation of their data that…

  8. Sensory Food Aversions in Infants and Toddlers

    ERIC Educational Resources Information Center

    Chatoor, Irene

    2009-01-01

    Sensory Food Aversion is one of the most common feeding disorders during the first 3 years of life, when young children are transitioned to self-feeding, and when issues of autonomy and dependency have to be negotiated between parents and child. In this article, the author discusses "picky eaters" and the importance of distinguishing between…

  9. Parsing Reward and Aversion in the Amygdala.

    PubMed

    Maren, Stephen

    2016-04-20

    The basolateral amygdala (BLA) is critical for encoding the value of stimuli. Beyeler et al. (2016) now show that distinct populations of BLA neurons, which are defined by their efferent targets, code reward and aversion. This arrangement promotes parallel processing of biologically relevant events. PMID:27100192

  10. Origins of Teachers' Selection of Aversive Interventions.

    ERIC Educational Resources Information Center

    Lee, Steven W.; Weis, Glenna

    This study was designed to replicate and improve upon Kaplan's 1992 study of the possible link between teachers' past experiences and use of aversive disciplinary strategies. The current study examines the possible effect of past home and school experience on both preservice and practicing teachers' choices of intervention. The first study…

  11. Demonstration Experiments in Learned Taste Aversions.

    ERIC Educational Resources Information Center

    Kling, J. W.

    1981-01-01

    This report describes the introductory psychology demonstration showing conditioned taste aversion in rats based on those animals' inability to distinguish between safe NaCl and toxic LiCl solutions. Test results showed the established phenomena of classical conditioning. Included is a discussion of the experiments relevance to behaviorist…

  12. Appetitive vs. Aversive conditioning in humans.

    PubMed

    Andreatta, Marta; Pauli, Paul

    2015-01-01

    In classical conditioning, an initially neutral stimulus (conditioned stimulus, CS) becomes associated with a biologically salient event (unconditioned stimulus, US), which might be pain (aversive conditioning) or food (appetitive conditioning). After a few associations, the CS is able to initiate either defensive or consummatory responses, respectively. Contrary to aversive conditioning, appetitive conditioning is rarely investigated in humans, although its importance for normal and pathological behaviors (e.g., obesity, addiction) is undeniable. The present study intents to translate animal findings on appetitive conditioning to humans using food as an US. Thirty-three participants were investigated between 8 and 10 am without breakfast in order to assure that they felt hungry. During two acquisition phases, one geometrical shape (avCS+) predicted an aversive US (painful electric shock), another shape (appCS+) predicted an appetitive US (chocolate or salty pretzel according to the participants' preference), and a third shape (CS-) predicted neither US. In a extinction phase, these three shapes plus a novel shape (NEW) were presented again without US delivery. Valence and arousal ratings as well as startle and skin conductance (SCR) responses were collected as learning indices. We found successful aversive and appetitive conditioning. On the one hand, the avCS+ was rated as more negative and more arousing than the CS- and induced startle potentiation and enhanced SCR. On the other hand, the appCS+ was rated more positive than the CS- and induced startle attenuation and larger SCR. In summary, we successfully confirmed animal findings in (hungry) humans by demonstrating appetitive learning and normal aversive learning. PMID:26042011

  13. Appetitive vs. Aversive conditioning in humans

    PubMed Central

    Andreatta, Marta; Pauli, Paul

    2015-01-01

    In classical conditioning, an initially neutral stimulus (conditioned stimulus, CS) becomes associated with a biologically salient event (unconditioned stimulus, US), which might be pain (aversive conditioning) or food (appetitive conditioning). After a few associations, the CS is able to initiate either defensive or consummatory responses, respectively. Contrary to aversive conditioning, appetitive conditioning is rarely investigated in humans, although its importance for normal and pathological behaviors (e.g., obesity, addiction) is undeniable. The present study intents to translate animal findings on appetitive conditioning to humans using food as an US. Thirty-three participants were investigated between 8 and 10 am without breakfast in order to assure that they felt hungry. During two acquisition phases, one geometrical shape (avCS+) predicted an aversive US (painful electric shock), another shape (appCS+) predicted an appetitive US (chocolate or salty pretzel according to the participants' preference), and a third shape (CS–) predicted neither US. In a extinction phase, these three shapes plus a novel shape (NEW) were presented again without US delivery. Valence and arousal ratings as well as startle and skin conductance (SCR) responses were collected as learning indices. We found successful aversive and appetitive conditioning. On the one hand, the avCS+ was rated as more negative and more arousing than the CS– and induced startle potentiation and enhanced SCR. On the other hand, the appCS+ was rated more positive than the CS– and induced startle attenuation and larger SCR. In summary, we successfully confirmed animal findings in (hungry) humans by demonstrating appetitive learning and normal aversive learning. PMID:26042011

  14. Dismissing Attachment Characteristics Dynamically Modulate Brain Networks Subserving Social Aversion

    PubMed Central

    Krause, Anna Linda; Borchardt, Viola; Li, Meng; van Tol, Marie-José; Demenescu, Liliana Ramona; Strauss, Bernhard; Kirchmann, Helmut; Buchheim, Anna; Metzger, Coraline D.; Nolte, Tobias; Walter, Martin

    2016-01-01

    Attachment patterns influence actions, thoughts and feeling through a person’s “inner working model”. Speech charged with attachment-dependent content was proposed to modulate the activation of cognitive-emotional schemata in listeners. We performed a 7 Tesla rest-task-rest functional magnetic resonance imaging (fMRI)-experiment, presenting auditory narratives prototypical of dismissing attachment representations to investigate their effect on 23 healthy males. We then examined effects of participants’ attachment style and childhood trauma on brain state changes using seed-based functional connectivity (FC) analyses, and finally tested whether subjective differences in responsivity to narratives could be predicted by baseline network states. In comparison to a baseline state, we observed increased FC in a previously described “social aversion network” including dorsal anterior cingulated cortex (dACC) and left anterior middle temporal gyrus (aMTG) specifically after exposure to insecure-dismissing attachment narratives. Increased dACC-seeded FC within the social aversion network was positively related to the participants’ avoidant attachment style and presence of a history of childhood trauma. Anxious attachment style on the other hand was positively correlated with FC between the dACC and a region outside of the “social aversion network”, namely the dorsolateral prefrontal cortex, which suggests decreased network segregation as a function of anxious attachment. Finally, the extent of subjective experience of friendliness towards the dismissing narrative was predicted by low baseline FC-values between hippocampus and inferior parietal lobule (IPL). Taken together, our study demonstrates an activation of networks related to social aversion in terms of increased connectivity after listening to insecure-dismissing attachment narratives. A causal interrelation of brain state changes and subsequent changes in social reactivity was further supported by

  15. Does the GNB3 C825T Polymorphism Influence Swimming Performance in Competitive Swimmers?

    PubMed Central

    Grenda, Agata; Sawczuk, Marek; Kaczmarczyk, Mariusz; Maciejewska, Agnieszka; Umiastowska, Danuta; Łubkowska, Wioletta; Żmijewski, Piotr; Cięszczyk, Paweł

    2015-01-01

    Single nucleotide polymorphism C825T located within the GNB3 gene has been proposed in the literature as the performance enhancing polymorphism in highly trained athletes. Therefore, the aim of the present study was to verify the hypothesis assuming an association between the C825T polymorphic site and performance of competitive swimmers. The frequencies of C/T alleles and distribution of CC, CT and TT genotypes of the C825T GNB3 polymorphism were compared between athletes and nonathletic controls as well as between sprint and endurance swimmers. Genomic DNA was extracted from 197 competitive swimmers (50 long distance swimmers (LDS) and 147 short distance swimmers (SDS)) and 379 sedentary volunteers. The allele frequencies and genotype distribution of the C825T polymorphic site were not significantly different when LDS and SDS were compared to sedentary controls. Gender-specific analysis did not reveal any significant differences in allele and genotype distribution, neither between female controls and female swimmers nor between male controls and male swimmers. No significant differences in allele frequencies and genotype distribution were observed when LDS and SDS as well as groups of swimmers stratified by gender were compared. The results of this study do not support the hypothesis that the C825T polymorphism of the GNB3 gene is associated with swimming performance in competitive swimmers. PMID:26557194

  16. Competition in Education.

    ERIC Educational Resources Information Center

    Rich, John Martin; DeVitis, Joseph L.

    This book discusses various major aspects of competition in education. It identifies competition within educational policies, programs, and practices, as well as the problems that certain forms of competition create. It also traces the influences of American competitive values on education. Chapter 1 provides an introductory overview of the…

  17. Taste aversions conditioned with partial body radiation exposures

    SciTech Connect

    Smith, J.C.; Hollander, G.R.; Spector, A.C. . Dept. of Psychology)

    1981-11-01

    Radiation-induced taste aversion was compared in rats which received partial body exposure to the head or abdomen with rats receiving whole body irradiation. Exposure levels ranged from 25 to 300 roentgens (R). In additional groups, saccharin aversion to partial body gamma ray exposures of the abdomen were conditioned in animals which had prior experience with the saccharin solution. Aversion was measured with a single-bottle short-term test, a 23-hour preference test and by the number of days taken to recover from the aversion. Whole-body exposure was most effective in conditioning the aversion, and exposure of the abdominal area was more effective than exposure to the head. Also, the higher the exposure, the stronger the aversion. Rats receiving prior experience with the saccharin did not condition as well as control rats with no prior saccharin experience. The possible role of radiation-induced taste aversion in human radiotherapy patients was discussed.

  18. Ecological Origins of Object Salience: Reward, Uncertainty, Aversiveness, and Novelty

    PubMed Central

    Ghazizadeh, Ali; Griggs, Whitney; Hikosaka, Okihide

    2016-01-01

    Among many objects around us, some are more salient than others (i.e., attract our attention automatically). Some objects may be inherently salient (e.g., brighter), while others may become salient by virtue of their ecological relevance through experience. However, the role of ecological experience in automatic attention has not been studied systematically. To address this question, we let subjects (macaque monkeys) view a large number of complex objects (>300), each experienced repeatedly (>5 days) with rewarding, aversive or no outcome association (mere-perceptual exposure). Test of salience was done on separate days using free viewing with no outcome. We found that gaze was biased among the objects from the outset, affecting saccades to objects or fixations within objects. When the outcome was rewarding, gaze preference was stronger (i.e., positive) for objects with larger or equal but uncertain rewards. The effects of aversive outcomes were variable. Gaze preference was positive for some outcome associations (e.g., airpuff), but negative for others (e.g., time-out), possibly due to differences in threat levels. Finally, novel objects attracted gaze, but mere perceptual exposure of objects reduced their salience (learned negative salience). Our results show that, in primates, object salience is strongly influenced by previous ecological experience and is supported by a large memory capacity. Owing to such high capacity for learned salience, the ability to rapidly choose important objects can grow during the entire life to promote biological fitness. PMID:27594825

  19. Ecological Origins of Object Salience: Reward, Uncertainty, Aversiveness, and Novelty.

    PubMed

    Ghazizadeh, Ali; Griggs, Whitney; Hikosaka, Okihide

    2016-01-01

    Among many objects around us, some are more salient than others (i.e., attract our attention automatically). Some objects may be inherently salient (e.g., brighter), while others may become salient by virtue of their ecological relevance through experience. However, the role of ecological experience in automatic attention has not been studied systematically. To address this question, we let subjects (macaque monkeys) view a large number of complex objects (>300), each experienced repeatedly (>5 days) with rewarding, aversive or no outcome association (mere-perceptual exposure). Test of salience was done on separate days using free viewing with no outcome. We found that gaze was biased among the objects from the outset, affecting saccades to objects or fixations within objects. When the outcome was rewarding, gaze preference was stronger (i.e., positive) for objects with larger or equal but uncertain rewards. The effects of aversive outcomes were variable. Gaze preference was positive for some outcome associations (e.g., airpuff), but negative for others (e.g., time-out), possibly due to differences in threat levels. Finally, novel objects attracted gaze, but mere perceptual exposure of objects reduced their salience (learned negative salience). Our results show that, in primates, object salience is strongly influenced by previous ecological experience and is supported by a large memory capacity. Owing to such high capacity for learned salience, the ability to rapidly choose important objects can grow during the entire life to promote biological fitness. PMID:27594825

  20. Potential aversive compounds in leafy spurge for ruminants and rats.

    PubMed

    Kronberg, S L; Lynch, W C; Cheney, C D; Walker, J W

    1995-10-01

    Several wild and domestic ruminant species and horses apparently will not consume leafy spurge (Euphorbia esula) while grazing range and pasture lands. It has been demonstrated that leafy spurge can elicit conditioned food aversions in cattle and sheep, and the aversion-eliciting capacity of leafy spurge may account for why cattle seldom graze this nutritious plant and why sheep may not readily consume it at some locations. The identity of the aversive compound(s) in leafy spurge is unknown, but several different diterpenoid ingenol esters have been isolated from its tissues, and we suspect that one or more ingenol esters may be aversion-eliciting compounds in leafy spurge. The objectives of this study were to determine whether or not leafy spurge is aversive to laboratory rats and if a crude acetone extract of leafy spurge, presumably containing ingenol esters and other phytochemicals, could generate an aversive response in sheep and laboratory rats. An additional objective was to determine whether or not a particular ingenol monobenzoate, which may be similar to ingenol esters in leafy spurge, might also elicit an aversive response from rats. Rats exhibited food aversions associated with leafy spurge (P < 0.05). An acetone extract of leafy spurge induced conditioned food aversions in both sheep and rats (P < 0.01). The ingenol 3-monobenzoate also induced conditioned food aversions in rats (P < 0.01). Our interpretation of these data is that rats can be used as a model for cattle and sheep with respect to their aversion to leafy spurge ingestion. Additionally, we suggest that one or more ingenol esters may be aversion-inducing agents in leafy spurge. However, others may exist in leafy spurge that are also aversive or are the only or prime aversive chemicals. PMID:24233671

  1. Behavioral architecture of opioid reward and aversion in C57BL/6 substrains

    PubMed Central

    Kirkpatrick, Stacey L.; Bryant, Camron D.

    2015-01-01

    Drug liking vs. drug disliking is a subjective motivational measure in humans that assesses the addiction liability of drugs. Variation in this trait is hypothesized to influence vulnerability vs. resilience toward substance abuse disorders and likely contains a genetic component. In rodents and humans, conditioned place preference (CPP)/aversion (CPA) is a Pavlovian conditioning paradigm whereby a learned preference for the drug-paired environment is used to infer drug liking whereas a learned avoidance or aversion is used to infer drug disliking. C57BL/6 inbred mouse substrains are nearly genetically identical, yet demonstrate robust differences in addiction-relevant behaviors, including locomotor sensitization to cocaine and consumption of ethanol. Here, we tested the hypothesis that B6 substrains would demonstrate differences in the rewarding properties of the mu opioid receptor agonist oxycodone (5 mg/kg, i.p.) and the aversive properties of the opioid receptor antagonist naloxone (4 mg/kg, i.p.). Both substrains showed similar degrees of oxycodone-induced CPP; however, there was a three-fold enhancement of naloxone-induced CPA in agonist-naïve C57BL/6J relative to C57Bl/6NJ mice. Exploratory factor analysis of CPP and CPA identified unique factors that explain variance in behavioral expression of reward vs. aversion. “Conditioned Opioid-Like Behavior” was a reward-based factor whereby drug-free locomotor variables resembling opioid treatment co-varied with the degree of CPP. “Avoidance and Freezing” was an aversion-based factor, whereby the increase in the number of freezing bouts co-varied with the degree of aversion. These results provide new insight into the behavioral architecture of the motivational properties of opioids. Future studies will use quantitative trait locus mapping in B6 substrains to identify novel genetic factors that contribute to the marked strain difference in NAL-CPA. PMID:25628547

  2. The influence of natural organic matter rigidity on the sorption, desorption, and competitive displacement rates of 1,2-dichlorobenzene.

    PubMed

    Ju, Daeyoung; Young, Thomas M

    2005-10-15

    The influence of natural organic matter (NOM) rigidity on the sorption, desorption, and competitive displacement rates of 1,2-Dichlorobenzene (1,2-DCB) was evaluated using batch reactor experiments with two surface soils (Yolo and Forbes) and a shale (Ohio). Previous characterization suggests that the shale NOM is the most reduced and condensed, the Yolo soil is the most oxidized and amorphous, and Forbes soil has an intermediate NOM structure. The rate study for each sorbent was conducted under the same reactor parameters, and 1,2-DCB mass-transfer rates were determined using the distributed first-order mass-transfer rate model based on the gamma probability density function. To measure competitive displacement rates, 1,2,4-trichlorobenzene (1,2,4-TCB) was delivered as a competitor after 34 days pre-equilibration. Higher fractions of contaminant subject to instantaneous mass transfer and much faster rates of approach to apparent sorption equilibrium are found in Yolo soil when compared with Forbes soil and the shale. The size of the instantaneously desorbing fraction thus appears inversely related to the hard carbon fraction. In the NOM compartment where mass transfer is rate-limited, rate coefficient distributions are shifted toward lower rates for desorption and competitive displacement of 1,2-DCB in Ohio shale, followed by Forbes soil. Sorption and desorption rate distributions are almost the same for the shale, while desorption rates are a few times greater than sorption rates in Yolo and Forbes soils. Mass-transfer coefficients for competitive displacement are considerably slower than those for desorption in Forbes soil and the shale. However, the mass-transfer rates for the two processes seem to be similar in Yolo soil, which has a NOM matrix comprising a relatively larger soft organic carbon fraction. The concept of "solute induced softening" is discussed as a mechanistic rationale for the experimental observations. PMID:16295861

  3. Influence of Hyphal Inoculum potential on the Competitive Success of Fungi Colonizing Wood.

    PubMed

    Song, Zewei; Vail, Andrew; Sadowsky, Michael J; Schilling, Jonathan S

    2015-05-01

    The relative amounts of hyphal inoculum in forest soils may determine the capacity for fungi to compete with and replace early colonizers of wood in ground contact. Our aim in this study was to test the flexibility of priority effects (colonization timing) by varying the timing of inoculum introduction (i.e., precolonization) and amount of inoculum (i.e., inoculum potential). We controlled these variables in soil-block microcosms using fungi with known competitive outcomes in similar conditions, tracking isolate-specific fungal biomass, and residue physiochemistry over time. In the precolonization trial (experiment I), a brown rot fungus Gloeophyllum trabeum was given 1, 3, or 5 weeks to precolonize wood blocks (oak, birch, pine, and spruce) prior the introduction of a white rot fungus, Irpex lacteus, a more aggressive colonizer in this set-up. In the inoculum potential trial (experiment II), the fungi were inoculated simultaneously, but with eightfold higher brown rot inoculum than that of experiment I. As expected, longer precolonization duration increased the chance for the less-competitive brown rot fungus to outcompete its white rot opponent. Higher brown rot fungal inoculum outside of the wood matrix also resulted in competitive success for the brown rot isolate in most cases. These temporal shifts in fungal dominance were detectable in a 'community snapshot' as isolate-specific quantitative PCR, but also as functionally-relevant consequences of wood rot type, including carbohydrate depolymerization and pH. These results from a controlled system reinforce fungal-fungal interaction and suggest that relative inoculum availability beyond the wood matrix (i.e., soils) might regulate the duration of priority effects and shift the functional trajectory of wood decomposition. PMID:25750000

  4. Inequity aversion and the evolution of cooperation.

    PubMed

    Ahmed, Asrar; Karlapalem, Kamalakar

    2014-02-01

    Evolution of cooperation is a widely studied problem in biology, social science, economics, and artificial intelligence. Most of the existing approaches that explain cooperation rely on some notion of direct or indirect reciprocity. These reciprocity based models assume agents recognize their partner and know their previous interactions, which requires advanced cognitive abilities. In this paper we are interested in developing a model that produces cooperation without requiring any explicit memory of previous game plays. Our model is based on the notion of inequity aversion, a concept introduced within behavioral economics, whereby individuals care about payoff equality in outcomes. Here we explore the effect of using income inequality to guide partner selection and interaction. We study our model by considering both the well-mixed and the spatially structured population and present the conditions under which cooperation becomes dominant. Our results support the hypothesis that inequity aversion promotes cooperative relationship among nonkin. PMID:25353529

  5. Sugar and fat: cravings and aversions.

    PubMed

    Yanovski, Susan

    2003-03-01

    Food cravings are extremely common, particularly among women. Cravings are frequently reported for specific types of foods, including chocolate and foods high in both sugar and fat. Cravings for specific macronutrients, such as carbohydrate, have been postulated to result from a physiological need to alter neurotransmitters in such states as eating disorders, affective disorders or obesity. However, studies of such cravings are often confounded by differing sensory properties of high and low carbohydrate foods. There is some evidence that sweet, high fat foods are preferred by women with binge-eating disorders and that those preferences are mediated by the endogenous opioid system. Aversion to fat is seen primarily in women with anorexia nervosa. However, it is possible that changes in fat preference may be achieved through behavioral or pharmacological approaches. An understanding of food cravings and aversions may lead to improved methods for the prevention and treatment of obesity and eating disorders. PMID:12612163

  6. Odor aversion learning by the rat fetus.

    PubMed

    Smotherman, W P

    1982-11-01

    Rat fetuses were exposed to an odor stimulus on day 20 of gestation via amniotic injection and then injected with LiCl. In a CER paradigm, 10 day old pups were trained to approach an anesthetized dam in a runway for suckling reinforcement. When running speeds had stabilized the odor stimulus experienced in-utero was introduced into the test chamber. This odor took on aversive properties as a function of its pairing with LiCl, as evidenced by a decrease in running speed on CER trials and increases in the number of trials that were terminated because pups failed to traverse the runway. These data indicate that the fetal rat is capable of odor aversion learning. PMID:6296892

  7. Inequity aversion and the evolution of cooperation

    NASA Astrophysics Data System (ADS)

    Ahmed, Asrar; Karlapalem, Kamalakar

    2014-02-01

    Evolution of cooperation is a widely studied problem in biology, social science, economics, and artificial intelligence. Most of the existing approaches that explain cooperation rely on some notion of direct or indirect reciprocity. These reciprocity based models assume agents recognize their partner and know their previous interactions, which requires advanced cognitive abilities. In this paper we are interested in developing a model that produces cooperation without requiring any explicit memory of previous game plays. Our model is based on the notion of inequity aversion, a concept introduced within behavioral economics, whereby individuals care about payoff equality in outcomes. Here we explore the effect of using income inequality to guide partner selection and interaction. We study our model by considering both the well-mixed and the spatially structured population and present the conditions under which cooperation becomes dominant. Our results support the hypothesis that inequity aversion promotes cooperative relationship among nonkin.

  8. Influence of prion strain on prion protein adsorption to soil in a competitive matrix.

    PubMed

    Saunders, Samuel E; Bartz, Jason C; Bartelt-Hunt, Shannon L

    2009-07-15

    It is likely that the soil environment serves as a stable reservoir of infectious chronic wasting disease (CWD) and scrapie prions, as well as a potential reservoir of bovine spongiform encephalopathy (BSE, or "mad cow" disease). Prion adsorption to soil may play an important role in prion mobility, proteolysis, and infectivity. Differences in PrP environmental fate are possible due to the strain- and species-dependent structure of PrP(Sc). Kinetic and isothermal studies of PrP adsorption to sand and two whole soils were conducted using HY and DY TME-infected hamster, uninfected hamster, and CWD-infected elk brain homogenates as competitive PrP sources. The role of the N-terminus in PrP adsorption was also investigated. We report strain and species differences in PrP adsorption to soil over time and as a function of aqueous concentration, indicating that the fate of prions in the environment may vary with the prion strain and species infected. Our data also provide evidence that the N-terminal region of PrP enhances adsorption to clay but may hinder adsorption to sand. PrP adsorption was maximal at an intermediate aqueous concentration, most likely due to the competitive brain homogenate matrix in which it enters the soil environment. PMID:19708348

  9. Different components of conditioned food aversion memory.

    PubMed

    Nikitin, Vladimir P; Solntseva, Svetlana V; Kozyrev, Sergey A; Nikitin, Pavel V; Shevelkin, Alexey V

    2016-07-01

    Memory reconsolidation processes and protein kinase Mzeta (PKMzeta) activity in memory maintenance and reorganization are poorly understood. Therefore, we examined memory reconsolidation and PKMzeta activity during the maintenance and reorganization of a conditioned food aversion memory among snails. These processes were specifically evaluated after administration of a serotonin receptor antagonist (methiothepin), NMDA glutamate receptor antagonist (MK-801), protein synthesis inhibitor (cycloheximide; CYH), or PKMzeta inhibitor (zeta inhibitory peptide; ZIP) either 2 or 10 days after aversion training. Two days post-training, injections of MK-801 or CYH, combined with a conditioned stimulus reminder, caused amnesia development, and a second training 11 days after this induction did not lead to long-term memory formation. Interestingly, MK-801 or CYH injections and the reminder 10 days after training did not affect memory retrieval. Methiothepin and the reminder, or ZIP without the reminder, at 2 and 10 days after training led to memory impairment, while a second training 11 days after amnesia induction resulted in memory formation. These results suggest that the maintenance of a conditioned food aversion involves two different components with variable dynamics. One component could be characterized by memory strengthening over time and involve N-methyl-D-aspartate receptors and protein synthesis reconsolidation at early, but not late, training stages. The other memory component could involve serotonin-dependent reconsolidation and Mzeta-like kinase activity at both early and late stages after learning. Deficiencies within these two components led to various forms of memory impairment, which differed in terms of the formation of a conditioned food aversion during the second training. PMID:27017957

  10. The influence of sex, line, and fight experience on aggressiveness of the Siamese fighting fish in intrasexual competition.

    PubMed

    Karino, K; Someya, C

    2007-07-01

    We examined the influence of sex, line, i.e., broods from different parents, and previous fight experience on the aggressiveness of the Siamese fighting fish Betta splendens in intrasexual competition. The innate aggressiveness of the fish against their mirror images was measured on the day prior to the direct fight with other individuals, and it was found to be influenced by the line type but not by the sex. In the direct fight with other individuals, the males invested more effort in the fight than the females. In addition, the individuals of a particular line that exhibited a lower innate aggressiveness spent less time in the direct fight and were often losers when compared with those of other lines. After the direct fight with other individuals, the aggressiveness of the fish against their mirror images was remarkably influenced by the outcome of the direct fight, i.e., the winners exhibited more aggressive behavior, whereas the losers exhibited a lesser degree of aggressive behavior. This influence of the previous fight experience on subsequent aggressiveness was the greatest in the individuals of the line that have exhibited the lowest innate aggressiveness. However, the positive effect of the winning experience or the negative effect of the losing experience on subsequent aggressiveness decreased following several days after the previous fight increased. PMID:17434689

  11. The influence of lactobacilli on the competitive exclusion of paratyphoid salmonellae in chickens.

    PubMed

    Soerjadi, A S; Stehman, S M; Snoeyenbos, G H; Weinack, O M; Smyser, C F

    1981-01-01

    The competitive exclusion of salmonellae by native gut microflora was investigated by treating chicks with various avian lactobacilli. The evaluation of protection was based on the number of salmonellae adhering to the mucosa of the crop and the cecum, enumeration of salmonellae in fecal droppings, and enrichment of cloacal swabs and fecal droppings using both individual and seeder bird tests. Lactobacilli reduced the number of salmonellae adhering to the crop mucosa by 1 to 2 logs. Treatment with lactobacilli did not lower the number of chickens shedding salmonellae or reduce the number of salmonellae adhering to the mucosa of the cecum. Lactobacilli as a single bacterial treatment played a minor role in protecting the crop, but no protection of the cecum was demonstrated. PMID:7039590

  12. [Misophonia or aversion to human sound: a clinical illustration].

    PubMed

    Jacot, C-R; Eric, T; Sentissi, O

    2015-02-18

    Misophonia, meaning hatred of sound, is a cluster of symptoms which is not completely included in anxiety disorders category as obsessive compulsive or as an impulsivity disorder. It is described as a chronic condition characterized by reactions, aversion to specific sounds that result in subsequent emotional. Indeed, this condition is relatively unknown and few psychiatrists have already faced this disorder causing in some individuals severe impairment. The investigation of a patient suffering of misophonia with severe impairment that we took into care in an outpatient psychiatric clinic in Geneva contributes to a better understanding of this condition and indicates potential factors that may co-occur and influence the clinical presentation. The good response in psychotherapy, has led us to carry out a brief review of the literature in order to better define and identify this disorder. PMID:25915989

  13. Opposing effects of appetitive and aversive cues on go/no-go behavior and motor excitability.

    PubMed

    Chiu, Yu-Chin; Cools, Roshan; Aron, Adam R

    2014-08-01

    Everyday life, as well as psychiatric illness, is replete with examples where appetitive and aversive stimuli hijack the will, leading to maladaptive behavior. Yet the mechanisms underlying this phenomenon are not well understood. Here we investigate how motivational cues influence action tendencies in healthy individuals with a novel paradigm. Behaviorally, we observed that an appetitive cue biased go behavior (making a response), whereas an aversive cue biased no-go behavior (withholding a response). We hypothesized that the origin of this behavioral go/no-go bias occurs at the motor system level. To test this, we used single-pulse TMS as a motor system probe (rather than a disruptive tool) to index motivational biasing. We found that the appetitive cue biased the participants to go more by relatively increasing motor system excitability, and that the aversive cue biased participants to no-go more by relatively decreasing motor system excitability. These results show, first, that maladaptive behaviors arise from motivational cues quickly spilling over into the motor system and biasing behavior even before action selection and, second, that this occurs in opposing directions for appetitive and aversive cues. PMID:24564469

  14. Emotion-induced loss aversion and striatal-amygdala coupling in low-anxious individuals

    PubMed Central

    Charpentier, Caroline J.; Martino, Benedetto De; Sim, Alena L.; Sharot, Tali; Roiser, Jonathan P.

    2016-01-01

    Adapting behavior to changes in the environment is a crucial ability for survival but such adaptation varies widely across individuals. Here, we asked how humans alter their economic decision-making in response to emotional cues, and whether this is related to trait anxiety. Developing an emotional decision-making task for functional magnetic resonance imaging, in which gambling decisions were preceded by emotional and non-emotional primes, we assessed emotional influences on loss aversion, the tendency to overweigh potential monetary losses relative to gains. Our behavioral results revealed that only low-anxious individuals exhibited increased loss aversion under emotional conditions. This emotional modulation of decision-making was accompanied by a corresponding emotion-elicited increase in amygdala-striatal functional connectivity, which correlated with the behavioral effect across participants. Consistent with prior reports of ‘neural loss aversion’, both amygdala and ventral striatum tracked losses more strongly than gains, and amygdala loss aversion signals were exaggerated by emotion, suggesting a potential role for this structure in integrating value and emotion cues. Increased loss aversion and striatal-amygdala coupling induced by emotional cues may reflect the engagement of adaptive harm-avoidance mechanisms in low-anxious individuals, possibly promoting resilience to psychopathology. PMID:26589451

  15. Preexposure to salty and sour taste enhances conditioned taste aversion to novel sucrose.

    PubMed

    Flores, Veronica L; Moran, Anan; Bernstein, Max; Katz, Donald B

    2016-05-01

    Conditioned taste aversion (CTA) is an intensively studied single-trial learning paradigm whereby animals are trained to avoid a taste that has been paired with malaise. Many factors influence the strength of aversion learning; prominently studied among these is taste novelty-the fact that preexposure to the taste conditioned stimulus (CS) reduces its associability. The effect of exposure to tastes other than the CS has, in contrast, received little investigation. Here, we exposed rats to sodium chloride (N) and citric acid (C), either before or within a conditioning session involving novel sucrose (S). Presentation of this taste array within the conditioning session weakened the resultant S aversion, as expected. The opposite effect, however, was observed when exposure to the taste array was provided in sessions that preceded conditioning: such experience enhanced the eventual S aversion-a result that was robust to differences in CS delivery method and number of tastes presented in conditioning sessions. This "non-CS preexposure effect" scaled with the number of tastes in the exposure array (experience with more stimuli was more effective than experience with fewer) and with the amount of exposure sessions (three preexposure sessions were more effective than two). Together, our results provide evidence that exposure and experience with the realm of tastes changes an animal's future handling of even novel tastes. PMID:27084929

  16. Characteristics of conditioned taste aversion produced by nicotine in rats.

    PubMed Central

    Kumar, R.; Pratt, J. A.; Stolerman, I. P.

    1983-01-01

    1 Nicotine produced conditioned taste aversions in rats which were directly related to the dose of nicotine and to the number of conditioning trials. 2 The tobacco alkaloid (-)-nicotine was four to five times as potent as its stereoisomer, (+)-nicotine. 3 Mecamylamine but not hexamethonium blocked the development of taste aversions produced by nicotine. 4 Mecamylamine did not block the development of taste aversions produced by apomorphine. 5 Prolonged treatment with mecamylamine prior to conditioning did not produce supersensitivity to nicotine. PMID:6135477

  17. The relative influences of climate and competition on tree growth along montane ecotones in the Rocky Mountains.

    PubMed

    Copenhaver-Parry, Paige E; Cannon, Ellie

    2016-09-01

    Distribution shifts of tree species are likely to be highly dependent upon population performance at distribution edges. Understanding the drivers of aspects of performance, such as growth, at distribution edges is thus crucial to accurately predicting responses of tree species to climate change. Here, we use a Bayesian model and sensitivity analysis to partition the effects of climate and crowding, as a metric of competition, on radial growth of three dominant conifer species along montane ecotones in the Rocky Mountains. These ecotones represent upper and lower distribution edges of two species, and span the distribution interior of the third species. Our results indicate a greater influence of climate (i.e., temperature and precipitation) than crowding on radial growth. Competition importance appears to increase towards regions of more favorable growing conditions, and precise responses to crowding and climate vary across species. Overall, our results suggest that climate will likely be the most important determinant of changes in tree growth at distribution edges of these montane conifers in the future. PMID:26873606

  18. Shared ancestry influences community stability by altering competitive interactions: evidence from a laboratory microcosm experiment using freshwater green algae

    PubMed Central

    Venail, Patrick A.; Alexandrou, Markos A.; Oakley, Todd H.; Cardinale, Bradley J.

    2013-01-01

    The impact of biodiversity on the stability of ecological communities has been debated among biologists for more than a century. Recently summarized empirical evidence suggests that biodiversity tends to enhance the temporal stability of community-level properties such as biomass; however, the underlying mechanisms driving this relationship remain poorly understood. Here, we report the results of a microcosm study in which we used simplified systems of freshwater microalgae to explore how the phylogenetic relatedness of species influences the temporal stability of community biomass by altering the nature of their competitive interactions. We show that combinations of two species that are more evolutionarily divergent tend to have lower temporal stability of biomass. In part, this is due to negative ‘selection effects’ in which bicultures composed of distantly related species are more likely to contain strong competitors that achieve low biomass. In addition, bicultures of distantly related species had on average weaker competitive interactions, which reduced compensatory dynamics and decreased the stability of community biomass. Our results demonstrate that evolutionary history plays a key role in controlling the mechanisms, which give rise to diversity–stability relationships. As such, patterns of shared ancestry may help us predict the ecosystem-level consequences of biodiversity loss. PMID:23945692

  19. Competition and Habitat Quality Influence Age and Sex Distribution in Wintering Rusty Blackbirds

    PubMed Central

    Mettke-Hofmann, Claudia; Hamel, Paul B.; Hofmann, Gerhard; Zenzal Jr., Theodore J.; Pellegrini, Anne; Malpass, Jennifer; Garfinkel, Megan; Schiff, Nathan

    2015-01-01

    Bird habitat quality is often inferred from species abundance measures during the breeding and non-breeding season and used for conservation management decisions. However, during the non-breeding season age and sex classes often occupy different habitats which suggest a need for more habitat-specific data. Rusty Blackbird (Euphagus carolinus) is a forested wetland specialist wintering in bottomland hardwood forests in the south-eastern U. S. and belongs to the most steeply declining songbirds in the U.S. Little information is available to support priority birds such as the Rusty Blackbird wintering in this threatened habitat. We assessed age and sex distribution and body condition of Rusty Blackbirds among the three major habitats used by this species in the Lower Mississippi Alluvial Valley and also measured food availability. Overall, pecan groves had the highest biomass mainly driven by the amount of nuts. Invertebrate biomass was highest in forests but contributed only a small percentage to overall biomass. Age and sex classes were unevenly distributed among habitats with adult males primarily occupying pecan groves containing the highest nut biomass, females being found in forests which had the lowest nut biomass and young males primarily staying in forest fragments along creeks which had intermediate nut biomass. Males were in better body condition than females and were in slightly better condition in pecan groves. The results suggest that adult males occupy the highest quality habitat and may competitively exclude the other age and sex classes. PMID:25946335

  20. Competition and habitat quality influence age and sex distribution in wintering rusty blackbirds.

    PubMed

    Mettke-Hofmann, Claudia; Hamel, Paul B; Hofmann, Gerhard; Zenzal, Theodore J; Pellegrini, Anne; Malpass, Jennifer; Garfinkel, Megan; Schiff, Nathan; Greenberg, Russell

    2015-01-01

    Bird habitat quality is often inferred from species abundance measures during the breeding and non-breeding season and used for conservation management decisions. However, during the non-breeding season age and sex classes often occupy different habitats which suggest a need for more habitat-specific data. Rusty Blackbird (Euphagus carolinus) is a forested wetland specialist wintering in bottomland hardwood forests in the south-eastern U. S. and belongs to the most steeply declining songbirds in the U.S. Little information is available to support priority birds such as the Rusty Blackbird wintering in this threatened habitat. We assessed age and sex distribution and body condition of Rusty Blackbirds among the three major habitats used by this species in the Lower Mississippi Alluvial Valley and also measured food availability. Overall, pecan groves had the highest biomass mainly driven by the amount of nuts. Invertebrate biomass was highest in forests but contributed only a small percentage to overall biomass. Age and sex classes were unevenly distributed among habitats with adult males primarily occupying pecan groves containing the highest nut biomass, females being found in forests which had the lowest nut biomass and young males primarily staying in forest fragments along creeks which had intermediate nut biomass. Males were in better body condition than females and were in slightly better condition in pecan groves. The results suggest that adult males occupy the highest quality habitat and may competitively exclude the other age and sex classes. PMID:25946335

  1. Interference competition: odours of an apex predator and conspecifics influence resource acquisition by red foxes.

    PubMed

    Leo, Viyanna; Reading, Richard P; Letnic, Mike

    2015-12-01

    Apex predators can impact smaller predators via lethal effects that occur through direct killing, and non-lethal effects that arise when fear-induced behavioural and physiological changes reduce the fitness of smaller predators. A general outcome of asymmetrical competition between co-existing predator species is that larger predators tend to suppress the abundances of smaller predators. Here, we investigate interference effects that an apex predator, the dingo (Canis dingo), has on the acquisition of food and water by the smaller red fox (Vulpes vulpes), by exposing free-ranging foxes to the odour of dingoes and conspecifics in an arid environment. Using giving-up densities we show that foxes foraged more apprehensively at predator-odour treatments than unscented controls, but their food intake did not differ between dingo- and fox-odour treatments. Using video analysis of fox behaviour at experimental water stations we show that foxes spent more time engaged in exploration behaviour at stations scented with fox odour and spent more time drinking at water stations scented with dingo odour. Our results provide support for the idea that dingo odour exerts a stronger interference effect on foxes than conspecific odour, but suggest that the odours of both larger dingoes and unfamiliar conspecifics curtailed foxes' acquisition of food resources. PMID:26296332

  2. Impulsivities and Parkinson's disease: delay aversion is not worsened by Deep Brain Stimulation of the subthalamic nucleus.

    PubMed

    Torta, Diana M E; Vizzari, Vincenzo; Castelli, Lorys; Zibetti, Maurizio; Lanotte, Michele; Lopiano, Leonardo; Geminiani, Giuliano

    2012-01-01

    Deep Brain Stimulation (DBS) of the Subthalamic Nucleus (STN) improves motor symptoms in Parkinson's disease (PD), but can exert detrimental effects on impulsivity. These effects are especially related to the inability to slow down when high-conflict choices have to be made. However, the influence that DBS has on delay aversion is still under-investigated. Here, we tested a group of 21 PD patients on and off stimulation (off medication) by using the Cambridge Gamble Task (CGT), a computerized task that allows the investigation of risk-related behaviours and delay aversion, and psychological questionnaires such as the Barratt Impulsiveness Scale (BIS), the Sensitivity to Punishment and to Reward Questionnaire (SPSRQ), and the Quick Delay Questionnaire (QDQ). We found that delay aversion scores on the CGT were no higher when patients were on stimulation as compared to when they were off stimulation. In contrast, PD patients reported feeling more impulsive in the off stimulation state, as revealed by significantly higher scores on the BIS. Higher scores on the sensitivity to punishment subscale of the SPSRQ highlighted that possible punishments influence patients' behaviours more than possible rewards. Significant correlations between delay aversion scores on the CGT and QDQ delay aversion subscale suggest that these two instruments can be used in synergy to reach a convergent validity. In conclusion, our results show that not all impulsivities are detrimentally affected by DBS of the STN and that the joint use of experimental paradigms and psychological questionnaires can provide useful insights in the study of impulsivity. PMID:22984415

  3. Asymmetries in body condition and order of arrival influence competitive ability and survival in a coral reef fish.

    PubMed

    Poulos, Davina E; McCormick, Mark I

    2015-11-01

    Trade-offs between traits that influence an individual's competitive ability are important in determining community assembly and coexistence of individuals sharing the same resources. Populations of coral reef fish are structurally complex, so it is important to understand how these populations are shaped as a result of an individual's suite of traits and those of its competitors. We conducted a 2 × 2 factorial field experiment that manipulated body condition (high or low, manipulated through a feeding regime) and residency (resident or intruder, where the resident arrived at the habitat 3 h before the intruder) to evaluate effects on competitive ability and survival. Prior residency alleviated the disadvantage of a low body condition with respect to aggression, which was similar between low-condition residents and high-condition intruders. However, high-condition residents displayed a significantly greater level of aggression than intruders, regardless of whether intruders were from high- or low-condition treatments. For intruders to have a high probability of becoming dominant, they needed to have a large body condition advantage. Mortality trajectories suggested that body condition modified the effect of prior residency, and intruders were more likely to suffer mortality if they had a low body condition because residents pushed them away from shelter. Our results highlight that the negative effects of some traits may be compensated for by the positive effects of other traits, and that the specific ecological context an individual faces (such as the characteristics of its competitors) can have a major influence on successful establishment and persistence. PMID:26220881

  4. Competition between pressure effects and airflow influence for the performance of plasma actuators

    SciTech Connect

    Kriegseis, J.; Barckmann, K.; Grundmann, S.; Frey, J.; Tropea, C.

    2014-05-15

    The present work addresses the combined influence of pressure variations and different airflow velocities on the discharge intensity of plasma actuators. Power consumption, plasma length, and discharge capacitance were investigated systematically for varying pressure levels (p = 0.1–1 bar) and airflow velocities (U{sub ∞}=0−100 m/s) to characterize and quantify the favorable and adverse effects on the discharge intensity. In accordance with previous reports, an increasing plasma actuator discharge intensity is observed for decreasing pressure levels. At constant pressure levels, an adverse airflow influence on the electric actuator performance is demonstrated. Despite the improved discharge intensity at lower pressure levels, the seemingly improved performance of the plasma actuators is accompanied with a more pronounced drop of the relative performance. These findings demonstrate the dependency of the (kinematic and thermodynamic) environmental conditions on the electric performance of plasma actuators, which in turn affects the control authority of plasma actuators for flow control applications.

  5. Maintaining the competitiveness of the American fisheries society journals: an assessment based on influence and cost-effectiveness

    USGS Publications Warehouse

    Hewitt, David A.; Link, Jason S.; Steinich, Dave R.; Wahl, David H.; Mather, Martha E.

    2009-01-01

    Recent changes in the landscape of scientific publishing prompted the Publications Overview Committee of the American Fisheries Society (AFS) to review the Society's portfolio of scientific journals. We evaluated journals based on metrics in two categories: (1) citation-based measures of the influence of a journal on the scientific literature, and (2) measures of the cost-effectiveness of a journal (citation rate adjusted for subscription cost). Over the long-term, we found that ecology journals had far stronger citation-based influence than fisheries and aquatic sciences journals, and that journals publishing primarily basic research had stronger influence than journals publishing applied research (including four AFS journals and Fisheries magazine). In evaluating the current status of fisheries and aquatic sciences journals, we found that metrics of influence and cost-effectiveness provided considerably different portrayals of journals relative to their peers. In terms of citation-based influence, we found that the AFS journal Transactions of the American Fisheries Society (TAFS) and Fisheries magazine were competitive with highly regarded peer fisheries journals, but that North American Journal of Aquaculture (NAJA) and Journal of Aquatic Animal Health (JAAH) were less influential than their peers. The citation-based influence of North American Journal of Fisheries Management (NAJFM) was intermediate between TAFS/Fisheries and NAJA/JAAH. For journals like NAJFM and NAJA, we expect that much of the scientific influence on policy and management is not captured by citations in the primary literature, and alternative methods of evaluation may be needed. All of the AFS journals ranked highly with regard to cost-effectiveness because their subscription costs are low, and these rankings are in accordance with membership needs and the strategic mission of AFS to provide broad and timely dissemination of scientific information. We conclude by suggesting

  6. Factors influencing performance of competitive and amateur rhythmic gymnastics--gender differences.

    PubMed

    Di Cagno, Alessandra; Baldari, Carlo; Battaglia, Claudia; Monteiro, Maria Dolores; Pappalardo, Alessandra; Piazza, Marina; Guidetti, Laura

    2009-05-01

    During last decade, male athletes were involved in official rhythmic gymnastics (RG) competitions. Aim of this study was to examine anthropometric characteristics and motor skills of male rhythmic gymnasts to identify guidelines in talent identification, selection and development training plans. Twenty-four gymnasts (age range 22+/-4 years), 12 male athletes and 12 female athletes, underwent two testing sessions: the previous session to assess anthropometric measures, and the second one to evaluate jumping ability using Optojump. Three vertical jumps: squat jump (SJ), counter-movement jump (CMJ), hopping test (HT) and three different technical jumps (Split Leap with stretched legs (SL); Cossack with 180 degrees of rotation (CK); Jeté with turn (JWT)) were evaluated. Male gymnasts had significant higher values in each anthropometric measure than females (p<0.01) except for sitting height/stature ratio, sitting height and fat mass (no significant differences). Female athletes were selected for their lowest fat mass. Height and ground contact time of technical leaps, squat jump and counter-movement jump, were significantly higher in male athletes than females. Height of hopping test (evaluating stiffness), and of difference between CMJ and squat jump (evaluating elastic properties of muscles) were no different between genders. Ground contact time of hopping test was significantly correlated (p<0.05) with ground contact time of technical leaps. Results of the present study suggest that similar anthropometric characteristics have to be researched for both gymnasts' gender. Reactivity and elastic muscle properties of the legs have to be research both in male and female athletes. PMID:18356108

  7. Plant traits related to nitrogen uptake influence plant-microbe competition.

    PubMed

    Moreau, Delphine; Pivato, Barbara; Bru, David; Busset, Hugues; Deau, Florence; Faivre, Céline; Matejicek, Annick; Strbik, Florence; Philippot, Laurent; Mougel, Christophe

    2015-08-01

    Plant species are important drivers of soil microbial communities. However, how plant functional traits are shaping these communities has received less attention though linking plant and microbial traits is crucial for better understanding plant-microbe interactions. Our objective was to determine how plant-microbe interactions were affected by plant traits. Specifically we analyzed how interactions between plant species and microbes involved in nitrogen cycling were affected by plant traits related to 'nitrogen nutrition in interaction with soil nitrogen availability. Eleven plant species, selected along an oligotrophic-nitrophilic gradient, were grown individually in a nitrogen-poor soil with two levels of nitrate availability. Plant traits for both carbon and nitrogen nutrition were measured and the genetic structure and abundance of rhizosphere. microbial communities, in particular the ammonia oxidizer and nitrate reducer guilds, were analyzed. The structure of the bacterial community in the rhizosphere differed significantly between plant species and these differences depended on nitrogen availability. The results suggest that the rate of nitrogen uptake per unit of root biomass and per day is a key plant trait, explaining why the effect of nitrogen availability on the structure of the bacterial community depends on the plant species. We also showed that the abundance of nitrate reducing bacteria always decreased with increasing nitrogen uptake per unit of root biomass per day, indicating that there was competition for nitrate between plants and nitrate reducing bacteria. This study demonstrates that nitrate-reducing microorganisms may be adversely affected by plants with a high nitrogen uptake rate. Our work puts forward the role of traits related to nitrogen in plant-microbe interactions, whereas carbon is commonly considered as the main driver. It also suggests that plant traits related to ecophysiological processes, such as nitrogen uptake rates, are more

  8. On the genetics of loss aversion: An interaction effect of BDNF Val66Met and DRD2/ANKK1 Taq1a.

    PubMed

    Voigt, Gesine; Montag, Christian; Markett, Sebastian; Reuter, Martin

    2015-12-01

    Loss aversion is the tendency to overweight losses compared with gains in decision situations. Several studies have investigated the neurobiological background of this phenomenon and it was found that activation in the mesolimbic-mesocortical dopamine system during a gambling decision correlates with loss aversion. In a behavioral experiment with N = 143 subjects, the present study investigates the influence of 2 functional single-nucleotide polymorphisms on the BDNF gene (BDNF Val66Met polymorphism) and ANKK1 gene (DRD2 Taq1a/ANKK1 polymorphism), that are known to affect the dopamine system, on loss aversion. Additionally, associations of alexithymia, a personality construct describing the disability to consciously experience emotions in the self, with loss aversion and with the mentioned polymorphisms were assessed using the TAS-20 questionnaire, to replicate associations that have been reported before. Results revealed a significant interaction effect of the 2 polymorphisms on loss aversion. Carriers of the genetic constellation 66Met+/A1+ had the lowest loss aversion scores, compared with all other allelic groups. According to the literature this allelic configuration is characterized by a relatively low D2/3 receptor binding in the striatum and an impaired activity-dependent secretion of BDNF. This is the first study showing that loss aversion is related to naturally occurring differences in dopamine function. PMID:26501178

  9. COMPETITIVE INFLUENCE OF PHOSPHORUS AND CALCIUM ON PB IN-VITRO BIOAVAILABILITY (S11-SCHECKEL101231-POSTER)

    EPA Science Inventory

    The bioavailability of a metal is heavily related to the speciation of the particular metal. Further, the complexity of examining metal bioavailability is compounded by the presence of competitive ions. Thus, equally contaminated soils with varying concentrations of competitive e...

  10. Sequence of host contact influences the outcome of competition among Aspergillus flavus isolates during host tissue invasion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biological control of aflatoxin contamination by Aspergillus flavus is achieved by competitive exclusion of aflatoxin producers by atoxigenic strains. However, factors dictating the extent to which competitive displacement occurs during host infection are unknown. The role of preemptive exclusion in...

  11. Does Conspecific Fighting Yield Conditioned Taste Aversion in Rats?

    ERIC Educational Resources Information Center

    Nakajima, Sadahiko; Kumazawa, Gaku; Ieki, Hayato; Hashimoto, Aya

    2012-01-01

    Running in an activity wheel yields conditioned aversion to a taste solution consumed before the running, but its underlying physiological mechanism is unknown. According to the claim that energy expenditure or general stress caused by physical exercise is a critical factor for this taste-aversion learning, not only running but also other…

  12. Self-Other Decision Making and Loss Aversion

    ERIC Educational Resources Information Center

    Polman, Evan

    2012-01-01

    In eight studies, we tested the prediction that making choices for others involves less loss aversion than making choices for the self. We found that loss aversion is significantly lessened among people choosing for others in scenarios describing riskless choice (Study 1), gambling (Studies 2 and 3), and social aspects of life, such as likeably…

  13. Reducing Aversion to Side Effects in Preventive Medical Treatment Decisions

    ERIC Educational Resources Information Center

    Waters, Erika A.; Weinstein, Neil D.; Colditz, Graham A.; Emmons, Karen M.

    2007-01-01

    Laypeople tend to be overly sensitive to side effects of treatments that prevent illness, possibly leading them to refuse beneficial therapies. This Internet-based study attempted to reduce such side effect aversion by adding graphic displays to the numerical risk probabilities. It also explored whether graphics reduce side effect aversion by…

  14. Optogenetic induction of aversive taste memory.

    PubMed

    Keene, Alex C; Masek, Pavel

    2012-10-11

    The Drosophila melanogaster gustatory system consists of several neuronal pathways representing diverse taste modalities. The two predominant modalities are a sweet-sensing pathway that mediates attraction, and a bitter-sensing pathway that mediates avoidance. A central question is how flies integrate stimuli from these pathways and generate the appropriate behavioral response. We have developed a novel assay for induction of taste memories. We demonstrate that the gustatory response to fructose is suppressed when followed by the presence of bitter quinine. We employ optogenetic neural activation using infrared laser in combination with heat-sensitive channel - TRPA1 to precisely activate gustatory neurons. This optogenetic system allows for spatially and temporally controlled activation of distinct neural classes in the gustatory circuit. We directly activated bitter-sensing neurons together with presentation of fructose for remote induction of aversive taste memories. Here we report that activation of bitter-sensing neurons in the proboscis suffices as a conditioning stimulus. Spatially restricted stimulation indicates that the conditioning stimulus is indeed a signal from the bitter neurons in the proboscis and it is independent of postingestive feedback. The coincidence of temporally specific activation of bitter-sensing neurons with fructose presentation is crucial for memory formation, establishing aversive taste learning in Drosophila as associative learning. Taken together, this optogenetic system provides a powerful new tool for interrogation of the central brain circuits that mediate memory formation. PMID:22820051

  15. Variation in the establishment of a non-native annual grass influences competitive interactions with Mojave Desert perennials

    USGS Publications Warehouse

    DeFalco, L.A.; Fernandez, G.C.J.; Nowak, R.S.

    2007-01-01

    Competition between native and non-native species can change the composition and structure of plant communities, but in deserts, the highly variable timing of resource availability also influences non-native plant establishment, thus modulating their impacts on native species. In a field experiment, we varied densities of the non-native annual grass Bromus madritensis ssp. rubens around individuals of three native Mojave Desert perennials-Larrea tridentata, Achnatherum hymenoides, and Pleuraphis rigida-in either winter or spring. For comparison, additional plots were prepared for the same perennial species and seasons, but with a mixture of native annual species as neighbors. Growth of perennials declined when Bromus was established in winter because Bromus stands had 2-3 months of growth and high water use before perennial growth began. However, water potentials for the perennials were not significantly reduced, suggesting that direct competition for water may not be the major mechanism driving reduced perennial growth. The impact of Bromus on Larrea was lower than for the two perennial grasses, likely because Larrea maintains low growth rates throughout the year, even after Bromus has completed its life cycle. This result contrasts with the perennial grasses, whose phenology completely overlaps with (Achnatherum) or closely follows (Pleuraphis) that of Bromus. In comparison, Bromus plants established in spring were smaller than those established in winter and thus did not effectively reduce growth of the perennials. Growth of perennials with mixed annuals as neighbors also did not differ from those with Bromus neighbors of equivalent biomass, but stands of these native annuals did not achieve the high biomass of Bromus stands that were necessary to reduce perennial growth. Seed dormancy and narrow requirements for seedling survivorship of native annuals produce densities and biomass lower than those achieved by Bromus; thus, impacts of native Mojave Desert

  16. Children do not exhibit ambiguity aversion despite intact familiarity bias

    PubMed Central

    Li, Rosa; Brannon, Elizabeth M.; Huettel, Scott A.

    2015-01-01

    The phenomenon of ambiguity aversion, in which risky gambles with known probabilities are preferred over ambiguous gambles with unknown probabilities, has been thoroughly documented in adults but never measured in children. Here, we use two distinct tasks to investigate ambiguity preferences of children (8- to 9-year-olds) and a comparison group of adults (19- to 27-year-olds). Across three separate measures, we found evidence for significant ambiguity aversion in adults but not in children and for greater ambiguity aversion in adults compared to children. As ambiguity aversion in adults has been theorized to result from a preference to bet on the known and avoid the unfamiliar, we separately measured familiarity bias and found that children, like adults, are biased towards the familiar. Our findings indicate that ambiguity aversion emerges across the course of development between childhood and adolescence, while a familiarity bias is already present in childhood. PMID:25601848

  17. Stated and revealed inequality aversion in three subject pools

    PubMed Central

    Beranek, Benjamin; Cubitt, Robin; Gächter, Simon

    2016-01-01

    This paper reports data from three subject pools (n=717 subjects) using techniques based on those of Loewenstein, et al. (1989) and Blanco, et al. (2011) to obtain parameters, respectively, of stated and revealed inequality aversion. We provide a replication opportunity for those papers, with two innovations: (i) a design which allows stated and revealed preferences to be compared at the individual level; (ii) assessment of robustness of findings across subjects from a UK university, a Turkish university and Amazon Mechanical Turk. Our findings on stated aversion to inequality are qualitatively similar to those of Loewenstein, et al. in each of our subject pools, whereas there are notable differences between some of our findings on revealed preference and those of Blanco, et al. We find that revealed advantageous inequality aversion is often stronger than revealed dis-advantageous inequality aversion. In most subject pools, we find some (weak) correlation between corresponding parameters of stated and revealed inequality aversion. PMID:27069847

  18. Assessing the Impact of the Funding Environment on Researchers' Risk Aversion: The Use of Citation Statistics

    ERIC Educational Resources Information Center

    Zoller, Frank A.; Zimmerling, Eric; Boutellier, Roman

    2014-01-01

    The funding environment has a profound impact on researchers' behavior. In particular, it influences their freedom and readiness to conduct research ventures with highly uncertain outcomes. In this conceptual paper, we propose a concise new methodology to evaluate researchers' risk aversion based on citation statistics. The derived…

  19. Habitat selection of two gobies (Microgobius gulosus, Gobiosoma robustum): influence of structural complexity, competitive interactions and presence of a predator

    USGS Publications Warehouse

    Schofield, P.J.

    2003-01-01

    Herein I compare the relative importance of preference for structurally complex habitat against avoidance of competitors and predators in two benthic fishes common in the Gulf of Mexico. The code goby Gobiosoma robustum Ginsburg and clown goby Microgobius gulosus (Girard) are common, ecologically similar fishes found throughout the Gulf of Mexico and in the southeastern Atlantic Ocean. In Florida Bay, these fishes exhibit habitat partitioning: G. robustum is most abundant in seagrass-dominated areas while M. gulosus is most abundant in sparsely vegetated habitats. In a small-scale field survey, I documented the microhabitat use of these species where their distributions overlap. In a series of laboratory experiments, I presented each species with structured (artificial seagrass) versus nonstructured (bare sand) habitats and measured their frequency of choosing either habitat type. I then examined the use of structured versus nonstructured habitats when the two species were placed together in a mixed group. Finally, I placed a predator (Opsanus beta) in the experimental aquaria to determine how its presence influenced habitat selection. In the field, G. robustum was more abundant in seagrass and M. gulosus was more abundant in bare mud. In the laboratory, both species selected grass over sand in allopatry. However, in sympatry, M. gulosus occupied sand more often when paired with G. robustum than when alone. G. robustum appears to directly influence the habitat choice of M. gulosus: It seems that M. gulosus is pushed out of the structured habitat that is the preferred habitat of G. robustum. Thus, competition appears to modify the habitat selection of these species when they occur in sympatry. Additionally, the presence of the toadfish was a sufficient stimulus to provoke both M. gulosus and G. robustum to increase their selection for sand (compared to single-species treatments). Distribution patterns of M. gulosus and G. robustum

  20. Features vs. Feelings: Dissociable representations of the acoustic features and valence of aversive sounds

    PubMed Central

    Kumar, Sukhbinder; von Kriegstein, Katharina; Friston, Karl; Griffiths, Timothy D

    2012-01-01

    This study addresses the neuronal representation of aversive sounds that are perceived as unpleasant. Functional magnetic resonance imaging (fMRI) in humans demonstrated responses in the amygdala and auditory cortex to aversive sounds. We show that the amygdala encodes both the acoustic features of a stimulus and its valence (perceived unpleasantness). Dynamic Causal Modelling (DCM) of this system revealed that evoked responses to sounds are relayed to the amygdala via auditory cortex. While acoustic features modulate effective connectivity from auditory cortex to the amygdala, the valence modulates the effective connectivity from amygdala to the auditory cortex. These results support a complex (recurrent) interaction between the auditory cortex and amygdala based on object-level analysis in the auditory cortex that portends the assignment of emotional valence in amygdala that in turn influences the representation of salient information in auditory cortex. PMID:23055488

  1. Prefrontal cortical effects on aversively motivated instrumental conditioning in rats: some ontogenic considerations.

    PubMed

    Brennan, J F

    1979-01-01

    During the last 20 years, an emerging body of data has delineated critical variables controlling the acquisition and retention of aversive experiences across ages. Focusing an the rat as subject organism, the behavioral literature on task- and age-specific findings is reviewed. Response inhibitory deficits in younger subjects are related to augmentation of stimulus control through discrimination training and reinstatement of components of original learning. Somewhat parallel and complementary to studies of behavioral development, advances in the neurophysiology and neuroanatomy of cortical functions have indicated the critical role of the prefrontal cortex in acquisition and retention of aversively motivated instrumental responses. Several studies of prefrontal damage administered at varying ages reveal the importance of neural development in both performance deficits as well as recovery of function. These preliminary experiments are discussed in light of constraints from appropriate cortical influences in consideration of the ontogeny of fear. PMID:547702

  2. The Competitive Influence of Li+, Na+, K+, Ag+, and H+ on the Fragmentation of a PEGylated Polymeric Excipient

    NASA Astrophysics Data System (ADS)

    Wei, Juan; Bristow, Anthony W. T.; O'Connor, Peter B.

    2015-01-01

    The collisionally activated dissociation (CAD) and electron capture dissociation (ECD) of doubly charged tocopheryl polyethylene glycol succinate (TPGS) have been examined. Li+, Na+, K+, Ag+, and H+ were selected in the study, and the competitive influence of each ion was investigated by fragmenting TPGS attached with two different cations, [M + X1 + X2]2+ (X1 and X2 refer to Li+, Na+, K+, Ag+, H+). For metallic adducts, CAD results show that the dissociation of ionic adducts from the precursor is most likely depending on the binding strength, where the affinity of each ion to the TPGS is in the order of Ag+ ≈ Li+ ˃ Na+ ˃ K+. Introducing more strongly bound adducts increases fragmentation. During ECD, however, the silver cation is lost most easily compared with the other alkali metal ions, but silver also shows a dominant role in producing fragmentations. Moreover, the charge carriers are lost in an order (Ag+ ˃ Na+ ˃ K+ ≥ Li+ where the loss of Ag is most easily) that appears to correlate with the standard reduction potential of the metallic ions (Ag+ ˃ Na+ ˃ K+ ˃ Li+). The ECD results suggest that the reduction potential of the charge carrier could be an important factor influencing the fragmentation, where the ion with a high reduction potential is more effective in capturing electrons, but may also be lost easily before leading to any fragmentation. Finally, a proton has the weakest binding with the TPGS according to the CAD results, and its dissociation in ECD follows the order of the reduction potential (Ag+ ˃ H+ ˃ Na+ ˃ K+ > Li+).

  3. The Relative Age Effect in Spanish Female Soccer Players. Influence of the Competitive Level and a Playing Position

    PubMed Central

    Sedano, Silvia; Vaeyens, Roel; Redondo, Juan Carlos

    2015-01-01

    The purposes of the study were to examine relative age effects (RAEs) in Spanish female soccer and to identify the influence of a playing position. The sample comprised all female players (n=4035) of five different competitive levels in the 2010–2013 seasons: First, Second and Third divisions (n=936, n=1711 and n=870, respectively), and National and Regional (n=232 and n=286, respectively) teams were included. Differences between the observed and expected birth-date distributions were tested based on data from the general Spanish population, using the chi-square statistic followed up by calculating odds ratios and 95% confidence intervals. Results revealed that the birth-date distributions of almost all groups of football players showed an overrepresentation of players born in the first quartile. Only in the lowest level was age distribution not significantly different from that of the general population. Moreover, the RAE risk progressively increased with a higher level of involvement. It was also observed that at some playing positions the birth-date distributions were significantly biased. That was the case for goalkeepers and defenders. It could be concluded that in the current structure of Spanish female soccer there is a relative age effect, probably due to the early processes of talent identification. PMID:26240656

  4. The Influence of Interspecific Competition and Host Preference on the Phylogeography of Two African Ixodid Tick Species

    PubMed Central

    Cangi, Nídia; Horak, Ivan G.; Apanaskevich, Dmitry A.; Matthee, Sonja; das Neves, Luís C. B. G.; Estrada-Peña, Agustín; Matthee, Conrad A.

    2013-01-01

    A comparative phylogeographic study on two economically important African tick species, Amblyomma hebraeum and Hyalomma rufipes was performed to test the influence of host specificity and host movement on dispersion. Pairwise AMOVA analyses of 277 mtDNA COI sequences supported significant population differentiation among the majority of sampling sites. The geographic mitochondrial structure was not supported by nuclear ITS-2 sequencing, probably attributed to a recent divergence. The three-host generalist, A. hebraeum, showed less mtDNA geographic structure, and a lower level of genetic diversity, while the more host-specific H. rufipes displayed higher levels of population differentiation and two distinct mtDNA assemblages (one predominantly confined to South Africa/Namibia and the other to Mozambique and East Africa). A zone of overlap is present in southern Mozambique. A mechanistic climate model suggests that climate alone cannot be responsible for the disruption in female gene flow. Our findings furthermore suggest that female gene dispersal of ticks is more dependent on the presence of juvenile hosts in the environment than on the ability of adult hosts to disperse across the landscape. Documented interspecific competition between the juvenile stages of H. rufipes and H. truncatum is implicated as a contributing factor towards disrupting gene flow between the two southern African H. rufipes genetic assemblages. PMID:24130813

  5. Proximity of foods in a competitive food environment influences consumption of a low calorie and a high calorie food.

    PubMed

    Privitera, Gregory J; Zuraikat, Faris M

    2014-05-01

    The objective of this study was to test if proximity of a food or preference for a food influences food intake in a competitive food environment in which one low calorie/low fat (apple slices) and one higher calorie/higher fat (buttered popcorn) food was available in the same environment. The proximity of popcorn and apple slices was manipulated and 56 participants were randomly assigned to groups. In Group Apples Near, apple slices were placed near (within arms reach) a participant and popcorn was placed far (2m away). In Group Popcorn Near, buttered popcorn was placed near and apple slices were placed far. As a control for the absence of a proximity manipulation, Group Both Near had both test foods placed near. Although participants rated the popcorn as more liked than apples, the food that was placed closer to the participant was consumed most in the two experimental groups, regardless of preference (R(2)=0.38). Total energy intake was reduced most when popcorn was placed far from a participant compared to when it was placed near (R(2)=0.24). The effects reported here were not moderated by BMI and did not vary by sex. In all, the results support the hypothesis that making a low calorie food more proximate will reduce total energy intake and increase intake of a low calorie food, even when a higher calorie and more preferred food is also available, but less proximate. PMID:24560689

  6. The Relative Age Effect in Spanish Female Soccer Players. Influence of the Competitive Level and a Playing Position.

    PubMed

    Sedano, Silvia; Vaeyens, Roel; Redondo, Juan Carlos

    2015-06-27

    The purposes of the study were to examine relative age effects (RAEs) in Spanish female soccer and to identify the influence of a playing position. The sample comprised all female players (n=4035) of five different competitive levels in the 2010-2013 seasons: First, Second and Third divisions (n=936, n=1711 and n=870, respectively), and National and Regional (n=232 and n=286, respectively) teams were included. Differences between the observed and expected birth-date distributions were tested based on data from the general Spanish population, using the chi-square statistic followed up by calculating odds ratios and 95% confidence intervals. Results revealed that the birth-date distributions of almost all groups of football players showed an overrepresentation of players born in the first quartile. Only in the lowest level was age distribution not significantly different from that of the general population. Moreover, the RAE risk progressively increased with a higher level of involvement. It was also observed that at some playing positions the birth-date distributions were significantly biased. That was the case for goalkeepers and defenders. It could be concluded that in the current structure of Spanish female soccer there is a relative age effect, probably due to the early processes of talent identification. PMID:26240656

  7. Loss aversion and 5HTT gene variants in adolescent anxiety.

    PubMed

    Ernst, Monique; Plate, Rista C; Carlisi, Christina O; Gorodetsky, Elena; Goldman, David; Pine, Daniel S

    2014-04-01

    Loss aversion, a well-documented behavioral phenomenon, characterizes decisions under risk in adult populations. As such, loss aversion may provide a reliable measure of risky behavior. Surprisingly, little is known about loss aversion in adolescents, a group who manifests risk-taking behavior, or in anxiety disorders, which are associated with risk-avoidance. Finally, loss aversion is expected to be modulated by genotype, particularly the serotonin transporter (SERT) gene variant, based on its role in anxiety and impulsivity. This genetic modulation may also differ between anxious and healthy adolescents, given their distinct propensities for risk taking. The present work examines the modulation of loss aversion, an index of risk-taking, and reaction-time to decision, an index of impulsivity, by the serotonin-transporter-gene-linked polymorphisms (5HTTLPR) in healthy and clinically anxious adolescents. Findings show that loss aversion (1) does manifest in adolescents, (2) does not differ between healthy and clinically anxious participants, and (3), when stratified by SERT genotype, identifies a subset of anxious adolescents who are high SERT-expressers, and show excessively low loss-aversion and high impulsivity. This last finding may serve as preliminary evidence for 5HTTLPR as a risk factor for the development of comorbid disorders associated with risk-taking and impulsivity in clinically anxious adolescents. PMID:24280015

  8. Acute stress affects risk taking but not ambiguity aversion

    PubMed Central

    Buckert, Magdalena; Schwieren, Christiane; Kudielka, Brigitte M.; Fiebach, Christian J.

    2014-01-01

    Economic decisions are often made in stressful situations (e.g., at the trading floor), but the effects of stress on economic decision making have not been systematically investigated so far. The present study examines how acute stress influences economic decision making under uncertainty (risk and ambiguity) using financially incentivized lotteries. We varied the domain of decision making as well as the expected value of the risky prospect. Importantly, no feedback was provided to investigate risk taking and ambiguity aversion independent from learning processes. In a sample of 75 healthy young participants, 55 of whom underwent a stress induction protocol (Trier Social Stress Test for Groups), we observed more risk seeking for gains. This effect was restricted to a subgroup of participants that showed a robust cortisol response to acute stress (n = 26). Gambling under ambiguity, in contrast to gambling under risk, was not influenced by the cortisol response to stress. These results show that acute psychosocial stress affects economic decision making under risk, independent of learning processes. Our results further point to the importance of cortisol as a mediator of this effect. PMID:24834024

  9. Conditioned aversion of aluminum sulfate in black ducks

    USGS Publications Warehouse

    Sparling, D.W.

    1990-01-01

    Three experiments were conducted to determine if reduced consumption of foods with elevated Al levels by black ducks (Anas rubripes) was due to taste aversion, conditioned taste aversion or malaise. Black ducks preferred a diet with 1,000 ppm Al over a control diet but ate less of a diet with 5,000 ppm Al. Prior experience with the high Al diet enhanced preference for the control diet. Changes in body weight and food consumption through time suggested that aversion to the high Al diet was a conditioned response to mild malaise.

  10. The Neural Foundations of Reaction and Action in Aversive Motivation.

    PubMed

    Campese, Vincent D; Sears, Robert M; Moscarello, Justin M; Diaz-Mataix, Lorenzo; Cain, Christopher K; LeDoux, Joseph E

    2016-01-01

    Much of the early research in aversive learning concerned motivation and reinforcement in avoidance conditioning and related paradigms. When the field transitioned toward the focus on Pavlovian threat conditioning in isolation, this paved the way for the clear understanding of the psychological principles and neural and molecular mechanisms responsible for this type of learning and memory that has unfolded over recent decades. Currently, avoidance conditioning is being revisited, and with what has been learned about associative aversive learning, rapid progress is being made. We review, below, the literature on the neural substrates critical for learning in instrumental active avoidance tasks and conditioned aversive motivation. PMID:26643998

  11. Conditioned food aversion to Ipomoea carnea var. fistulosa induced by Baccharis coridifolia in goats

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Baccharis coridifolia is a plant that induces strong conditioned food aversion in ruminants. This research aimed to induce a conditioned food aversion to Ipomoea carnea var. fistulosa in goats, using B. coridifolia as an aversive agent, and to compare the aversion induced by this plant with the aver...

  12. Rats taste-aversive learning with cyclosporine a is not affected by contextual changes.

    PubMed

    Tuerkmen, Akin; Bösche, Katharina; Lückemann, Laura; Engler, Harald; Schedlowski, Manfred; Hadamitzky, Martin

    2016-10-01

    In conditioned taste aversion (CTA) rats associate a novel taste (conditioned stimulus; CS) with a treatment (unconditioned stimulus; US) that induces symptoms of malaise. During retrieval, animals learn that the CS no longer predicts the US, with the consequence that the behavior elicited by the CS extinguishes. Importantly, CTA data with lithium chloride (LiCl) as US indicate that extinction learning is affected by changing the physical context. However, if this is also the case in different taste-aversion paradigms employing compounds other than LiCL as US is unknown. Against this background the present study investigated in a CTA paradigm with saccharin as CS and the immunosuppressant cyclosporine A (CsA) as US the influence of contextual changes on CTA extinction. Our results show, that extinction of a learned CS-US association with CsA is not prone to contextual changes. Due to the direct effects of CsA on CNS functioning, CTA with this immunosuppressant apparently operates under different mechanisms compared to other drugs, such as LiCl. These data indicate that taste aversive learning and its extinction are not necessarily specific to the context in which it is learned but also depends, at least in part, on the physiological and neuropharmacological effects of the drug employed as US. PMID:27316343

  13. Coordinating a Supply Chain with a Loss-Averse Retailer and Effort Dependent Demand

    PubMed Central

    Li, Liying

    2014-01-01

    This study investigates the channel coordination issue of a supply chain with a risk-neutral manufacturer and a loss-averse retailer facing stochastic demand that is sensitive to sales effort. Under the loss-averse newsvendor setting, a distribution-free gain/loss-sharing-and-buyback (GLB) contract has been shown to be able to coordinate the supply chain. However, we find that a GLB contract remains ineffective in managing the supply chain when retailer sales efforts influence the demand. To effectively coordinate the channel, we propose to combine a GLB contract with sales rebate and penalty (SRP) contract. In addition, we discover a special class of gain/loss contracts that can coordinate the supply chain and arbitrarily allocate the expected supply chain profit between the manufacturer and the retailer. We then analyze the effect of loss aversion on the retailer's decision-making behavior and supply chain performance. Finally, we perform a numerical study to illustrate the findings and gain additional insights. PMID:25197696

  14. Coordinating a supply chain with a loss-averse retailer and effort dependent demand.

    PubMed

    Li, Liying; Wang, Yong

    2014-01-01

    This study investigates the channel coordination issue of a supply chain with a risk-neutral manufacturer and a loss-averse retailer facing stochastic demand that is sensitive to sales effort. Under the loss-averse newsvendor setting, a distribution-free gain/loss-sharing-and-buyback (GLB) contract has been shown to be able to coordinate the supply chain. However, we find that a GLB contract remains ineffective in managing the supply chain when retailer sales efforts influence the demand. To effectively coordinate the channel, we propose to combine a GLB contract with sales rebate and penalty (SRP) contract. In addition, we discover a special class of gain/loss contracts that can coordinate the supply chain and arbitrarily allocate the expected supply chain profit between the manufacturer and the retailer. We then analyze the effect of loss aversion on the retailer's decision-making behavior and supply chain performance. Finally, we perform a numerical study to illustrate the findings and gain additional insights. PMID:25197696

  15. Loss-aversion or loss-attention: the impact of losses on cognitive performance.

    PubMed

    Yechiam, Eldad; Hochman, Guy

    2013-03-01

    Losses were found to improve cognitive performance, and this has been commonly explained by increased weighting of losses compared to gains (i.e., loss aversion). We examine whether effects of losses on performance could be modulated by two alternative processes: an attentional effect leading to increased sensitivity to task incentives; and a contrast-related effect. Empirical data from five studies show that losses improve performance even when the enhanced performance runs counter to the predictions of loss aversion. In Study 1-3 we show that in various settings, when an advantageous option produces large gains and small losses, participants select this alternative at a higher rate than when it does not produce losses. Consistent with the joint influence of attention and contrast-related processes, this effect is smaller when a disadvantageous alternative produces the losses. In Studies 4 and 5 we find a positive effect on performance even with no contrast effects (when a similar loss is added to all alternatives). These findings indicate that both attention and contrast-based processes are implicated in the effect of losses on performance, and that a positive effect of losses on performance is not tantamount to loss aversion. PMID:23334108

  16. Food Aversions and Cravings during Pregnancy on Yasawa Island, Fiji.

    PubMed

    McKerracher, Luseadra; Collard, Mark; Henrich, Joseph

    2016-09-01

    Women often experience novel food aversions and cravings during pregnancy. These appetite changes have been hypothesized to work alongside cultural strategies as adaptive responses to the challenges posed by pregnancy (e.g., maternal immune suppression). Here, we report a study that assessed whether data from an indigenous population in Fiji are consistent with the predictions of this hypothesis. We found that aversions focus predominantly on foods expected to exacerbate the challenges of pregnancy. Cravings focus on foods that provide calories and micronutrients while posing few threats to mothers and fetuses. We also found that women who experience aversions to specific foods are more likely to crave foods that meet nutritional needs similar to those provided by the aversive foods. These findings are in line with the predictions of the hypothesis. This adds further weight to the argument that appetite changes may function in parallel with cultural mechanisms to solve pregnancy challenges. PMID:27180176

  17. Asymmetric and frequency-dependent pollinator-mediated interactions may influence competitive displacement in two vernal pool plants.

    PubMed

    Runquist, Ryan Briscoe; Stanton, Maureen L

    2013-02-01

    A plant species immigrating into a community may experience a rarity disadvantage due to competition for the services of pollinators. These negative reproductive interactions have the potential to lead to competitive displacement or exclusion of a species from a site. In this study, we used one- and two-species arrays of potted plants to test for density and frequency dependence in pollinator-mediated and above-ground intraspecific and interspecific competition between two species of Limnanthes that have overlapping ranges, but rarely occur in close sympatry. There were asymmetric competitive effects; the species responded differently to their frequency within 16-plant replacement series arrays. Limnanthes douglasii rosea experienced stronger reductions in lifetime and per-flower fertility, likely due to pollinator-mediated competition with Limnanthes alba. This effect may be linked to asymmetrical competition through heterospecific pollen transfer. This study demonstrates that pollinator-mediated competition may discourage establishment of L. d. rosea in sites already occupied by its congener. PMID:23134452

  18. The Comparative Analysis of Aversive and Ordinary Noise.

    NASA Astrophysics Data System (ADS)

    Mobley, C. Marion, Jr.

    There is a vast amount of literature concerning the psychological and physiological effects of ordinary noise on the individual. However, few publications have addressed the analysis of aversive noise. This research analyzes three noises which produce the familiar goose flesh or chilling effect responsivity. These aversive sounds which are made by chalk squeaking on the chalkboard, fingernails on the chalkboard and rubbing styrofoam against a smooth surface are digitally compared to ordinary noise to show how these aversive sounds differ from sounds which are only annoying. This work, which uses Fast Fourier Transform (FFT) analysis is a combination with cross correlation analysis and other innovative methods to produce comparative data on noises, illustrates subtle differences between ordinary and aversive noise which may be useful for future work in acoustics or experimental psychology. The literature review shows disagreement among the numerous works on the effects of ordinary noise on human subjects. One explanation for this difference is the failure to adequately measure and define the dynamic nature of the noise used. The existing literature also establishes that a mixture of tones plus random noise is more annoying (but not aversive) than either the random noise or the tones alone. This investigation shows that one property of aversive noises is the combination of randomness plus tones which vary rapidly with time. This paper utilizes a new digital technique which improves the FFT analyzer resolution by a factor of 25. The resulting +/-2 Hz accuracy facilitated the presentation of frequency variation as a function of time data. Other computer generated graphical data includes the percent harmonic deviation as a function of time, the rate of change of fundamental frequency, and the rate of change in harmonic deviation. From these dynamic data, average values are calculated which show the aversive noise to be consistently greater in mean frequency deviation

  19. Results from two research projects concerning aversion responses including the blink reflex

    NASA Astrophysics Data System (ADS)

    Reidenbach, Hans-Dieter; Dollinger, Klaus; Hofmann, Joachim

    2005-04-01

    In order to examine the safety philosophy for laser classes 2 and 2M according to the international laser standard IEC 60825-1, which is based on the existence of aversion responses including the blink reflex, two research projects have been funded by the Federal Institute of Occupational Safety and Health (FIOSH) in Germany. In total, 2,250 volunteers have been investigated in the blink-reflex study in various test situations, where a collimated beam, a divergent beam, a scanned laser line or LED irradiation have been used as a bright optical stimulus. The various test situations included, for example, a free laser beam (like that used in the case of laser adjustment), an eye-tracking system, in which visual tasks have been performed, or LEDs used as single elements or in a cluster. 796 volunteers took part in the aversion response study. Concerning the blink reflex, the mean value of the frequency has been estimated to be 18.36 % within a range extending from 13.8 % up to 36.1 % depending on various parameters and applied optical sources. Their respective influences will be explained. Aversion responses, like head and eye movements, have been found to be relatively seldom events, since only 4.65 % of volunteers showed a reaction which belonged to this category of inherent, physiological, protection reactions. The different parameters which are mainly responsible for the respective results concerning the blink reflex and aversion responses will be dealt with and explained, as they have been experimentally achieved up to now.

  20. Imagery rescripting: Is incorporation of the most aversive scenes necessary?

    PubMed

    Dibbets, Pauline; Arntz, Arnoud

    2016-05-01

    During imagery rescripting (ImRs) an aversive memory is relived and transformed to have a more positive outcome. ImRs is frequently applied in psychological treatment and is known to reduce intrusions and distress of the memory. However, little is known about the necessity to incorporate the central aversive parts of the memory in ImRs. To examine this necessity one hundred participants watched an aversive film and were subsequently randomly assigned to one of four experimental conditions: ImRs including the aversive scenes (Late ImRs), ImRs without the aversive scenes (Early ImRs), imaginal exposure (IE) or a control condition (Cont). Participants in the IE intervention reported the highest distress levels during the intervention; Cont resulted in the lowest levels of self-reported distress. For the intrusion frequency, only the late ImRs resulted in fewer intrusions compared to the Cont condition; Early ImRs produced significantly more intrusions than the Late ImRs or IE condition. Finally, the intrusions of the Late ImRs condition were reported as less vivid compared to the other conditions. To conclude, it seems beneficial including aversive scenes in ImRs after an analogue trauma induction. PMID:26076101

  1. A Moist Crevice for Word Aversion: In Semantics Not Sounds

    PubMed Central

    Thibodeau, Paul H.

    2016-01-01

    Why do people self-report an aversion to words like “moist”? The present studies represent an initial scientific exploration into the phenomenon of word aversion by investigating its prevalence and cause. Results of five experiments indicate that about 10–20% of the population is averse to the word “moist.” This population often speculates that phonological properties of the word are the cause of their displeasure. However, data from the current studies point to semantic features of the word–namely, associations with disgusting bodily functions–as a more prominent source of peoples’ unpleasant experience. “Moist,” for averse participants, was notable for its valence and personal use, rather than imagery or arousal–a finding that was confirmed by an experiment designed to induce an aversion to the word. Analyses of individual difference measures suggest that word aversion is more prevalent among younger, more educated, and more neurotic people, and is more commonly reported by females than males. PMID:27119522

  2. Intrinsic competition and competitor-free-space influence the coexistence of parasitoids (Hymenoptera: Braconidae: Opiinae) of neotropical tephritidae (Diptera)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Endoparasitoid larvae may eliminate heterospecific competitors by physical or physiological means. The outcomes of these intrinsic competitions are often predictable with one species typically eliminating the other. The opiine braconids Doryctobracon areolatus (Szepligeti) and Utetes anastrephae (Vi...

  3. Recreational scuba divers' aversion to low-frequency underwater sound.

    PubMed

    Fothergill, D M; Sims, J R; Curley, M D

    2001-01-01

    Increasing use of active low-frequency sonar by submarines and ships raises the risk of accidental exposure of recreational divers to low-frequency underwater sound (LFS). This study aimed to characterize the subjective responses of recreational scuba divers to LFS to ascertain the extent to which LFS may impact their enjoyment, comfort, or time spent underwater. Seventeen male and nine female recreational scuba divers participated. Diving was conducted in an acoustically transparent tank located within a larger anechoic pool. Subjects wore scuba gear and were positioned I m below the surface in a prone position. The sound transducer was located 4 m directly below the diver's head. Sound exposures consisted of three signal types (pure tone, 30 Hz hyperbolic sweep up, and 30 Hz hyperbolic sweep down) each presented at six center frequencies from 100 to 500 Hz and six sound pressure levels(SPL) ranging from 130 to 157 dB re 1 microPa. The duration of each sound exposure was 7 s. Subjects responded via an underwater console to rate aversion to LFS on a category-ratio scale, and to indicate the presence or absence of vibration of any body part. Aversion to LFS and the percent incidence of vibration increased as the SPL increased. The percent incidence of vibration decreased linearly with increasing frequency. At the highest SPL the probability that an aversion rating would exceed Very Severe (7 on the category-ratio scale) was predicted to be 19%. There was no significant difference in aversion among signal types. The 100 Hz frequency was the most aversive frequency (P < 0.05). A plot of aversion vs. frequency showed a U-shaped function with minimum aversion at 250 Hz. In conclusion, diver aversion to LFS is dependent upon SPL and center frequency. The highest aversion rating was given for 100 Hz, this frequency corresponded with the greatest probability of detecting vibration. Factors other than vibration seem to account for aversion to the highest frequencies. Our

  4. Optimistic bias and pessimistic realism in judgments of contingency with aversive or rewarding outcomes.

    PubMed

    Sonoda, Akihito

    2002-10-01

    A depressive personality influences judgments of contingency. This is called "depressive realism." The present experiment examined whether optimistic traits, as measured by various scales, are correlated with judgments of contingency. The valences of the target stimuli were aversive or rewarding (noise avoidance or gaining points). Analysis indicated that the optimistic subjects (as measured by explanatory style for negative events) tend to overestimate noncontingent events; however, optimism measured by other scales did not show such an effect. The findings are discussed in terms of a self-defensive attributional bias. PMID:12416837

  5. Aversive Counterconditioning Attenuates Reward Signaling in the Ventral Striatum

    PubMed Central

    Kaag, Anne Marije; Schluter, Renée S.; Karel, Peter; Homberg, Judith; van den Brink, Wim; Reneman, Liesbeth; van Wingen, Guido A.

    2016-01-01

    Appetitive conditioning refers to the process of learning cue-reward associations and is mediated by the mesocorticolimbic system. Appetitive conditioned responses are difficult to extinguish, especially for highly salient reward such as food and drugs. We investigate whether aversive counterconditioning can alter reward reinstatement in the ventral striatum in healthy volunteers using functional magnetic resonance imaging (fMRI). In the initial conditioning phase, two different stimuli were reinforced with a monetary reward. In the subsequent counterconditioning phase, one of these stimuli was paired with an aversive shock to the wrist. In the following extinction phase, none of the stimuli were reinforced. In the final reinstatement phase, reward was reinstated by informing the participants that the monetary gain could be doubled. Our fMRI data revealed that reward signaling in the ventral striatum and ventral tegmental area following reinstatement was smaller for the stimulus that was counterconditioned with an electrical shock, compared to the non-counterconditioned stimulus. A functional connectivity analysis showed that aversive counterconditioning strengthened striatal connectivity with the hippocampus and insula. These results suggest that reward signaling in the ventral striatum can be attenuated through aversive counterconditioning, possibly by concurrent retrieval of the aversive association through enhanced connectivity with hippocampus and insula. PMID:27594829

  6. Aversive Counterconditioning Attenuates Reward Signaling in the Ventral Striatum.

    PubMed

    Kaag, Anne Marije; Schluter, Renée S; Karel, Peter; Homberg, Judith; van den Brink, Wim; Reneman, Liesbeth; van Wingen, Guido A

    2016-01-01

    Appetitive conditioning refers to the process of learning cue-reward associations and is mediated by the mesocorticolimbic system. Appetitive conditioned responses are difficult to extinguish, especially for highly salient reward such as food and drugs. We investigate whether aversive counterconditioning can alter reward reinstatement in the ventral striatum in healthy volunteers using functional magnetic resonance imaging (fMRI). In the initial conditioning phase, two different stimuli were reinforced with a monetary reward. In the subsequent counterconditioning phase, one of these stimuli was paired with an aversive shock to the wrist. In the following extinction phase, none of the stimuli were reinforced. In the final reinstatement phase, reward was reinstated by informing the participants that the monetary gain could be doubled. Our fMRI data revealed that reward signaling in the ventral striatum and ventral tegmental area following reinstatement was smaller for the stimulus that was counterconditioned with an electrical shock, compared to the non-counterconditioned stimulus. A functional connectivity analysis showed that aversive counterconditioning strengthened striatal connectivity with the hippocampus and insula. These results suggest that reward signaling in the ventral striatum can be attenuated through aversive counterconditioning, possibly by concurrent retrieval of the aversive association through enhanced connectivity with hippocampus and insula. PMID:27594829

  7. Differences in Risk Aversion between Young and Older Adults

    PubMed Central

    Albert, Steven M.; Duffy, John

    2013-01-01

    Research on decision-making strategies among younger and older adults suggests that older adults may be more risk averse than younger people in the case of potential losses. These results mostly come from experimental studies involving gambling paradigms. Since these paradigms involve substantial demands on memory and learning, differences in risk aversion or other features of decision-making attributed to age may in fact reflect age-related declines in cognitive abilities. In the current study, older and younger adults completed a simpler, paired lottery choice task used in the experimental economics literature to elicit risk aversion. A similar approach was used to elicit participants' discount rates. The older adult group was more risk averse than younger adults (p < .05) and also had a higher discount rate (15.6-21.0% vs. 10.3-15.5%, p < .01), indicating lower expected utility from future income. Risk aversion and implied discount rates were weakly correlated. It may be valuable to investigate developmental changes in neural correlates of decision-making across the lifespan. PMID:24319671

  8. The Influence of Athlete Sex, Context, and Performance on High School Basketball Coaches' Use of Regret Messages during Competition

    ERIC Educational Resources Information Center

    Turman, Paul D.

    2007-01-01

    This study examined video footage (i.e., pregame, halftime, and postgame) of high school basketball coaches' interactions with their male and female athletes during competition, focusing on coaches' use of various regret messages. Participants included 20 high school basketball coaches who were found to use a combination of regret messages:…

  9. Conditioned taste aversion, drugs of abuse and palatability

    PubMed Central

    Lin, Jian-You; Arthurs, Joe; Reilly, Steve

    2014-01-01

    LIN, J.-Y., J. Arthurs and S. Reilly. Conditioned taste aversion: Palatability and drugs of abuse. NEUROSCI BIOBEHAV REV XX(x) XXX-XXX, 2014. – We consider conditioned taste aversion to involve a learned reduction in the palatability of a taste (and hence in amount consumed) based on the association that develops when a taste experience is followed by gastrointestinal malaise. The present article evaluates the well-established finding that drugs of abuse, at doses that are otherwise considered rewarding and self-administered, cause intake suppression. Our recent work using lick pattern analysis shows that drugs of abuse also cause a palatability downshift and, therefore, support conditioned taste aversion learning. PMID:24813806

  10. The time course of the aversive conflict signal.

    PubMed

    Fritz, Julia; Dreisbach, Gesine

    2015-01-01

    The idea that conflicts are aversive signals recently has gained strong support by both physiological as well as psychological evidence. However, the time course of the aversive signal has not been subject to direct investigation. In the present study, participants had to judge the valence of neutral German words after being primed with conflict or non-conflict Stroop stimuli in three experiments with varying SOA (200 ms, 400 ms, 800 ms) and varying prime presentation time. Conflict priming effects (i.e., increased frequencies of negative judgments after conflict as compared to non-conflict primes) were found for SOAs of 200 ms and 400 ms, but absent (or even reversed) with a SOA of 800 ms. These results imply that the aversiveness of conflicts is evaluated automatically with short SOAs, but is actively counteracted with prolonged prime presentation. PMID:25270558

  11. Motion Sickness-Induced Food Aversions in the Squirrel Monkey

    NASA Technical Reports Server (NTRS)

    Roy, M. Aaron; Brizzee, Kenneth R.

    1979-01-01

    Conditioned aversions to colored, flavored water were established in Squirrel monkeys (Saimiri sciureus) by following consumption with 90 min of simultaneous rotational and vertical stimulation. The experimental group (N= 13) drank significantly less of the green, almond-flavored test solution than did the control group (N=14) during three post-treatment preference testing days. Individual differences were noted in that two experimental monkeys readily drank the test solution after rotational stimulation. Only two of the experimental monkeys showed emesis during rotation, yet 10 monkeys in this group developed an aversion. These results suggest that: (1) motion sickness can be readily induced in Squirrel monkeys with simultaneous rotational and vertical stimulation, and (2) that conditioned food aversions are achieved in the absence of emesis in this species.

  12. Gender Differences in Risk Aversion Among Chinese University Students.

    PubMed

    Lam, Desmond

    2015-12-01

    This paper examines gender differences in risk aversion among Chinese university students. Chinese females are proposed to be more risk averse and require a higher risk premium when faced with a gamble option in the gain-domain frame as compared to Chinese males. Two groups of 100 participants each (male = 100 and female = 100 in total) were recruited to fill up questionnaires that included items relating to objective probability lotteries. Within each group, it was found that Chinese males and females did not differ in their risk aversion. However, results show that Chinese males tend to react more readily to rising risk premium by taking up options with higher expected values when compared to Chinese females. Current findings will have useful implications to marketers (particularly, promoters of gambling products) and problem gambling counselors. PMID:25112219

  13. The influence of social evaluation on cerebral cortical activity and motor performance: a study of "Real-Life" competition.

    PubMed

    Hatfield, Bradley D; Costanzo, Michelle E; Goodman, Ronald N; Lo, Li-Chuan; Oh, Hyuk; Rietschel, Jeremy C; Saffer, Mark; Bradberry, Trent; Contreras-Vidal, Jose; Haufler, Amy

    2013-11-01

    Motor performance in a social evaluative environment was examined in participants (N = 19) who completed a pistol shooting task under both performance-alone (PA) and competitive (C) conditions. Electroencephalographic (EEG), autonomic, and psychoendocrine activity were recorded in addition to kinematic measures of the aiming behavior. State anxiety, heart rate, and cortisol were modestly elevated during C and accompanied by relative desynchrony of high-alpha power, increased cortico-cortical communication between motor and non-motor regions, and degradation of the fluency of aiming trajectory, but maintenance of performance outcome (i.e., score). The findings reveal that performance in a complex social-evaluative environment characterized by competition results in elevated cortical activity beyond that essentially required for motor performance that translated as less efficient motor behavior. PMID:23954302

  14. The influence of egocentrism and focalism on people's optimism in competitions: when what affects us equally affects me more.

    PubMed

    Windschitl, Paul D; Kruger, Justin; Simms, Ericka Nus

    2003-09-01

    Six experiments investigated people's optimism in competitions. The studies involved hypothetical and real competitions (course grades in Experiments 1 and 2, a trivia game in Experiments 3-5, and a poker game in Experiment 6) in which the presence of shared adversities and benefits (factors that would generally hinder or help the absolute performance of all competitors) was manipulated. Shared adversities tended to reduce people's subjective likelihoods of winning, whereas shared benefits tended to increase them. The findings suggest that when people judge their likelihood of winning, their assessments of their own strengths and weaknesses have greater impact than their assessments of their competitors' strengths and weaknesses. We identify egocentrism and focalism as two causes of the bias. The experiments revealed moderators of this bias, but also illustrated its robust nature across a variety of conditions. PMID:14498778

  15. Loss Aversion and Time-Differentiated Electricity Pricing

    SciTech Connect

    Spurlock, C. Anna

    2015-06-01

    I develop a model of loss aversion over electricity expenditure, from which I derive testable predictions for household electricity consumption while on combination time-of-use (TOU) and critical peak pricing (CPP) plans. Testing these predictions results in evidence consistent with loss aversion: (1) spillover effects - positive expenditure shocks resulted in significantly more peak consumption reduction for several weeks thereafter; and (2) clustering - disproportionate probability of consuming such that expenditure would be equal between the TOUCPP or standard flat-rate pricing structures. This behavior is inconsistent with a purely neoclassical utility model, and has important implications for application of time-differentiated electricity pricing.

  16. Sex differences in the effects of ethanol pre-exposure during adolescence on ethanol-induced conditioned taste aversion in adult rats

    PubMed Central

    Sherrill, Luke K.; Berthold, Claire; Koss, Wendy A.; Juraska, Janice M.; Gulley, Joshua M.

    2011-01-01

    Alcohol use, which typically begins during adolescence and differs between males and females, is influenced by both the rewarding and aversive properties of the drug. One way adolescent alcohol use may modulate later consumption is by reducing alcohol s aversive properties. Here, we used a conditioned taste aversion (CTA) paradigm to determine if pre-exposure to alcohol (ethanol) during adolescence would attenuate ethanol-induced CTA assessed in adulthood in a sex-dependent manner. Male and female Long-Evans rats were given intraperitoneal (i.p.) injections of saline or 3.0 g/kg ethanol in a binge-like pattern during postnatal days (PD) 35–45. In adulthood (> PD 100), rats were given access to 0.1% saccharin, followed by saline or ethanol (1.0 or 1.5 g/kg, i.p.), over four conditioning sessions. We found sex differences in ethanol-induced CTA, with males developing a more robust aversion earlier in conditioning. Sex differences in the effects of pre-exposure were also evident: males, but not females, showed an attenuated CTA in adulthood following ethanol pre-exposure, which occurred approximately nine weeks earlier. Taken together, these findings indicate that males are more sensitive to the aversive properties of ethanol than females. In addition, the ability of pre-exposure to the ethanol US to attenuate CTA is enhanced in males compared to females. PMID:21767576

  17. Sex differences in the effects of ethanol pre-exposure during adolescence on ethanol-induced conditioned taste aversion in adult rats.

    PubMed

    Sherrill, Luke K; Berthold, Claire; Koss, Wendy A; Juraska, Janice M; Gulley, Joshua M

    2011-11-20

    Alcohol use, which typically begins during adolescence and differs between males and females, is influenced by both the rewarding and aversive properties of the drug. One way adolescent alcohol use may modulate later consumption is by reducing alcohol's aversive properties. Here, we used a conditioned taste aversion (CTA) paradigm to determine if pre-exposure to alcohol (ethanol) during adolescence would attenuate ethanol-induced CTA assessed in adulthood in a sex-dependent manner. Male and female Long-Evans rats were given intraperitoneal (i.p.) injections of saline or 3.0g/kg ethanol in a binge-like pattern during postnatal days (PD) 35-45. In adulthood (>PD 100), rats were given access to 0.1% saccharin, followed by saline or ethanol (1.0 or 1.5g/kg, i.p.), over four conditioning sessions. We found sex differences in ethanol-induced CTA, with males developing a more robust aversion earlier in conditioning. Sex differences in the effects of pre-exposure were also evident: males, but not females, showed an attenuated CTA in adulthood following ethanol pre-exposure, which occurred approximately nine weeks earlier. Taken together, these findings indicate that males are more sensitive to the aversive properties of ethanol than females. In addition, the ability of pre-exposure to the ethanol US to attenuate CTA is enhanced in males compared to females. PMID:21767576

  18. A Survey Data Response to the Teaching of Utility Curves and Risk Aversion

    ERIC Educational Resources Information Center

    Hobbs, Jeffrey; Sharma, Vivek

    2011-01-01

    In many finance and economics courses as well as in practice, the concept of risk aversion is reduced to the standard deviation of returns, whereby risk-averse investors prefer to minimize their portfolios' standard deviations. In reality, the concept of risk aversion is richer and more interesting than this, and can easily be conveyed through…

  19. Onset and Offset of Aversive Events Establish Distinct Memories Requiring Fear and Reward Networks

    ERIC Educational Resources Information Center

    Andreatta, Marta; Fendt, Markus; Muhlberger, Andreas; Wieser, Matthias J.; Imobersteg, Stefan; Yarali, Ayse; Gerber, Bertram; Pauli, Paul

    2012-01-01

    Two things are worth remembering about an aversive event: What made it happen? What made it cease? If a stimulus precedes an aversive event, it becomes a signal for threat and will later elicit behavior indicating conditioned fear. However, if the stimulus is presented upon cessation of the aversive event, it elicits behavior indicating…

  20. The Use of "Mild" Aversive Stimuli for Control of Stereotypic and Self-Injurious Behaviors.

    ERIC Educational Resources Information Center

    Alberto, Paul A.

    The use of mild aversives to control self-injurious and stereotypic behaviors of severely emotionally disturbed children is considered. Research is reviewed on the ethics and effectiveness of aversive stimuli. Mild aversives include a form of nonseclusionary timeout known as facial screening, the administration of certain irritating substances…

  1. Competition during the milk-feeding stage influences the development of feeding behavior of pair-housed dairy calves.

    PubMed

    Miller-Cushon, E K; Bergeron, R; Leslie, K E; Mason, G J; DeVries, T J

    2014-10-01

    This study investigated how the feeding behavior of pair-housed calves develops in response to reduced teat and feed place availability. Twenty Holstein bull calves were pair housed and provided with milk replacer (MR) and grain concentrate ad libitum via either (1) 1 teat and feed bucket/pen, such that calves could not feed simultaneously [competitive feeding (CF)] or (2) 2 teats and feed buckets/pen [noncompetitive feeding (NCF)]. The calves were weaned during wk 7 of life by incrementally diluting the MR. Postweaning, all pens were managed identically and offered a complete pelleted diet ad libitum via 2 feed buckets/pen (NCF) in period 1 (wk 8 and 9) and period 3 (wk 12 and 13) and exposed to a competitive challenge with CF in period 2 (wk 10 and 11). Feeding times and competitive interactions were recorded from video for 3 d/wk in wk 2, 4, and 6 and 2 d/wk in wk 8 to 13. Meal criteria were used to calculate daily meal frequency, meal time, and synchronized meal time (the percentage of meal time when calves within the pen were engaged in simultaneous meals). Milk replacer intake was subject to a treatment × week interaction, with calves in CF pens having lower MR intake (wk 2: 8.3 vs. 10.0 L/calf per day for CF vs. NCF), but compensating by increasing intake to a greater extent over time (wk 4-5: 13.3 vs. 11.7 L/d for CF vs. NCF). Corresponding to MR intake, meal frequencies and feeding times evolved differently over this period, increasing in CF pens and decreasing in NCF pens (wk 2: 5.8 vs. 11.1 and wk 4-6: 6.2 vs. 5.1 meals/d for CF vs. NCF). Calves in CF pens also spent less time engaged in synchronized meals (28 vs. 51% of meal time; standard error=7.1) and displaced each other 5 times more frequently during synchronized eating. Postweaning, calves in previously CF pens maintained 5 times greater displacement frequencies and had fewer overlapping meals than calves in previously NCF pens (34.5 vs. 40.7% of meals, respectively). Postweaning, when calves

  2. Effect Size Estimates in Chemical Aversion Treatments of Alcoholism.

    ERIC Educational Resources Information Center

    Thurber, Steven

    1985-01-01

    Reports that aggregate studies on alcohol aversion therapy tended to support a moderate level of treatment impact that may have noteworthy practical import. Emetics appeared to generate fairly consistent findings; a paralysis-inducing chemical may produce variable results. (Author/NRB)

  3. Conditioning food aversions to Ipomoea carnea in sheep

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ipomoea carnea is a toxic plant in Brazil that often poisons sheep. Conditioned food aversion may be a tool to reduce intoxication problems in grazing sheep. Fifteen sheep were adapted to consume I. carnea for 36 days. Subsequently sheep were randomly divided into three groups of five sheep each. ...

  4. Gaze Aversion during Children's Transient Knowledge and Learning

    ERIC Educational Resources Information Center

    Doherty-Sneddon, Gwyneth; Phelps, Fiona G.; Calderwood, Lesley

    2009-01-01

    Looking away from an interlocutor's face during demanding cognitive activity can help adults and children answer challenging mental arithmetic and verbal-reasoning questions (Glenberg, Schroeder, & Robertson, 1998; Phelps, Doherty-Sneddon, & Warnock, 2006). While such "gaze aversion" (GA) is used far less by 5-year-old school children, its use…

  5. Loss Aversion and Inhibition in Dynamical Models of Multialternative Choice

    ERIC Educational Resources Information Center

    Usher, Marius; McClelland, James L.

    2004-01-01

    The roles of loss aversion and inhibition among alternatives are examined in models of the similarity, compromise, and attraction effects that arise in choices among 3 alternatives differing on 2 attributes. R. M. Roe, J. R. Busemeyer, and J. T. Townsend (2001) have proposed a linear model in which effects previously attributed to loss aversion…

  6. A Classroom Demonstration of Taste-Aversion Learning.

    ERIC Educational Resources Information Center

    Best, Michael R.; Batsell, Jr., W. Robert

    1998-01-01

    Describes a demonstration that recreates the central features of taste aversion (learning to avoid distinctively flavored food or drink paired with gastrointestinal illness) research. Rats are allowed to drink a saccharine flavored solution and then are given an injection of sodium chloride. They associate the unpleasant effects with the solution.…

  7. ABA, AAB and ABC Renewal in Taste Aversion Learning

    ERIC Educational Resources Information Center

    Bernal-Gamboa, Rodolfo; Juarez, Yectivani; Gonzalez-Martin, Gabriela; Carranza, Rodrigo; Sanchez-Carrasco, Livia; Nieto, Javier

    2012-01-01

    Context renewal is identified when the conditioned response (CR) elicited by an extinguished conditioned stimulus (CS) reappears as a result of changing the contextual cues during the test. Two experiments were designed for testing contextual renewal in a conditioned taste aversion preparation. Experiment 1 assessed ABA and AAB context renewal,…

  8. Overcoming Learning Aversion in Evaluating and Managing Uncertain Risks.

    PubMed

    Cox, Louis Anthony Tony

    2015-10-01

    Decision biases can distort cost-benefit evaluations of uncertain risks, leading to risk management policy decisions with predictably high retrospective regret. We argue that well-documented decision biases encourage learning aversion, or predictably suboptimal learning and premature decision making in the face of high uncertainty about the costs, risks, and benefits of proposed changes. Biases such as narrow framing, overconfidence, confirmation bias, optimism bias, ambiguity aversion, and hyperbolic discounting of the immediate costs and delayed benefits of learning, contribute to deficient individual and group learning, avoidance of information seeking, underestimation of the value of further information, and hence needlessly inaccurate risk-cost-benefit estimates and suboptimal risk management decisions. In practice, such biases can create predictable regret in selection of potential risk-reducing regulations. Low-regret learning strategies based on computational reinforcement learning models can potentially overcome some of these suboptimal decision processes by replacing aversion to uncertain probabilities with actions calculated to balance exploration (deliberate experimentation and uncertainty reduction) and exploitation (taking actions to maximize the sum of expected immediate reward, expected discounted future reward, and value of information). We discuss the proposed framework for understanding and overcoming learning aversion and for implementing low-regret learning strategies using regulation of air pollutants with uncertain health effects as an example. PMID:26491992

  9. Transfer of Aversive Respondent Elicitation in Accordance with Equivalence Relations

    ERIC Educational Resources Information Center

    Valverde, Miguel Rodriguez; Luciano, Carmen; Barnes-Holmes, Dermot

    2009-01-01

    The present study investigates the transfer of aversively conditioned respondent elicitation through equivalence classes, using skin conductance as the measure of conditioning. The first experiment is an attempt to replicate Experiment 1 in Dougher, Augustson, Markham, Greenway, and Wulfert (1994), with different temporal parameters in the…

  10. Absolute Risk Aversion and the Returns to Education.

    ERIC Educational Resources Information Center

    Brunello, Giorgio

    2002-01-01

    Uses 1995 Italian household income and wealth survey to measure individual absolute risk aversion of 1,583 married Italian male household heads. Uses this measure as an instrument for attained education in a standard-log earnings equation. Finds that the IV estimate of the marginal return to schooling is much higher than the ordinary least squares…

  11. The Path to Aversive Interventions: Four Mothers' Perceptions

    ERIC Educational Resources Information Center

    Brown, Fredda; Traniello, Dina A.

    2010-01-01

    An interview was conducted with each of four mothers to gain an understanding of their perceptions of the educational and behavioral history of their children leading up to placement in a residential facility that used aversive interventions, including contingent electric skin shock. Semistructured instruments were used to understand each family's…

  12. Context Dependency of Conditioned Aversions to Familiar and Novel Fluids

    ERIC Educational Resources Information Center

    Ishii, Kiyoshi; Iguchi, Yoshio; Sawa, Kosuke

    2006-01-01

    Using a context discrimination procedure and rats as the subjects, the formation of context-dependent aversions to novel and familiar fluids was investigated. Experiment 1 revealed that context dependency could be established to a novel fluid (saccharin) after three cycles of context discrimination training and that the acquired context dependency…

  13. Conditioning food aversions to Ipomoea carnea var. Fistulosa in sheep

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ipomoea carnea is a toxic plant in Brazil that often poisons sheep. Conditioned food aversion may be a tool to reduce intoxication problems in grazing sheep. Fifteen sheep were adapted to consume I. carnea for 36 days. Subsequently sheep were randomly divided into three groups of five sheep each. ...

  14. Assessment of the aversion coefficient in nuclear safety in Hungary.

    PubMed

    Eged, Katalin; Kanyár, Béla; Kis, Zoltán; Tatay, Tibor

    2002-06-01

    The key elements of the optimization practice as applied to radiation protection are the monetary value of the averted person-sievert and the aversion coefficient. Determination of the monetary value of the unit averted person-sievert (as alpha(base)-parameter) in Hungary was presented in a previous paper. The estimation of this parameter was carried out by the willingness-to-pay (WTP) method associated with averted occupational exposure (at the NPP Paks/Hungary). The aversion coefficient predicts the importance of dose reduction based on the magnitude of the dose. The assessment of the aversion coefficient occurred also by means of the WTP method in the spring of 2000. Its value has been estimated on the basis of individual preferences concerning the distribution of individual exposure in nuclear safety. The results achieved by the WTP among the radiation specialists from the NPP Paks, Hungary, assessed a value for the aversion coefficient of 1.86 over the whole range of individual exposure levels. This value is a bit greater than the value obtained in France (1.7) and the higher coefficient expresses a higher priority to reduce the highest individual exposures. PMID:12046754

  15. Competitive Intelligence.

    ERIC Educational Resources Information Center

    Bergeron, Pierrette; Hiller, Christine A.

    2002-01-01

    Reviews the evolution of competitive intelligence since 1994, including terminology and definitions and analytical techniques. Addresses the issue of ethics; explores how information technology supports the competitive intelligence process; and discusses education and training opportunities for competitive intelligence, including core competencies…

  16. Competition, Competitive Repulsion, and Coexistence

    PubMed Central

    Darlington, P. J.

    1972-01-01

    This manuscript is concerned with concepts rather than abstruse details or mathematics. Discussed are: competition; extended competition, proposed for competition in the strict sense, extended and modified by all related interactions including predation, parasitism, disease, and even cooperation, all of which can be “weapons of competition”; competitive repulsion, proposed for the sum of forces that determine spacings, including ecologic spacings, of individuals and populations; Darwin (biotic) equilibriums; competitive extinction, Gause's principle, limited and limiting resources, and single-resource competition; de facto coexistence of competing species, exemplified by green plants competing for sunlight; niche competition; the two concepts of competitive exclusion; devision of resources and of their utilizers; cause and effect in real situations; and niches, niche overlap, and coexistence. Stressed is the complexity of the real world, and the confusion that can and does arise from modeling it too simply. PMID:4508308

  17. Variation in the Williams syndrome GTF2I gene and anxiety proneness interactively affect prefrontal cortical response to aversive stimuli.

    PubMed

    Jabbi, M; Chen, Q; Turner, N; Kohn, P; White, M; Kippenhan, J S; Dickinson, D; Kolachana, B; Mattay, V; Weinberger, D R; Berman, K F

    2015-01-01

    Characterizing the molecular mechanisms underlying the heritability of complex behavioral traits such as human anxiety remains a challenging endeavor for behavioral neuroscience. Copy-number variation (CNV) in the general transcription factor gene, GTF2I, located in the 7q11.23 chromosomal region that is hemideleted in Williams syndrome and duplicated in the 7q11.23 duplication syndrome (Dup7), is associated with gene-dose-dependent anxiety in mouse models and in both Williams syndrome and Dup7. Because of this recent preclinical and clinical identification of a genetic influence on anxiety, we examined whether sequence variation in GTF2I, specifically the single-nucleotide polymorphism rs2527367, interacts with trait and state anxiety to collectively impact neural response to anxiety-laden social stimuli. Two hundred and sixty healthy adults completed the Tridimensional Personality Questionnaire Harm Avoidance (HA) subscale, a trait measure of anxiety proneness, and underwent functional magnetic resonance imaging (fMRI) while matching aversive (fearful or angry) facial identity. We found an interaction between GTF2I allelic variations and HA that affects brain response: in individuals homozygous for the major allele, there was no correlation between HA and whole-brain response to aversive cues, whereas in heterozygotes and individuals homozygous for the minor allele, there was a positive correlation between HA sub-scores and a selective dorsolateral prefrontal cortex (DLPFC) responsivity during the processing of aversive stimuli. These results demonstrate that sequence variation in the GTF2I gene influences the relationship between trait anxiety and brain response to aversive social cues in healthy individuals, supporting a role for this neurogenetic mechanism in anxiety. PMID:26285132

  18. Variation in the Williams syndrome GTF2I gene and anxiety proneness interactively affect prefrontal cortical response to aversive stimuli

    PubMed Central

    Jabbi, M; Chen, Q; Turner, N; Kohn, P; White, M; Kippenhan, J S; Dickinson, D; Kolachana, B; Mattay, V; Weinberger, D R; Berman, K F

    2015-01-01

    Characterizing the molecular mechanisms underlying the heritability of complex behavioral traits such as human anxiety remains a challenging endeavor for behavioral neuroscience. Copy-number variation (CNV) in the general transcription factor gene, GTF2I, located in the 7q11.23 chromosomal region that is hemideleted in Williams syndrome and duplicated in the 7q11.23 duplication syndrome (Dup7), is associated with gene-dose-dependent anxiety in mouse models and in both Williams syndrome and Dup7. Because of this recent preclinical and clinical identification of a genetic influence on anxiety, we examined whether sequence variation in GTF2I, specifically the single-nucleotide polymorphism rs2527367, interacts with trait and state anxiety to collectively impact neural response to anxiety-laden social stimuli. Two hundred and sixty healthy adults completed the Tridimensional Personality Questionnaire Harm Avoidance (HA) subscale, a trait measure of anxiety proneness, and underwent functional magnetic resonance imaging (fMRI) while matching aversive (fearful or angry) facial identity. We found an interaction between GTF2I allelic variations and HA that affects brain response: in individuals homozygous for the major allele, there was no correlation between HA and whole-brain response to aversive cues, whereas in heterozygotes and individuals homozygous for the minor allele, there was a positive correlation between HA sub-scores and a selective dorsolateral prefrontal cortex (DLPFC) responsivity during the processing of aversive stimuli. These results demonstrate that sequence variation in the GTF2I gene influences the relationship between trait anxiety and brain response to aversive social cues in healthy individuals, supporting a role for this neurogenetic mechanism in anxiety. PMID:26285132

  19. Interactions between radiation and amphetamine in taste-aversion learning and the role of the area postrema in amphetamine-induced conditioned taste aversions

    SciTech Connect

    Rabin, B.M.; Hunt, W.A.; Lee, J.

    1987-01-01

    Three experiments were run to assess the role of the area postrema in taste-aversion learning resulting from combined treatment with subthreshold unconditioned stimuli and in the acquisition of an amphetamine-induced taste aversion. In the first experiment, it was shown that combined treatment with subthreshold radiation (15 rad) and subthreshold amphetamine (0.5 mg/kg, IP) resulted in the acquisition of a taste aversion. The second experiment showed that lesions of the area postrema blocked taste aversion learning produced by two subthreshold doses of amphetamine. In the third experiment, which looked at the dose-response curve for amphetamine-induced taste aversion learning to intact rats and rats with area postrema lesions, it was shown that both groups of rats acquired taste aversions following injection of amphetamine, although the rats with lesions showed a less-severe aversion than the intact rats. The results are interpreted as indicating that amphetamine-induced taste-aversion learning may involve area post-remamediated mechanisms, particularly at the lower doses, but an intact area postrema is not a necessary condition of the acquisition of an amphetamine-induced taste aversion.

  20. Competitive testing of health behavior theories: how do benefits, barriers, subjective norm, and intention influence mammography behavior?

    PubMed Central

    Murphy, Caitlin C.; Vernon, Sally W.; Diamond, Pamela M.; Tiro, Jasmin A.

    2013-01-01

    Background Competitive hypothesis testing may explain differences in predictive power across multiple health behavior theories. Purpose We tested competing hypotheses of the Health Belief Model (HBM) and Theory of Reasoned Action (TRA) to quantify pathways linking subjective norm, benefits, barriers, intention, and mammography behavior. Methods We analyzed longitudinal surveys of women veterans randomized to the control group of a mammography intervention trial (n=704). We compared direct, partial mediation, and full mediation models with Satorra-Bentler χ2 difference testing. Results Barriers had a direct and indirect negative effect on mammography behavior; intention only partially mediated barriers. Benefits had little to no effect on behavior and intention; however, it was negatively correlated with barriers. Subjective norm directly affected behavior and indirectly affected intention through barriers. Conclusions Our results provide empiric support for different assertions of HBM and TRA. Future interventions should test whether building subjective norm and reducing negative attitudes increases regular mammography. PMID:23868613

  1. The influence of nitrogen deposition, competition and desiccation on growth and regeneration of Racomitrium lanuginosum (Hedw.) brid.

    PubMed

    Jones, M L M; Oxley, E R B; Ashenden, T W

    2002-01-01

    Racomitrium lanuginosum shoot growth was studied under the combined effects of N deposition (0, 20, 40 and 60 kg N ha(-1) year(-1)). competition with Festuca ovina, and a drought pre-treatment. Moss regeneration from shoot fragments was also investigated. Growth was initially stimulated at the 60 kg N level. However, after 6 months, growth was lower in all N treatments than in the 0 kg N control. Reductions in shoot growth first became apparent in the pre-desiccated moss, while moss shoots grew longer when surrounded by a F. ovina canopy. Optimum regeneration occurred at 20-40 kg N on bare soil, and at 0-20 kg N under a F. ovina canopy. These results suggest that current N deposition in upland Wales is already detrimental to growth of this species, and to regeneration under certain conditions. This species may be affected under predicted climatic scenarios of increased summer drought in Britain. PMID:12395851

  2. Genetically-based trade-offs in response to stoichiometric food quality influence competition in a keystone aquatic herbivore.

    PubMed

    Jeyasingh, Punidan D; Weider, Lawrence J; Sterner, Robert W

    2009-11-01

    The genetic basis of organism response to stoichiometric mismatches between environmental availability and somatic demand is still poorly understood. This study reports a consistent genotype x environment interaction related to phosphorus : carbon availability to Daphnia. In multiple pairs of Daphnia pulicaria clones, genetic variation at the phosphoglucose isomerase (Pgi) locus indicated that Pgi-heterozygotes out competed Pgi-homozygotes under high P : C conditions, whereas the opposite outcome was observed under low P : C conditions. Estimates of phosphorus use efficiency indicated that homozygotes were significantly more efficient. However, homozygotes were comparatively less homeostatic. We hypothesize that lower specific activity of Pgi from homozygotes, which results in lowered energetic efficiency during the second glycolytic step, may underlie the competitive advantage enjoyed by homozygotes under low P : C (i.e. excess C) conditions. Our results show that analysing stoichiometric mismatches between diet and consumer should advance our quest for a fundamental understanding of the mechanisms driving genotype-environment interactions. PMID:19719840

  3. The influence of competition between plant functional types in the Canadian Terrestrial Ecosystem Model (CTEM) v. 2.0

    NASA Astrophysics Data System (ADS)

    Melton, Joe; Arora, Vivek

    2015-04-01

    The Canadian Terrestrial Ecosystem Model (CTEM) is the interactive vegetation component in the earth system modelling framework of the Canadian Centre for Climate Modelling and Analysis (CCCma). In its current framework, CTEM uses prescribed fractional coverage of plant functional types (PFTs) in each grid cell. In reality, vegetation cover is continually adjusting to changes in climate, atmospheric composition, and anthropogenic forcing, for example, through human-caused fires and CO2 fertilization. These changes in vegetation spatial patterns occur over timescales of years to centuries as tree migration is a slow process and vegetation distributions inherently have inertia. Here, we present version 2.0 of CTEM that includes a representation of competition between PFTs through a modified version of the Lotka-Volterra (L-V) predator-prey equations. The simulated areal extents of CTEM's seven non-crop PFTs are compared with available observation-based estimates, and simulations using unmodified L-V equations (similar to other models like TRIFFID), to demonstrate that the model is able to represent the broad spatial distributions of its seven PFTs at the global scale. Differences remain, however, since representing the multitude of plant species with just seven non-crop PFTs only allows the large scale climatic controls on the distributions of PFTs to be captured. As expected, PFTs that exist in climate niches are difficult to represent either due to the coarse spatial resolution of the model and the corresponding driving climate or the limited number of PFTs used to model the terrestrial ecosystem processes. The geographic and zonal distributions of primary terrestrial carbon pools and fluxes from the versions of CTEM that use prescribed and dynamically simulated fractional coverage of PFTs compare reasonably with each other and observation-based estimates. These results illustrate that the parametrization of competition between PFTs in CTEM behaves in a reasonably

  4. Age differences in conditioned place preferences and taste aversions to nicotine.

    PubMed

    Dannenhoffer, Carol A; Spear, Linda P

    2016-07-01

    Adolescents and adults differ in their behavioral sensitivities to drugs of abuse, including nicotine. Studies have shown that both rewarding and aversive properties of drugs of abuse can exist concomitantly. The present study investigated the ontogeny of these opposing qualities across a range of doses using a combined conditioned taste aversion and place preference paradigm in pair-housed rats that were not deprived of food or water. Results indicated that adolescents were more sensitive to the rewarding properties of nicotine than adults. In contrast, although all doses produced a taste aversion at both ages in the same rats, the aversion was weaker at lower than high doses in adolescents whereas adults showed strong aversion at all doses, suggesting modest attenuation in nicotine's aversive properties among adolescents relative to adults. Thus, attenuated aversive and accented appetitive sensitivities of adolescents to nicotine can be experienced simultaneously in the same animals. © 2016 Wiley Periodicals, Inc. Dev Psychobiol 58: 660-666, 2016. PMID:27027859

  5. Viral competition and maternal immunity influence the clinical disease caused by very virulent infectious bursal disease virus.

    PubMed

    Jackwood, Daral J

    2011-09-01

    The very virulent form of infectious bursal disease virus (vvIBDV) causes an immunosuppressive disease that is further characterized by the rapid onset of morbidity and high mortality in susceptible chickens. In 2009, vvIBDV was first reported in California, U. S. A., and since that time only a few cases of acute infectious bursal disease attributed to vvIBDV have been recognized in California. In other countries where vvIBDV has become established, it rapidly spreads to most poultry-producing regions. Two factors that may be involved in limiting the spread or reducing the severity of the clinical disease caused by vvIBDV in the U. S. A. are maternal immunity and competition with endemic variant strains of the virus. In this study, the ability of vvIBDV to infect and cause disease in maternally immune layer chickens was examined at weekly intervals over a 5-wk period during which their neutralizing maternal antibodies waned. Birds inoculated with vvIBDV at 2, 3, and 4 wk of age seemed healthy throughout the duration of the experiment, but macroscopic and microscopic lesions were observed in their bursa tissues. A real-time reverse transcriptase-polymerase chain reaction (RT-PCR) assay also confirmed the presence of vvIBDV RNA in their bursa tissues, indicating this virus was infecting the birds even at 2 wk of age when neutralizing maternal antibodies to infectious bursal disease virus were still relatively high (> 2000 geometric mean antibody titer). No mortality was observed in any birds when inoculated at 2, 3, or 4 wk of age; however, inoculation at 5 and 6 wk of age resulted in 10% and 20% mortality, respectively. Three experiments on the competition between vvIBDV and the two variant viruses T1 and FF6 were conducted. In all three experiments, specific-pathogen-free (SPF) birds that were inoculated with only the vvIBDV became acutely moribund, and except for Experiment 1 (62% mortality) all succumbed to the infection within 4 days of being exposed. When the

  6. Eliciting and Measuring Betrayal Aversion using the BDM Mechanism*

    PubMed Central

    Quercia, Simone

    2016-01-01

    Betrayal aversion has been operationalized as the evidence that subjects demand a higher risk premium to take social risks compared to natural risks. This evidence has been first shown by Bohnet and Zeckhauser (2004) using an adaptation of the Becker – DeGroot – Marschak mechanism (BDM, Becker et al. (1964)). We compare their implementation of the BDM mechanism with a new version designed to facilitate subjects’ comprehension. We find that, although the two versions produce different distributions of values, the size of betrayal aversion, measured as an average treatment difference between social and natural risk settings, is not different across the two versions. We further show that our implementation is preferable to use in practice as it reduces substantially subjects’ mistakes and the likelihood of noisy valuations. PMID:27366658

  7. Competitive fitness during feast and famine: how SOS DNA polymerases influence physiology and evolution in Escherichia coli.

    PubMed

    Corzett, Christopher H; Goodman, Myron F; Finkel, Steven E

    2013-06-01

    Escherichia coli DNA polymerases (Pol) II, IV, and V serve dual roles by facilitating efficient translesion DNA synthesis while simultaneously introducing genetic variation that can promote adaptive evolution. Here we show that these alternative polymerases are induced as cells transition from exponential to long-term stationary-phase growth in the absence of induction of the SOS regulon by external agents that damage DNA. By monitoring the relative fitness of isogenic mutant strains expressing only one alternative polymerase over time, spanning hours to weeks, we establish distinct growth phase-dependent hierarchies of polymerase mutant strain competitiveness. Pol II confers a significant physiological advantage by facilitating efficient replication and creating genetic diversity during periods of rapid growth. Pol IV and Pol V make the largest contributions to evolutionary fitness during long-term stationary phase. Consistent with their roles providing both a physiological and an adaptive advantage during stationary phase, the expression patterns of all three SOS polymerases change during the transition from log phase to long-term stationary phase. Compared to the alternative polymerases, Pol III transcription dominates during mid-exponential phase; however, its abundance decreases to <20% during long-term stationary phase. Pol IV transcription dominates as cells transition out of exponential phase into stationary phase and a burst of Pol V transcription is observed as cells transition from death phase to long-term stationary phase. These changes in alternative DNA polymerase transcription occur in the absence of SOS induction by exogenous agents and indicate that cell populations require appropriate expression of all three alternative DNA polymerases during exponential, stationary, and long-term stationary phases to attain optimal fitness and undergo adaptive evolution. PMID:23589461

  8. Are ambiguity aversion and ambiguity intolerance identical? A neuroeconomics investigation

    PubMed Central

    Tanaka, Yusuke; Fujino, Junya; Ideno, Takashi; Okubo, Shigetaka; Takemura, Kazuhisa; Miyata, Jun; Kawada, Ryosaku; Fujimoto, Shinsuke; Kubota, Manabu; Sasamoto, Akihiko; Hirose, Kimito; Takeuchi, Hideaki; Fukuyama, Hidenao; Murai, Toshiya; Takahashi, Hidehiko

    2015-01-01

    In recent years, there has been growing interest in understanding a person's reaction to ambiguous situations, and two similar constructs related to ambiguity, “ambiguity aversion” and “ambiguity intolerance,” are defined in different disciplines. In the field of economic decision-making research, “ambiguity aversion” represents a preference for known risks relative to unknown risks. On the other hand, in clinical psychology, “ambiguity intolerance” describes the tendency to perceive ambiguous situations as undesirable. However, it remains unclear whether these two notions derived from different disciplines are identical or not. To clarify this issue, we combined an economic task, psychological questionnaires, and voxel-based morphometry (VBM) of structural brain magnetic resonance imaging (MRI) in a sample of healthy volunteers. The individual ambiguity aversion tendency parameter, as measured by our economic task, was negatively correlated with agreeableness scores on the self-reported version of the Revised NEO Personality Inventory. However, it was not correlated with scores of discomfort with ambiguity, one of the subscales of the Need for Closure Scale. Furthermore, the ambiguity aversion tendency parameter was negatively correlated with gray matter (GM) volume of areas in the lateral prefrontal cortex and parietal cortex, whereas ambiguity intolerance was not correlated with GM volume in any region. Our results suggest that ambiguity aversion, described in decision theory, may not necessarily be identical to ambiguity intolerance, referred to in clinical psychology. Cautious applications of decision theory to clinical neuropsychiatry are recommended. PMID:25698984

  9. Worry tendencies predict brain activation during aversive imagery.

    PubMed

    Schienle, Anne; Schäfer, Axel; Pignanelli, Roman; Vaitl, Dieter

    2009-09-25

    Because of its abstract nature, worrying might function as an avoidance response in order to cognitively disengage from fearful imagery. The present functional magnetic resonance imaging study investigated neural correlates of aversive imagery and their association with worry tendencies, as measured by the Penn State Worry Questionnaire (PSWQ). Nineteen healthy women first viewed, and subsequently imagined pictures from two categories, 'threat' and 'happiness'. Worry tendencies were negatively correlated with brain activation in the anterior cingulate cortex, the prefrontal cortex (dorsolateral, dorsomedial, ventrolateral), the parietal cortex and the insula. These negative correlations between PSWQ scores and localized brain activation were specific for aversive imagery. Moreover, activation in the above mentioned regions was positively associated with the experienced vividness of both pleasant and unpleasant mental pictures. As the identified brain regions are involved in emotion regulation, vivid imagery and memory retrieval, a lowered activity in high PSWQ scorers might be associated with cognitive disengagement from aversive imagery as well as insufficient refresh rates of mental pictures. Our preliminary findings encourage future imagery studies on generalized anxiety disorder patients, as one of the main symptoms of this disorder is excessive worrying. PMID:19545612

  10. The absence of reward induces inequity aversion in dogs

    PubMed Central

    Range, Friederike; Horn, Lisa; Viranyi, Zsófia; Huber, Ludwig

    2009-01-01

    One crucial element for the evolution of cooperation may be the sensitivity to others' efforts and payoffs compared with one's own costs and gains. Inequity aversion is thought to be the driving force behind unselfish motivated punishment in humans constituting a powerful device for the enforcement of cooperation. Recent research indicates that non-human primates refuse to participate in cooperative problem-solving tasks if they witness a conspecific obtaining a more attractive reward for the same effort. However, little is known about non-primate species, although inequity aversion may also be expected in other cooperative species. Here, we investigated whether domestic dogs show sensitivity toward the inequity of rewards received for giving the paw to an experimenter on command in pairs of dogs. We found differences in dogs tested without food reward in the presence of a rewarded partner compared with both a baseline condition (both partners rewarded) and an asocial control situation (no reward, no partner), indicating that the presence of a rewarded partner matters. Furthermore, we showed that it was not the presence of the second dog but the fact that the partner received the food that was responsible for the change in the subjects' behavior. In contrast to primate studies, dogs did not react to differences in the quality of food or effort. Our results suggest that species other than primates show at least a primitive version of inequity aversion, which may be a precursor of a more sophisticated sensitivity to efforts and payoffs of joint interactions. PMID:19064923

  11. Friendly competition.

    PubMed

    Chambers, David W

    2006-01-01

    Competition that is characterized by rules, often informal, agreed among mutually accepted participants, and that gives the competitors a special, advantageous status with others is called friendly competition. Dentists have engaged in it deeply and it is good for the profession. Friendly competition offers the advantages of spillover of commonly useful information and technologies, stimulation of innovation, a united and convenient face to customers and suppliers, and standards that promote growth. Friendly competition increases the size of the pie, regardless of market share. Paradoxically, this is even true for the little guy in the shadow of the giant. If carried to extremes, unfriendly competition leads to destroying competitors, the confusion of multiple rules, and encouragement of disruptive change. PMID:17477218

  12. Space allowance and barriers influence cow competition for mixed rations fed on a feed-pad between bouts of grazing.

    PubMed

    Hetti Arachchige, A D; Fisher, A D; Wales, W J; Auldist, M J; Hannah, M C; Jongman, E C

    2014-01-01

    barriers increased cow feeding time and decreased the number of feeding bouts in relation to the total time feed was available, particularly in subordinate cows, and reduced the number of cow displacements during feeding. We conclude that increasing the feeding space from 0.6 to 0.75 to 1.0m reduces aggressive interactions and improves cow feeding behavior, with the effects being greatest for subordinate cows. The use of feed barriers further reduces competition at the feed trough in a partial mixed ration feeding system. PMID:24746131

  13. Calorie supply does not alleviate running-based taste aversion learning in rats.

    PubMed

    Nakajima, Sadahiko

    2011-12-01

    Voluntary running establishes aversion to the paired taste in rats. A proposed mechanism underlying this taste aversion learning is energy expenditure caused by the running. The energy expenditure hypothesis predicts that running-based taste aversion should be alleviated by a calorie supply since this would compensate for the energy expended by running. Accordingly, running-based taste aversion would be less readily established to a caloric substance (20% sucrose solution) than to a noncaloric substance (0.2% sodium saccharin solution). Because the sucrose and saccharin aversions were equivalent in Experiment 1, the validity of the energy expenditure hypothesis was questioned. Experiments 2 and 3 also pose a problem for this hypothesis, as post-session calorie supply by glucose tablets failed to alleviate running-based aversion to salty water. PMID:21843567

  14. Effects of subdiaphragmatic vagotomy on the acquisition of a radiation-induced conditioned taste aversion

    SciTech Connect

    Hunt, W.A.; Rabin, B.M.; Lee, J.

    1987-01-01

    The effect of subdiaphragmatic vagotomy on the acquisition of a radiation-induced taste aversion was examined to assess the importance of the vagus nerve in transmitting information on the peripheral toxicity of radiation to the brain. Vagotomy had no effect on taste aversion learning, consistent with reports using other toxins. The data support the involvement of a blood-borne factor in the acquisition of taste aversion induced by ionizing radiation.

  15. Conditioned taste aversion and motion sickness in cats and squirrel monkeys

    NASA Technical Reports Server (NTRS)

    Fox, Robert A.; Corcoran, Meryl Lee; Brizzee, Kenneth R.

    1991-01-01

    The relationship between vomiting and conditioned taste aversion was studied in intact cats and squirrel monkeys and in cats and squirrel monkeys in which the area postrema was ablated by thermal cautery. In cats conditioned 7-12 months after ablation of the area postrema, three successive treatments with xylazine failed to produce either vomiting or conditioned taste aversion to a novel fluid. Intact cats, however, vomited and formed a conditioned aversion. In squirrel monkeys conditioned 6 months after ablation of the area postrema, three treatments with lithium chloride failed to produce conditioned taste aversion. Intact monkeys did condition with these treatments. Neither intact nor ablated monkeys vomited or evidenced other signs of illness when injected with lithium chloride. When the same ablated cats and monkeys were exposed to a form of motion that produced vomiting prior to surgery, conditioned taste aversion can be produced after ablation of the area postrema. The utility of conditioned taste aversion as a measure of subemetic motion sickness is discussed by examining agreement and disagreement between identifications of motion sickness by conditioned taste aversion and vomiting. It is suggested that a convincing demonstration of the utility of conditioned taste aversion as a measure of nausea requires the identification of physiological correlates of nausea, and caution should be exercised when attempting to interpret conditioned taste aversion as a measure of nausea.

  16. Competition for land

    PubMed Central

    Smith, Pete; Gregory, Peter J.; van Vuuren, Detlef; Obersteiner, Michael; Havlík, Petr; Rounsevell, Mark; Woods, Jeremy; Stehfest, Elke; Bellarby, Jessica

    2010-01-01

    A key challenge for humanity is how a future global population of 9 billion can all be fed healthily and sustainably. Here, we review how competition for land is influenced by other drivers and pressures, examine land-use change over the past 20 years and consider future changes over the next 40 years. Competition for land, in itself, is not a driver affecting food and farming in the future, but is an emergent property of other drivers and pressures. Modelling studies suggest that future policy decisions in the agriculture, forestry, energy and conservation sectors could have profound effects, with different demands for land to supply multiple ecosystem services usually intensifying competition for land in the future. In addition to policies addressing agriculture and food production, further policies addressing the primary drivers of competition for land (population growth, dietary preference, protected areas, forest policy) could have significant impacts in reducing competition for land. Technologies for increasing per-area productivity of agricultural land will also be necessary. Key uncertainties in our projections of competition for land in the future relate predominantly to uncertainties in the drivers and pressures within the scenarios, in the models and data used in the projections and in the policy interventions assumed to affect the drivers and pressures in the future. PMID:20713395

  17. Investigating motion sickness using the conditioned taste aversion paradigm

    NASA Technical Reports Server (NTRS)

    Fox, Robert A.

    1991-01-01

    The avoidance of foods which are associated with uncomfortable or aversive internal states has long been recognized. Many people are aware, either directly or via anecdotal reports, of individuals who avoid foods which were eaten just before the onset of sickness. Awareness of this phenomenon can be traced to the writings of John Locke. The disruption of diet during cancer therapy is sometimes ascribed to the attribution of an unpleasant quality to foods eaten preceding the sickness induced by therapy itself. In addition, it has long been recognized by the manufacturers of rodent poisons that animals avoid the injection of food treated with nonlethal doses of poison. An important part of the laboratory study of this phenomenon was directed toward studying the role learning plays in this type of avoidance behavior. Following the lead of Garcia and his associates, this avoidance has come to be interpreted as arising from a form of classical conditioning. In typical laboratory studies of this bahavior, a novel food is ingested just prior to exposure to some stimulus, commonly poisoning or irradiation, which produces illness. Following the terminology of classical conditioning, it is common to describe this procedure as one of 'pairing' a conditioned stimulus (CS), the novel food, with an unconditioned stimulus (US), the illness induced by toxicosis or irradiation. Avoidance of the food in succeeding feeding opportunities is viewed as a learned response or a conditioned taste aversion (CTA). Garcia et al. asserted that motion sickness could produce 'gustatory' aversions, but passive motion was first reported as an US to establish CTA by Green and Rachlin. The purpose is to review the manner in which CTA has been used to study motion sickness. Numerous reviews concentrating on other aspects of CTA are available in the existing literature. Readers are encouraged to consult the various papers and edited books for extensive information on other aspects of this literature.

  18. Learning context modulates aversive taste strength in honey bees.

    PubMed

    de Brito Sanchez, Maria Gabriela; Serre, Marion; Avarguès-Weber, Aurore; Dyer, Adrian G; Giurfa, Martin

    2015-03-01

    The capacity of honey bees (Apis mellifera) to detect bitter substances is controversial because they ingest without reluctance different kinds of bitter solutions in the laboratory, whereas free-flying bees avoid them in visual discrimination tasks. Here, we asked whether the gustatory perception of bees changes with the behavioral context so that tastes that are less effective as negative reinforcements in a given context become more effective in a different context. We trained bees to discriminate an odorant paired with 1 mol l(-1) sucrose solution from another odorant paired with either distilled water, 3 mol l(-1) NaCl or 60 mmol l(-1) quinine. Training was either Pavlovian [olfactory conditioning of the proboscis extension reflex (PER) in harnessed bees], or mainly operant (olfactory conditioning of free-walking bees in a Y-maze). PER-trained and maze-trained bees were subsequently tested both in their original context and in the alternative context. Whereas PER-trained bees transferred their choice to the Y-maze situation, Y-maze-trained bees did not respond with a PER to odors when subsequently harnessed. In both conditioning protocols, NaCl and distilled water were the strongest and the weakest aversive reinforcement, respectively. A significant variation was found for quinine, which had an intermediate aversive effect in PER conditioning but a more powerful effect in the Y-maze, similar to that of NaCl. These results thus show that the aversive strength of quinine varies with the learning context, and reveal the plasticity of the bee's gustatory system. We discuss the experimental constraints of both learning contexts and focus on stress as a key modulator of taste in the honey bee. Further explorations of bee taste are proposed to understand the physiology of taste modulation in bees. PMID:25788729

  19. Two cases of food aversion with semantic dementia.

    PubMed

    Thompson, Alexandra E; Clark, Camilla N; Hardy, Christopher J; Fletcher, Phillip D; Greene, John; Rohrer, Jonathan D; Warren, Jason D

    2016-06-01

    Accounts of altered eating behavior in semantic dementia generally emphasize gluttony and abnormal food preferences. Here we describe two female patients with no past history of eating disorders who developed early prominent aversion to food in the context of an otherwise typical semantic dementia syndrome. One patient (aged 57) presented features in line with anorexia nervosa while the second patient (aged 58) presented with a syndrome more suggestive of bulimia nervosa. These cases add to the growing spectrum of apparently dichotomous behavior patterns in the frontotemporal dementias and illustrate a potentially under-recognized cause of eating disorders presenting in later life. PMID:26963051

  20. Two cases of food aversion with semantic dementia

    PubMed Central

    Thompson, Alexandra E.; Clark, Camilla N.; Hardy, Christopher J.; Fletcher, Phillip D.; Greene, John; Rohrer, Jonathan D.; Warren, Jason D.

    2016-01-01

    ABSTRACT Accounts of altered eating behavior in semantic dementia generally emphasize gluttony and abnormal food preferences. Here we describe two female patients with no past history of eating disorders who developed early prominent aversion to food in the context of an otherwise typical semantic dementia syndrome. One patient (aged 57) presented features in line with anorexia nervosa while the second patient (aged 58) presented with a syndrome more suggestive of bulimia nervosa. These cases add to the growing spectrum of apparently dichotomous behavior patterns in the frontotemporal dementias and illustrate a potentially under-recognized cause of eating disorders presenting in later life. PMID:26963051

  1. Effects of Phenibut and Citrocard on Non-Competitive and Competitive Behavior during Provoked Aggression in Animals.

    PubMed

    Bagmetova, V V; Krivitskaya, A N; Tyurenkov, I N

    2015-05-01

    Anti-aggressive effects of phenibut (25 mg/kg) and its structural analogue citrocard (50 mg/kg) were revealed in rats under condition of provoked intraspecific aggression. These substances significantly decreased manifestations of aggression in animals: they increased the latency of attacks and reduced their number. Anti-aggressive effects of citrocard were more pronounced than effects of phenibut under conditions of non-competitive aggression induced by fear of inescapable painful exposure or under conditions of competitive aggression reflecting the ability of animals to reveal adaptive social communicative skills in aversive situation. PMID:26033589

  2. EDITORIAL: Physics competitions Physics competitions

    NASA Astrophysics Data System (ADS)

    Jordens, H.; Mathelitsch, L.

    2009-11-01

    1. Physics competitions: aims and realizations One aim of physics competitions is to increase the interest of young students, primarily at upper secondary level, to physics and natural sciences in general. A competition has motivational aspects known usually from sports events or games—comparing one's own ability with others, of course with the desire to be better and to win. If competitions reach nationwide and even international levels, additional stimulation is created. Competitions provide greatest attraction to possible winners, to the group of gifted people in a particular field. This implies that science contests are excellent tools for the promotion of talented students. Traditional teaching has been shown to have problems in supporting this group of students. Very often teachers are overstretched with the demands of teaching both low- and high-level students. Extracurricular activities are therefore a good chance to relieve the teacher, and to give talented students the opportunity for appropriate training and challenge. The competitions, however, have a broader impact and address more young people than one might guess from the statements above. Training courses and selection at school level give a larger group of students extra and, to some extent, complimentary education in physics. The degree of complexity of the tasks corresponds very often to the standards of the next level of education in the school system. Interestingly, many physics competitions have their origin in countries beyond the former Iron Curtain. They started as regional and national tournaments, were joined by neighbouring countries and have grown, in some cases, to events with participants from more than 80 countries. Although the features mentioned above are common to the different competitions, there are distinct differences between them [1]. The International Physics Olympiad (IPhO) is the oldest international physics competition for students at upper secondary level [2]. It dates

  3. The effects of competition and competitiveness on cardiovascular activity.

    PubMed

    Harrison, L K; Denning, S; Easton, H L; Hall, J C; Burns, V E; Ring, C; Carroll, D

    2001-07-01

    Cardiovascular activity was measured at resting baseline and in response to a car racing game, undertaken in competition or in cooperation with an experimenter, or individually. Competitiveness and win and goal orientations were assessed by questionnaire. Competition provoked increases in blood pressure and heart rate, and a significant shortening of the preejection period, an index of enhanced beta-adrenergic influences on the heart. The cooperation task was largely without effect, and although the solo task affected cardiovascular activity, it did so to a lesser extent and much less consistently than did the competition task. The three task conditions, then, were largely distinguishable by their capacity to activate beta-adrenergic processes. Participants high in competitiveness and desire to win showed higher blood pressure reactions and greater shortening of the preejection period to competition than those low in these characteristics. PMID:11446573

  4. Feeding activity and influence of intraspecific competition on zooplankton communities by jundiá (Rhamdia quelen Quoy and Gaimard, 1824) in laboratory.

    PubMed

    Brandão-Gonçalves, L; Sebastien, N Y

    2013-11-01

    Experiments were designed to determine if the juvenile forms of jundia (Rhamdia quelen) exhibit selectivity feeding on zooplanktonic organisms and the influence of intraspecific competition on the diet. The fish were maintained in 5000-L containers, and after seven days from birth, they were acclimated in experimental units with different densities and supplied with water containing plankton (natural), where they remained for 24 h in the environment with food. In the first seven days at densities of 5 and 10 fish.L-1, the fish selected the Rotifera more intensely, and at densities of 20 and 40 fish.L-1, the Cladocera were more selected. At 14 days of age, the Cladocera were the most selected for all densities of fish. At 21 days of age, the juvenile forms of jundia maintained a preference for Cladocera, and there was an increase in the capture of Copepoda at a density of 40 fish.L-1. At 28 days of age, the Cladocera were the most captured at densities of 5 to 20 fish.L-1, and the consumption of copepods increased at a density of 40 fish.L-1. The juvenile forms of Rhamdia quelen showed a high feeding preference for Cladocera at all the ages tested (7, 14, 21 and 28 days), but the density of fish per litre influenced the capture of the preferential food. This study showed that the juvenile forms of jundia had a more rapid response to the presence of food at densities of more than 10 fish.L-1, and that at higher densities the fish decreased interactions of territorial defense and formed schools, which allowed the foraging of zooplanktonic organisms, larger in size, more agile and of greater energy gain, such as the Cladocera and copepods. PMID:24789392

  5. Influence of epitaxial growth on phase competition in Pr 0.5Sr 0.5MnO 3 films

    NASA Astrophysics Data System (ADS)

    Chen, Liping; Chen, Yuansha; Ma, Yubin; Lian, Guijun; Zhang, Yan; Xiong, Guangcheng

    2012-03-01

    A series of Pr0.5Sr0.5MnO3 (PSMO) films with various thickness were epitaxially grown on substrates of (0 0 1)-oriented (LaAlO3)0.3(SrAl0.5Ta0.5O3)0.7 (LSAT), LaAlO3 (LAO) and SrTiO3 (STO), and (0 1 1)-oriented STO using pulse laser deposition. Influence of epitaxial growth on phase competition was investigated. A ferromagnetic metal to antiferromagnetic insulator (FMM-AFI) transition upon cooling is present in both largely compressed situations deposited on LAO (0 0 1) and tensile cases deposited on STO (0 0 1) but absent in little strained films grown on LSAT (0 0 1), indicating that the antiferromagnetic insulating state is favored by strains. On the other hand, the 400 nm films deposited on (0 1 1)-oriented STO as well as LAO substrates show FMM-AFI transition. These results reveal that both the orientation of epitaxial growth and substrate-induced strain affect the FMM-AFI transition.

  6. Drug Predictive Cues Activate Aversion-Sensitive Striatal Neurons That Encode Drug Seeking

    PubMed Central

    Wheeler, Daniel S.; Robble, Mykel A.; Hebron, Emily M.; Dupont, Matthew J.; Ebben, Amanda L.

    2015-01-01

    Drug-associated cues have profound effects on an addict's emotional state and drug-seeking behavior. Although this influence must involve the motivational neural system that initiates and encodes the drug-seeking act, surprisingly little is known about the nature of such physiological events and their motivational consequences. Three experiments investigated the effect of a cocaine-predictive stimulus on dopamine signaling, neuronal activity, and reinstatement of cocaine seeking. In all experiments, rats were divided into two groups (paired and unpaired), and trained to self-administer cocaine in the presence of a tone that signaled the immediate availability of the drug. For rats in the paired group, self-administration sessions were preceded by a taste cue that signaled delayed drug availability. Assessments of hedonic responses indicated that this delay cue became aversive during training. Both the self-administration behavior and the immediate cue were subsequently extinguished in the absence of cocaine. After extinction of self-administration behavior, the presentation of the aversive delay cue reinstated drug seeking. In vivo electrophysiology and voltammetry recordings in the nucleus accumbens measured the neural responses to both the delay and immediate drug cues after extinction. Interestingly, the presentation of the delay cue simultaneously decreased dopamine signaling and increased excitatory encoding of the immediate cue. Most importantly, the delay cue selectively enhanced the baseline activity of neurons that would later encode drug seeking. Together these observations reveal how cocaine cues can modulate not only affective state, but also the neurochemical and downstream neurophysiological environment of striatal circuits in a manner that promotes drug seeking. PMID:25948270

  7. Drug predictive cues activate aversion-sensitive striatal neurons that encode drug seeking.

    PubMed

    Wheeler, Daniel S; Robble, Mykel A; Hebron, Emily M; Dupont, Matthew J; Ebben, Amanda L; Wheeler, Robert A

    2015-05-01

    Drug-associated cues have profound effects on an addict's emotional state and drug-seeking behavior. Although this influence must involve the motivational neural system that initiates and encodes the drug-seeking act, surprisingly little is known about the nature of such physiological events and their motivational consequences. Three experiments investigated the effect of a cocaine-predictive stimulus on dopamine signaling, neuronal activity, and reinstatement of cocaine seeking. In all experiments, rats were divided into two groups (paired and unpaired), and trained to self-administer cocaine in the presence of a tone that signaled the immediate availability of the drug. For rats in the paired group, self-administration sessions were preceded by a taste cue that signaled delayed drug availability. Assessments of hedonic responses indicated that this delay cue became aversive during training. Both the self-administration behavior and the immediate cue were subsequently extinguished in the absence of cocaine. After extinction of self-administration behavior, the presentation of the aversive delay cue reinstated drug seeking. In vivo electrophysiology and voltammetry recordings in the nucleus accumbens measured the neural responses to both the delay and immediate drug cues after extinction. Interestingly, the presentation of the delay cue simultaneously decreased dopamine signaling and increased excitatory encoding of the immediate cue. Most importantly, the delay cue selectively enhanced the baseline activity of neurons that would later encode drug seeking. Together these observations reveal how cocaine cues can modulate not only affective state, but also the neurochemical and downstream neurophysiological environment of striatal circuits in a manner that promotes drug seeking. PMID:25948270

  8. Influence of resource levels, organic compounds, and laboratory colonization on interspecific competition between the Asian tiger mosquito (Aedes albopictus) and the southern house mosquito (Culex quinquefasciatus)

    PubMed Central

    Allgood, David W.; Yee, Donald A.

    2013-01-01

    The mosquitoes Aedes albopictus (Skuse) and Culex quinquefasciatus (Say) (Diptera:Culicidae) are common inhabitants of tyres and other artificial containers, which constitute important peridomestic mosquito breeding habitats. We tested the hypotheses that interspecific resource competition between the larvae of these species is asymmetrical, that the concentration of chemicals associated with decomposing detritus affects their competitive outcome, and that wild and colonized strains of Cx. quinquefasciatus are affected differently by competition with Ae. albopictus. We conducted two laboratory competition experiments wherein we measured survivorship and estimated population growth (λ’) of both species under multiple mixed-species densities. Under varying resource levels, competition was asymmetrical with Ae. albopictus causing competitive reductions or exclusions of Cx. quinquefasciatus under limited resources. In a second experiment, which used both wild and colonized strains of Cx. quinquefasciatus, organic chemical compounds associated with decomposing detritus did not affect the competitive outcome. The colonized strain of Cx. quinquefasciatus had greater survivorship, adult mass, and faster development times than the wild strain, but both strains were similarly affected by competition with Ae. albopictus. Competition between these species may have important consequences for vector population dynamics, especially in areas where tyres and artificial containers constitute the majority of mosquito breeding habitats. PMID:24444185

  9. Increasing Cognitive Load Reduces Interference from Masked Appetitive and Aversive but Not Neutral Stimuli

    PubMed Central

    Uher, Rudolf; Brooks, Samantha J.; Bartholdy, Savani; Tchanturia, Kate; Campbell, Iain C.

    2014-01-01

    Interactions between cognition and emotion are important for survival, often occurring in the absence of awareness. These interactions have been proposed to involve competition between cognition and emotion for attentional resources. Emotional stimuli have been reported to impair performance on cognitive tasks of low, but not high, load if stimuli are consciously perceived. This study explored whether this load-dependent interference effect occurred in response to subliminal emotional stimuli. Masked emotional (appetitive and aversive), but not neutral, stimuli interfered with performance accuracy but not response time on a cognitive task (n-back) at low (1-back), but not high (2-back) load. These results show that a load-dependent interference effect applies to masked emotional stimuli and that the effect generalises across stimulus categories with high motivational value. This supports models of selective attention that propose that cognition and emotion compete for attentional resources. More specifically, interference from masked emotional stimuli at low load suggests that attention is biased towards salient stimuli, while dissipation of interference under high load involves top-down regulation of attention. Our data also indicate that top-down goal-directed regulation of attention occurs in the absence of awareness and does not require metacognitive monitoring or evaluation of bias over behaviour, i.e., some degree of self-regulation occurs at a non-conscious level. PMID:24709953

  10. AGE-DEPENDENT MDPV-INDUCED TASTE AVERSIONS AND THERMOREGULATION IN ADOLESCENT AND ADULT RATS

    PubMed Central

    Merluzzi, Andrew P.; Hurwitz, Zachary E.; Briscione, Maria A.; Cobuzzi, Jennifer L.; Wetzell, Bradley; Rice, Kenner C.; Riley, Anthony L.

    2013-01-01

    Adolescent rats are more sensitive to the rewarding and less sensitive to the aversive properties of various drugs of abuse than their adult counterparts. Given a nationwide increase in use of “bath salts,” the present experiment employed the conditioned taste aversion procedure to assess the aversive effects of 3,4-methylenedioxypyrovalerone (MDPV; 0, 1.0, 1.8 or 3.2 mg/kg), a common constituent in “bath salts,” in adult and adolescent rats. As similar drugs induce thermoregulatory changes in rats, temperature was recorded following MDPV administration to assess if thermoregulatory changes were related to taste aversion conditioning. Both age groups acquired taste aversions, although these aversions were weaker and developed at a slower rate in the adolescent subjects. Adolescents increased and adults decreased body temperature following MDPV administration with no correlation to aversions. The relative insensitivity of adolescents to the aversive effects of MDPV suggests that MDPV may confer an increased risk in this population. PMID:24122728

  11. Further Evidence for the Summation of Latent Inhibition and Overshadowing in Rats' Conditioned Taste Aversion

    ERIC Educational Resources Information Center

    Nagaishi, Takatoshi; Nakajima, Sadahiko

    2008-01-01

    Repeated exposures to a target taste (X) attenuated subsequent development of rats' conditioned aversion to X (latent inhibition effect). Presentation of another taste (A) after X in conditioning (serial X-A compound conditioning) also attenuated conditioned X aversion compared with conditioning without A (overshadowing). Furthermore, the latent…

  12. Choice by Value Encoding and Value Construction: Processes of Loss Aversion

    ERIC Educational Resources Information Center

    Willemsen, Martijn C.; Bockenholt, Ulf; Johnson, Eric J.

    2011-01-01

    Loss aversion and reference dependence are 2 keystones of behavioral theories of choice, but little is known about their underlying cognitive processes. We suggest an additional account for loss aversion that supplements the current account of the value encoding of attributes as gains or losses relative to a reference point, introducing a value…

  13. Appetitive but Not Aversive Olfactory Conditioning Modifies Antennal Movements in Honeybees

    ERIC Educational Resources Information Center

    Cholé, Hanna; Junca, Pierre; Sandoz, Jean-Christophe

    2015-01-01

    In honeybees, two olfactory conditioning protocols allow the study of appetitive and aversive Pavlovian associations. Appetitive conditioning of the proboscis extension response (PER) involves associating an odor, the conditioned stimulus (CS) with a sucrose solution, the unconditioned stimulus (US). Conversely, aversive conditioning of the sting…

  14. The Procerebrum Is Necessary for Odor-Aversion Learning in the Terrestrial Slug "Limax Valentianus"

    ERIC Educational Resources Information Center

    Kasai, Yoko; Watanabe, Satoshi; Kirino, Yutaka; Matsuo, Ryota

    2006-01-01

    The terrestrial slug "Limax" has a highly developed ability to associate the odor of some foods (e.g., carrot juice) with aversive stimuli such as the bitter taste of quinidine solution. The procerebrum (PC) is a part of the slug's brain thought to be involved in odor-aversion learning, but direct evidence is still lacking. Here, the authors…

  15. FLAVOR AVERSIONS INDUCED BY THALLIUM SULFATE: IMPORTANCE OF ROUTE OF ADMINISTRATION

    EPA Science Inventory

    Flavor aversions induced by thallium sulfate: Importance of route of administration. Neurobehavioral Toxicology and Teratology, 00: 00-00, 1985. Flavor aversions induced by intraperitoneal (i.p.) and oral (p.o.) administration of thallium sulfate were compared in a repeated trial...

  16. RSK2 Signaling in Brain Habenula Contributes to Place Aversion Learning

    ERIC Educational Resources Information Center

    Darcq, Emmanuel; Koebel, Pascale; Del Boca, Carolina; Pannetier, Solange; Kirstetter, Anne-Sophie; Garnier, Jean-Marie; Hanauer, Andre; Befort, Katia; Kieffer, Brigitte L.

    2011-01-01

    RSK2 is a Ser/Thr kinase acting in the Ras/MAPK pathway. "Rsk2" gene deficiency leads to the Coffin-Lowry Syndrome, notably characterized by cognitive deficits. We found that "mrsk2" knockout mice are unable to associate an aversive stimulus with context in a lithium-induced conditioned place aversion task requiring both high-order cognition and…

  17. Conditioned food aversion for control of poisoning by Ipomoea carnea subsp. fistulosa

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conditioned food aversion is a technique that can be used to train livestock to avoid ingestion of poisonous plants. This study tested the efficacy and durability of conditioned food aversion to eliminate goat’s consumption of Ipomoea carnea subsp. fistulosa. We used 14 young Moxotó goats, which wer...

  18. Effects of Swim Stress on Neophobia and Reconditioning Using a Conditioned Taste Aversion Procedure

    ERIC Educational Resources Information Center

    Walker, Jennifer M.; Ramsey, Ashley K.; Fowler, Stephanie W.; Schachtman, Todd R.

    2012-01-01

    Previous research has found that swim stress during a classical conditioning trial attenuates conditioned taste aversion (CTA). In the current study, rats were used to examine the effects of inescapable swim stress on the habituation of neophobia to a flavored solution and reacquisition of an extinguished conditioned taste aversion. In Experiment…

  19. Uncertainty, loss aversion, and markets for energy efficiency

    SciTech Connect

    Greene, David L

    2010-01-01

    Increasing energy efficiency is critical to mitigating greenhouse gas emissions from fossil-fuel combustion, reducing oil dependence, and achieving a sustainable global energy system. The tendency of markets to neglect apparently cost-effective energy efficiency options has been called the efficiency gap or energy paradox. The market for energy efficiency in new, energy-using durable goods, however, appears to have a bias that leads to undervaluation of future energy savings relative to their expected value. This paper argues that the bias is chiefly produced by the combination of substantial uncertainty about the net value of future fuel savings and the loss aversion of typical consumers. This framework relies on the theory of contextdependent preferences. The uncertainty-loss aversion bias against energy efficiency is quantifiable, making it potentially correctible by policy measures. The welfare economics of such policies remains unresolved. Data on the costs of increased fuel economy of new passenger cars, taken from a National Research Council study, illustrate how an apparently cost-effective increase in energy efficiency would be uninteresting to lossaverse consumers.

  20. Oxytocin facilitates protective responses to aversive social stimuli in males

    PubMed Central

    Striepens, Nadine; Scheele, Dirk; Kendrick, Keith M.; Becker, Benjamin; Schäfer, Lea; Schwalba, Knut; Reul, Jürgen; Maier, Wolfgang; Hurlemann, René

    2012-01-01

    The neuropeptide oxytocin (OXT) can enhance the impact of positive social cues but may reduce that of negative ones by inhibiting amygdala activation, although it is unclear whether the latter causes blunted emotional and mnemonic responses. In two independent double-blind placebo-controlled experiments, each involving over 70 healthy male subjects, we investigated whether OXT affects modulation of startle reactivity by aversive social stimuli as well as subsequent memory for them. Intranasal OXT potentiated acoustic startle responses to negative stimuli, without affecting behavioral valence or arousal judgments, and biased subsequent memory toward negative rather than neutral items. A functional MRI analysis of this mnemonic effect revealed that, whereas OXT inhibited amygdala responses to negative stimuli, it facilitated left insula responses for subsequently remembered items and increased functional coupling between the left amygdala, left anterior insula, and left inferior frontal gyrus. Our results therefore show that OXT can potentiate the protective and mnemonic impact of aversive social information despite reducing amygdala activity, and suggest that the insula may play a role in emotional modulation of memory. PMID:23074247

  1. The capsaicin receptor participates in artificial sweetener aversion.

    PubMed

    Riera, Céline E; Vogel, Horst; Simon, Sidney A; Damak, Sami; le Coutre, Johannes

    2008-11-28

    Artificial sweeteners such as saccharin, aspartame, acesulfame-K, and cyclamate produce at high concentrations an unpleasant after-taste that is generally attributed to bitter and metallic taste sensations. To identify receptors involved with the complex perception of the above compounds, preference tests were performed in wild-type mice and mice lacking the TRPV1 channel or the T1R3 receptor, the latter being necessary for the perception of sweet taste. The sweeteners, including cyclamate, displayed a biphasic response profile, with the T1R3 mediated component implicated in preference. At high concentrations imparting off-taste, omission of TRPV1 reduced aversion. In a heterologous expression system the Y511A point mutation in the vanilloid pocket of TRPV1 did not affect saccharin and aspartame responses but abolished cyclamate and acesulfame-K activities. The results rationalize artificial sweetener tastes and off-tastes by showing that at low concentrations, these molecules stimulate the gustatory system through the hedonically positive T1R3 pathway, and at higher concentrations, their aversion is partly mediated by TRPV1. PMID:18804451

  2. Aversive learning modulates cortical representations of object categories.

    PubMed

    Dunsmoor, Joseph E; Kragel, Philip A; Martin, Alex; LaBar, Kevin S

    2014-11-01

    Experimental studies of conditioned learning reveal activity changes in the amygdala and unimodal sensory cortex underlying fear acquisition to simple stimuli. However, real-world fears typically involve complex stimuli represented at the category level. A consequence of category-level representations of threat is that aversive experiences with particular category members may lead one to infer that related exemplars likewise pose a threat, despite variations in physical form. Here, we examined the effect of category-level representations of threat on human brain activation using 2 superordinate categories (animals and tools) as conditioned stimuli. Hemodynamic activity in the amygdala and category-selective cortex was modulated by the reinforcement contingency, leading to widespread fear of different exemplars from the reinforced category. Multivariate representational similarity analyses revealed that activity patterns in the amygdala and object-selective cortex were more similar among exemplars from the threat versus safe category. Learning to fear animate objects was additionally characterized by enhanced functional coupling between the amygdala and fusiform gyrus. Finally, hippocampal activity co-varied with object typicality and amygdala activation early during training. These findings provide novel evidence that aversive learning can modulate category-level representations of object concepts, thereby enabling individuals to express fear to a range of related stimuli. PMID:23709642

  3. The Commonality of Loss Aversion across Procedures and Stimuli

    PubMed Central

    Kim, Byoung W.; Gilman, Jodi M.; Kuster, John K.; Blood, Anne J.; Kuhnen, Camelia M.

    2015-01-01

    Individuals tend to give losses approximately 2-fold the weight that they give gains. Such approximations of loss aversion (LA) are almost always measured in the stimulus domain of money, rather than objects or pictures. Recent work on preference-based decision-making with a schedule-less keypress task (relative preference theory, RPT) has provided a mathematical formulation for LA similar to that in prospect theory (PT), but makes no parametric assumptions in the computation of LA, uses a variable tied to communication theory (i.e., the Shannon entropy or information), and works readily with non-monetary stimuli. We evaluated if these distinct frameworks described similar LA in healthy subjects, and found that LA during the anticipation phase of the PT-based task correlated significantly with LA related to the RPT-based task. Given the ease with which non-monetary stimuli can be used on the Internet, or in animal studies, these findings open an extensive range of applications for the study of loss aversion. Furthermore, the emergence of methodology that can be used to measure preference for both social stimuli and money brings a common framework to the evaluation of preference in both social psychology and behavioral economics. PMID:26394306

  4. The importance of risk-aversion as a measurable psychological parameter governing risk-taking behaviour

    NASA Astrophysics Data System (ADS)

    Thomas, P. J.

    2013-09-01

    A utility function with risk-aversion as its sole parameter is developed and used to examine the well-known psychological phenomenon, whereby risk averse people adopt behavioural strategies that are extreme and apparently highly risky. The pioneering work of the psychologist, John W. Atkinson, is revisited, and utility theory is used to extend his mathematical model. His explanation of the psychology involved is improved by regarding risk-aversion not as a discrete variable with three possible states: risk averse, risk neutral and risk confident, but as continuous and covering a large range. A probability distribution is derived, the "motivational density", to describe the process of selecting tasks of different degrees of difficulty. An assessment is then made of practicable methods for measuring risk-aversion.

  5. Distinct Midbrain and Habenula Pathways Are Involved in Processing Aversive Events in Humans

    PubMed Central

    D'Ardenne, Kimberlee; McClure, Samuel M.

    2015-01-01

    Emerging evidence implicates the midbrain dopamine system and its interactions with the lateral habenula in processing aversive information and learning to avoid negative outcomes. We examined neural responses to unexpected, aversive events using methods specialized for imaging the midbrain and habenula in humans. Robust activation to aversive relative to neutral events was observed in the habenula and two regions within the ventral midbrain: one located within the ventral tegmental area (VTA) and the other in the substantia nigra (SN). Aversive processing increased functional connectivity between the VTA and the habenula, putamen, and medial prefrontal cortex, whereas the SN exhibited a different pattern of functional connectivity. Our findings provide evidence for a network comprising the VTA and SN, the habenula, and mesocorticolimbic structures that supports processing aversive events in humans. PMID:25568114

  6. Mice Lacking Serotonin 2C Receptors Have increased Affective Responses to Aversive Stimuli

    PubMed Central

    Bonasera, Stephen J.; Schenk, A. Katrin; Luxenberg, Evan J.; Wang, Xidao; Basbaum, Allan; Tecott, Laurence H.

    2015-01-01

    Although central serotonergic systems are known to influence responses to noxious stimuli, mechanisms underlying serotonergic modulation of pain responses are unclear. We proposed that serotonin 2C receptors (5-HT2CRs), which are expressed within brain regions implicated in sensory and affective responses to pain, contribute to the serotonergic modulation of pain responses. In mice constitutively lacking 5-HT2CRs (2CKO mice) we found normal baseline sensory responses to noxious thermal, mechanical and chemical stimuli. In contrast, 2CKO mice exhibited a selective enhancement of affect-related ultrasonic afterdischarge vocalizations in response to footshock. Enhanced affect-related responses to noxious stimuli were also exhibited by 2CKO mice in a fear-sensitized startle assay. The extent to which a brief series of unconditioned footshocks produced enhancement of acoustic startle responses was markedly increased in 2CKO mice. As mesolimbic dopamine pathways influence affective responses to noxious stimuli, and these pathways are disinhibited in 2CKO mice, we examined the sensitivity of footshock-induced enhancement of startle to dopamine receptor blockade. Systemic administration of the dopamine D2/D3 receptor antagonist raclopride selectively reduced footshock-induced enhancement of startle without influencing baseline acoustic startle responses. We propose that 5-HT2CRs regulate affective behavioral responses to unconditioned aversive stimuli through mechanisms involving the disinhibition of ascending dopaminergic pathways. PMID:26630489

  7. EDITORIAL: Physics competitions Physics competitions

    NASA Astrophysics Data System (ADS)

    Jordens, H.; Mathelitsch, L.

    2009-11-01

    1. Physics competitions: aims and realizations One aim of physics competitions is to increase the interest of young students, primarily at upper secondary level, to physics and natural sciences in general. A competition has motivational aspects known usually from sports events or games—comparing one's own ability with others, of course with the desire to be better and to win. If competitions reach nationwide and even international levels, additional stimulation is created. Competitions provide greatest attraction to possible winners, to the group of gifted people in a particular field. This implies that science contests are excellent tools for the promotion of talented students. Traditional teaching has been shown to have problems in supporting this group of students. Very often teachers are overstretched with the demands of teaching both low- and high-level students. Extracurricular activities are therefore a good chance to relieve the teacher, and to give talented students the opportunity for appropriate training and challenge. The competitions, however, have a broader impact and address more young people than one might guess from the statements above. Training courses and selection at school level give a larger group of students extra and, to some extent, complimentary education in physics. The degree of complexity of the tasks corresponds very often to the standards of the next level of education in the school system. Interestingly, many physics competitions have their origin in countries beyond the former Iron Curtain. They started as regional and national tournaments, were joined by neighbouring countries and have grown, in some cases, to events with participants from more than 80 countries. Although the features mentioned above are common to the different competitions, there are distinct differences between them [1]. The International Physics Olympiad (IPhO) is the oldest international physics competition for students at upper secondary level [2]. It dates

  8. GABAA receptors predict aversion-related brain responses: an fMRI-PET investigation in healthy humans.

    PubMed

    Hayes, Dave J; Duncan, Niall W; Wiebking, Christine; Pietruska, Karin; Qin, Pengmin; Lang, Stefan; Gagnon, Jean; Bing, Paul Gravel; Verhaeghe, Jeroen; Kostikov, Alexey P; Schirrmacher, Ralf; Reader, Andrew J; Doyon, Julien; Rainville, Pierre; Northoff, Georg

    2013-07-01

    The perception of aversive stimuli is essential for human survival and depends largely on environmental context. Although aversive brain processing has been shown to involve the sensorimotor cortex, the neural and biochemical mechanisms underlying the interaction between two independent aversive cues are unclear. Based on previous work indicating ventromedial prefrontal cortex (vmPFC) involvement in the mediation of context-dependent emotional effects, we hypothesized a central role for the vmPFC in modulating sensorimotor cortex activity using a GABAergic mechanism during an aversive-aversive stimulus interaction. This approach revealed differential activations within the aversion-related network (eg, sensorimotor cortex, midcingulate, and insula) for the aversive-aversive, when compared with the aversive-neutral, interaction. Individual differences in sensorimotor cortex signal changes during the aversive-aversive interaction were predicted by GABAA receptors in both vmPFC and sensorimotor cortex. Together, these results demonstrate the central role of GABA in mediating context-dependent effects in aversion-related processing. PMID:23389691

  9. Below the Surface: Analogical Similarity and Retrieval Competition in Reminding.

    ERIC Educational Resources Information Center

    Wharton, Charles M.; And Others

    1994-01-01

    Three experiments involving 222 undergraduates investigated whether and when human memory retrieval is influenced by structural consistency. In all experiments, retrieval competition was manipulated. Results indicate that both retrieval competition and structural consistency influence reminding. Implications for psychological and artificial…

  10. Alcohol-induced heart rate response dampening during aversive and rewarding stress paradigms in subjects at risk for alcoholism.

    PubMed

    Croissant, Bernhard; Rist, Fred; Demmel, Ralf; Olbrich, Robert

    2006-08-01

    Individuals with a family history of alcoholism (FH+) are at risk to develop alcohol problems. In several studies, psychophysiological stress responses were more attenuated by alcohol in FH+ than in FH- subjects. However, it is not clear from these studies, if this stronger stress-response dampening effect of alcohol (SRD) in FH+ subjects is confined to aversive stimuli, or would hold for nonaversive stress conditions as well. Also, male and female FH+ subjects seem to respond differently to the alcohol challenge, but have rarely been directly compared in a SRD paradigm. Participants were 54 female and 63 male healthy adults; 31 women were daughters (DOAs) and 40 men were sons (SOAs) of alcohol-dependent fathers. The remaining 23 women (DONAs) and 23 men (SONAs) had no FH of any alcohol use disorder. The participants took part in two laboratory sessions, one with and one without alcohol. In each session, three stressor procedures were presented. Heart rate is the main dependent variable in this report. SOAs, but not SONAs showed a tendency towards SRD. Among female participants, a strong SRD occurred, but contrary to our expectation only in controls. Stress responses and SRD effects were somewhat stronger in the aversive than in the rewarding task. The extent of alcohol induced SRD was strongly influenced by BAL and the amplitude of the stress response in the no-alcohol condition (multiple regression analysis). Thus, aversive tasks might have the advantage of eliciting stronger stress responses than rewarding tasks, thereby providing better conditions for observing differences in alcohol induced SRD between FH+ and FH- subjects. PMID:16386812

  11. Influence of Yo-Yo IR2 Scores on Internal and External Workloads and Fatigue Responses of Tag Football Players during Tournament Competition

    PubMed Central

    2015-01-01

    The purpose of this study was to: a) identify changes in jump height and perceived well-being as indirect markers of fatigue, b) determine the internal and external workloads performed by players, and c) examine the influence of Yo-Yo IR2 on changes in jump height, perceived well-being and internal and external workloads during a tag football tournament. Microtechnology devices combined with heart rate (HR) chest straps provided external and internal measures of match work-rate and workload for twelve male tag football players during the 2014 Australian National Championships. Jump height and perceived well-being were assessed prior to and during the tournament as indirect measures of fatigue. Changes in work-rate, workload and fatigue measures between high- and low-fitness groups were examined based on players’ Yo-Yo IR2 score using a median split technique. The low- and high-fitness groups reported similar mean HR, PlayerloadTM/min, and distance/min for matches, however the low-fitness group reported higher perceived match-intensities (ES = 0.90–1.35) for several matches. Further, the high-fitness group reported higher measures of tournament workload, including distance (ES = 0.71), PlayerloadTM (ES = 0.85) and Edwards’ training impulse (TRIMP) (ES = 1.23) than the low-fitness group. High- and low-fitness groups both showed large decreases (ES = 1.46–1.49) in perceived well-being during the tournament, although jump height did not decrease below pre-tournament values. Increased Yo-Yo IR2 appears to offer a protective effect against player fatigue despite increased workloads during a tag football tournament. It is vital that training programs adequately prepare tag football players for tournament competition to maximise performance and minimise player fatigue. PMID:26465599

  12. EDITORIAL: Physics competitions Physics competitions

    NASA Astrophysics Data System (ADS)

    Jordens, H.; Mathelitsch, L.

    2010-07-01

    This editorial opens the second special section on physics competitions in European Journal of Physics. In the first section last year, we asked for feedback on the idea of such a section and on the content of the articles. We received no answer whatsoever, which can be interpreted in two ways: the section is not interesting enough to raise motivation for feedback, or the reader is satisfied. Having no indication which scenario is the correct one, we are optimistic and favour the second. The section at hand contains three articles. Again, as last year, the organizer of the annual Olympiad reports on tasks and outcomes of this competition. The Olympiad took place in Merida, Mexico, and was by far the largest event with 316 contestants from 68 countries. Again, the predominance of Asian/Chinese students was manifest, showing how serious the training is taken by both their authorities and students. Unfortunately, the winners of the last International Young Physicists' Tournament (IYPT), the team from Korea, did not accept the offer to report on their prize-winning contribution. We are thankful that two students from Austria, who achieved second place with their team, took over and reported on the task which they presented in the finals of the competition. It connects the fields of sport and physics and explains a special move in skateboarding. The third contribution introduces a different competition, 'International Conference of Young Scientists'. On one hand, as in the Olympiad, it addresses individuals, not teams. On the other, as in the IYPT, students have several months to prepare and also the quality of the presentation is an important element of the judgment. In fact, this competition comes closer to real scientific research compared to the other events. Finally and again, we hope that this section will serve several purposes: To show the competitions as a very important tool in the support of gifted students. To raise awareness amongst university teachers, and

  13. Gustatory insular cortex, aversive taste memory and taste neophobia

    PubMed Central

    Lin, Jian-You; Arthurs, Joe; Reilly, Steve

    2015-01-01

    Prior research indicates a role for the gustatory insular cortex (GC) in taste neophobia. Rats with lesions of the GC show much weaker avoidance to a novel and potentially dangerous taste than do neurologically intact animals. The current study used the retention of conditioned taste aversion (CTA) as a tool to determine whether the GC modulates neophobia by processing taste novelty or taste danger. The results show that GC lesions attenuate CTA retention (Experiment 1) and impair taste neophobia (Experiment 2). Given that normal CTA retention does not involve the processing of taste novelty, the pattern of results suggests that the GC is involved in taste neophobia via its function in processing the danger conveyed by a taste stimulus. PMID:25617666

  14. Executive control suppresses pupillary responses to aversive stimuli.

    PubMed

    Cohen, Noga; Moyal, Natali; Henik, Avishai

    2015-12-01

    Adaptive behavior depends on the ability to effectively regulate emotional responses. Continuous failure in the regulation of emotions can lead to heightened physiological reactions and to various psychopathologies. Recently, several behavioral and neuroimaging studies showed that exertion of executive control modulates emotion. Executive control is a high-order operation involved in goal-directed behavior, especially in the face of distractors or temptations. However, the role of executive control in regulating emotion-related physiological reactions is unknown. Here we show that exercise of executive control modulates reactivity of both the sympathetic and the parasympathetic components of the autonomic nervous system. Specifically, we demonstrate that both pupillary light reflex and pupil dilation for aversive stimuli are attenuated following recruitment of executive control. These findings offer new insights into the very basic mechanisms of emotion processing and regulation, and can lead to novel interventions for people suffering from emotion dysregulation psychopathologies. PMID:26410694

  15. Dissecting neural pathways for forgetting in Drosophila olfactory aversive memory

    PubMed Central

    Shuai, Yichun; Hirokawa, Areekul; Ai, Yulian; Zhang, Min; Li, Wanhe; Zhong, Yi

    2015-01-01

    Recent studies have identified molecular pathways driving forgetting and supported the notion that forgetting is a biologically active process. The circuit mechanisms of forgetting, however, remain largely unknown. Here we report two sets of Drosophila neurons that account for the rapid forgetting of early olfactory aversive memory. We show that inactivating these neurons inhibits memory decay without altering learning, whereas activating them promotes forgetting. These neurons, including a cluster of dopaminergic neurons (PAM-β′1) and a pair of glutamatergic neurons (MBON-γ4>γ1γ2), terminate in distinct subdomains in the mushroom body and represent parallel neural pathways for regulating forgetting. Interestingly, although activity of these neurons is required for memory decay over time, they are not required for acute forgetting during reversal learning. Our results thus not only establish the presence of multiple neural pathways for forgetting in Drosophila but also suggest the existence of diverse circuit mechanisms of forgetting in different contexts. PMID:26627257

  16. Correlates of academic procrastination: discomfort, task aversiveness, and task capability.

    PubMed

    Milgram, N; Marshevsky, S; Sadeh, C

    1995-03-01

    The relationships among five aspects of academic procrastination--behavioral delay, personal upset about the delay, task aversiveness, task capability, and the desire to reduce behavioral delay--were investigated in 10th-grade Israeli students (N = 195). Upset about delay was weakly related to delay itself, and--unlike delay--was strongly related to perceived capability to perform academic tasks and to the desire to change delaying behavior. Students delayed more on academic tasks labeled unpleasant than pleasant, were neutral in between, and were correspondingly more upset about the former than the latter. They more frequently acknowledged reasons for academic procrastination that were less threatening to their self-image (e.g., problems in time management) than reasons that were more threatening (e.g., lack of ability). Interest in reducing delay is related more to self-perceived ability to handle tasks than to time spent procrastinating or reasons given for procrastinating. PMID:7760291

  17. Control of polydipsic drinking by a taste aversion procedure.

    PubMed

    Clarke, J C; Westbrook, R F

    1978-09-01

    Rats were given daily sessions with free access to food and saccharin flavored water. After fluid consumption had stabilized food was delivered once every minute. Water was always available in the home cage. All rats showed the marked increase in fluid consumption known as schedule-induced polydipsia. The rats were then poisoned with lithium chloride after each of three sessions in an attempt to condition a taste aversion to the saccharin. On recovery from the toxicosis all rats showed first a reduction and then a recovery in saccharin intake. To establish the nature of this effect, the rats were poisoned after saccharin consumption in the home cage. Again there was a marked reduction in polydipsic drinking in the experimental chamber. These results indicate that common incentive mechanisms govern normal and polydipsic drinking and stand in contrast to published results pointing to different drive systems in the brain mediating normal and polydipsic drinking. PMID:714977

  18. Dissecting neural pathways for forgetting in Drosophila olfactory aversive memory.

    PubMed

    Shuai, Yichun; Hirokawa, Areekul; Ai, Yulian; Zhang, Min; Li, Wanhe; Zhong, Yi

    2015-12-01

    Recent studies have identified molecular pathways driving forgetting and supported the notion that forgetting is a biologically active process. The circuit mechanisms of forgetting, however, remain largely unknown. Here we report two sets of Drosophila neurons that account for the rapid forgetting of early olfactory aversive memory. We show that inactivating these neurons inhibits memory decay without altering learning, whereas activating them promotes forgetting. These neurons, including a cluster of dopaminergic neurons (PAM-β'1) and a pair of glutamatergic neurons (MBON-γ4>γ1γ2), terminate in distinct subdomains in the mushroom body and represent parallel neural pathways for regulating forgetting. Interestingly, although activity of these neurons is required for memory decay over time, they are not required for acute forgetting during reversal learning. Our results thus not only establish the presence of multiple neural pathways for forgetting in Drosophila but also suggest the existence of diverse circuit mechanisms of forgetting in different contexts. PMID:26627257

  19. Comparison of dependent measures used to quantify radiation-induced taste aversion

    SciTech Connect

    Spector, A.C.; Smith, J.C.; Hollander, G.R. . Dept. of Psychology)

    1981-11-01

    Several commonly used measures of conditioned taste aversion were compared under a variety of experimental conditions. In the first experiment an aversion to a saccharin solution (0.1%) was conditioned by pairing this taste substance with a single 100 R exposure to Cobalt-60. Comparisons were performed between the following measures: a short-term single-bottle test, a 22-hour two-bottle preference test, a measure quantifying recovery from the aversion along with other measures derived from these tests. Appropriate control groups received saccharin and sham exposure, water and sham exposure, and water and radiation exposure in order to measure both neophobia and enhanced neophobia. In Experiment 2 the total whole body radiation exposure used to condition the taste aversion was varied in different groups from 50 to 300 R exposures and the effect on conditioning was measured using the dependent variables described in Experiment 1. In Experiment 3 radiation-induced taste aversion was studied in rats which had prior exposures to the saccharin solution. In all three studies it was shown that different interpretations result from measuring the conditioned aversion with the different dependent variables commonly used, and several measures are needed to give a fair and accurate description of learned taste aversion.

  20. Habituation of rapid sympathetic response to aversive timbre eliminated by change in basal sympathovagal balance.

    PubMed

    Ooishi, Yuuki; Kashino, Makio

    2012-08-01

    We studied the difference in the habituation of the rapid sympathetic response to slightly and highly aversive timbres in 68 males. We measured the decrease in the blood volume pulse amplitude (BVP response) as the rapid sympathetic response and the low- (0.04-0.15 Hz) to high- (0.15-0.40 Hz) frequency (LF/HF) ratio of heart rate variability as the sympathovagal balance. The BVP response was suppressed for slightly aversive timbres that had been presented once before, but not for a highly aversive timbre. In contrast, the prior presentation of a highly aversive timbre enhanced the BVP response to a slightly aversive timbre. Only a highly aversive timbre reduced the LF/HF ratio. We suggest that the lack of habituation of the rapid sympathetic response to an aversive timbre is the result of the balance between the effects of the increase caused by the change in sympathovagal balance to vagal dominance and the decrease caused by classical habituation. PMID:22646525

  1. Kappa Opioid Receptors on Dopaminergic Neurons Are Necessary for Kappa-Mediated Place Aversion

    PubMed Central

    Chefer, Vladimir I; Bäckman, Cristina M; Gigante, Eduardo D; Shippenberg, Toni S

    2013-01-01

    Kappa-opioid receptor (KOR) agonists have dysphoric properties in humans and are aversive in rodents. This has been attributed to the activation of KORs within the mesolimbic dopamine (DA) system. However, the role of DA in KOR-mediated aversion and stress remains divisive as recent studies have suggested that activation of KORs on serotonergic neurons may be sufficient to mediate aversive behaviors. To address this question, we used conditional knock-out (KO) mice with KORs deleted on DA neurons (DATCre/wt/KORloxp/loxp, or DATCre-KOR KO). In agreement with previous findings, control mice (DATCre/wt/KORwt/wt or WT) showed conditioned place aversion (CPA) to the systemically administered KOR agonist U69,593. In contrast, DATCre-KOR KO mice did not exhibit CPA with this same agonist. In addition, in vivo microdialysis showed that systemic U69,593 decreased overflow of DA in the nucleus accumbens (NAc) in WT mice, but had no effect in DATCre-KOR KO mice. Intra- ventral tegmental area (VTA) delivery of KORs using an adeno-associated viral gene construct, resulted in phenotypic rescue of the KOR-mediated NAc DA response and aversive behavior in DATCre-KOR KO animals. These results provide evidence that KORs on VTA DA neurons are necessary to mediate KOR-mediated aversive behavior. Therefore, our data, along with recent findings, suggest that the neuronal mechanisms of KOR-mediated aversive behavior may include both dopaminergic and serotonergic components. PMID:23921954

  2. Medial frontal negativity reflects advantageous inequality aversion of proposers in the ultimatum game: An ERP study.

    PubMed

    Wang, Guangrong; Li, Jianbiao; Li, Zheng; Wei, Mengxing; Li, Shaodong

    2016-05-15

    Inequality aversion is a typical form of fairness preferences, which can explain the behaviors in many social exchange situations such as the ultimatum game (UG). There are two kinds of inequality aversion-disadvantageous inequality aversion of responders and advantageous inequality aversion of proposers in the ultimatum game. Although neuroscience research has reported neural correlates of disadvantageous inequality aversion, there are still debates about advantageous inequality aversion of proposers. In this paper, we developed a variant of ultimatum game in which participants played the UG as proposers. On each trial, first, the offer was randomly presented, then, participants as proposers decided whether to choose this offer; next, responders decided whether to accept or not. Offers that responders got 1-20% of the pie are defined as advantageous unfair offers of proposers, whereas offers that responders got 31-50% are defined as fair offers. Event-related brain potentials recorded from the participants showed that more negative-going medial frontal negativity (MFN) was elicited by advantageous unfair offers compared to fair offers in the early time window (250-350ms), which suggested that proposers were averse to advantageous inequality. PMID:26930614

  3. Toxic but Drank: Gustatory Aversive Compounds Induce Post-ingestional Malaise in Harnessed Honeybees

    PubMed Central

    Ayestaran, Ainara

    2010-01-01

    Background Deterrent substances produced by plants are relevant due to their potential toxicity. The fact that most of these substances have an unpalatable taste for humans and other mammals contrasts with the fact that honeybees do not reject them in the range of concentrations in which these compounds are present in flower nectars. Here we asked whether honeybees detect and ingest deterrent substances and whether these substances are really toxic to them. Results We show that pairing aversive substances with an odor retards learning of this odor when it is subsequently paired with sucrose. Harnessed honeybees in the laboratory ingest without reluctance a considerable volume (20 µl) of various aversive substances, even if some of them induce significant post-ingestional mortality. These substances do not seem, therefore, to be unpalatable to harnessed bees but induce a malaise-like state that in some cases results in death. Consistently with this finding, bees learning that one odor is associated with sugar, and experiencing in a subsequent phase that the sugar was paired with 20 µl of an aversive substance (devaluation phase), respond less than control bees to the odor and the sugar. Such stimulus devaluation can be accounted for by the malaise-like state induced by the aversive substances. Conclusion Our results indicate that substances that taste bitter to humans as well as concentrated saline solutions base their aversive effect on the physiological consequences that their ingestion generates in harnessed bees rather than on an unpalatable taste. This conclusion is only valid for harnessed bees in the laboratory as freely-moving bees might react differently to aversive compounds could actively reject aversive substances. Our results open a new possibility to study conditioned taste aversion based on post-ingestional malaise and thus broaden the spectrum of aversive learning protocols available in honeybees. PMID:21060877

  4. Mothers' depressive symptoms predict both increased and reduced negative reactivity: aversion sensitivity and the regulation of emotion.

    PubMed

    Dix, Theodore; Moed, Anat; Anderson, Edward R

    2014-07-01

    This study examined whether, as mothers' depressive symptoms increase, their expressions of negative emotion to children increasingly reflect aversion sensitivity and motivation to minimize ongoing stress or discomfort. In multiple interactions over 2 years, negative affect expressed by 319 mothers and their children was observed across variations in mothers' depressive symptoms, the aversiveness of children's immediate behavior, and observed differences in children's general negative reactivity. As expected, depressive symptoms predicted reduced maternal negative reactivity when child behavior was low in aversiveness, particularly with children who were high in negative reactivity. Depressive symptoms predicted high negative reactivity and steep increases in negative reactivity as the aversiveness of child behavior increased, particularly when high and continued aversiveness from the child was expected (i.e., children were high in negative reactivity). The findings are consistent with the proposal that deficits in parenting competence as depressive symptoms increase reflect aversion sensitivity and motivation to avoid conflict and suppress children's aversive behavior. PMID:24796661

  5. Learned taste aversions induced by high doses of monosodium L-glutamate.

    PubMed

    Vogel, J R; Nathan, B A

    1975-01-01

    Learned taste aversions, as measured by increased time to complete 100 licks of a sweetened condensed milk solution, were demonstrated by laboratory rats 4 days after consumption of the milk solution paired with high oral doses of monosodium 1-glutamate (MSG). The hesitancy of the rats to consume milk on the test session cannot be simply attributed to direct action of the drug on motivation (e.g., hunger) or to drug debilitation. MSG has been reported to occasionally cause aversive effects in humans (Chinese restaurant syndrome), and the present experiments demonstrate that the effects of MSG are aversive to laboratory rats as well. PMID:1208638

  6. A Preliminary Analysis of Self-Control with Aversive Events: The Effects of Task Magnitude and Delay on the Choices of Children with Autism

    ERIC Educational Resources Information Center

    Lerman, Dorothea C.; Addison, Laura R.; Kodak, Tiffany

    2006-01-01

    When faced with a choice between two aversive events, a person exhibits self-control by choosing a smaller, more immediate aversive event over a larger, delayed aversive event. Task demands are often aversive to children with autism and other developmental disabilities. The purpose of this study was to evaluate behavioral sensitivity to…

  7. Malaysian competition

    SciTech Connect

    Jeffs, E.

    1994-11-01

    Two years ago, the first tentative steps were taken to privatize the Malaysian electricity supply industry with the flotation of 25 percent of Tenaga Nasional Bhd. At the same time the terms were defined for independent power generation, and plans were drawn up for six projects. Now, with six independent power producer projects under construction adding more capacity than the partly privatized TNB, the utility`s station managers are concerned they will be at a competitive disadvantage unless they can operate under the same type of power sales agreement.

  8. EDITORIAL: Physics competitions Physics competitions

    NASA Astrophysics Data System (ADS)

    Jordens, H.; Mathelitsch, L.

    2011-07-01

    International tests on competences, such as TIMSS or PISA, and knowledge of young students have revealed low average scores in many countries, often unexpectedly. One effective measure to increase the average standard of a population is to bring the last third of the group to a higher level. Therefore, many nations put some effort into this activity. This brings the danger that not enough attention is paid to students at the other end, those who are talented. Indeed, it is a very difficult task for a teacher to support the less able and at the same time challenge the gifted students, to lead them to the limits of their abilities and provide for a smooth transition to university study. Physics competitions have been proven to fulfil these last demands to a large degree, and therefore are an important additional and, to some extent, complementary tool for the promotion of talented students. This third special section on physics competitions in European Journal of Physics contains three papers, each dealing with a different form of science contest. The first continues the series of presentations of tasks performed at the International Young Physicists' Tournament, which was held in Vienna in 2011. First place went to the team from Singapore, and they have put their investigation on vertical oscillations of coupled magnets into written form (not required by the tournament, where an oral presentation and a defence and discussion are the central aspects). Their paper shows how rich in physics this problem is, and what level of solutions high-school students can already achieve. Sadly, those responsible for the organization of last year's International Physics Olympiad did not provide us with a report on this competition. This is unfortunate, since the Olympiad in Zagreb was very successful and, in particular, the experimental tasks were creative and demanding. Very similar to the aims and the execution of the Physics Olympiad is the International Olympiad on Astronomy

  9. Medial prefrontal cortex dopamine controls the persistent storage of aversive memories

    PubMed Central

    Gonzalez, María C.; Kramar, Cecilia P.; Tomaiuolo, Micol; Katche, Cynthia; Weisstaub, Noelia; Cammarota, Martín; Medina, Jorge H.

    2014-01-01

    Medial prefrontal cortex (mPFC) is essential for initial memory processing and expression but its involvement in persistent memory storage has seldom been studied. Using the hippocampus dependent inhibitory avoidance learning task and the hippocampus-independent conditioned taste aversion paradigm together with specific dopamine receptor agonists and antagonists we found that persistence but not formation of long-term aversive memories requires dopamine D1/D5 receptors activation in mPFC immediately after training and, depending on the task, between 6 and 12 h later. Our results indicate that besides its well-known participation in retrieval and early consolidation, mPFC also modulates the endurance of long-lasting aversive memories regardless of whether formation of the aversive mnemonic trace requires the participation of the hippocampus. PMID:25506318

  10. Acquisition of lithium chloride- and radiation-induced taste aversions in hypophysectomized rats

    SciTech Connect

    Rabin, B.M.; Hunt, W.A.; Lee, J.

    1983-03-01

    The effects of hypophysectomy on the acquisition of conditioned taste aversions following injection of lithium chloride and following exposure to ionizing radiation were studied using a two-bottle preference test. Hypophysectomy did not disrupt the acquisition of a taste aversion following either treatment. The results are interpreted as: (a) suggesting that pituitary/adrenal hormones do not mediate the acquisition of a conditioned taste aversion following injections of lithium chloride or following exposure to ionizing radiation in a two-bottle preference test, and (b) consistent with other research suggesting that the involvement of pituitary/adrenal hormones in taste aversion learning may be related to the conflict induced by using a one-bottle test and not to the learning itself.

  11. Medial prefrontal cortex dopamine controls the persistent storage of aversive memories.

    PubMed

    Gonzalez, María C; Kramar, Cecilia P; Tomaiuolo, Micol; Katche, Cynthia; Weisstaub, Noelia; Cammarota, Martín; Medina, Jorge H

    2014-01-01

    Medial prefrontal cortex (mPFC) is essential for initial memory processing and expression but its involvement in persistent memory storage has seldom been studied. Using the hippocampus dependent inhibitory avoidance learning task and the hippocampus-independent conditioned taste aversion paradigm together with specific dopamine receptor agonists and antagonists we found that persistence but not formation of long-term aversive memories requires dopamine D1/D5 receptors activation in mPFC immediately after training and, depending on the task, between 6 and 12 h later. Our results indicate that besides its well-known participation in retrieval and early consolidation, mPFC also modulates the endurance of long-lasting aversive memories regardless of whether formation of the aversive mnemonic trace requires the participation of the hippocampus. PMID:25506318

  12. Distinct Subpopulations of Nucleus Accumbens Dynorphin Neurons Drive Aversion and Reward.

    PubMed

    Al-Hasani, Ream; McCall, Jordan G; Shin, Gunchul; Gomez, Adrian M; Schmitz, Gavin P; Bernardi, Julio M; Pyo, Chang-O; Park, Sung Il; Marcinkiewcz, Catherine M; Crowley, Nicole A; Krashes, Michael J; Lowell, Bradford B; Kash, Thomas L; Rogers, John A; Bruchas, Michael R

    2015-09-01

    The nucleus accumbens (NAc) and the dynorphinergic system are widely implicated in motivated behaviors. Prior studies have shown that activation of the dynorphin-kappa opioid receptor (KOR) system leads to aversive, dysphoria-like behavior. However, the endogenous sources of dynorphin in these circuits remain unknown. We investigated whether dynorphinergic neuronal firing in the NAc is sufficient to induce aversive behaviors. We found that photostimulation of dynorphinergic cells in the ventral NAc shell elicits robust conditioned and real-time aversive behavior via KOR activation, and in contrast, photostimulation of dorsal NAc shell dynorphin cells induced a KOR-mediated place preference and was positively reinforcing. These results show previously unknown discrete subregions of dynorphin-containing cells in the NAc shell that selectively drive opposing behaviors. Understanding the discrete regional specificity by which NAc dynorphinerigic cells regulate preference and aversion provides insight into motivated behaviors that are dysregulated in stress, reward, and psychiatric disease. PMID:26335648

  13. Symptom-dependent taste aversion induced by an anticoagulant rodenticide in the brown rat (Rattus norvegicus).

    PubMed

    Smith, P; Inglis, I R; Cowan, D P; Kerins, G M; Bull, D S

    1994-09-01

    In a series of 3 experiments with different experimental paradigms, feeding patterns of laboratory rats (Rattus norvegicus) were monitored in 2-choice feeding tests after intubation with a sublethal dose of an anticoagulant rodenticide. We report for the first time that contrary to accepted wisdom, anticoagulants can induce taste aversions. Furthermore, we report behavioral symptoms within the 1st day after dosing. Our data suggest that the taste aversion is induced through an inhibition of the vitamin K cycle and is transient, attenuating over the same period as the levels of vitamin K-dependent proteins return to normal. Because the taste aversion is expressed most strongly when symptoms are most pronounced and is not expressed after symptoms have disappeared, we term this novel form of control symptom-dependent taste aversion. PMID:7924258

  14. Distinct Subpopulations of Nucleus Accumbens Dynorphin Neurons Drive Aversion and Reward

    PubMed Central

    Al-Hasani, Ream; McCall, Jordan G.; Shin, Gunchul; Gomez, Adrian M.; Schmitz, Gavin P.; Bernardi, Julio M.; Pyo, Chang-O.; Park, Sung Il; Marcinkiewcz, Catherine M.; Crowley, Nicole A.; Krashes, Michael J.; Lowell, Bradford B.; Kash, Thomas L.; Rogers, John A.; Bruchas, Michael R.

    2015-01-01

    SUMMARY The nucleus accumbens (NAc) and the dynorphinergic system are widely implicated in motivated behaviors. Prior studies have shown that activation of the dynorphin-kappa opioid receptor (KOR) system leads to aversive, dysphoria-like behavior. However, the endogenous sources of dynorphin in these circuits remain unknown. We investigated whether dynorphinergic neuronal firing in the NAc is sufficient to induce aversive behaviors. We found that photostimulation of dynorphinergic cells in the ventral NAc shell elicits robust conditioned and real-time aversive behavior via KOR activation, and in contrast, photostimulation of dorsal NAc shell dynorphin cells induced a KOR-mediated place preference and were positively reinforcing. These results show previously unknown discrete subregions of dynorphin-containing cells in the NAc shell that selectively drive opposing behaviors. Understanding the discrete regional specificity by which NAc dynorphinerigic cells regulate preference and aversion provides insight into motivated behaviors that are dysregulated in stress, reward, and psychiatric disease. PMID:26335648

  15. Non-aversive treatment of repetitive absconding behaviour in clients with severe neuropsychiatric disorders.

    PubMed

    Giles, Gordon Muir; Wilson, James; Dailey, William

    2009-01-01

    Research relating to the causes and treatment of absconding behaviour among individuals with severe neuropsychiatric disability is reviewed and a non-aversive intervention is reported. Interventions with two clients with severe neuropsychiatric disability and repetitive absconding behaviour are presented in a multiple-baseline within-client single-case format. Multiple empirical treatment approaches were applied to culminate in a successful non-aversive intervention. The effective intervention used reinforcement approaches that were congruent with the client's goals rather than increased restriction. The design of one case included reversal, indicating that it was the intervention, not other factors, that reduced the absconding behaviour. Absconding attempts and absconding incidents were reduced to zero using non-aversive interventions where more restrictive interventions had failed to have a lasting impact. A counter-intuitive non-aversive intervention was effective in eliminating dangerous absconding behaviour in two clients with severe neuropsychiatric disorders. PMID:19101841

  16. Role of the cardiac nerve in the adaptive changes of heart rate in response to an aversive stimulus in Megalobulimus mogianensis.

    PubMed

    Romero, S M B; Hoffmann, A

    2008-05-01

    The effect of an aversive stimulus represented by contact with a hot plate on the heart rate of Megalobulimus mogianensis was evaluated with electrocardiogram recording in intact snails (N = 8). All stimulated animals showed an increase in heart rate, with mean values ranging from 35.6 +/- 1.2 (basal heart rate) to 43.8 +/- 0.9 bpm (post-stimulation heart rate). The cardioacceleration was followed by gradual recovery of the basal heart rate, with mean recovery times varying from 4.3 +/- 0.3 to 5.8 +/- 0.6 min. Repetition of the stimulus did not affect the magnitude of variation nor did it influence the basal heart rate recovery time. To investigate the role of the cardiac nerve in mediating the heart rate alterations induced by the aversive stimulus, denervated (N = 8) and sham-operated (N = 8) animals were also tested. Although the aversive stimulus caused the heart rate to increase significantly in both experimental groups, the mean increase in heart rate in denervated animals (4.4 +/- 0.4 bpm) was 57% of the value obtained in sham-operated animals (7.7 +/- 1.3 bpm), indicating that the cardiac nerve is responsible for 43% of the cardioacceleration induced by the aversive stimulus. The cardioacceleration observed in denervated snails may be due to an increase in venous return promoted by the intense muscular activity associated with the withdrawal response. Humoral factors may also be involved. A probable delaying inhibitory effect of the cardiac nerve on the recuperation of the basal heart rate is suggested. PMID:18545816

  17. Relationship between Fear Conditionability and Aversive Memories: Evidence from a Novel Conditioned-Intrusion Paradigm

    PubMed Central

    Wegerer, Melanie; Blechert, Jens; Kerschbaum, Hubert; Wilhelm, Frank H.

    2013-01-01

    Intrusive memories – a hallmark symptom of posttraumatic stress disorder (PTSD) – are often triggered by stimuli possessing similarity with cues that predicted or accompanied the traumatic event. According to learning theories, intrusive memories can be seen as a conditioned response to trauma reminders. However, direct laboratory evidence for the link between fear conditionability and intrusive memories is missing. Furthermore, fear conditioning studies have predominantly relied on standardized aversive stimuli (e.g. electric stimulation) that bear little resemblance to typical traumatic events. To investigate the general relationship between fear conditionability and aversive memories, we tested 66 mentally healthy females in a novel conditioned-intrusion paradigm designed to model real-life traumatic experiences. The paradigm included a differential fear conditioning procedure with neutral sounds as conditioned stimuli and short violent film clips as unconditioned stimuli. Subsequent aversive memories were assessed through a memory triggering task (within 30 minutes, in the laboratory) and ambulatory assessment (involuntary aversive memories in the 2 days following the experiment). Skin conductance responses and subjective ratings demonstrated successful differential conditioning indicating that naturalistic aversive film stimuli can be used in a fear conditioning experiment. Furthermore, aversive memories were elicited in response to the conditioned stimuli during the memory triggering task and also occurred in the 2 days following the experiment. Importantly, participants who displayed higher conditionability showed more aversive memories during the memory triggering task and during ambulatory assessment. This suggests that fear conditioning constitutes an important source of persistent aversive memories. Implications for PTSD and its treatment are discussed. PMID:24244407

  18. How do working-memory-related demand, reasoning ability and aversive reinforcement modulate conflict monitoring?

    PubMed Central

    Leue, Anja; Weber, Bernd; Beauducel, André

    2014-01-01

    Conflict monitoring is a process of stimulus evaluation and a pre-requisite for subsequent recruitment of cognitive control and behavioral adaptations. This study investigated how experimentally manipulated working-memory-related cognitive demand and aversive reinforcement modulate individual differences of conflict monitoring intensity and behavioral adjustments. Individual differences were assessed by means of an anxiety-related trait dimension (trait-BIS) and by means of reasoning abilities—a core determinant of intelligence. Moreover, we investigated the special role of verbal reasoning ability and figural reasoning ability for the modulation of the conflict monitoring intensity. Ninety participants performed a go/nogo task with four conditions each comprising a combination of low vs. high working-memory-related cognitive demand and low vs. high aversive reinforcement. No effect of aversive reinforcement was observed for the N2 amplitude. The fronto-central nogo N2 amplitude was more pronounced for high demand vs. low demand suggesting that cognitive demand served as an aversive costly event. Higher total reasoning abilities were associated with more intense conflict monitoring and shorter response times with increasing aversive reinforcement (defined as verbal error-feedback vs. monetary loss). Individuals with higher trait-BIS scores demonstrated a more intense conflict monitoring even in conditions with low aversive reinforcement and also a more cautious responding (i.e., response times slowing) with increasing aversive reinforcement indicating a focus on negative feedback prevention. The findings provide evidence for the conflict monitoring theory and suggest that working-memory-related demand overrules the impact of aversive reinforcement on conflict monitoring intensity. Reasoning abilities and anxiety-related traits go along with an intensification of conflict monitoring but differences in the flexibility of behavioral adjustment. PMID:24782739

  19. Neural loss aversion differences between depression patients and healthy individuals: A functional MRI investigation

    PubMed Central

    Pillai Geethabhavan Rajesh, Purushothaman; Kesavadas, Chandrasekharan; Rappai Mary, Paramban; Seema, Satish; Radhakrishnan, Ashalatha; Sitaram, Ranganatha

    2015-01-01

    Neuroeconomics employs neuroscience techniques to explain decision-making behaviours. Prospect theory, a prominent model of decision-making, features a value function with parameters for risk and loss aversion. Recent work with normal participants identified activation related to loss aversion in brain regions including the amygdala, ventral striatum, and ventromedial prefrontal cortex. However, the brain network for loss aversion in pathologies such as depression has yet to be identified. The aim of the current study is to employ the value function from prospect theory to examine behavioural and neural manifestations of loss aversion in depressed and healthy individuals to identify the neurobiological markers of loss aversion in economic behaviour. We acquired behavioural data and fMRI scans while healthy controls and patients with depression performed an economic decision-making task. Behavioural loss aversion was higher in patients with depression than in healthy controls. fMRI results revealed that the two groups shared a brain network for value function including right ventral striatum, ventromedial prefrontal cortex, and right amygdala. However, the neural loss aversion results revealed greater activations in the right dorsal striatum and the right anterior insula for controls compared with patients with depression, and higher activations in the midbrain region ventral tegmental area for patients with depression compared with controls. These results suggest that while the brain network for loss aversion is shared between depressed and healthy individuals, some differences exist with respect to differential activation of additional areas. Our findings are relevant to identifying neurobiological markers for altered decision-making in the depressed. PMID:25923684

  20. Neural loss aversion differences between depression patients and healthy individuals: A functional MRI investigation.

    PubMed

    Chandrasekhar Pammi, V S; Pillai Geethabhavan Rajesh, Purushothaman; Kesavadas, Chandrasekharan; Rappai Mary, Paramban; Seema, Satish; Radhakrishnan, Ashalatha; Sitaram, Ranganatha

    2015-04-01

    Neuroeconomics employs neuroscience techniques to explain decision-making behaviours. Prospect theory, a prominent model of decision-making, features a value function with parameters for risk and loss aversion. Recent work with normal participants identified activation related to loss aversion in brain regions including the amygdala, ventral striatum, and ventromedial prefrontal cortex. However, the brain network for loss aversion in pathologies such as depression has yet to be identified. The aim of the current study is to employ the value function from prospect theory to examine behavioural and neural manifestations of loss aversion in depressed and healthy individuals to identify the neurobiological markers of loss aversion in economic behaviour. We acquired behavioural data and fMRI scans while healthy controls and patients with depression performed an economic decision-making task. Behavioural loss aversion was higher in patients with depression than in healthy controls. fMRI results revealed that the two groups shared a brain network for value function including right ventral striatum, ventromedial prefrontal cortex, and right amygdala. However, the neural loss aversion results revealed greater activations in the right dorsal striatum and the right anterior insula for controls compared with patients with depression, and higher activations in the midbrain region ventral tegmental area for patients with depression compared with controls. These results suggest that while the brain network for loss aversion is shared between depressed and healthy individuals, some differences exist with respect to differential activation of additional areas. Our findings are relevant to identifying neurobiological markers for altered decision-making in the depressed. PMID:25923684

  1. Testosterone, cortisol, and human competition.

    PubMed

    Casto, Kathleen V; Edwards, David A

    2016-06-01

    Testosterone and cortisol figure prominently in the research literature having to do with human competition. In this review, we track the history of this literature, concentrating particularly on major theoretical and empirical contributions, and provide commentary on what we see as important unresolved issues. In men and women, athletic competition is typically associated with an increase in testosterone (T) and cortisol (C). Hormone changes in response to non-athletic competition are less predictable. Person (e.g., power motivation, mood, aggressiveness, social anxiety, sex, and baseline levels of T and C) and context (e.g., whether a competition is won or lost, the closeness of the competition, whether the outcome is perceived as being influenced by ability vs. chance, provocations) factors can influence hormone responses to competition. From early on, studies pointed to a positive relationship between T and dominance motivation/status striving. Recent research, however, suggests that this relationship only holds for individuals with low levels of C - this is the core idea of the dual-hormone hypothesis, and it is certain that the broadest applications of the hypothesis have not yet been realized. Individuals differ with respect to the extent to which they embrace competition, but the hormonal correlates of competitiveness remain largely unexplored. Although rapid increases in both T and C associated with competition are likely adaptive, we still know very little about the psychological benefits of these hormonal changes. Administration studies have and will continue to contribute to this inquiry. We close with a discussion of what, we think, are important methodological and mechanistic issues for future research. PMID:27103058

  2. Sleep deprivation alters choice strategy without altering uncertainty or loss aversion preferences

    PubMed Central

    Mullette-Gillman, O'Dhaniel A.; Kurnianingsih, Yoanna A.; Liu, Jean C. J.

    2015-01-01

    Sleep deprivation alters decision making; however, it is unclear what specific cognitive processes are modified to drive altered choices. In this manuscript, we examined how one night of total sleep deprivation (TSD) alters economic decision making. We specifically examined changes in uncertainty preferences dissociably from changes in the strategy with which participants engage with presented choice information. With high test-retest reliability, we show that TSD does not alter uncertainty preferences or loss aversion. Rather, TSD alters the information the participants rely upon to make their choices. Utilizing a choice strategy metric which contrasts the influence of maximizing and satisficing information on choice behavior, we find that TSD alters the relative reliance on maximizing information and satisficing information, in the gains domain. This alteration is the result of participants both decreasing their reliance on cognitively-complex maximizing information and a concomitant increase in the use of readily-available satisficing information. TSD did not result in a decrease in overall information use in either domain. These results show that sleep deprivation alters decision making by altering the informational strategies that participants employ, without altering their preferences. PMID:26500479

  3. Auditory-visual aversive stimuli modulate the conscious experience of fear.

    PubMed

    Taffou, Marine; Guerchouche, Rachid; Drettakis, George; Viaud-Delmon, Isabelle

    2013-01-01

    In a natural environment, affective information is perceived via multiple senses, mostly audition and vision. However, the impact of multisensory information on affect remains relatively undiscovered. In this study, we investigated whether the auditory-visual presentation of aversive stimuli influences the experience of fear. We used the advantages of virtual reality to manipulate multisensory presentation and to display potentially fearful dog stimuli embedded in a natural context. We manipulated the affective reactions evoked by the dog stimuli by recruiting two groups of participants: dog-fearful and non-fearful participants. The sensitivity to dog fear was assessed psychometrically by a questionnaire and also at behavioral and subjective levels using a Behavioral Avoidance Test (BAT). Participants navigated in virtual environments, in which they encountered virtual dog stimuli presented through the auditory channel, the visual channel or both. They were asked to report their fear using Subjective Units of Distress. We compared the fear for unimodal (visual or auditory) and bimodal (auditory-visual) dog stimuli. Dog-fearful participants as well as non-fearful participants reported more fear in response to bimodal audiovisual compared to unimodal presentation of dog stimuli. These results suggest that fear is more intense when the affective information is processed via multiple sensory pathways, which might be due to a cross-modal potentiation. Our findings have implications for the field of virtual reality-based therapy of phobias. Therapies could be refined and improved by implicating and manipulating the multisensory presentation of the feared situations. PMID:24319928

  4. Transcranial direct current stimulation over prefrontal cortex diminishes degree of risk aversion.

    PubMed

    Ye, Hang; Chen, Shu; Huang, Daqiang; Wang, Siqi; Jia, Yongmin; Luo, Jun

    2015-06-26

    Previous studies have established that transcranial direct current stimulation (tDCS) is a powerful technique for manipulating the activity of the human cerebral cortex. Many studies have found that weighing the risks and benefits in decision-making involves a complex neural network that includes the dorsolateral prefrontal cortex (DLPFC). We studied whether participants change the balance of risky and safe responses after receiving tDCS applied over the right and left prefrontal cortex. A total of 60 healthy volunteers performed a risk task while they received either anodal tDCS over the right prefrontal cortex, with cathodal over the left; anodal tDCS over the left prefrontal cortex, with cathodal over the right; or sham stimulation. The participants tended to choose less risky options after receiving sham stimulation, demonstrating that the task might be highly influenced by the "wealth effect". There was no statistically significant change after either right anodal/left cathodal or left anodal/right cathodal tDCS, indicating that both types of tDCS impact the participants' degrees of risk aversion, and therefore, counteract the wealth effect. We also found gender differences in the participants' choices. These findings extend the notion that DLPFC activity is critical for risk decision-making. Application of tDCS to the right/left DLPFC may impact a person's attitude to taking risks. PMID:25956033

  5. Aversion-related Circuitry in the Cerebellum: Responses to Noxious Heat and Unpleasant Images

    PubMed Central

    Moulton, Eric A.; Elman, Igor; Pendse, Gautam; Schmahmann, Jeremy; Becerra, Lino; Borsook, David

    2011-01-01

    The cerebellum is reliably activated during both acute and chronic pain conditions, but it is unclear if the response to aversive painful stimuli can be generalized to other aversive stimuli. We hypothesized that cerebellar activation during pain reflects higher-level encoding of aversive stimuli. We used functional magnetic resonance imaging (fMRI) to compare cerebellar responses in 11 healthy volunteers to noxious heat (46°C) applied to the hand and to the passive viewing of images selected from the International Affective Picture System (IAPS). Aversive stimuli in the form of noxious heat and unpleasant pictures (unpleasant vs. neutral) activated overlapping areas in the posterior cerebellum, specifically in hemispheric lobule VI, Crus I, and VIIb. Pleasant pictures (pleasant vs. neutral) did not share the same pattern of activation as observed with the aversive stimuli. Cerebellar areas that showed functional overlap with both heat pain and unpleasant picture viewing were significantly inversely correlated with fMRI signals measured in limbic system structures, including the anterior hypothalamus, subgenual anterior cingulate cortex, and the parahippocampal gyrus. Heat specific functional connectivity was detected in many regions including primary motor cortex, secondary somatosensory cortex, anterior insula, and the periaqueductal gray. The overlap between cerebellar lobuli reactive to noxious heat and passive viewing of unpleasant images suggest that the cerebellum may contain specific regions involved in encoding generalized aversive processing. The separate cortical networks suggest that noxious heat evoked responses in the cerebellum can be divided into sensorimotor and emotional networks. PMID:21389234

  6. Extremely Sparse Olfactory Inputs Are Sufficient to Mediate Innate Aversion in Drosophila

    PubMed Central

    Gao, Xiaojing J.; Clandinin, Thomas R.; Luo, Liqun

    2015-01-01

    Innate attraction and aversion to odorants are observed throughout the animal kingdom, but how olfactory circuits encode such valences is not well understood, despite extensive anatomical and functional knowledge. In Drosophila melanogaster, ~50 types of olfactory receptor neurons (ORNs) each express a unique receptor gene, and relay information to a cognate type of projection neurons (PNs). To examine the extent to which the population activity of ORNs is required for olfactory behavior, we developed a genetic strategy to block all ORN outputs, and then to restore output in specific types. Unlike attraction, aversion was unaffected by simultaneous silencing of many ORNs, and even single ORN types previously shown to convey neutral valence sufficed to mediate aversion. Thus, aversion may rely on specific activity patterns in individual ORNs rather than the number or identity of activated ORNs. ORN activity is relayed into the brain by downstream circuits, with excitatory PNs (ePN) representing a major output. We found that silencing the majority of ePNs did not affect aversion, even when ePNs directly downstream of single restored ORN types were silenced. Our data demonstrate the robustness of olfactory aversion, and suggest that its circuit mechanism is qualitatively different from attraction. PMID:25927233

  7. Loss aversion is associated with bilateral insula volume. A voxel based morphometry study.

    PubMed

    Markett, S; Heeren, G; Montag, C; Weber, B; Reuter, M

    2016-04-21

    Loss aversion is a decision bias, reflecting a greater sensitivity to losses than to gains in a decision situation. Recent neuroscientific research has shown that mesocorticolimbic structures like ventromedial prefrontal cortex and the ventral striatum constitute a bidirectional neural system that processes gains and losses and exhibits a neural basis of loss aversion. On a functional and structural level, the amygdala and insula also seem to play an important role in the processing of loss averse behavior. By applying voxel-based morphometry to structural brain images in N=41 healthy participants, the current study provides further evidence for the relationship of brain structure and loss aversion. The results show a negative correlation of gray matter volume in bilateral posterior insula as well as left medial frontal gyrus with individual loss aversion. Hence, higher loss aversion is associated with lower gray matter volume in these brain areas. Both structures have been discussed to play important roles in the brain's salience network, where the posterior insula is involved in interoception and the detection of salience. The medial frontal gyrus might impact decision making through its dense connections with the anterior cingulate cortex. A possible explanation for the present finding is that structural differences in these regions alter the processing of losses and salience, possibly biasing decision making towards avoidance of negative outcomes. PMID:27012426

  8. Porter's Five Competitive Forces Framework and Other Factors That Influence the Choice of Response Strategies Adopted by Public Universities in Kenya

    ERIC Educational Resources Information Center

    Mathooko, Francis M.; Ogutu, Martin

    2015-01-01

    Purpose: The purpose of this paper is to establish the extent to which Porter's five competitive forces (PFCF) framework, among other factors drive the choice of response strategies adopted by public universities in Kenya. Design/Methodology/Approach: The study design was descriptive and utilized a cross-sectional survey of all the public…

  9. Muscarinic ACh Receptors Contribute to Aversive Olfactory Learning in Drosophila

    PubMed Central

    Silva, Bryon; Molina-Fernández, Claudia; Ugalde, María Beatriz; Tognarelli, Eduardo I.; Angel, Cristian; Campusano, Jorge M.

    2015-01-01

    The most studied form of associative learning in Drosophila consists in pairing an odorant, the conditioned stimulus (CS), with an unconditioned stimulus (US). The timely arrival of the CS and US information to a specific Drosophila brain association region, the mushroom bodies (MB), can induce new olfactory memories. Thus, the MB is considered a coincidence detector. It has been shown that olfactory information is conveyed to the MB through cholinergic inputs that activate acetylcholine (ACh) receptors, while the US is encoded by biogenic amine (BA) systems. In recent years, we have advanced our understanding on the specific neural BA pathways and receptors involved in olfactory learning and memory. However, little information exists on the contribution of cholinergic receptors to this process. Here we evaluate for the first time the proposition that, as in mammals, muscarinic ACh receptors (mAChRs) contribute to memory formation in Drosophila. Our results show that pharmacological and genetic blockade of mAChRs in MB disrupts olfactory aversive memory in larvae. This effect is not explained by an alteration in the ability of animals to respond to odorants or to execute motor programs. These results show that mAChRs in MB contribute to generating olfactory memories in Drosophila. PMID:26380118

  10. Reduced Palatability in Pain-Induced Conditioned Taste Aversions

    PubMed Central

    Lin, Jian-You; Arthurs, Joe; Reilly, Steve

    2013-01-01

    The current study investigated whether internal pain-inducing agents can modulate palatability of a tastant in the same way as illness-inducing agents (e.g., lithium chloride). Similar to traditional conditioned taste aversion (CTA) experiments, during conditioning the rats were exposed to a saccharin solution followed by intraperitoneal injections of either gallamine (Experiment 1) or hypertonic sodium chloride (NaCl; Experiments 1 and 2). In addition to the total amount consumed, the time of each lick was recorded for lick pattern analysis. The results showed that both gallamine and hypertonic NaCl caused suppression in saccharin intake. Importantly, both lick cluster size and initial lick rate (the measures of taste palatability) were reduced as well. This pattern of results suggests that these pain-inducing agents reduce the hedonic value of the associated tastant and thus CTA is acquired. The current finding serves as evidence supporting the view that CTA is a broadly tuned mechanism that can be triggered by changes in internal body states following consummatory experience. PMID:23769688

  11. Aversive learning shapes neuronal orientation tuning in human visual cortex

    PubMed Central

    McTeague, Lisa M.; Gruss, L. Forest; Keil, Andreas

    2015-01-01

    The responses of sensory cortical neurons are shaped by experience. As a result perceptual biases evolve, selectively facilitating the detection and identification of sensory events that are relevant for adaptive behaviour. Here we examine the involvement of human visual cortex in the formation of learned perceptual biases. We use classical aversive conditioning to associate one out of a series of oriented gratings with a noxious sound stimulus. After as few as two grating-sound pairings, visual cortical responses to the sound-paired grating show selective amplification. Furthermore, as learning progresses, responses to the orientations with greatest similarity to the sound-paired grating are increasingly suppressed, suggesting inhibitory interactions between orientation-selective neuronal populations. Changes in cortical connectivity between occipital and fronto-temporal regions mirror the changes in visuo-cortical response amplitudes. These findings suggest that short-term behaviourally driven retuning of human visual cortical neurons involves distal top–down projections as well as local inhibitory interactions. PMID:26215466

  12. Does the kappa opioid receptor system contribute to pain aversion?

    PubMed Central

    Cahill, Catherine M.; Taylor, Anna M. W.; Cook, Christopher; Ong, Edmund; Morón, Jose A.; Evans, Christopher J.

    2014-01-01

    The kappa opioid receptor (KOR) and the endogenous peptide-ligand dynorphin have received significant attention due the involvement in mediating a variety of behavioral and neurophysiological responses, including opposing the rewarding properties of drugs of abuse including opioids. Accumulating evidence indicates this system is involved in regulating states of motivation and emotion. Acute activation of the KOR produces an increase in motivational behavior to escape a threat, however, KOR activation associated with chronic stress leads to the expression of symptoms indicative of mood disorders. It is well accepted that KOR can produce analgesia and is engaged in chronic pain states including neuropathic pain. Spinal studies have revealed KOR-induced analgesia in reversing pain hypersensitivities associated with peripheral nerve injury. While systemic administration of KOR agonists attenuates nociceptive sensory transmission, this effect appears to be a stress-induced effect as anxiolytic agents, including delta opioid receptor agonists, mitigate KOR agonist-induced analgesia. Additionally, while the role of KOR and dynorphin in driving the dysphoric and aversive components of stress and drug withdrawal has been well characterized, how this system mediates the negative emotional states associated with chronic pain is relatively unexplored. This review provides evidence that dynorphin and the KOR system contribute to the negative affective component of pain and that this receptor system likely contributes to the high comorbidity of mood disorders associated with chronic neuropathic pain. PMID:25452729

  13. Lack of insula reactivity to aversive stimuli in schizophrenia.

    PubMed

    Linnman, Clas; Coombs, Garth; Goff, Donald C; Holt, Daphne J

    2013-01-01

    Patients with schizophrenia may have altered pain perception, as suggested by clinical reports of pain insensitivity, and recent neuroimaging findings. Here, we examined neural responses to an aversive electrical stimulus and the immediate anticipation of such a stimulus using fMRI and a classical conditioning paradigm, which involved pairing an electrical shock with a neutral photograph. Fifteen men with schizophrenia and 13 healthy men, matched for demographic characteristics, electrical stimulation level and scan movement, were studied. The shock induced robust responses in midbrain, thalamus, cingulate gyrus, insula and somatosensory cortex in both groups. However, compared to controls, the schizophrenic patients displayed significantly lower activation of the middle insula (p(FWE)=0.002, T=5.72, cluster size=24 voxels). Moreover, the lack of insula reactivity in the schizophrenia group was predicted by the magnitude of positive symptoms (r=-0.46, p=0.04). In contrast, there were no significant differences between the two groups in the magnitude of neural responses during anticipation of the shock. These findings provide support for the existence of a basic deficit in interoceptive perception in schizophrenia, which could play a role in the generation and/or maintenance of psychotic states. PMID:23201307

  14. Lack of insula reactivity to aversive stimuli in schizophrenia

    PubMed Central

    Linnman, Clas; Coombs, Garth; Goff, Donald C.; Holt, Daphne J.

    2012-01-01

    Patients with schizophrenia may have altered pain perception, as suggested by clinical reports of pain insensitivity, and recent neuroimaging findings. Here, we examined neural responses to an aversive electrical stimulus and the immediate anticipation of such a stimulus using fMRI and a classical conditioning paradigm, which involved pairing an electrical shock with a neutral photograph. Fifteen men with schizophrenia and 13 healthy men, matched for demographic characteristics, electrical stimulation level and scan movement, were studied. The shock induced robust responses in midbrain, thalamus, cingulate gyrus, insula and somatosensory cortex in both groups. However, compared to controls, the schizophrenic patients displayed significantly lower activation of the middle insula (pFWE = 0.002, T=5.72, cluster size =24 voxels). Moreover, the lack of insula reactivity in the schizophrenia group was predicted by the magnitude of positive symptoms (r = −0.46, p=0.04). In contrast, there were no significant differences between the two groups in the magnitude of neural responses during anticipation of the shock. These findings provide support for the existence of a basic deficit in interoceptive perception in schizophrenia, which could play a role in the generation and/or maintenance of psychotic states. PMID:23201307

  15. Impairment of aversive memory reconsolidation by localized intracranial electrical stimulation.

    PubMed

    Stehberg, Jimmy; Levy, Dino; Zangen, Abraham

    2009-03-01

    Reconsolidation of long-term memory is blocked in animal models by macromolecular synthesis inhibitors, resulting in item-specific post-retrieval amnesia. The induction of such amnesia could ameliorate traumatic memories and phobias. However, this pharmacological approach is of limited value in humans because of toxicity. Here we report that reconsolidation of conditioned taste aversion in the rat is impaired by localized intracranial electrical stimulation. Lasting impairment was obtained only when stimulation was applied during memory reactivation and only to the dysgranular insular cortex bilaterally, which subserves the memory, but not to adjacent brain sites. The ability to learn a new association was not affected. The same method blocked new memory consolidation, but produced anterograde amnesia, reminiscent of the known effect of non-localized electroconvulsive therapy. Our results suggest that localized electrical microstimulation, such as produced by deep-brain stimulation or deep transcranial magnetic stimulation, could be used to impair long-term memory if applied during memory reactivation, and could lead to the development of a novel treatment for intractable post-traumatic stress disorder. PMID:19200060

  16. Instructed knowledge shapes feedback-driven aversive learning in striatum and orbitofrontal cortex, but not the amygdala.

    PubMed

    Atlas, Lauren Y; Doll, Bradley B; Li, Jian; Daw, Nathaniel D; Phelps, Elizabeth A

    2016-01-01

    Socially-conveyed rules and instructions strongly shape expectations and emotions. Yet most neuroscientific studies of learning consider reinforcement history alone, irrespective of knowledge acquired through other means. We examined fear conditioning and reversal in humans to test whether instructed knowledge modulates the neural mechanisms of feedback-driven learning. One group was informed about contingencies and reversals. A second group learned only from reinforcement. We combined quantitative models with functional magnetic resonance imaging and found that instructions induced dissociations in the neural systems of aversive learning. Responses in striatum and orbitofrontal cortex updated with instructions and correlated with prefrontal responses to instructions. Amygdala responses were influenced by reinforcement similarly in both groups and did not update with instructions. Results extend work on instructed reward learning and reveal novel dissociations that have not been observed with punishments or rewards. Findings support theories of specialized threat-detection and may have implications for fear maintenance in anxiety. PMID:27171199

  17. Competitive science: is competition ruining science?

    PubMed

    Fang, Ferric C; Casadevall, Arturo

    2015-04-01

    Science has always been a competitive undertaking. Despite recognition of the benefits of cooperation and team science, reduced availability of funding and jobs has made science more competitive than ever. Here we consider the benefits of competition in providing incentives to scientists and the adverse effects of competition on resource sharing, research integrity, and creativity. The history of science shows that transformative discoveries often occur in the absence of competition, which only emerges once fields are established and goals are defined. Measures to encourage collaboration and ameliorate competition in the scientific enterprise are discussed. PMID:25605760

  18. Competitive Science: Is Competition Ruining Science?

    PubMed Central

    Casadevall, Arturo

    2015-01-01

    Science has always been a competitive undertaking. Despite recognition of the benefits of cooperation and team science, reduced availability of funding and jobs has made science more competitive than ever. Here we consider the benefits of competition in providing incentives to scientists and the adverse effects of competition on resource sharing, research integrity, and creativity. The history of science shows that transformative discoveries often occur in the absence of competition, which only emerges once fields are established and goals are defined. Measures to encourage collaboration and ameliorate competition in the scientific enterprise are discussed. PMID:25605760

  19. Lunabotics Mining Competition

    NASA Technical Reports Server (NTRS)

    Mueller, Rob; Murphy, Gloria

    2010-01-01

    This slide presentation describes a competition to design a lunar robot (lunabot) that can be controlled either remotely or autonomously, isolated from the operator, and is designed to mine a lunar aggregate simulant. The competition is part of a systems engineering curriculum. The 2010 competition winners in five areas of the competition were acknowledged, and the 2011 competition was announced.

  20. Common brain activations for painful and non-painful aversive stimuli

    PubMed Central

    2012-01-01

    Background Identification of potentially harmful stimuli is necessary for the well-being and self-preservation of all organisms. However, the neural substrates involved in the processing of aversive stimuli are not well understood. For instance, painful and non-painful aversive stimuli are largely thought to activate different neural networks. However, it is presently unclear whether there is a common aversion-related network of brain regions responsible for the basic processing of aversive stimuli. To help clarify this issue, this report used a cross-species translational approach in humans (i.e. meta-analysis) and rodents (i.e. systematic review of functional neuroanatomy). Results Animal and human data combined to show a core aversion-related network, consisting of similar cortical (i.e. MCC, PCC, AI, DMPFC, RTG, SMA, VLOFC; see results section or abbreviation section for full names) and subcortical (i.e. Amyg, BNST, DS, Hab, Hipp/Parahipp, Hyp, NAc, NTS, PAG, PBN, raphe, septal nuclei, Thal, LC, midbrain) regions. In addition, a number of regions appeared to be more involved in pain-related (e.g. sensory cortex) or non-pain-related (e.g. amygdala) aversive processing. Conclusions This investigation suggests that aversive processing, at the most basic level, relies on similar neural substrates, and that differential responses may be due, in part, to the recruitment of additional structures as well as the spatio-temporal dynamic activity of the network. This network perspective may provide a clearer understanding of why components of this circuit appear dysfunctional in some psychiatric and pain-related disorders. PMID:22676259

  1. Ethanol induces second-order aversive conditioning in adolescent and adult rats

    PubMed Central

    Pautassi, Ricardo Marcos; Myers, Mallory; Spear, Linda Patia; Molina, Juan Carlos; Spear, Norman E.

    2011-01-01

    Alcohol abuse and dependence is considered a developmental disorder with etiological onset during late childhood and adolescence, and understanding age-related differences in ethanol sensitivity is important. Low to moderate ethanol doses (0.5 and 2.0 g/kg, i.g.) induce single-trial, appetitive second-order place conditioning (SOC) in adolescent, but not adult, rats. Recent studies have demonstrated that adolescents may be less sensitive than adults to the aversive properties of ethanol, reflected by conditioned taste aversion. The present study assessed the aversive motivational effects of high-dose ethanol (3.0 and 3.25 g/kg, i.g., for adolescent and adults, respectively) using SOC. These doses were derived from Experiment 1, which found similar blood and brain ethanol levels in adolescent and adult rats given 3.0 and 3.25 g/kg ethanol, respectively. In Experiment 2, animals received ethanol or vehicle paired with intraoral pulses of sucrose (conditioned stimulus 1 [CS1]). After one, two, or three conditioning trials, rats were presented with the CS1 while in a distinctive chamber (CS2). When tested for CS2 preference, ethanol-treated animals exhibited reduced preference for the CS2 compared with controls. This result, indicative of ethanol-mediated aversive place conditioning, was similar for adolescents and adults, for females and males, and after one, two, or three training trials. One finding, however, suggested that adolescents were less sensitive than adults to ethanol’s aversive effects at the intermediate level of training. In conjunction with previous results, the present study showed that in adolescent rats subjected to SOC, ethanol’s hedonic effects vary from appetitive to aversive as the ethanol dose increases. Adolescent and adult animals appear to perceive the post-ingestive effects of high-dose ethanol as similarly aversive when assessed by SOC. PMID:21187242

  2. Competitive spirit

    NASA Astrophysics Data System (ADS)

    2000-01-01

    Leicester University will host the 65 international teams of students who will assemble in July for this year's International Physics Olympiad . The last time the Olympiad came to the UK was in 1986 in London, and it was the notable enthusiasm of the Leicester Physics and Astronomy department which persuaded the Olympiad Committee to give them the chance of organizing the prestigious event. The students taking part from all over the world are studying physics at A-level or an equivalent standard and they will take part in an intellectual marathon of theoretical and practical examinations. Each national team comprises five students selected from three rounds of competition and the teams will receive an official welcome from the city, as well as opportunities to visit some of the important educational and cultural centres of the surrounding region. The finalists will also be able to test their skills and initiative at the Challenger Learning Centre, which forms part of Leicester's new National Space Science Centre. Specific information on the event can be found on the Olympiad-2000 website at www.star.le.ac.uk/IphO-2000 . The Rudolf Ortvay problem solving contest in physics, which takes place in November, is a tradition of Eötvös University in Budapest, Hungary. The competition was first opened to international participants in 1998, enabling students from universities around the world to show their knowledge, ingenuity, problem-solving skills and physical insight into problems that are far beyond routine level. The problems (30 - 35 each year) are chosen from different branches of theoretical as well as applied physics. They have varying levels of difficulty, and every contestant can send solutions for ten problems. The focus is not on school-level problem-solving routines but rather on the `physical' way of thinking, recognition of the heart of the problem and an appropriate choice of mathematics. The majority of the assigned problems are original, few having

  3. Competitive spirit

    NASA Astrophysics Data System (ADS)

    2000-01-01

    Leicester University will host the 65 international teams of students who will assemble in July for this year's International Physics Olympiad . The last time the Olympiad came to the UK was in 1986 in London, and it was the notable enthusiasm of the Leicester Physics and Astronomy department which persuaded the Olympiad Committee to give them the chance of organizing the prestigious event. The students taking part from all over the world are studying physics at A-level or an equivalent standard and they will take part in an intellectual marathon of theoretical and practical examinations. Each national team comprises five students selected from three rounds of competition and the teams will receive an official welcome from the city, as well as opportunities to visit some of the important educational and cultural centres of the surrounding region. The finalists will also be able to test their skills and initiative at the Challenger Learning Centre, which forms part of Leicester's new National Space Science Centre. Specific information on the event can be found on the Olympiad-2000 website at www.star.le.ac.uk/IphO-2000 . The Rudolf Ortvay problem solving contest in physics, which takes place in November, is a tradition of Eötvös University in Budapest, Hungary. The competition was first opened to international participants in 1998, enabling students from universities around the world to show their knowledge, ingenuity, problem-solving skills and physical insight into problems that are far beyond routine level. The problems (30 - 35 each year) are chosen from different branches of theoretical as well as applied physics. They have varying levels of difficulty, and every contestant can send solutions for ten problems. The focus is not on school-level problem-solving routines but rather on the `physical' way of thinking, recognition of the heart of the problem and an appropriate choice of mathematics. The majority of the assigned problems are original, few having

  4. Attenuation of radiation- and drug-induced conditioned taste aversions following area postrema lesions in the rat

    SciTech Connect

    Rabin, B.M.; Hunt, W.A.; Lee, J.

    1983-02-01

    The effects of lesions of the area postrema on the acquisition of radiation- and drug-induced (histamine and lithium chloride) conditioned taste aversions were investigated. The results indicated that area postrema lesions caused a significant attenuation of the aversion produced by pairing a novel sucrose solution with radiation (100 rad) or drug injection. Further, the area postrema lesions produced a similar level of attenuation of the taste aversion in all three treatment conditions. The results are discussed in terms of the implications of this finding for defining the mechanisms by which exposure to ionizing radiation can lead to the acquisition of a conditioned taste aversion.

  5. Comparison of larkspur alkaloid extract and lithium chloride in maintaining cattle aversion to larkspur in the field.

    PubMed

    Ralphs, M H; Olsen, J D

    1992-04-01

    Lithium chloride (LiCl) and larkspur (Delphinium barbeyi) alkaloid extract were compared in their effect as an emetic to create taste aversions to fresh larkspur. They were further compared in the field to determine whether the indigenous larkspur alkaloids were more effective in maintaining the aversion when conditioned cattle were subjected to the social pressure (social facilitation) of control cattle eating larkspur. Taste aversions were produced in two groups of 1-yr-old cattle by offering fresh larkspur and then gavaging with either LiCl at 200 mg/kg of BW or larkspur alkaloid extract at 1.1 to 1.6 mL/kg of BW. The third group (control) was gavaged with water. The alkaloid group was slower to form an aversion than the lithium group, requiring four doses compared with two doses. All groups were then taken to larkspur-infested rangeland to test the aversion in the field. In the first field trial in which groups grazed separately, both aversion-induced groups generally abstained from eating larkspur. In the second trial in which all groups grazed together, both aversion-induced groups consumed less than half as much larkspur as the controls, but neither group abstained completely. Larkspur alkaloids did not maintain the aversion to larkspur to a greater degree than did LiCl when aversion-induced cattle were subjected to social facilitation. PMID:1316344

  6. Impaired conditioned taste aversion learning in spinophilin knockout mice.

    PubMed

    Stafstrom-Davis, C A; Ouimet, C C; Feng, J; Allen, P B; Greengard, P; Houpt, T A

    2001-01-01

    Plasticity in dendritic spines may underlie learning and memory. Spinophilin, a protein enriched in dendritic spines, has the properties of a scaffolding protein and is believed to regulate actin cytoskeletal dynamics affecting dendritic spine morphology. It also binds protein phosphatase-1 (PP-1), an enzyme that regulates dendritic spine physiology. In this study, we tested the role of spinophilin in conditioned taste aversion learning (CTA) using transgenic spinophilin knockout mice. CTA is a form of associative learning in which an animal rejects a food that has been paired previously with a toxic effect (e.g., a sucrose solution paired with a malaise-inducing injection of lithium chloride). Acquisition and extinction of CTA was tested in spinophilin knockout and wild-type mice using taste solutions (sucrose or sodium chloride) or flavors (Kool-Aid) paired with moderate or high doses of LiCl (0.15 M, 20 or 40 mL/kg). When sucrose or NaCl solutions were paired with a moderate dose of LiCl, spinophilin knockout mice were unable to learn a CTA. At the higher dose, knockout mice acquired a CTA but extinguished more rapidly than wild-type mice. A more salient flavor stimulus (taste plus odor) revealed similar CTA learning at both doses of LiCl in both knockouts and wild types. Sensory processing in the knockouts appeared normal because knockout mice and wild-type mice expressed identical unconditioned taste preferences in two-bottle tests, and identical lying-on-belly responses to acute LiCl. We conclude that spinophilin is a candidate molecule required for normal CTA learning. PMID:11584074

  7. Effect of risk aversion on prioritizing conservation projects.

    PubMed

    Tulloch, Ayesha I T; Maloney, Richard F; Joseph, Liana N; Bennett, Joseph R; Di Fonzo, Martina M I; Probert, William J M; O'Connor, Shaun M; Densem, Jodie P; Possingham, Hugh P

    2015-04-01

    Conservation outcomes are uncertain. Agencies making decisions about what threat mitigation actions to take to save which species frequently face the dilemma of whether to invest in actions with high probability of success and guaranteed benefits or to choose projects with a greater risk of failure that might provide higher benefits if they succeed. The answer to this dilemma lies in the decision maker's aversion to risk--their unwillingness to accept uncertain outcomes. Little guidance exists on how risk preferences affect conservation investment priorities. Using a prioritization approach based on cost effectiveness, we compared 2 approaches: a conservative probability threshold approach that excludes investment in projects with a risk of management failure greater than a fixed level, and a variance-discounting heuristic used in economics that explicitly accounts for risk tolerance and the probabilities of management success and failure. We applied both approaches to prioritizing projects for 700 of New Zealand's threatened species across 8303 management actions. Both decision makers' risk tolerance and our choice of approach to dealing with risk preferences drove the prioritization solution (i.e., the species selected for management). Use of a probability threshold minimized uncertainty, but more expensive projects were selected than with variance discounting, which maximized expected benefits by selecting the management of species with higher extinction risk and higher conservation value. Explicitly incorporating risk preferences within the decision making process reduced the number of species expected to be safe from extinction because lower risk tolerance resulted in more species being excluded from management, but the approach allowed decision makers to choose a level of acceptable risk that fit with their ability to accommodate failure. We argue for transparency in risk tolerance and recommend that decision makers accept risk in an adaptive management

  8. Psychophysical and Neural Correlates of Auditory Attraction and Aversion

    NASA Astrophysics Data System (ADS)

    Patten, Kristopher Jakob

    This study explores the psychophysical and neural processes associated with the perception of sounds as either pleasant or aversive. The underlying psychophysical theory is based on auditory scene analysis, the process through which listeners parse auditory signals into individual acoustic sources. The first experiment tests and confirms that a self-rated pleasantness continuum reliably exists for 20 various stimuli (r = .48). In addition, the pleasantness continuum correlated with the physical acoustic characteristics of consonance/dissonance (r = .78), which can facilitate auditory parsing processes. The second experiment uses an fMRI block design to test blood oxygen level dependent (BOLD) changes elicited by a subset of 5 exemplar stimuli chosen from Experiment 1 that are evenly distributed over the pleasantness continuum. Specifically, it tests and confirms that the pleasantness continuum produces systematic changes in brain activity for unpleasant acoustic stimuli beyond what occurs with pleasant auditory stimuli. Results revealed that the combination of two positively and two negatively valenced experimental sounds compared to one neutral baseline control elicited BOLD increases in the primary auditory cortex, specifically the bilateral superior temporal gyrus, and left dorsomedial prefrontal cortex; the latter being consistent with a frontal decision-making process common in identification tasks. The negatively-valenced stimuli yielded additional BOLD increases in the left insula, which typically indicates processing of visceral emotions. The positively-valenced stimuli did not yield any significant BOLD activation, consistent with consonant, harmonic stimuli being the prototypical acoustic pattern of auditory objects that is optimal for auditory scene analysis. Both the psychophysical findings of Experiment 1 and the neural processing findings of Experiment 2 support that consonance is an important dimension of sound that is processed in a manner that aids

  9. The paradox of drug taking: the role of the aversive effects of drugs.

    PubMed

    Riley, Anthony L

    2011-04-18

    In 1991, Woods described the paradoxical nature of eating, specifically, that it produced aversive and negative effects. He noted in this analysis the multiple physiological and behavior adaptations, both learned and unlearned, that were aimed at regulating food intake and reducing its aversive, disruptive effects. From this position, he argued that consumption reflected a balance of the positive and aversive effects of eating. The present review extends this analysis to drug use and abuse, i.e., that drug taking itself also is a balance of reward and aversion. Although traditionally the analysis of drug use and abuse has focused on a drug's positive and negative rewarding effects, the present review highlights the aversive effects of these same drugs, e.g., cocaine, morphine, alcohol, and describes such effects as protective in nature. This balance and the manner by which it can be impacted by subject and experiential factors are described with a focus on genetic models of drug abuse using the Lewis and Fischer inbred rat strains. PMID:21118698

  10. Anatomical disassociation of amphetamine's rewarding and aversive effects: an intracranial microinjection study.

    PubMed

    Carr, G D; White, N M

    1986-01-01

    Amphetamine has rewarding properties in some behavioral paradigms, such as self-administration and conditioned place preference (CPP), but an aversive component is also apparent when the drug is tested with the conditioned taste aversion (CTA) paradigm. The present study was an attempt to determine the neuroanatomical substrates of the drug's rewarding and aversive effects. Previous evidence suggested that amphetamine's stimulation of activity in dopaminergic synapses is critical for both effects. Amphetamine was therefore micro-injected bilaterally (10 micrograms/0.5 microliter per side) into six different dopaminergic sites, each in a different group of animals: the medial prefrontal cortex, nucleus accumbens, anteromedial caudate nucleus, lateroventral caudate nucleus, amygdala, and the region subjacent to the area postrema (AP region). The effects of these injections in both the taste and place conditioning paradigms were examined in separate experiments. Of the six sites, a significant CPP was observed only with accumbens injections and a significant CTA was observed only with AP region injections. It was concluded that the accumbens plays a primary role in mediating the rewarding effects of amphetamine and that the AP region plays a primary role in mediating the CTA. This constitutes an anatomical disassociation of amphetamine's rewarding and aversive effects. The differential associative bias of place-reward and taste-aversion learning apparent in the results is discussed. PMID:3088661

  11. Pattern of cortical activation during processing of aversive stimuli in traumatized survivors of war and torture.

    PubMed

    Catani, Claudia; Adenauer, Hannah; Keil, Julian; Aichinger, Hannah; Neuner, Frank

    2009-09-01

    Posttraumatic stress disorder (PTSD) has been associated with an altered processing of threat-related stimuli. In particular, an attentional bias towards threat cues has been consistently found in behavioral studies. However, it is unclear whether increased attention towards threat cues translates into preferential processing as neurophysiological studies have yielded inconsistent findings. The aim of the present study was to investigate the neocortical activity related to the processing of aversive stimuli in patients with PTSD. 36 survivors of war and torture with PTSD, 21 Trauma Controls and 20 Unexposed Subjects participated in a visual evoked magnetic field study using flickering pictures of varying affective valence as stimulus material. Minimum norm source localization was carried out to estimate the distribution of sources of the evoked neuromagnetic activity in the brain. Statistical permutation analyses revealed reduced steady-state visual evoked field amplitudes over occipital areas in response to aversive pictures for PTSD patients and for Trauma Controls in comparison to unexposed subjects. Furthermore, PTSD patients showed a hyperactivation of the superior parietal cortex selectively in response to aversive stimuli, which was related to dissociative symptoms as well as to torture severity. The results indicate a different pattern of cortical activation driven by aversive stimuli depending on the experience of multiple traumatic events and PTSD. Whereas, a decreased visual processing of aversive stimuli seems to be associated with trauma exposure in general, the superior parietal activity might represent a specific process linked to the diagnosis of PTSD. PMID:19360450

  12. Organization of Neural Systems for Aversive Information Processing: Pain, Error, and Punishment

    PubMed Central

    Kobayashi, Shunsuke

    2012-01-01

    The avoidance of aversive events is critically important for the survival of organisms. It has been proposed that the medial pain system, including the amygdala, periaqueductal gray (PAG), and anterior cingulate cortex (ACC), contains the neural circuitry that signals pain affect and negative value. This system appears to have multiple defense mechanisms, such as rapid stereotyped escape, aversive association learning, and cognitive adaptation. These defense mechanisms vary in speed and flexibility, reflecting different strategies of self-protection. Over the course of evolution, the medial pain system appears to have developed primitive, associative, and cognitive solutions for aversive avoidance. There may be a functional grading along the caudal-rostral axis, such that the amygdala-PAG system underlies automatic and autonomic responses, the amygdala-orbitofrontal system contributes to associative learning, and the ACC controls cognitive processes in cooperation with the lateral prefrontal cortex. A review of behavioral and physiological studies on the aversive system is presented, and a conceptual framework for understanding the neural organization of the aversive avoidance system is proposed. PMID:23049496

  13. Role of the area postrema in radiation-induced taste aversion learning and emesis in cats

    SciTech Connect

    Rabin, B.M.; Hunt, W.A.; Chedester, A.L.; Lee, J.

    1986-01-01

    The role of the area postrema in radiation-induced emesis and taste aversion learning and the relationship between these behaviors were studied in cats. The potential involvement of neural factors which might be independent of the area postrema was minimized by using low levels of ionizing radiation (100 rads at a dose rate of 40 rads/min) to elicit a taste aversion, and by using body-only exposures (4500 and 6000 rads at 450 rads/min) to produce emesis. Lesions of the area postrema disrupted both taste aversion learning and emesis following irradiation. These results, which indicate that the area postrema is involved in the mediation of both radiation-induced emesis and taste aversion learning in cats under these experimental conditions, are interpreted as being consistent with the hypotheses that similar mechanisms mediate both responses to exposure to ionizing radiation, and that the taste aversion learning paradigm can therefore serve as a model system for studying radiation-induced emesis.

  14. Effect of stimulus context and repeated aversive visual stimulation on the cardiac correlate of attention.

    PubMed

    Lefave, M K; Neufeld, R W

    1977-02-01

    The experiment investigated cardiac deceleration responses to repeated presentations of an aversive visual stimulus (a slide of a mutilated homicide victim) as a function of interspersing presentations of different types of other provocative visual stimuli amidst the aversive stimulus. 30 male volunteers were divided into three groups of 10 subjects each. One group viewed the aversive stimulus randomly interspersed with presentations of female nudes (positive context); a second group viewed the aversive stimulus amidst presentations of slides of skin-disease patients (negative context); and the third group viewed the aversive slide surrounded by presentations of other male undergraduates (neutral context). After repeatedly viewing the single homocide-victim slide, subjects viewed five different homicide scenes without contextual slides. These identical procedures were repeated during a second experimental session. A significant context-by-sessions interaction (p less than .05) reflected a decrement in cardiac deceleration over sessions for the positive context and an increase in deceleration from the first to the second session for the negative context. The neutral context did not affect cardiac deceleration over sessions. The series of different homicide scenes elicited greater cardiac deceleration than repeated exposures to the same slide. These results were discussed in terms of the possible role of stimulus context in affecting attention and vigilant-avoidant coping orientations. PMID:840594

  15. Aversive Learning in Honeybees Revealed by the Olfactory Conditioning of the Sting Extension Reflex

    PubMed Central

    Vergoz, Vanina; Roussel, Edith; Sandoz, Jean-Christophe; Giurfa, Martin

    2007-01-01

    Invertebrates have contributed greatly to our understanding of associative learning because they allow learning protocols to be combined with experimental access to the nervous system. The honeybee Apis mellifera constitutes a standard model for the study of appetitive learning and memory since it was shown, almost a century ago, that bees learn to associate different sensory cues with a reward of sugar solution. However, up to now, no study has explored aversive learning in bees in such a way that simultaneous access to its neural bases is granted. Using odorants paired with electric shocks, we conditioned the sting extension reflex, which is exhibited by harnessed bees when subjected to a noxious stimulation. We show that this response can be conditioned so that bees learn to extend their sting in response to the odorant previously punished. Bees also learn to extend the proboscis to one odorant paired with sugar solution and the sting to a different odorant paired with electric shock, thus showing that they can master both appetitive and aversive associations simultaneously. Responding to the appropriate odorant with the appropriate response is possible because two different biogenic amines, octopamine and dopamine subserve appetitive and aversive reinforcement, respectively. While octopamine has been previously shown to substitute for appetitive reinforcement, we demonstrate that blocking of dopaminergic, but not octopaminergic, receptors suppresses aversive learning. Therefore, aversive learning in honeybees can now be accessed both at the behavioral and neural levels, thus opening new research avenues for understanding basic mechanisms of learning and memory. PMID:17372627

  16. Twins less frequent than expected among male births in risk averse populations.

    PubMed

    Karasek, Deborah; Goodman, Julia; Gemmill, Alison; Falconi, April; Hartig, Terry; Magganas, Aristotle; Catalano, Ralph

    2015-06-01

    Male twin gestations exhibit higher incidence of fetal morbidity and mortality than singleton gestations. From an evolutionary perspective, the relatively high rates of infant and child mortality among male twins born into threatening environments reduce the fitness of these gestations, making them more vulnerable to fetal loss. Women do not perceive choosing to spontaneously abort gestations although the outcome may result from estimates, made without awareness, of the risks of continuing a pregnancy. Here, we examine whether the non-conscious decisional biology of gestation can be linked to conscious risk aversion. We test this speculation by measuring the association between household surveys in Sweden that gauge financial risk aversion in the population and the frequency of twins among live male births. We used time-series regression methods to estimate our suspected associations and Box-Jenkins modeling to ensure that autocorrelation did not confound the estimation or reduce its efficiency. We found, consistent with theory, that financial risk aversion in the population correlates inversely with the odds of a twin among Swedish males born two months later. The odds of a twin among males fell by approximately 3.5% two months after unexpectedly great risk aversion in the population. This work implies that shocks that affect population risk aversion carry implications for fetal loss in vulnerable twin pregnancies. PMID:25917386

  17. Development of an aversive Pavlovian-to-instrumental transfer task in rat

    PubMed Central

    Campese, Vincent; McCue, Margaret; Lázaro-Muñoz, Gabriel; LeDoux, Joseph E.; Cain, Christopher K.

    2013-01-01

    Pavlovian-to-instrumental transfer (PIT) is an effect whereby a classically conditioned stimulus (CS) enhances ongoing instrumental responding. PIT has been extensively studied with appetitive conditioning but barely at all with aversive conditioning. Although it's been argued that conditioned suppression is a form of aversive PIT, this effect is fundamentally different from appetitive PIT because the CS suppresses, instead of facilitates, responding. Five experiments investigated the importance of a variety of factors on aversive PIT in a rodent Sidman avoidance paradigm in which ongoing shuttling behavior (unsignaled active avoidance or USAA) was facilitated by an aversive CS. Experiment 1 demonstrated a basic PIT effect. Experiment 2 found that a moderate amount of USAA extinction produces the strongest PIT with shuttling rates best at around 2 responses per minute prior to the CS. Experiment 3 tested a protocol in which the USAA behavior was required to reach the 2-response per minute mark in order to trigger the CS presentation and found that this produced robust and reliable PIT. Experiment 4 found that the Pavlovian conditioning US intensity was not a major determinant of PIT strength. Experiment 5 demonstrated that if the CS and US were not explicitly paired during Pavlovian conditioning, PIT did not occur, showing that CS-US learning is required. Together, these studies demonstrate a robust, reliable and stable aversive PIT effect that is amenable to analysis of neural circuitry. PMID:24324417

  18. Bitter receptor gene (TAS2R38) P49A genotypes and their associations with aversion to vegetables and sweet/fat foods in Malaysian subjects.

    PubMed

    Ooi, Shee-Xuen; Lee, Pui-Leng; Law, Huey-Yi; Say, Yee-How

    2010-01-01

    Recently, the bitter receptor gene (TAS2R38) was identified to be responsible for phenylthiocarbamide (PTC) bitter sensitivity. Its two predominant haplotypes at three Single Nucleotide Polymorphisms (SNPs) are found to be definitive for the PTC status, which the ProAlaVal and AlaValIle haplotypes are associated with tasters and non-tasters, respectively. TAS2R38 haplotypes have been reported to influence food preferences (like cruciferous vegetables and fat foods) and cardiovascular disease risk factors. We examined, in 215 Malaysian subjects (100 males, 115 females), the association of the P49A SNP of TAS2R38 with anthropometric measurements and aversion to a list of 36 vegetables, 4 soy products, green tea and 37 sweet/fat foods. The subjects were successfully genotyped as 110 PA, 81 PP and 24 AA (with the A49 allelic frequency of 0.37), by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP). Ethnicity (Malay, Chinese or Indian), but not gender, was associated with the P49A TAS2R38 genotypes (p<0.001). However, no significant differences in terms of Body Mass Index, Total Body Fat, waist circumference and Waist-Hip Ratio were found between the genotypes (p<0.05). Only aversions to green tea, mayonnaise and whipped cream, but not soy products, vegetables, and other sweet/fat foods, were associated with the P49A genotypes (p<0.05). Therefore, the P49A SNP of the bitter receptor gene TAS2R38 could not serve as a predictor of anthropometric measurements and aversion to vegetables or sweet/fat foods in the sampled Malaysian subjects, and this suggests the existence of other possible factors influencing food selection among Malaysians. PMID:21147709

  19. Off-vertical rotation produces conditioned taste aversion and suppressed drinking in mice

    NASA Technical Reports Server (NTRS)

    Fox, R. A.; Lauber, A. H.; Daunton, N. G.; Phillips, M.; Diaz, L.

    1984-01-01

    The effects of off-vertical rotation upon the intake of tap water immediately after rotation and upon conditioned taste aversion were assessed in mice with the tilt of the rotation axis varying from 5 to 20 deg from the earth-vertical. Conditioned taste aversion occurred in all mice that were rotated, but the intake of tap water was suppressed only in mice that were rotated at 15 or 20 deg of tilt. The greater suppression of tap-water intake and the stronger conditioned aversion in the mouse as the angle of tilt was increased in this experiment are consistent with predictions from similar experiments with human subjects, where motion sickness develops more rapidly as the angle of tilt is increased. It was suggested that off-vertical rotation may be a useful procedure for insuring experimental control over vestibular stimulation in animal studies of motion sickness.

  20. Olfactory aversion: notes on procedure, with speculations on its mechanism of effect.

    PubMed

    Laws, D R

    2001-10-01

    The use of a self-administered noxious agent to suppress deviant sexual arousal is the focus of this paper. A recommended procedure for the use of olfactory aversion is described. Data from two publications by the author, wherein different noxious agents had been used, are presented and discussed. Several explanations for the mechanism of effect in olfactory aversion have been offered. Two of these, one using a nausea-producing agent and one using a pain-producing agent are described. The procedure using the pain-producing agent is the simplest to implement, the least ambiguous, and offers the least cumbersome explanation for the behavioral effect observed in olfactory aversion. However, a conditioning explanation is probably too simple. Several examples of cognitive mediation in conditioning procedures are presented and discussed. PMID:11677928

  1. Estradiol enhances the acquisition of lithium chloride-induced conditioned taste aversion in castrated male rats

    NASA Astrophysics Data System (ADS)

    Lin, Shih-Fan; Tsai, Yuan-Feen; Tai, Mei-Yun; Yeh, Kuei-Ying

    2015-10-01

    The present study examined the effects of short-term treatment with ovarian hormones on the acquisition of conditioned taste aversion (CTA). Adult male rats were castrated and randomly divided into LiCl- and saline-treated groups. Nineteen days after castration, all of the animals were subjected to 23.5-h daily water deprivation for seven successive days (day 1 to day 7). On the conditioning day (day 8), the rats received either a 4 ml/kg of 0.15 M LiCl or the same dose of saline injection immediately after administration of a 2 % sucrose solution during the 30-min water session. Starting from day 6, rats in both groups received one of the following treatments: daily subcutaneous injection of (1) estradiol alone (30 μg/kg; estradiol benzoate (E) group), (2) estradiol plus progesterone (500 μg; E + progesterone (P) group), or (3) olive oil. From day 9 to day 11, all of the rats were given daily two-bottle preference tests during the 30-min fluid session. The estradiol and estradiol plus progesterone treatments in the LiCl groups resulted in significantly lower preference scores for the sucrose solution compared with the olive oil treatment groups, but no difference in preference score was seen between these two groups. These results indicate that both the estradiol and estradiol plus progesterone treatments in the LiCl groups enhanced the acquisition of CTA learning and suggest that estradiol affects the acquisition of CTA mediated by an activational effect in male rats, whereas progesterone treatment does not influence the effects of estradiol on the acquisition of CTA.

  2. fMRI neurofeedback of amygdala response to aversive stimuli enhances prefrontal-limbic brain connectivity.

    PubMed

    Paret, Christian; Ruf, Matthias; Gerchen, Martin Fungisai; Kluetsch, Rosemarie; Demirakca, Traute; Jungkunz, Martin; Bertsch, Katja; Schmahl, Christian; Ende, Gabriele

    2016-01-15

    Down-regulation of the amygdala with real-time fMRI neurofeedback (rtfMRI NF) potentially allows targeting brain circuits of emotion processing and may involve prefrontal-limbic networks underlying effective emotion regulation. Little research has been dedicated to the effect of rtfMRI NF on the functional connectivity of the amygdala and connectivity patterns in amygdala down-regulation with neurofeedback have not been addressed yet. Using psychophysiological interaction analysis of fMRI data, we present evidence that voluntary amygdala down-regulation by rtfMRI NF while viewing aversive pictures was associated with increased connectivity of the right amygdala with the ventromedial prefrontal cortex (vmPFC) in healthy subjects (N=16). In contrast, a control group (N=16) receiving sham feedback did not alter amygdala connectivity (Group×Condition t-contrast: p<.05 at cluster-level). Task-dependent increases in amygdala-vmPFC connectivity were predicted by picture arousal (β=.59, p<.05). A dynamic causal modeling analysis with Bayesian model selection aimed at further characterizing the underlying causal structure and favored a bottom-up model assuming predominant information flow from the amygdala to the vmPFC (xp=.90). The results were complemented by the observation of task-dependent alterations in functional connectivity of the vmPFC with the visual cortex and the ventrolateral PFC in the experimental group (Condition t-contrast: p<.05 at cluster-level). Taken together, the results underscore the potential of amygdala fMRI neurofeedback to influence functional connectivity in key networks of emotion processing and regulation. This may be beneficial for patients suffering from severe emotion dysregulation by improving neural self-regulation. PMID:26481674

  3. Attending to the outcome of others: disadvantageous inequity aversion in male capuchin monkeys (Cebus apella).

    PubMed

    Fletcher, Grace E

    2008-09-01

    Brosnan and de Waal [Nature 425:297-299, 2003] reported that capuchin monkeys responded negatively to unequal reward distributions between themselves and another individual when comparing their own rewards with that of their partner. It was suggested that social emotions provided the underlying motivation for such behavior and that this inequity aversion is specific to the social domain. However, alternative hypotheses such as the "frustration effect" or the "food expectation hypothesis" may provide more parsimonious explanations for Brosnan and de Waal's [Nature 425:297-299] results, while others have argued that these findings are not congruent with the Fehr-Schmidt inequity aversion model cited by the authors. The claim that inequity aversion behavior is specific to the social domain has also been questioned, as primates also develop expectations about rewards in the absence of partners, and react negatively when those expectations are violated. In this study, a modified Dictator game was used to investigate whether capuchins would exhibit either disadvantageous inequity aversion behavior or reference-dependent expectancy violation in social and nonsocial conditions, respectively. When given the choice between an equitable and an inequitable outcome, the subjects showed disadvantageous inequity aversion behavior, choosing the equitable outcome significantly more in the social condition. In the nonsocial condition, however, subjects did not show negative expectancy violation resulting from the formation of reference-dependent expectations, choosing the equitable outcome at chance levels. These results suggest that capuchins attend to differential payoffs and that they are averse to inequity, which is disadvantageous to themselves. PMID:18521838

  4. Lesions of the Medial Prefrontal Cortex Abolish Conditioned Aversion Associated with Sexual Behavior in Male Rats

    PubMed Central

    Davis, Jon F.; Loos, Maarten; Di Sebastiano, Andrea R.; Brown, Jennifer L.; Lehman, Michael N.; Coolen, Lique M.

    2010-01-01

    BACKGROUND An inability to inhibit behaviors once they become maladaptive is a component of several psychiatric illnesses and the medial prefrontal cortex (mPFC) was identified as a potential mediator of behavioral inhibition. The current study tested if the mPFC is involved in inhibition of sexual behavior when associated with aversive outcomes. METHODS Using male rats, effects of lesions of the infralimbic (IL) and prelimbic (PL) areas of the mPFC on expression of sexual behavior and ability to inhibit mating were tested using a paradigm of copulation-contingent aversion. RESULTS mPFC lesions did not alter expression of sexual behavior. In contrast, mPFC lesions completely blocked the acquisition of sex-aversion conditioning and lesioned animals continued to mate, in contrast to the robust behavioral inhibition towards copulation in mPFC intact males, resulting in only 22% of intact males continuing to mate. However, rats with mPFC lesions were capable of forming a conditioned place preference to sexual reward and conditioned place aversion for lithium chloride, suggesting that these lesions did not alter associative learning or sensitivity for lithium chloride. DISCUSSION The current study indicates that animals with mPFC lesions are likely capable of forming the associations with aversive outcomes of their behavior, but lack the ability to suppress seeking of sexual reward in the face of aversive consequences. These data may contribute to a better understanding of a common pathology underlying impulse control disorders as compulsive sexual behavior has a high prevalence of comorbidity with psychiatric disorders and Parkinson’s Disease. PMID:20346444

  5. Striatal-Enriched Protein Tyrosine Phosphatase Controls Responses to Aversive Stimuli: Implication for Ethanol Drinking

    PubMed Central

    Legastelois, Rémi; Darcq, Emmanuel; Wegner, Scott A.; Lombroso, Paul J.; Ron, Dorit

    2015-01-01

    The STriatal-Enriched protein tyrosine Phosphatase (STEP) is a brain-specific phosphatase whose dysregulation in expression and/or activity is associated with several neuropsychiatric disorders. We recently showed that long-term excessive consumption of ethanol induces a sustained inhibition of STEP activity in the dorsomedial striatum (DMS) of mice. We further showed that down-regulation of STEP expression in the DMS, and not in the adjacent dorsolateral striatum, increases ethanol intake, suggesting that the inactivation of STEP in the DMS contributes to the development of ethanol drinking behaviors. Here, we compared the consequence of global deletion of the STEP gene on voluntary ethanol intake to the consumption of an appetitive rewarding substance (saccharin) or an aversive solution (quinine or denatonium). Whereas saccharin intake was similar in STEP knockout (KO) and wild type (WT) littermate mice, the consumption of ethanol as well as quinine and denatonium was increased in STEP KO mice. These results suggested that the aversive taste of these substances was masked upon deletion of the STEP gene. We therefore hypothesized that STEP contributes to the physiological avoidance towards aversive stimuli. To further test this hypothesis, we measured the responses of STEP KO and WT mice to lithium-induced conditioned place aversion (CPA) and found that whereas WT mice developed lithium place aversion, STEP KO mice did not. In contrast, conditioned place preference (CPP) to ethanol was similar in both genotypes. Together, our results indicate that STEP contributes, at least in part, to the protection against the ingestion of aversive agents. PMID:25992601

  6. The learning curves of competitive programming

    NASA Astrophysics Data System (ADS)

    Garcia, Jose R.; Aguirre, Vanessa E.

    2014-10-01

    Universities around the world have implemented competitive programming as an approach to teach computer science courses. They have empirically validated this approach as a successful pedagogical tool. However, there are no conclusive results that describe the degree in which competitive programming affects the learning process of the students. In this paper, we report on the learning curves obtained from analyzing ten years of TopCoder algorithm competitions. We discuss on how these learning curves apply to university courses and can help us explain the influence of competitive programming in a class.

  7. The aversiveness of carbon dioxide stunning in pigs and a comparison of the CO(2) stunner crate vs. the V-restrainer.

    PubMed

    Jongman; Barnett; Hemsworth

    2000-03-22

    Using aversion learning techniques, the relative aversiveness of CO(2) to pigs in comparison to a shock with an electric prodder, and the aversiveness of a CO(2)-stunner crate in comparison to the aversiveness of a V-belt restrainer used for electric stunning were examined. The results showed that 90% CO(2) was considerably less aversive than an electric shock with a prodder. However, during exposure to 90% CO(2) all pigs lost conscious, which may have affected their memory of the procedure. The pigs remained conscious after exposure to 60% CO(2) and again showed virtually no aversion towards the stunner crate, while an electric shock with a prodder appeared highly aversive. The aversion to the V-restrainer belt and the CO(2) crate were similar. PMID:10719190

  8. Failure of Serial Taste-Taste Compound Presentations to Produce Overshadowing of Extinction of Conditioned Taste Aversion

    ERIC Educational Resources Information Center

    Pineno, Oskar

    2010-01-01

    Two experiments were conducted to study overshadowing of extinction in a conditioned taste aversion preparation. In both experiments, aversive conditioning with sucrose was followed by extinction treatment with either sucrose alone or in compound with another taste, citric acid. Experiment 1 employed a simultaneous compound extinction treatment…

  9. The Effect of Swimming Experience on Acquisition and Retention of Swimming-Based Taste Aversion Learning in Rats

    ERIC Educational Resources Information Center

    Masaki, Takahisa; Nakajima, Sadahiko

    2010-01-01

    Swimming endows rats with an aversion to a taste solution consumed before swimming. The present study explored whether the experience of swimming before or after the taste-swimming trials interferes with swimming-based taste aversion learning. Experiment 1 demonstrated that a single preexposure to 20 min of swimming was as effective as four or…

  10. Impact of appetitive and aversive outcomes on brain responses: linking the animal and human literatures

    PubMed Central

    Bissonette, Gregory B.; Gentry, Ronny N.; Padmala, Srikanth; Pessoa, Luiz; Roesch, Matthew R.

    2014-01-01

    Decision-making is motivated by the possibility of obtaining reward and/or avoiding punishment. Though many have investigated behavior associated with appetitive or aversive outcomes, few have examined behaviors that rely on both. Fewer still have addressed questions related to how anticipated appetitive and aversive outcomes interact to alter neural signals related to expected value, motivation, and salience. Here we review recent rodent, monkey, and human research that address these issues. Further development of this area will be fundamental to understanding the etiology behind human psychiatric diseases and cultivating more effective treatments. PMID:24624062

  11. [Apparative aversive therapy in combination with verbal suggestions in special obsessional syndromes (initial investigation)].

    PubMed

    Dummer, W

    1977-12-01

    The author restricts the use of aversion therapy by means of deliberate production of pain to obsessional, especially therapy-resistant disturbances of a permanent nature, with consideration being, of course, given to ethical factors. Experiences worthy of generalization are derived from methodically varied courses of treatment, bringing out suggestive moments subliminally involved in any therapeutical situation and also specifically used by the therapist. In addition, the author emphasizes the need for simultaneously developing, besides aversion therapy, positive attitudes and behavior patterns. PMID:609650

  12. Conditioned taste aversion induced by motion is prevented by selective vagotomy in the rat

    NASA Technical Reports Server (NTRS)

    Fox, Robert A.; Mckenna, Susan

    1991-01-01

    The role of the vagus nerve in motion-induced conditioned taste aversion (CTA) was studied in hooded rats. Animals with complete, selective gastric vagotomy failed to form conditioned taste aversion after multiple conditioning sessions in which the conditioned stimulus (a cider vinegar solution) was drunk immediately before a 30-min exposure to vertical axis rotation at 150 deg/s. Results are discussed with reference to the use of CTA as a measure of motion-induced 'sickness' or gastrointestinal disturbance, and because motion-induced CTA requires that both the vagus nerve and the vestibular apparatus be intact, in light of the possible convergence of vegal and vestibular functions.

  13. Role for the rostromedial tegmental nucleus in signaling the aversive properties of alcohol

    PubMed Central

    Glover, Elizabeth J.; McDougle, Molly J.; Siegel, Griffin S.; Jhou, Thomas C.; Chandler, L. Judson

    2016-01-01

    Background While the rewarding effects of alcohol contribute significantly to its addictive potential, it is becoming increasingly appreciated that alcohol’s aversive properties also play an important role in the propensity to drink. Despite this, the neurobiological mechanism for alcohol’s aversive actions is not well understood. The rostromedial tegmental nucleus (RMTg) was recently characterized for its involvement in aversive signaling and has been shown to encode the aversive properties of cocaine, yet its involvement in alcohol’s aversive actions have not been elucidated. Methods Adult male and female Long-Evans rats underwent conditioned taste aversion (CTA) procedures where exposure to a novel saccharin solution was paired with i.p. administration of saline, lithium chloride (LiCl), or ethanol (EtOH). Control rats underwent the same paradigm except that drug and saccharin exposure were explicitly unpaired. Saccharin consumption was measured on test day in the absence of drug administration and rats were sacrificed 90–105 min following access to saccharin. Brains were subsequently harvested and processed for cFos immunohistochemistry. The number of cFos labeled neurons was counted in the RMTg and the lateral habenula (LHb) – a region that sends prominent glutamatergic input to the RMTg. Results In rats that received paired drug and saccharin exposure, EtOH and LiCl induced significant CTA compared to saline to a similar degree in males and females. Both EtOH- and LiCl-induced CTA significantly enhanced cFos expression in the RMTg and LHb but not the hippocampus. Similar to behavioral measures, no significant effect of sex on CTA-induced cFos expression was observed. cFos expression in both the RMTg and LHb was significantly correlated to CTA magnitude with greater cFos being associated with more pronounced CTA. In addition, cFos expression in the RMTg was positively correlated with LHb cFos. Conclusions These data suggest that the RMTg and LHb are

  14. Competition in the Marketplace.

    ERIC Educational Resources Information Center

    Schug, Mark C.; And Others

    1984-01-01

    The conceptual introduction to this issue focuses on two questions: why study competition and what is a competitive market. Four instructional units follow, beginning with "Choosing Competitors." This preschool and kindergarten unit involves students in competitive games (naming colors), role playing competitive behaviors, comparing toys, and…

  15. Essays on competition in electricity markets

    NASA Astrophysics Data System (ADS)

    Bustos Salvagno, Ricardo Javier

    The first chapter shows how technology decisions affect entry in commodity markets with oligopolistic competition, like the electricity market. I demonstrate an entry deterrence effect that works through cost uncertainty. Technology's cost uncertainty affects spot market expected profits through forward market trades. Therefore, incentives to engage in forward trading shape firms' decisions on production technologies. I show that high-cost but low-risk technologies are adopted by risk-averse incumbents to deter entry. Strategic technology adoption can end in a equilibrium where high-cost technologies prevail over low-cost but riskier ones. In the case of incumbents who are less risk-averse than entrants, entry deterrence is achieved by choosing riskier technologies. The main results do not depend on who chooses their technology first. Chapter two examines the Chilean experience on auctions for long-term supply contracts in electricity markets from 2006 to 2011. Using a divisible-good auction model, I provide a theoretical framework that explains bidding behavior in terms of expected spot prices and contracting positions. The model is extended to include potential strategic behavior on contracting decisions. Empirical estimations confirm the main determinants of bidding behavior and show heterogeneity in the marginal cost of over-contracting depending on size and incumbency. Chapter three analyzes the lag in capacity expansion in the Chilean electricity market from 2000 to 2004. Regarded as a result of regulatory uncertainty, the role of delays in the construction of a large hydro-power plant has been overlooked by the literature. We argue that those delays postponed projected investment and gave small windows of opportunity that only incumbents could take advantage of. We are able to retrace the history of investments through real-time information from the regulator's reports and a simple model enables us to explain the effect of those delays on suggested and under

  16. Host defence mediates interspecific competition in ectoparasites.

    PubMed

    Bush, Sarah E; Malenke, Jael R

    2008-05-01

    1. Interspecific competition influences which, how many and where species coexist in biological communities. Interactions between species in different trophic levels can mediate interspecific competition; e.g. predators are known to reduce competition between prey species by suppressing their population sizes. A parallel phenomenon may take place in host-parasite systems, with host defence mediating competition between parasite species. 2. We experimentally investigated the impact of host defence (preening) on competitive interactions between two species of feather-feeding lice: 'wing' lice Columbicola columbae and 'body' lice Campanulotes compar. Both species are host-specific parasites that co-occur on rock pigeons Columba livia. 3. We show that wing lice and body lice compete and that host defence mediates the magnitude of this competitive interaction. 4. Competition is asymmetrical; wing louse populations are negatively impacted by body lice, but not vice versa. This competitive asymmetry is consistent with the fact that body lice predominate in microhabitats on the host's body that offer the most food and the most space. 5. Our results indicate that host-defence-mediated competition can influence the structure of parasite communities and may play a part in the evolution of parasite diversity. PMID:18194262

  17. Effects of antiemetics on the acquisition and recall of radiation- and lithium chloride-induced conditioned taste aversions

    SciTech Connect

    Rabin, B.M.; Hunt, W.A.

    1983-04-01

    A series of experiments were run to evaluate the effect of antiemetics on the acquisition and recall of a conditioned taste aversion induced by exposure to ionizing radiation or by injection of lithium chloride. Groups of male rats were exposed to 100 rad gamma radiation or 3 mEq/kg lithium chloride following consumption of a 10% sucrose solution. They were then injected with saline or with one of three antiemetics (prochlorperazine, trimethobenzamide, or cyclizine) at dose levels that have been reported to be effective in attenuating a previously acquired lithium chloride-induced taste aversion. The pretreatments with antiemetics had no effect on the acquisition or recall of either the lithium chloride- or radiation-induced taste aversion. The data suggest that antiemetics do not disrupt lithium chloride-induced taste aversions as previously reported, nor do they effect radiation-induced taste aversion learning.

  18. The effects of uncontrollable, unpredictable aversive and appetitive events: similar effects warrant similar, but not identical, explanations?

    PubMed

    Job, R F Soames

    2002-01-01

    Exposure to uncontrollable, unpredictable appetitive events produces a variety of cognitive debilitations and vegetative changes, as does exposure to uncontrollable, unpredictable aversive events. Similarities include impaired escape from aversive events, impaired discrimination, finicky consumption, analgesia, and body weight loss. However, in stark contrast, uncontrollable aversive stress causes reduced motor activity where as similar appetitive treatment does not; aversively induced debilitation is causally related to energy regulation, whereas the appetitively induced effects are not. Parallel mechanisms are suggested to explain these effects in terms of a revised anxiety account of the aversive effects, and a frustration account of the appetitive effects. Finally, factors likely to limit important research to resolve the many remaining issues are identified: negative presentation of animal research, political decision making, and ignorance and fear in committees which review the ethics of research. PMID:12069366

  19. Effects of the neuroleptic alpha-flupenthixol on latent inhibition in aversively- and appetitively-motivated paradigms: evidence for dopamine-reinforcer interactions.

    PubMed

    Killcross, A S; Dickinson, A; Robbins, T W

    1994-06-01

    Three experiments examined the influence of the dopamine (DA) D1/D2 receptor antagonist alpha-flupenthixol on the latent inhibition (LI) effect. LI is a phenomenon which is manifest when non-reinforced pre-exposure to a stimulus retards subsequent conditioning to that stimulus, and has been proposed as an animal model of the selective attentional processes that are disrupted in acute schizophrenia. Experiment 1 extended previous findings that neuroleptics enhance the LI effect in conditioned suppression paradigms in rats to alpha-flupenthixol (0.23 mg/kg). Experiment 2 demonstrated that this enhancement of the LI effect was also seen in a parallel appetitively-motivated conditioning paradigm at the same dose. In both Experiment 1 and Experiment 2, the enhancement of the LI effect by alpha-flupenthixol appeared to be accompanied by a decrease in the impact of the reinforcer (be it appetitive or aversive). Experiment 3 investigated the possible role of the reinforcer in the effect of alpha-flupenthixol on the LI effect in the aversive, conditioned suppression paradigm by increasing the intensity of footshock in rats treated with alpha-flupenthixol. Increasing the intensity of the footshock completely abolished the enhancement of LI found following injection of alpha-flupenthixol, a result which could not be attributed to a floor effect. The results provide no support for interpretations of the influence of DA manipulations on the LI effect that draw parallels with deficits in selective attention observed in acute schizophrenia. PMID:7862895

  20. Fos and Egr1 Expression in the Rat Brain in Response to Olfactory Cue after Taste-Potentiated Odor Aversion Retrieval

    ERIC Educational Resources Information Center

    Cattarelli, Martine; Dardou, David; Datiche, Frederique

    2006-01-01

    When an odor is paired with a delayed illness, rats acquire a relatively weak odor aversion. In contrast, rats develop a strong aversion to an olfactory cue paired with delayed illness if it is presented simultaneously with a gustatory cue. Such a conditioning effect has been referred to as taste-potentiated odor aversion learning (TPOA). TPOA is…

  1. Influence of salinity, competition and food supply on the growth of Gobiosoma robustum and Microgobius gulosus from Florida Bay, U. S. A.

    USGS Publications Warehouse

    Schofield, P.J.

    2004-01-01

    The code Gobiosoma robustum and clown Microgobius gulosus gobies were grown in the laboratory over 27 days at two salinities (5 and 35), two food levels [low (a fixed proportion of initial mass) and high (saturation)] and both with and without the presence of the other species. Both species exhibited greatest growth at the high food level and the low (5) salinity. Neither species was affected by the presence of the other species, and there were no overall differences in growth between the two species. Thus, the observed competitive superiority of G. robustum over M. gulosus does not seem to confer an advantage relative to feeding success. Furthermore, as growth of G. robustum was greater at the lower salinity, it is clear that some factor other than salinity is restricting this species from north-eastern Florida Bay. Additional work on the importance of predation and food resources in various regions of Florida Bay is needed to further evaluate the underlying mechanisms responsible for the bay-wide distribution of these species. ?? 2004 The Fisheries Society of the British Isles.

  2. The entorhinal cortex is involved in conditioned odor and context aversions

    PubMed Central

    Ferry, Barbara; Herbeaux, Karine; Javelot, Hervé; Majchrzak, Monique

    2015-01-01

    In a natural environment, avoidance of a particular food source is mostly determined by a previous intake experience during which sensory stimuli such as food odor, become aversive through a simple associative conditioned learning. Conditioned odor aversion learning (COA) is a food conditioning paradigm that results from the association between a tasteless scented solution (conditioned stimulus, CS) and a gastric malaise (unconditioned stimulus, US) that followed its ingestion. In the present experimental conditions, acquisition of COA also led to acquisition of aversion toward the context in which the CS was presented (conditioned context aversion, CCA). Previous data have shown that the entorhinal cortex (EC) is involved in the memory processes underlying COA acquisition and context fear conditioning, but whether EC lesion modulates CCA acquisition has never be investigated. To this aim, male Long-Evans rats with bilateral EC lesion received CS-US pairings in a particular context with different interstimulus intervals (ISI). The results showed that the establishment of COA with long ISI obtained in EC-lesioned rats is associated with altered CCA learning. Since ISI has been suggested to be the determining factor in the odor- and context-US association, our results show that the EC is involved in the processes that control both associations relative to ISI duration. PMID:26483624

  3. Responses to Defense Cutbacks: The Dislocation Aversion Approach. Research and Evaluation Report Series 97-C.

    ERIC Educational Resources Information Center

    Social Policy Research Associates, Menlo Park, CA.

    Of the 19 projects conducted as part of the Defense Conversion Adjustment (DCA) Demonstration administered by the U.S. Department of Labor's Office of Work-Based Learning, 9 tested the dislocation aversion approach. The projects attempted to alleviate the negative impacts of defense cutbacks on communities, firms, and workers. Six projects…

  4. Development of Gaze Aversion: Qualitative Changes over the Early School Years

    ERIC Educational Resources Information Center

    Doherty-Sneddon, Gwyneth; Phelps, Fiona; Clark, Julia

    2007-01-01

    Looking away from an interlocutor's face during demanding cognitive activity can help adults and children answer challenging mental-arithmetic and verbal-reasoning questions (Glenberg, Schroeder, & Robertson, 1998; Phelps, Doherty-Sneddon, & Warnock, 2006). Whilst such "gaze aversion" (GA) is used far less by 5-year-old schoolchildren, its use…

  5. A comparison of neural responses to appetitive and aversive stimuli in humans and other mammals.

    PubMed

    Hayes, Dave J; Duncan, Niall W; Xu, Jiameng; Northoff, Georg

    2014-09-01

    Distinguishing potentially harmful or beneficial stimuli is necessary for the self-preservation and well-being of all organisms. This assessment requires the ongoing valuation of environmental stimuli. Despite much work on the processing of aversive- and appetitive-related brain signals, it is not clear to what degree these two processes interact across the brain. To help clarify this issue, this report used a cross-species comparative approach in humans (i.e. meta-analysis of imaging data) and other mammals (i.e. targeted review of functional neuroanatomy in rodents and non-human primates). Human meta-analysis results suggest network components that appear selective for appetitive (e.g. ventromedial prefrontal cortex, ventral tegmental area) or aversive (e.g. cingulate/supplementary motor cortex, periaqueductal grey) processing, or that reflect overlapping (e.g. anterior insula, amygdala) or asymmetrical, i.e. apparently lateralized, activity (e.g. orbitofrontal cortex, ventral striatum). However, a closer look at the known value-related mechanisms from the animal literature suggests that all of these macroanatomical regions are involved in the processing of both appetitive and aversive stimuli. Differential spatiotemporal network dynamics may help explain similarities and differences in appetitive- and aversion-related activity. PMID:25010558

  6. Psychophysiological and subjective indicators of aversive pavlovian conditioning in generalized social phobia.

    PubMed

    Hermann, Christiane; Ziegler, Silvio; Birbaumer, Niels; Flor, Herta

    2002-08-15

    Aversive conditioning has been proposed as an important etiologic mechanism in social phobia; however, empirical evidence is scarce and has not relied on a detailed analysis of the acquisition and extinction of the conditioned emotional response. Fourteen men sustaining generalized social phobia and 19 healthy control subjects participated in differential aversive conditioning with two neutral faces as conditioned stimuli and an aversive odor as unconditioned stimulus. Subjective and peripheral physiological responses were obtained. Both groups were successfully conditioned as reflected by differential subjective (valence, arousal, subjective unconditioned stimulus expectancy) and peripheral physiological responses (skin conductance, startle response). There was no evidence for an enhanced conditionability in the social phobics; however, they showed an enhanced unconditioned stimulus expectancy, especially for the nonreinforced conditioned stimuli during acquisition, and a delayed extinction of the conditioned skin conductance response as well as a certain dissociation between subjective and physiological responses.The enhanced unconditioned stimulus expectancy during acquisition and the overall elevated subjective arousal suggest that, under threat, subjects with generalized social phobia may be more prone to associate neutral social cues and an aversive outcome. Furthermore, delayed extinction of the conditioned response seems to contribute to the etiology and maintenance of generalized social phobia. PMID:12208640

  7. Student Aversion to Borrowing: Who Borrows and Who Doesn't

    ERIC Educational Resources Information Center

    Cunningham, Alisa F.; Santiago, Deborah A.

    2008-01-01

    For millions of students, the increasing cost of a college education, combined with lower rates of growth in grant aid, have resulted in additional reliance on student loans to pay for college. The large and growing role of student loans introduces a concern that an aversion to borrowing could be limiting college enrollment choices for some…

  8. Further Analysis of Variables That Affect Self-Control with Aversive Events

    ERIC Educational Resources Information Center

    Perrin, Christopher J.; Neef, Nancy A.

    2012-01-01

    The purpose of this study was to examine variables that affect self-control in the context of academic task completion by elementary school children with autism. In the baseline assessment of Study 1, mathematics problem completion was shown to be an aversive event, and sensitivity to task magnitude, task difficulty, and delay to task completion…

  9. Glucocorticoids Enhance Taste Aversion Memory via Actions in the Insular Cortex and Basolateral Amygdala

    ERIC Educational Resources Information Center

    Miranda, Maria Isabel; Quirarte, Gina L.; Rodriguez-Garcia, Gabriela; McGaugh, James L.; Roozendaal, Benno

    2008-01-01

    It is well established that glucocorticoid hormones strengthen the consolidation of hippocampus-dependent spatial and contextual memory. The present experiments investigated glucocorticoid effects on the long-term formation of conditioned taste aversion (CTA), an associative learning task that does not depend critically on hippocampal function.…

  10. Conditioned food aversion to control poisoning by Ipomoea carnea subsp. fistulosa in goats

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ipomoea carnea is a toxic plant often ingested by livestock in Brazil. Three experiments were conducted to determine if conditioned food aversion was effective in reducing goats’ consumption of I. carnea. In the fi rst experiment, 10 mildly intoxicated goats that had been eating I. carnea were avert...

  11. Measuring Aversion to Debt: An Experiment among Student Loan Candidates. Policy Research Working Paper 5737

    ERIC Educational Resources Information Center

    Caetano, Gregorio; Patrinos, Harry A.; Palacios, Miguel

    2011-01-01

    This paper reports the results of an experiment designed to test for the presence of debt aversion. The population who participated in the experiment were recent financial aid candidates and the experiment focused on student loans. The goal is to shed new light on different aspects of the perceptions with respect to debt. These perceptions can…

  12. Conditioned food aversion to control outbreaks of intoxication by Ipomoea carnea and Turbina cordata in goats

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conditioned food aversion is used to train livestock to avoid the ingestion of toxic plants. This technique was used to control Turbina cordata poisoning in goats in one farm, and to control Ipomoea carnea subsp. istulosa poisoning in another farm. The goats were penned at night and the next mornin...

  13. A CHRNA5 Smoking Risk Variant Decreases the Aversive Effects of Nicotine in Humans.

    PubMed

    Jensen, Kevin P; DeVito, Elise E; Herman, Aryeh I; Valentine, Gerald W; Gelernter, Joel; Sofuoglu, Mehmet

    2015-11-01

    Genome-wide association studies have implicated the CHRNA5-CHRNA3-CHRNB4 gene cluster in risk for heavy smoking and several smoking-related disorders. The heavy smoking risk allele might reduce the aversive effects of nicotine, but this hypothesis has not been tested in humans. We evaluated the effects of a candidate causal variant in CHRNA5, rs16969968, on the acute response to nicotine in European American (EA) and African American (AA) smokers (n=192; 50% AA; 73% male). Following overnight abstinence from nicotine, participants completed a protocol that included an intravenous (IV) dose of saline and two escalating IV doses of nicotine. The outcomes evaluated were the aversive, pleasurable, and stimulatory ratings of nicotine's effects, cardiovascular reactivity to nicotine, withdrawal severity, and cognitive performance before and after the nicotine administration session. The heavy smoking risk allele (rs16969968*A; frequency=28% (EA) and 6% (AA)) was associated with lower ratings of aversive effects (P<5 × 10(-8)) with marked specificity. This effect was evident in EA and AA subjects analyzed as separate groups and was most robust at the highest nicotine dose. Rs16969968*A was also associated with greater improvement on a measure of cognitive control (Stroop Task) following nicotine administration. These findings support differential aversive response to nicotine as one likely mechanism for the association of CHRNA5-CHRNA3-CHRNB4 with heavy smoking. PMID:25948103

  14. Neural Correlates of Appetitive-Aversive Interactions in Pavlovian Fear Conditioning

    ERIC Educational Resources Information Center

    Nasser, Helen M.; McNally, Gavan P.

    2013-01-01

    We used Pavlovian counterconditioning in rats to identify the neural mechanisms for appetitive-aversive motivational interactions. In Stage I, rats were trained on conditioned stimulus (CS)-food (unconditioned stimulus [US]) pairings. In Stage II, this appetitive CS was transformed into a fear CS via pairings with footshock. The development of…

  15. Differential Endocannabinoid Regulation of Extinction in Appetitive and Aversive Barnes Maze Tasks

    ERIC Educational Resources Information Center

    Harloe, John P.; Thorpe, Andrew J.; Lichtman, Aron H.

    2008-01-01

    CB[subscript 1] receptor-compromised animals show profound deficits in extinguishing learned behavior from aversive conditioning tasks, but display normal extinction learning in appetitive operant tasks. However, it is difficult to discern whether the differential involvement of the endogenous cannabinoid system on extinction results from the…

  16. Expression and pharmacological modulation of visceral pain-induced conditioned place aversion in mice.

    PubMed

    Bagdas, Deniz; Muldoon, Pretal P; AlSharari, Shakir; Carroll, F Ivy; Negus, S Stevens; Damaj, M Imad

    2016-03-01

    Pain encompasses both a sensory as well as an affective dimension and these are differentially processed in the brain and periphery. It is therefore important to develop animal models to reflect the non-reflexive assays in pain. In this study, we compared effects of the mu opioid receptor agonist morphine, the nonsteroidal anti-inflammatory drug ketoprofen and the kappa receptor opioid agonist U50,488H and antagonist JDTic on acetic acid-induced stretching and acetic acid-induced aversion in the condition place aversion (CPA) test in male ICR mice. Intraperitoneal administration of acetic acid (0.32-1%) was equipotent in stimulating stretching and CPA. Ketoprofen, morphine and U50,488H all inhibited the acid-induced stretching. Ketoprofen and morphine also blocked the acid-induced CPA but U50,488H failed to do so. The reversal ability of ketoprofen and morphine on acid-induced CPA is unique to pain-stimulated place aversion since these drugs failed to reduce non-noxious LiCl-induced CPA. Overall, this study characterized and validated a preclinical mouse model of pain-related aversive behavior that can be used to assess genetic and biological mechanisms of pain as well as improving the predictive validity of preclinical studies on candidate analgesics. PMID:26639043

  17. Are apes inequity averse? New data on the token-exchange paradigm.

    PubMed

    Bräuer, Juliane; Call, Josep; Tomasello, Michael

    2009-02-01

    Recent studies have produced mixed evidence about inequity aversion in nonhuman primates. Brosnan et al. [Proceedings of the Royal Society of London. Series B. Biological Sciences 272:253-258, 2005] found inequity aversion in chimpanzees and argued that effort is crucial, if subjects are to evaluate how they are rewarded in comparison to a competitor for an identical performance. In this study we investigated inequity aversion with chimpanzees, bonobos and orangutans, using the method of Brosnan et al. [Proceedings of the Royal Society of London. Series B. Biological Sciences 272:253-258, 2005] after introducing some methodological improvements. Subjects always received a less-preferred food in exchange for a token, whereas the competitor received either the same type of food for their token (equity) or a more favored food for it (inequity). Apes did not refuse more of the less-preferred food when a competitor had received the more favored food. Thus, with an improved methodology we failed to reproduce the findings of Brosnan et al. [Proceedings of the Royal Society of London. Series B. Biological Sciences 272:253-258, 2005] that apes show inequity aversion. PMID:19021260

  18. Conditioned flavor aversion and location avoidance in hamsters from toxic extract of tall larkspur (Delphinium barbeyi)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Studies were conducted to address conditioned flavour aversion (CFA) and place avoidance learning in hamsters given injections of alkaloid extracts from tall larkspur (Delphinium barbeyi), to determine if larkspur had reinforcing or negative properties sufficient to cause place avoidance or preferen...

  19. Steroid Hormone (20-Hydroxyecdysone) Modulates the Acquisition of Aversive Olfactory Memories in Pollen Forager Honeybees

    ERIC Educational Resources Information Center

    Geddes, Lisa H.; McQuillan, H. James; Aiken, Alastair; Vergoz, Vanina; Mercer, Alison R.

    2013-01-01

    Here, we examine effects of the steroid hormone, 20-hydroxyecdysone (20-E), on associative olfactory learning in the honeybee, "Apis mellifera." 20-E impaired the bees' ability to associate odors with punishment during aversive conditioning, but did not interfere with their ability to associate odors with a food reward (appetitive…

  20. Using Food Aversion to Decrease Severe Pica by a Child with Autism

    ERIC Educational Resources Information Center

    Ferreri, Summer J.; Tamm, Lori; Wier, Kristin G.

    2006-01-01

    Food aversion was shown to be effective in the reduction of plastic pica by a 4-year-old boy with autism. The participant was suffering from digestive complications due to the ingestion of plastic from a variety of toys. The intervention was initially conducted in the child's preschool classroom during instructional periods and was systematically…

  1. Emetic and Electric Shock Alcohol Aversion Therapy: Six- and Twelve-Month Follow-Up.

    ERIC Educational Resources Information Center

    Cannon, Dale S.; Baker, Timothy B.

    1981-01-01

    Follow-up data are presented for 6- and 12-months on male alcoholics (N=20) who received either a multifaceted inpatient alcoholism treatment program alone (controls) or emetic or shock aversion therapy in addition to that program. Both emetic and control subjects compiled more days of abstinence than shock subjects. (Author)

  2. Swimming-Induced Taste Aversion and Its Prevention by a Prior History of Swimming

    ERIC Educational Resources Information Center

    Masaki, Takahisa; Nakajima, Sadahiko

    2004-01-01

    In two experiments, the evidence showed that 20 min of forced swimming by rats caused aversion to a taste solution consumed before swimming. When one of two taste solutions (sodium saccharin or sodium chloride, counterbalanced across rats) was paired with swimming and the other was not, the rats' intakes of these two solutions showed less…

  3. On the Integration of Risk Aversion and Average-Performance Optimization in Reservoir Control

    NASA Astrophysics Data System (ADS)

    Nardini, Andrea; Piccardi, Carlo; Soncini-Sessa, Rodolfo

    1992-02-01

    The real-time operation of a reservoir is a matter of trade-off between the two criteria of risk aversion (to avoid dramatic failures) and average-performance optimization (to yield the best long-term average performance). A methodology taking into account both criteria is presented m this paper to derive "off-line" infinite-horizon control policies for a single multipurpose reservoir, where the management goals are water supply and flood control. According to this methodology, the reservoir control policy is derived in two steps: First, a (min-max) risk aversion problem is formulated, whose solution is not unique, but rather a whole set of policies, all equivalent from the point of view of the risk-aversion objectives. Second, a stochastic average-performance optimization problem is solved, to select from the set previously obtained the best policy from the point of view of the average-performance objectives. The methodology has several interesting features: the rnin-max (or "guaranteed performance") approach, which is particularly suited whenever "weak" users are affected by the consequences of the decision-making process; the flexible definition of a "risk aversion degree," by the selection of those inflow sequences which are particularly feared; and the two-objective analysis which provides the manager with a whole set of alternatives among which he (she) will select the one that yields the desired trade-off between the management goals.

  4. Behavioral activation system modulation on brain activation during appetitive and aversive stimulus processing.

    PubMed

    Barrós-Loscertales, Alfonso; Ventura-Campos, Noelia; Sanjuán-Tomás, Ana; Belloch, Vicente; Parcet, Maria-Antònia; Avila, César

    2010-03-01

    The reinforcement sensitivity theory (RST) proposed the behavioral activation system (BAS) as a neurobehavioral system that is dependent on dopamine-irrigated structures and that mediates the individual differences in sensitivity and reactivity to appetitive stimuli associated with BAS-related personality traits. Theoretical developments propose that high BAS sensitivity is associated with both enhanced appetitive stimuli processing and the diminished processing of aversive stimuli. The objective of this study was to analyze how individual differences in BAS functioning were associated with brain activation during erotic and aversive picture processing while subjects were involved in a simple goal-directed task. Forty-five male participants took part in this study. The task activation results confirm the activation of the reward and punishment brain-related structures while viewing erotic and aversive pictures, respectively. The SR scores show a positive correlation with activation of the left lateral prefrontal cortex, the mesial prefrontal cortex and the right occipital cortex while viewing erotic pictures, and a negative correlation with the right lateral prefrontal cortex and the left occipital cortex while viewing aversive pictures. In summary, the SR scores modulate the activity of the cortical areas in the prefrontal and the occipital cortices that are proposed to modulate the BAS and the BIS-FFFS. PMID:20147458

  5. Examining Relationships between Executive Functioning and Delay Aversion in Attention Deficit Hyperactivity Disorder

    ERIC Educational Resources Information Center

    Karalunas, Sarah L.; Huang-Pollock, Cynthia L.

    2011-01-01

    Although motivation and cognition are often examined separately, recent theory suggests that a delay-averse motivational style may negatively impact development of executive functions (EFs), such as working memory (WM) and response inhibition (RI) for children with Attention Deficit Hyperactivity Disorder (ADHD; Sonuga-Barke, 2002). This model…

  6. A Choice Procedure to Assess the Aversive Effects of Drugs in Rodents

    ERIC Educational Resources Information Center

    Podlesnik, Christopher A.; Jimenez-Gomez, Corina; Woods, James H.

    2010-01-01

    The goal of this series of experiments was to develop an operant choice procedure to examine rapidly the punishing effects of intravenous drugs in rats. First, the cardiovascular effects of experimenter-administered intravenous histamine, a known aversive drug, were assessed to determine a biologically active dose range. Next, rats responded on…

  7. Aversive Racism and Intergroup Contact Theories: Cultural Competence in a Segregated World

    ERIC Educational Resources Information Center

    Rodenborg, Nancy A.; Boisen, Laura A.

    2013-01-01

    The United States remains highly segregated, and social work students are likely to live and work in segregated contexts. What implications does this have for their cultural competence? Does segregation affect social workers' ability to serve diverse clients without bias? This article reviews two social psychology theories, aversive racism…

  8. Delay Aversion in Attention Deficit/Hyperactivity Disorder: An Empirical Investigation of the Broader Phenotype

    ERIC Educational Resources Information Center

    Bitsakou, Paraskevi; Psychogiou, Lamprini; Thompson, Margaret; Sonuga-Barke, Edmund J. S.

    2009-01-01

    Background: Delay-related motivational processes are impaired in children with Attention Deficit/Hyperactivity Disorder (ADHD). Here we explore the impact of ADHD on the performance of three putative indices of Delay Aversion (DAv): (i) the choice for immediate over delayed reward; (ii) slower reaction times following delay; and (iii) increased…

  9. "A Lifelong Aversion to Writing": What if Writing Courses Emphasized Motivation?

    ERIC Educational Resources Information Center

    Sullivan, Patrick

    2011-01-01

    There has been a great deal of groundbreaking research done on motivation during the last twenty-five years, and all of it points to the importance of intrinsic motivation. This research has very significant ramifications for teachers of English. In this essay, the author engages the issue of "aversion" that Linda Brodkey raises in her essay…

  10. Context Switch Effects and Context Experience in Rats' Conditioned Taste Aversion

    ERIC Educational Resources Information Center

    Leon, Samuel P.; Callejas-Aguilera, Jose E.; Rosas, Juan M.

    2012-01-01

    Context specificity of rats' conditioned taste aversion as a function of context experience was assessed in two experiments. Rats received a single pairing between a flavor X and a LiCl injection in a distinctive context (context A) being subsequently tested either in the same context or in a different but equally familiar context (context B).…

  11. Field Dependency, n Power and Locus of Control Variables in Alcohol Aversion.

    ERIC Educational Resources Information Center

    Query, William T.

    1983-01-01

    Compared individual differences and treatment effectiveness in male volunteer alcoholics (N=47) in a 10-day electroconditioning aversion program. Follow-up showed combination therapy was more successful. Internals and hard liquor drinkers tended to be abstinent as predicted. Field dependency was a more unstable variable for outcome. (Author/JAC)

  12. Cycloheximide impairs reconsolidation of a contextually reactivated memory in a conditioned taste aversion paradigm.

    PubMed

    Flint, Robert W; Marino, Christina L

    2007-04-01

    Rats were used to examine the impact of systemic protein synthesis inhibition (PSI) on the reconsolidation of a contextually reactivated memory of conditioned taste aversion (CTA). Rats were administered intraperitoneal injections of saline or lithium chloride (LiCl; .15 M) following exposure to a novel sucrose solution in a unique context. Seven days later, rats were injected subcutaneously with saline or cycloheximide (CXM; 1 mg/kg) and returned to their home cage or placed into the CTA training context in the absence of the target conditioned stimulus to reactivate the training memory. At testing, LiCl-trained rats that had been given CXM at reactivation had significantly greater difference scores (sucrose-water) in comparison with LiCl/CXM rats that had not been given a reactivation treatment and LiCl/saline memory-reactivated rats. These results suggest that context re-exposure effectively reactivates memory of CTA training that may be weakened through PSI. Extinction tests revealed rapid attenuation of taste aversions in all of the LiCl-injected groups. The involvement of taste-potentiated aversions and the role of the context in taste aversion conditioning are discussed. PMID:17469933

  13. Gaze Aversion as a Cognitive Load Management Strategy in Autism Spectrum Disorder and Williams Syndrome

    ERIC Educational Resources Information Center

    Doherty-Sneddon, Gwyneth; Riby, Deborah M.; Whittle, Lisa

    2012-01-01

    Background: During face-to-face questioning, typically developing children and adults use gaze aversion (GA), away from their questioner, when thinking. GA increases with question difficulty and improves the accuracy of responses. This is the first study to investigate whether individuals with autism spectrum disorder (ASD; associated with reduced…

  14. Gaze Aversion during Social Style Interactions in Autism Spectrum Disorder and Williams Syndrome

    ERIC Educational Resources Information Center

    Doherty-Sneddon, Gwyneth; Whittle, Lisa; Riby, Deborah M.

    2013-01-01

    During face-to-face interactions typically developing individuals use gaze aversion (GA), away from their questioner, when thinking. GA is also used when individuals with autism (ASD) and Williams syndrome (WS) are thinking during question-answer interactions. We investigated GA strategies during face-to-face social style interactions with…

  15. Behavioral activation system modulation on brain activation during appetitive and aversive stimulus processing

    PubMed Central

    Ventura-Campos, Noelia; Sanjuán-Tomás, Ana; Belloch, Vicente; Parcet, Maria-Antònia; Ávila, César

    2010-01-01

    The reinforcement sensitivity theory (RST) proposed the behavioral activation system (BAS) as a neurobehavioral system that is dependent on dopamine-irrigated structures and that mediates the individual differences in sensitivity and reactivity to appetitive stimuli associated with BAS-related personality traits. Theoretical developments propose that high BAS sensitivity is associated with both enhanced appetitive stimuli processing and the diminished processing of aversive stimuli. The objective of this study was to analyze how individual differences in BAS functioning were associated with brain activation during erotic and aversive picture processing while subjects were involved in a simple goal-directed task. Forty-five male participants took part in this study. The task activation results confirm the activation of the reward and punishment brain-related structures while viewing erotic and aversive pictures, respectively. The SR scores show a positive correlation with activation of the left lateral prefrontal cortex, the mesial prefrontal cortex and the right occipital cortex while viewing erotic pictures, and a negative correlation with the right lateral prefrontal cortex and the left occipital cortex while viewing aversive pictures. In summary, the SR scores modulate the activity of the cortical areas in the prefrontal and the occipital cortices that are proposed to modulate the BAS and the BIS-FFFS. PMID:20147458

  16. Antennal and locomotor responses to attractive and aversive odors in the searching cockroach.

    PubMed

    Nishiyama, Katsuhiro; Okada, Jiro; Toh, Yoshihiro

    2007-09-01

    The behavioral responses to attractive and aversive odors were examined in blinded adult male cockroaches under tethered-walking conditions. A sex pheromone-like stimulant derived from adult virgin females and artificially synthesized limonene were used as attractive and aversive odor sources, respectively. When a searching animal was stimulated with the attractive female-derived odor, the horizontal deflections of both the antennae were increased, and in most cases the vertical antennal positions were shifted downward. The stimulation also significantly decreased the walking speed of the animal. These behavioral changes imply a careful search in the immediate surroundings. The aftereffect of the sex pheromone was more pronounced on locomotion than on antennal movement. On the other hand, stimulation with the aversive odor (limonene) tended to suppress active antennal movement, and also increased the walking speed. Immediately after the withdrawal of the aversive odor, the active movement of the antennae was resumed, and the walking speed rapidly decreased to a level approximately the same as that of the control period. These results indicate that the responses to the qualitatively opposite types of odor are reciprocal to each other with regard to both antennal movement and locomotion. PMID:17609964

  17. Hedonic and Nucleus Accumbens Neural Responses to a Natural Reward Are Regulated by Aversive Conditioning

    ERIC Educational Resources Information Center

    Roitman, Mitchell F.; Wheeler, Robert A.; Tiesinga, Paul H. E.; Roitman, Jamie D.; Carelli, Regina M.

    2010-01-01

    The nucleus accumbens (NAc) plays a role in hedonic reactivity to taste stimuli. Learning can alter the hedonic valence of a given stimulus, and it remains unclear how the NAc encodes this shift. The present study examined whether the population response of NAc neurons to a taste stimulus is plastic using a conditioned taste aversion (CTA)…

  18. Acquisition and Performance of Two-Way Shuttlebox Avoidance: Effects of Aversive Air Intensity

    ERIC Educational Resources Information Center

    Myers, T.M.; Cohn, S.I.; Clark, M.G.

    2005-01-01

    Thirty-two male C57BL/6J mice were trained on a signaled shuttlebox avoidance task using pressurized air as an aversive stimulus. Subjects were randomly assigned to one of four different air intensities (10, 20, 40, or 55psi) and exposed to 51 trials per session for 20 sessions. Area under the curve analyses and a two-parameter, nonlinear…

  19. Conditioned Taste Aversion Is Enhanced When the Unconditioned Stimulus Is Presented in a Different Context

    ERIC Educational Resources Information Center

    Ishii, Kiyoshi; Iguchi, Yoshio; Fukumoto, Kazuya; Nakayasu, Tomohiro

    2008-01-01

    Using a conditioned taste aversion procedure with rats as the subjects, two experiments examined the effect of presenting a conditioned stimulus (CS saccharin solution) in one context followed by an unconditioned stimulus (US LiCl) in a different context. Experiment 1 showed that animals which received the above-mentioned procedure (Group D)…

  20. Differential Involvement of the Central Amygdala in Appetitive versus Aversive Learning

    ERIC Educational Resources Information Center

    Lipp, Hans-Peter; Kaczmarek, Leszek; Werka, Tomasz; Knapska, Ewelina; Walasek, Grazyna; Nikolaev, Evgeni; Neuhausser-Wespy, Frieder

    2006-01-01

    Understanding the function of the distinct amygdaloid nuclei in learning comprises a major challenge. In the two studies described herein, we used c-Fos immunolabeling to compare the engagement of various nuclei of the amygdala in appetitive and aversive instrumental training procedures. In the first experiment, rats that had already acquired a…

  1. Loss-Aversion or Loss-Attention: The Impact of Losses on Cognitive Performance

    ERIC Educational Resources Information Center

    Yechiam, Eldad; Hochman, Guy

    2013-01-01

    Losses were found to improve cognitive performance, and this has been commonly explained by increased weighting of losses compared to gains (i.e., loss aversion). We examine whether effects of losses on performance could be modulated by two alternative processes: an attentional effect leading to increased sensitivity to task incentives; and a…

  2. Tell-Tale Eyes: Children's Attribution of Gaze Aversion as a Lying Cue

    ERIC Educational Resources Information Center

    Einav, Shiri; Hood, Bruce M.

    2008-01-01

    This study examined whether the well-documented adult tendency to perceive gaze aversion as a lying cue is also evident in children. In Experiment 1, 6-year-olds, 9-year-olds, and adults were shown video vignettes of speakers who either maintained or avoided eye contact while answering an interviewer's questions. Participants evaluated whether the…

  3. Exposure to Sexist Humor and Rape Proclivity: The Moderator Effect of Aversiveness Ratings

    ERIC Educational Resources Information Center

    Romero-Sanchez, Monica; Duran, Mercedes; Carretero-Dios, Hugo; Megias, Jesus L.; Moya, Miguel

    2010-01-01

    The aim of this study is to explore the effect of exposure to sexist humor about women on men's self-reported rape proclivity. Earlier studies have shown that exposure to this type of humor increases rape proclivity and that funniness responses to jokes are a key element to consider. However, the role of aversiveness responses has not been…

  4. UK Higher Education: Competitive Forces in the 21st Century.

    ERIC Educational Resources Information Center

    Webber, G. C.

    2000-01-01

    Considers United Kingdom higher education in the context of Michael Porter's book, "Competitive Strategy," which discusses five forces governing competition. Focusing mainly, but not exclusively, on teaching, the monograph identifies critical factors that have influenced the balance of competitive forces in higher education and identifies ways in…

  5. Decomposing Self-Control: Individual Differences in Goal Pursuit Despite Interfering Aversion, Temptation, and Distraction.

    PubMed

    Steimke, Rosa; Stelzel, Christine; Gaschler, Robert; Rothkirch, Marcus; Ludwig, Vera U; Paschke, Lena M; Trempler, Ima; Kathmann, Norbert; Goschke, Thomas; Walter, Henrik

    2016-01-01

    Self-control can be defined as the ability to exert control over ones impulses. Currently, most research in the area relies on self-report. Focusing on attentional control processes involved in self-control, we modified a spatial selective attentional cueing task to test three domains of self-control experimentally in one task using aversive, tempting, and neutral picture-distractors. The aims of the study were (1) to investigate individual differences in the susceptibility to aversive, tempting, and neutral distraction within one paradigm and (2) to test the association of these three self-control domains to conventional measures of self-control including self-report. The final sample consisted of 116 participants. The task required participants to identify target letters "E" or "F" presented at a cued target location while the distractors were presented. Behavioral and eyetracking data were obtained during the performance of the task. High task performance was encouraged via monetary incentives. In addition to the attentional self-control task, self-reported self-control was assessed and participants performed a color Stroop task, an unsolvable anagram task and a delay of gratification task using chocolate sweets. We found that aversion, temptation, and neutral distraction were associated with significantly increased error rates, reaction times and gaze pattern deviations. Overall task performance on our task correlated with self-reported self-control ability. Measures of aversion, temptation, and distraction showed moderate split-half reliability, but did not correlate with each other across participants. Additionally, participants who made a self-controlled decision in the delay of gratification task were less distracted by temptations in our task than participants who made an impulsive choice. Our individual differences analyses suggest that (1) the ability to endure aversion, resist temptations and ignore neutral distractions are independent of each other and

  6. Medial Amygdala Lesions Selectively Block Aversive Pavlovian–Instrumental Transfer in Rats

    PubMed Central

    McCue, Margaret G.; LeDoux, Joseph E.; Cain, Christopher K.

    2014-01-01

    Pavlovian conditioned stimuli (CSs) play an important role in the reinforcement and motivation of instrumental active avoidance (AA). Conditioned threats can also invigorate ongoing AA responding [aversive Pavlovian–instrumental transfer (PIT)]. The neural circuits mediating AA are poorly understood, although lesion studies suggest that lateral, basal, and central amygdala nuclei, as well as infralimbic prefrontal cortex, make key, and sometimes opposing, contributions. We recently completed an extensive analysis of brain c-Fos expression in good vs. poor avoiders following an AA test (Martinez et al., 2013, Learning and Memory). This analysis identified medial amygdala (MeA) as a potentially important region for Pavlovian motivation of instrumental actions. MeA is known to mediate defensive responding to innate threats as well as social behaviors, but its role in mediating aversive Pavlovian–instrumental interactions is unknown. We evaluated the effect of MeA lesions on Pavlovian conditioning, Sidman two-way AA conditioning (shuttling) and aversive PIT in rats. Mild footshocks served as the unconditioned stimulus in all conditioning phases. MeA lesions had no effect on AA but blocked the expression of aversive PIT and 22 kHz ultrasonic vocalizations in the AA context. Interestingly, MeA lesions failed to affect Pavlovian freezing to discrete threats but reduced freezing to contextual threats when assessed outside of the AA chamber. These findings differentiate MeA from lateral and central amygdala, as lesions of these nuclei disrupt Pavlovian freezing and aversive PIT, but have opposite effects on AA performance. Taken together, these results suggest that MeA plays a selective role in the motivation of instrumental avoidance by general or uncertain Pavlovian threats. PMID:25278858

  7. Pentylenetetrazol produces a state-dependent conditioned place aversion to alcohol withdrawal in mice.

    PubMed

    Chester, Julia A; Coon, Laran E

    2010-04-01

    The purpose of this study was to determine if aversive effects of alcohol withdrawal could be detected in mice using the place conditioning procedure and whether the GABA(A) receptor antagonist, pentylenetetrazol (PTZ), would increase the aversive effects of alcohol withdrawal and increase the probability of detecting conditioned place aversion. Subjects were alcohol-naïve mice from a specific line selectively bred for low alcohol preference (LAP1; n=91) and were assigned to three groups: alcohol withdrawal, PTZ alone, and PTZ+alcohol withdrawal. On four trials, mice received either a 4.0 g/kg intraperitoneal (i.p.) injection of alcohol (alcohol withdrawal, PTZ+alcohol withdrawal groups) or saline (PTZ group) 8 h prior to being placed on a distinctive floor texture for a 30-min conditioning session. Five minutes before these sessions, mice in the PTZ and PTZ+alcohol withdrawal groups received PTZ (5.0 mg/kg; i.p.) and the alcohol withdrawal group received saline. On intervening days mice received two saline injections at the same time points prior to being placed on a different floor texture. Post-conditioning floor preference was assessed in two 60-min tests; the first test was drug-free and the second test was state-dependent. Neither alcohol withdrawal nor PTZ produced significant place conditioning. The PTZ+alcohol withdrawal group showed a significant place aversion during the state-dependent test. These data suggest that the combined stimulus properties of PTZ and alcohol withdrawal facilitated the expression of conditioned place aversion to alcohol withdrawal. PMID:20138906

  8. Pentylenetetrazol Produces a State-Dependent Conditioned Place Aversion to Alcohol Withdrawal in Mice

    PubMed Central

    Chester, Julia A.; Coon, Laran E.

    2010-01-01

    The purpose of this study was to determine if aversive effects of alcohol withdrawal could be detected in mice using the place conditioning procedure and whether the GABAA receptor antagonist, pentylenetetrazol (PTZ), would increase the aversive effects of alcohol withdrawal and increase the probability of detecting conditioned place aversion. Subjects were alcohol-naïve mice from a specific line selectively bred for low alcohol preference (LAP1; n=91) and were assigned to three groups: alcohol withdrawal, PTZ alone, and PTZ + alcohol withdrawal. On four trials, mice received either a 4.0 g/kg intraperitoneal (i.p.) injection of alcohol (alcohol withdrawal, PTZ + alcohol withdrawal groups) or saline (PTZ group) 8 hrs prior to being placed on a distinctive floor texture for a 30-min conditioning session. Five min before these sessions, mice in the PTZ and PTZ + alcohol withdrawal groups received PTZ (5.0 mg/kg; i.p.) and the alcohol withdrawal group received saline. On intervening days mice received two saline injections at the same time points prior to being placed on a different floor texture. Post-conditioning floor preference was assessed in two 60-min tests; the first test was drug-free and the second test was state-dependent. Neither alcohol withdrawal nor PTZ produced significant place conditioning. The PTZ + alcohol withdrawal group showed a significant place aversion during the state-dependent test. These data suggest that the combined stimulus properties of PTZ and alcohol withdrawal facilitated the expression of conditioned place aversion to alcohol withdrawal. PMID:20138906

  9. Decomposing Self-Control: Individual Differences in Goal Pursuit Despite Interfering Aversion, Temptation, and Distraction

    PubMed Central

    Steimke, Rosa; Stelzel, Christine; Gaschler, Robert; Rothkirch, Marcus; Ludwig, Vera U.; Paschke, Lena M.; Trempler, Ima; Kathmann, Norbert; Goschke, Thomas; Walter, Henrik

    2016-01-01

    Self-control can be defined as the ability to exert control over ones impulses. Currently, most research in the area relies on self-report. Focusing on attentional control processes involved in self-control, we modified a spatial selective attentional cueing task to test three domains of self-control experimentally in one task using aversive, tempting, and neutral picture-distractors. The aims of the study were (1) to investigate individual differences in the susceptibility to aversive, tempting, and neutral distraction within one paradigm and (2) to test the association of these three self-control domains to conventional measures of self-control including self-report. The final sample consisted of 116 participants. The task required participants to identify target letters “E” or “F” presented at a cued target location while the distractors were presented. Behavioral and eyetracking data were obtained during the performance of the task. High task performance was encouraged via monetary incentives. In addition to the attentional self-control task, self-reported self-control was assessed and participants performed a color Stroop task, an unsolvable anagram task and a delay of gratification task using chocolate sweets. We found that aversion, temptation, and neutral distraction were associated with significantly increased error rates, reaction times and gaze pattern deviations. Overall task performance on our task correlated with self-reported self-control ability. Measures of aversion, temptation, and distraction showed moderate split-half reliability, but did not correlate with each other across participants. Additionally, participants who made a self-controlled decision in the delay of gratification task were less distracted by temptations in our task than participants who made an impulsive choice. Our individual differences analyses suggest that (1) the ability to endure aversion, resist temptations and ignore neutral distractions are independent of each

  10. Serotonin 2A receptors contribute to the regulation of risk-averse decisions

    PubMed Central

    Macoveanu, Julian; Rowe, James B; Hornboll, Bettina; Elliott, Rebecca; Paulson, Olaf B; Knudsen, Gitte M; Siebner, Hartwig R

    2013-01-01

    Pharmacological studies point to a role of the neurotransmitter serotonin (5-HT) in regulating the preference for risky decisions, yet the functional contribution of specific 5-HT receptors remains to be clarified. We used pharmacological fMRI to investigate the role of the 5-HT2A receptors in processing negative outcomes and regulating risk-averse behavior. During fMRI, twenty healthy volunteers performed a gambling task under two conditions: with or without blocking the 5-HT2A receptors. The volunteers repeatedly chose between small, likely rewards and large, unlikely rewards. Choices were balanced in terms of expected utility and potential loss. Acute blockade of the 5-HT2A receptors with ketanserin made participants more risk-averse. Ketanserin selectively reduced the neural response of the frontopolar cortex to negative outcomes that were caused by low-risk choices and were associated with large missed rewards. In the context of normal 5-HT2A receptor function, ventral striatum displayed a stronger response to low-risk negative outcomes in risk-taking as opposed to risk-averse individuals. This (negative) correlation between the striatal response to low-risk negative outcomes and risk-averse choice behavior was abolished by 5-HT2A receptor blockade. The results provide the first evidence for a critical role of 5-HT2A receptor function in regulating risk-averse behavior. We suggest that the 5-HT2A receptor system facilitates risk-taking behavior by modulating the outcome evaluation of “missed” reward. These results have implications for understanding the neural basis of abnormal risk-taking behavior, for instance in pathological gamblers. PMID:23810974

  11. Long-term changes in amphetamine-induced reinforcement and aversion in rats following exposure to 56Fe particle.

    PubMed

    Rabin, B M; Joseph, J A; Shukitt-Hale, B

    2003-01-01

    Exposing rats to heavy particles produces alterations in the functioning of dopaminergic neurons and in the behaviors that depend upon the integrity of the dopaminergic system. Two of these dopamine-dependent behaviors include amphetamine-induced reinforcement, measure using the conditioned place preference procedure, and amphetamine-induced reinforcement, measured using the conditioned place preference procedure, and amphetamine-induced aversion, measured using the conditioned taste aversion. Previous research has shown that exposing rats to 1.0 Gy of 1GeV/n 56Fe particles produced a disruption of an amphetamine-induced taste aversion 3 days following exposure, but produced an apparent enhancement of the aversion 112 days following exposure. The present experiments were designed to provide a further evaluation of these results by examining taste aversion learning 154 days following exposure to 1.0 Gy 56Fe particles and to establish the convergent validity of the taste aversion results by looking at the effects of exposure on the establishment of an amphetamine-induced conditioned place preference 3, 7, and 16 weeks following irradiation. The taste aversion results failed to confirm the apparent enhancement of the amphetamine-induced CTA observed in the prior experiment. However, exposure to 56Fe particles prevented the acquisition of amphetamine-induced place preference at all three-time intervals. The results are interpreted as indicating that exposure to heavy particles can produce long-term changes in behavioral functioning. PMID:12577984

  12. Dissociation of the Role of Infralimbic Cortex in Learning and Consolidation of Extinction of Recent and Remote Aversion Memory.

    PubMed

    Awad, Walaa; Ferreira, Guillaume; Maroun, Mouna

    2015-10-01

    Medial prefrontal circuits have been reported to undergo a major reorganization over time and gradually take a more important role for remote emotional memories such as contextual fear memory or food aversion memory. The medial prefrontal cortex, and specifically its ventral subregion, the infralimbic cortex (IL), was also reported to be critical for recent memory extinction of contextual fear conditioning and conditioned odor aversion. However, its exact role in the extinction of remotely acquired information is still not clear. Using postretrieval blockade of protein synthesis or inactivation of the IL, we showed that the IL is similarly required for extinction consolidation of recent and remote fear memory. However, in odor aversion memory, the IL was only involved in extinction consolidation of recent, but not remote, memory. In contrast, only remote retrieval of aversion memory induced c-Fos activation in the IL and preretrieval inactivation of the IL with lidocaine impaired subsequent extinction of remote but not recent memory, indicating IL is necessary for extinction learning of remote aversion memory. In contrast to the effects in odor aversion, our data show that the involvement of the IL in the consolidation of fear extinction does not depend on the memory age. More importantly, our data indicate that the IL is implicated in the extinction of fear and nonfear-based associations and suggest dissociation in the engagement of the IL in the learning and consolidation of food aversion extinction over time. PMID:25872918

  13. Not so bad: avoidance and aversive discounting modulate threat appraisal in anterior cingulate and medial prefrontal cortex

    PubMed Central

    Schlund, Michael W.; Brewer, Adam T.; Richman, David M.; Magee, Sandy K.; Dymond, Simon

    2015-01-01

    The dorsal anterior cingulate (adACC) and dorsal medial prefrontal cortex (dmPFC) play a central role in the discrimination and appraisal of threatening stimuli. Yet, little is known about what specific features of threatening situations recruit these regions and how avoidance may modulate appraisal and activation through prevention of aversive events. In this investigation, 30 healthy adults underwent functional neuroimaging while completing an avoidance task in which responses to an Avoidable CS+ threat prevented delivery of an aversive stimulus, but not to an Unavoidable CS+ threat. Extinction testing was also completed where CSs were presented without aversive stimulus delivery and an opportunity to avoid. The Avoidable CS+ relative to the Unavoidable CS+ was associated with reductions in ratings of negative valence, fear, and US expectancy and activation. Greater regional activation was consistently observed to the Unavoidable CS+ during avoidance, which declined during extinction. Individuals exhibiting greater aversive discounting—that is, those more avoidant of immediate monetary loss compared to a larger delayed loss—also displayed greater activation to the Unavoidable CS+, highlighting aversive discounting as a significant individual difference variable. These are the first results linking adACC/dmPFC reactivity to avoidance-based reductions of aversive events and modulation of activation by individual differences in aversive discounting. PMID:26113813

  14. Long-term changes in amphetamine-induced reinforcement and aversion in rats following exposure to 56Fe particle

    NASA Technical Reports Server (NTRS)

    Rabin, B. M.; Joseph, J. A.; Shukitt-Hale, B.

    2003-01-01

    Exposing rats to heavy particles produces alterations in the functioning of dopaminergic neurons and in the behaviors that depend upon the integrity of the dopaminergic system. Two of these dopamine-dependent behaviors include amphetamine-induced reinforcement, measure using the conditioned place preference procedure, and amphetamine-induced reinforcement, measured using the conditioned place preference procedure, and amphetamine-induced aversion, measured using the conditioned taste aversion. Previous research has shown that exposing rats to 1.0 Gy of 1GeV/n 56Fe particles produced a disruption of an amphetamine-induced taste aversion 3 days following exposure, but produced an apparent enhancement of the aversion 112 days following exposure. The present experiments were designed to provide a further evaluation of these results by examining taste aversion learning 154 days following exposure to 1.0 Gy 56Fe particles and to establish the convergent validity of the taste aversion results by looking at the effects of exposure on the establishment of an amphetamine-induced conditioned place preference 3, 7, and 16 weeks following irradiation. The taste aversion results failed to confirm the apparent enhancement of the amphetamine-induced CTA observed in the prior experiment. However, exposure to 56Fe particles prevented the acquisition of amphetamine-induced place preference at all three-time intervals. The results are interpreted as indicating that exposure to heavy particles can produce long-term changes in behavioral functioning. c2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved.

  15. Real and hypothetical endowment effects when exchanging lottery tickets: Is regret a better explanation than loss aversion?

    PubMed

    Kogler, Christoph; Kühberger, Anton; Gilhofer, Rainer

    2013-08-01

    The endowment effect is the finding that possession of an item adds to its value. We introduce a new procedure for testing this effect: participants are divided into two groups. Possession group participants inspect a numbered lottery ticket and know it is theirs, while inspection group participants only inspect a lottery ticket without being endowed with it. Subsequently participants choose between playing the lottery with this (possessed or inspected) ticket, or exchanging it for another one. Our procedure tests for the effect of endowment while controlling for the influence of transaction costs as well as for inspection effects and the influence of bargaining roles (buyer vs. seller), which often afflict experimentation with the endowment effect. In a real setting, tickets in possession were valued significantly higher than inspected tickets. Contrary to some findings in the literature participants also correctly predicted these valuation differences in a hypothetical situation, both for themselves as well as for others. Furthermore, our results suggest that regret rather than loss aversion may be the source of the endowment effect in an experimental setting using lottery tickets. Applying our procedure to a setting employing riskless objects in form of mugs revealed rather ambiguous results, thus emphasizing that the role of regret might be less prominent in non-lottery settings. PMID:23913998

  16. Lunar Regolith Excavation Competition

    NASA Technical Reports Server (NTRS)

    Liles, Cassandra

    2009-01-01

    The Lunar Regolith Excavation Competition is a new competition that needs graphics, logos, rules, as well as an arena. Although this is the first year of the competition, the competition is modeled after an existing competition, the Centennial Lunar Excavator Challenge. This competition however is aimed at college students. This makes the challenge identifying key aspects of the original competition and modeling them to fit into an easier task, and creating exciting advertisement that helps encourage participation. By using a youth focus group, young insight, as well as guiding advice from experts in the field, hopefully an arena can be designed and built, rules can be molded and created to fit, and alluring graphics can be printed to bring about a successful first year of the Lunar Regolith Excavation Competition.

  17. Profound reduction in sensitivity to the aversive effects of methamphetamine in mice bred for high methamphetamine intake

    PubMed Central

    Shabani, Shkelzen; McKinnon, Carrie S.; Cunningham, Christopher L.; Phillips, Tamara J.

    2011-01-01

    Reduced sensitivity to aversive effects of methamphetamine (MA) may increase risk for MA abuse. Studies in two replicate sets of mouse lines that were selectively bred for high and low levels of MA intake support this view. Current studies examined the extent of insensitivity to aversive MA effects of mice bred for high levels of MA drinking. Conditioning procedures in which drugs are delivered shortly after cue exposure have been used to detect aversive drug effects and, in some cases, are more sensitive to such effects. Aversive effects induced by MA injected immediately after exposure to cues from two different sensory modalities were examined. In addition, effects of higher MA doses than those used previously were examined. MA-associated place conditioning utilized tactile cues, whereas MA-induced taste conditioning utilized a novel tastant. Second replicate, MA high drinking (MAHDR-2) and low drinking (MALDR-2) mice were treated with doses of MA up to 4 mg/kg. MAHDR-2 mice were insensitive to aversive effects of MA, except after place conditioning with the 4 mg/kg dose; MALDR-2 mice exhibited sensitivity to aversive effects of MA at doses as low as 1 mg/kg. These studies show that the expression of aversion is dependent upon procedure and MA dose, and that MAHDR-2 mice have markedly reduced sensitivity to the aversive effects of MA. The current and previous results support a strong genetic relationship between level of MA intake and level of sensitivity to aversive effects of MA, a factor that could impact risk for MA use in humans. PMID:22118879

  18. Strategizing for Intense Competition.

    ERIC Educational Resources Information Center

    Hahn, William; Bourgeois, Ernest J., Jr.

    1999-01-01

    Examines trend toward more aggressive student recruiting strategies by colleges and universities, applying a model that assesses five competitive forces-cause and effect of competition, the expanding marketplace, substitute products, buyer power, and supplier power, and examines various strategies for dealing with these competitive forces, such as…

  19. In Defence of Competition.

    ERIC Educational Resources Information Center

    Prvulovich, Zika Rad

    1982-01-01

    Examines objections to competition as presented by educational philosopher Michael Fielding and others. The two major types of criticism of competition are that it is unfair and divisive and that it is selfish and immoral. The author advocates educational experiences which combine self-competition with cooperation. (AM)

  20. Competitive Anxiety in Sport.

    ERIC Educational Resources Information Center

    Martens, Rainer; And Others

    This book is a comprehensive review of competitive anxiety research that has used the Sport Competition Anxiety Test, or SCAT (a trait scale), and the Competitive State Anxiety Inventory-2 (CSAI-2). The book describes the theoretical basis and development procedures for both scales, including detailed information on reliability and validity. In…

  1. Competitive Stress and the Youth Sport Experience.

    ERIC Educational Resources Information Center

    Scanlan, Tara K.; Passer, Michael

    1981-01-01

    Competitive stress occurs when a child perceives that he is not performing to athletic standards. Results of a study done on boys from 16 soccer teams indicate that pregame stress was influenced by the child's perceived capabilities, and postgame stress was influenced by his perception of his actual performance. (JN)

  2. Belowground competition among invading detritivores.

    PubMed

    Chang, Chih-Han; Szlavecz, Katalin; Filley, Timothy; Buyer, Jeffrey S; Bernard, Michael J; Pitz, Scott L

    2016-01-01

    The factors regulating soil animal communities are poorly understood. Current theory favors niche complementarity and facilitation over competition as the primary forms of non-trophic interspecific interaction in soil fauna; however, competition has frequently been suggested as an important community-structuring factor in earthworms, ecosystem engineers that influence belowground processes. To date, direct evidence of competition in earthworms is lacking due to the difficulty inherent in identifying a limiting resource for saprophagous animals. In the present study, we offer the first direct evidence of interspecific competition for food in this dominant soil detritivore group by combining field observations with laboratory mesocosm experiments using 13C and 15N double-enriched leaf litter to track consumption patterns. In our experiments, the Asian invasive species Amynthas hilgendorfi was a dominant competitor for leaf litter against two European species currently invading the temperate deciduous forests in North America. This competitive advantage may account for recent invasion success of A. hilgendorfi in forests with established populations of European species, and we hypothesize that specific phenological differences play an important role in determining the outcome of the belowground competition. In contrast, Eisenoides lonnbergi, a common native species in the Eastern United States, occupied a unique trophic position with limited interactions with other species, which may contribute to its persistence in habitats dominated by invasive species. Furthermore, our results supported neither the hypothesis that facilitation occurs between species of different functional groups nor the hypothesis that species in the same group exhibit functional equivalency in C and N translocation in the soil. We propose that species identity is a more powerful approach to understand earthworm invasion and its impacts on belowground processes. PMID:27008785

  3. Complex dynamics of a MC-MS pricing model for a risk-averse supply chain with after-sale investment

    NASA Astrophysics Data System (ADS)

    Ma, Junhai; Sun, Lijian

    2015-09-01

    In this paper, we investigate the pricing strategy of the manufacturers and that of a common retailer, including their after-sale investment in a risk-averse supply chain. As the demand is not always for sure, the supply chain follows Manufacturers Cooperating (MC) and Manufacturers Stackelberg (MS). The main objective of the paper is to investigate the influence of the decision parameters such as the after-sale investment, wholesale price adjustment speed and risk preference on the stability and utilities of the risk-averse supply chain. The dynamic phenomena, such as the bifurcation, chaos and sensitivity to initial values are analyzed with 2D-bifurcation diagrams, double largest Lyapunov exponent and basins of attraction. The study shows that the faster the adjustment speed is, the more profits the retailer can make, but on the other hand, it is no good to manufacturers. Risk tolerance levels (RM and RR) affect the utility of the manufacturers and that of the retailer differently. A feedback control method is used to control the chaos in the supply chain.

  4. Cognitive Decline Is Associated with Risk Aversion and Temporal Discounting in Older Adults without Dementia

    PubMed Central

    James, Bryan D.; Boyle, Patricia A.; Yu, Lei; Han, S. Duke; Bennett, David A.

    2015-01-01

    Risk aversion and temporal discounting are preferences that are strongly linked to sub-optimal financial and health decision making ability. Prior studies have shown they differ by age and cognitive ability, but it remains unclear whether differences are due to age-related cognitive decline or lower cognitive abilities over the life span. We tested the hypothesis that cognitive decline is associated with higher risk aversion and temporal discounting in 455 older persons without dementia from the Memory and Aging Project, a longitudinal cohort study of aging in Chicago. All underwent repeated annual cognitive evaluations using a detailed battery including 19 tests. Risk aversion was measured using standard behavioral economics questions: participants were asked to choose between a certain monetary payment versus a gamble in which they could gain more or nothing; potential gamble gains varied across questions. Temporal discounting: participants were asked to choose between an immediate, smaller payment and a delayed, larger one; two sets of questions addressed small and large stakes based on payment amount. Regression analyses were used to examine whether prior rate of cognitive decline predicted level of risk aversion and temporal discounting, controlling for age, sex, and education. Over an average of 5.5 (SD=2.9) years, cognition declined at an average of 0.016 units per year (SD=0.03). More rapid cognitive decline predicted higher levels of risk aversion (p=0.002) and temporal discounting (small stakes: p=0.01, high stakes: p=0.006). Further, associations between cognitive decline and risk aversion (p=0.015) and large stakes temporal discounting (p=0.026) persisted in analyses restricted to persons without any cognitive impairment (i.e., no dementia or mild cognitive impairment); the association of cognitive decline and small stakes temporal discounting was no longer statistically significant (p=0.078). These findings are consistent with the hypothesis that

  5. Cognitive decline is associated with risk aversion and temporal discounting in older adults without dementia.

    PubMed

    James, Bryan D; Boyle, Patricia A; Yu, Lei; Han, S Duke; Bennett, David A

    2015-01-01

    Risk aversion and temporal discounting are preferences that are strongly linked to sub-optimal financial and health decision making ability. Prior studies have shown they differ by age and cognitive ability, but it remains unclear whether differences are due to age-related cognitive decline or lower cognitive abilities over the life span. We tested the hypothesis that cognitive decline is associated with higher risk aversion and temporal discounting in 455 older persons without dementia from the Memory and Aging Project, a longitudinal cohort study of aging in Chicago. All underwent repeated annual cognitive evaluations using a detailed battery including 19 tests. Risk aversion was measured using standard behavioral economics questions: participants were asked to choose between a certain monetary payment versus a gamble in which they could gain more or nothing; potential gamble gains varied across questions. Temporal discounting: participants were asked to choose between an immediate, smaller payment and a delayed, larger one; two sets of questions addressed small and large stakes based on payment amount. Regression analyses were used to examine whether prior rate of cognitive decline predicted level of risk aversion and temporal discounting, controlling for age, sex, and education. Over an average of 5.5 (SD=2.9) years, cognition declined at an average of 0.016 units per year (SD=0.03). More rapid cognitive decline predicted higher levels of risk aversion (p=0.002) and temporal discounting (small stakes: p=0.01, high stakes: p=0.006). Further, associations between cognitive decline and risk aversion (p=0.015) and large stakes temporal discounting (p=0.026) persisted in analyses restricted to persons without any cognitive impairment (i.e., no dementia or mild cognitive impairment); the association of cognitive decline and small stakes temporal discounting was no longer statistically significant (p=0.078). These findings are consistent with the hypothesis that

  6. Direct intra-accumbal infusion of a beta-adrenergic receptor antagonist abolishes WIN 55,212-2-induced aversion

    PubMed Central

    Carvalho, Ana Franky; Van Bockstaele, Elisabeth J.

    2011-01-01

    The cannabinoid system is known to interact with a variety of neuromodulators in the central nervous system and impacts diverse behaviors. Previous studies have demonstrated that limbic norepinephrine is a critical determinant in the behavioral expression of cannabinoid-induced aversion. The present study was carried out to define the adrenergic receptor subtype involved in mediating cannabinoid-induced behavioral responses. An acute microinjection of the β1-adrenergic receptor blocker, betaxolol, directly into the nucleus accumbens (Acb), was able to prevent WIN 55,212-2-induced aversion, but not lithium-induced aversion, as measured in a place conditioning paradigm. These results suggest that noradrenergic transmission in the Acb is important for cannabinoid-induced aversion and that beta-adrenergic antagonists may be effective in counteracting negative side effects of cannabinoid-based agents. PMID:21693171

  7. Once is too much: Conditioned aversion develops immediately and predicts future cocaine self-administration behavior in rats

    PubMed Central

    Colechio, Elizabeth M.; Imperio, Caesar G.; Grigson, Patricia S.

    2014-01-01

    Rats emit aversive taste reactivity (TR) behavior (i.e., gapes) following intraoral delivery of a cocaine-paired taste cue and greater conditioned aversive TR at the end of training predicts greater drug-seeking and taking. Here, we examined the development of this conditioned aversive TR behavior on a trial by trial basis in an effort to determine when the change in behavior occurs and whether early changes in this behavior can be used to predict later drug-taking. The results show that conditioned aversive TR to a cocaine-paired cue occurs very early in training (i.e., following as few as 1 – 2 taste-drug pairings) and, importantly, that it can be used to predict later drug-seeking and drug-taking in rats. PMID:24773440

  8. Induction of latent memory for conditioned food aversion and its transformation into "active" state depend on translation and transcription processes.

    PubMed

    Solntseva, S V; Nikitin, V P

    2014-05-01

    Mechanisms of induction and retrieval of latent (hidden) memory for conditioned food aversion were investigated in snails. After initial training (single combination of a food stimulus with electric shock), aversive reactions to presentation of the conditioned food stimulus were not revealed. Repeated presentation of the stimuli in 12 days after the first combination was followed by the appearance of aversive food reactions that persisted for at least 14 days. Injections of inhibitors of protein (cycloheximide) or RNA (α-amanitin) synthesis immediately after the first or second combined presentation of the stimuli disturbed skill performance. We hypothesized that single combination of food and reinforcing stimuli led to translation- and transcription-dependent induction of latent conditioned food aversion memory. Transformation of this memory into an active state after repeated presentation of the stimulus combination also depends on the synthesis of new proteins and RNA. PMID:24906957

  9. Effects of Personal Causation and Perceived Control on Responses to an Aversive Environment: The More Control, the Better

    ERIC Educational Resources Information Center

    Sherrod, Drury R.; And Others

    1977-01-01

    A laboratory experiment was conducted to investigate the effects on reactions to aversive noise of three types of personal control: control over the initiation of noise, control over its termination, and combined control over both initiation and termination. (Editor)

  10. Influence of stress on fear memory processes in an aversive differential conditioning paradigm in humans.

    PubMed

    Bentz, Dorothée; Michael, Tanja; Wilhelm, Frank H; Hartmann, Francina R; Kunz, Sabrina; von Rohr, Isabelle R Rudolf; de Quervain, Dominique J-F

    2013-07-01

    It is widely assumed that learning and memory processes play an important role in the pathogenesis, expression, maintenance and therapy of anxiety disorders, such as phobias or post-traumatic stress disorder (PTSD). Memory retrieval is involved in symptom expression and maintenance of these disorders, while memory extinction is believed to be the underlying mechanism of behavioral exposure therapy of anxiety disorders. There is abundant evidence that stress and stress hormones can reduce memory retrieval of emotional information, whereas they enhance memory consolidation of extinction training. In this study we aimed at investigating if stress affects these memory processes in a fear conditioning paradigm in healthy human subjects. On day 1, fear memory was acquired through a standard differential fear conditioning procedure. On day 2 (24h after fear acquisition), participants either underwent a stressful cold pressor test (CPT) or a control condition, 20 min before memory retrieval testing and extinction training. Possible prolonged effects of the stress manipulation were investigated on day 3 (48 h after fear acquisition), when memory retrieval and extinction were tested again. On day 2, men in the stress group showed a robust cortisol response to stress and showed lower unconditioned stimulus (US) expectancy ratings than men in the control group. This reduction in fear memory retrieval was maintained on day 3. In women, who showed a significantly smaller cortisol response to stress than men, no stress effects on fear memory retrieval were observed. No group differences were observed with respect to extinction. In conclusion, the present study provides evidence that stress can reduce memory retrieval of conditioned fear in men. Our findings may contribute to the understanding of the effects of stress and glucocorticoids on fear symptoms in anxiety disorders and suggest that such effects may be sex-specific. PMID:23333200

  11. The influence of π-conjugation on competitive pathways: charge transfer or electron transfer in new D-π-A and D-π-Si-π-A dyads.

    PubMed

    Cho, Yang-Jin; Lee, Ah-Rang; Kim, So-Yoen; Cho, Minji; Han, Won-Sik; Son, Ho-Jin; Cho, Dae Won; Kang, Sang Ook

    2016-08-17

    In order to elucidate the influence of π-conjugation on photoinduced electron transfer (PET) and intramolecular charge transfer processes, donor-π-acceptor dyads (D-π-A (1) and D-π-Si-π-A (2)) were newly synthesized. In these dyads, carbazole and triazine moieties acted as the electron donor and acceptor, respectively. The fluorescence of dyad 1 red-shifted as the solvent polarity was increased. The electron charge distribution of the excited state of dyad 1 was delocalized in the acceptor moiety, forming the charge transfer D(δ+)-π-A(δ-) dyad in the excited state. In the excited state of dyad 1, the π-conjugation acted as the linker for charge transfer between the donor and acceptor moieties. A large dipole moment change (Δμ = 45.6 D) between the ground and excited states was determined using the Lippert-Mataga plot. Furthermore, the fluorescence of dyad 1 was observed upon two-photon excitation. In contrast, dyad 2, in which the π-conjugation is disconnected by a Si-atom in the linker, displayed weak dual-emission: a short-wavelength emission at around 350 nm arising from the monomeric species and a long-wavelength one assigned to the emission from an intramolecular exciplex between the donor and acceptor moieties. The weak emission of dyad 2 indicates that the D(+)˙-π-Si-π-A(-)˙ species was generated through a PET process in the excited state. The cationic radical species of the carbazole and the anionic radical species of the triazine, which show transient absorption (TA) bands at around 780 and 530 nm, respectively, were characterized using the femtosecond TA method. PMID:27485173

  12. Competitive dynamics on complex networks.

    PubMed

    Zhao, Jiuhua; Liu, Qipeng; Wang, Xiaofan

    2014-01-01

    We consider a dynamical network model in which two competitors have fixed and different states, and each normal agent adjusts its state according to a distributed consensus protocol. The state of each normal agent converges to a steady value which is a convex combination of the competitors' states, and is independent of the initial states of agents. This implies that the competition result is fully determined by the network structure and positions of competitors in the network. We compute an Influence Matrix (IM) in which each element characterizing the influence of an agent on another agent in the network. We use the IM to predict the bias of each normal agent and thus predict which competitor will win. Furthermore, we compare the IM criterion with seven node centrality measures to predict the winner. We find that the competitor with higher Katz Centrality in an undirected network or higher PageRank in a directed network is most likely to be the winner. These findings may shed new light on the role of network structure in competition and to what extent could competitors adjust network structure so as to win the competition. PMID:25068622

  13. Competitive Dynamics on Complex Networks

    NASA Astrophysics Data System (ADS)

    Zhao, Jiuhua; Liu, Qipeng; Wang, Xiaofan

    2014-07-01

    We consider a dynamical network model in which two competitors have fixed and different states, and each normal agent adjusts its state according to a distributed consensus protocol. The state of each normal agent converges to a steady value which is a convex combination of the competitors' states, and is independent of the initial states of agents. This implies that the competition result is fully determined by the network structure and positions of competitors in the network. We compute an Influence Matrix (IM) in which each element characterizing the influence of an agent on another agent in the network. We use the IM to predict the bias of each normal agent and thus predict which competitor will win. Furthermore, we compare the IM criterion with seven node centrality measures to predict the winner. We find that the competitor with higher Katz Centrality in an undirected network or higher PageRank in a directed network is most likely to be the winner. These findings may shed new light on the role of network structure in competition and to what extent could competitors adjust network structure so as to win the competition.

  14. Dorsal medial prefrontal cortex contributes to conditioned taste aversion memory consolidation and retrieval.

    PubMed

    Gonzalez, Maria Carolina; Villar, Maria Eugenia; Igaz, Lionel M; Viola, Haydée; Medina, Jorge H

    2015-12-01

    The medial prefrontal cortex (mPFC) is known for its role in decision making and memory processing, including the participation in the formation of extinction memories. However, little is known regarding its contribution to aversive memory consolidation. Here we demonstrate that neural activity and protein synthesis are required in the dorsal mPFC for memory formation of a conditioned taste aversion (CTA) task and that this region is involved in the retrieval of recent and remote long-term CTA memory. In addition, both NMDA receptor and CaMKII activity in dorsal mPFC are needed for CTA memory consolidation, highlighting the complexity of mPFC functions. PMID:26493441

  15. Deficient aversive-potentiated startle and the triarchic model of psychopathy: The role of boldness.

    PubMed

    Esteller, Àngels; Poy, Rosario; Moltó, Javier

    2016-05-01

    This study examined the contribution of the phenotypic domains of boldness, meanness, and disinhibition of the triarchic conceptualization of psychopathy (Patrick, Fowles, & Krueger, 2009) to deficient aversive-potentiated startle in a mixed-gender sample of 180 undergraduates. Eyeblink responses to noise probes were recorded during a passive picture-viewing task (erotica, neutral, threat, and mutilation). Deficient threat vs. neutral potentiation was uniquely related to increased boldness scores, thus suggesting that the diminished defensive reaction to aversive stimulation is specifically linked to the charm, social potency and venturesomeness features of psychopathy (boldness), but not to features such as callousness, coldheartedness and cruelty traits (meanness), even though both phenotypes theoretically share the same underlying low-fear disposition. Our findings provide further evidence of the differential association between distinct psychopathy components and deficits in defensive reactivity and strongly support the validity of the triarchic model of psychopathy in disentangling the etiology of this personality disorder. PMID:27033014

  16. The effects of area postrema lesions and selective vagotomy on motion-induced conditioned taste aversion

    NASA Technical Reports Server (NTRS)

    Fox, Robert A.; Sutton, R. L.; Mckenna, Susan

    1991-01-01

    Conditioned taste aversion (CTA) is one of several behaviors which was suggested as a putative measure of motion sickness in rats. A review is made of studies which used surgical disruption of area postrema or the vagus nerve to investigate whether CTA and vomiting induced by motion may depend on common neural pathways or structures. When the chemoreceptive function of the area postrema (AP) is destroyed by complete ablation, rats develop CTA and cats and monkeys develop CTA and vomit. Thus the AP is not crucially involved in either CTA or vomiting induced by motion. However, after complete denervation of the stomach or after labyrinthectomy rats do not develop CTA when motion is used as the unconditioned stimulus. Studies of brainstem projections of the vagus nerve, the area postrema, the periaqueductal grey, and the vestibular system are used as the basis for speculation about regions which could mediate both motion-induced vomiting and behavioral food aversion.

  17. FURTHER ANALYSIS OF VARIABLES THAT AFFECT SELF-CONTROL WITH AVERSIVE EVENTS

    PubMed Central

    Perrin, Christopher J; Neef, Nancy A

    2012-01-01

    The purpose of this study was to examine variables that affect self-control in the context of academic task completion by elementary school children with autism. In the baseline assessment of Study 1, mathematics problem completion was shown to be an aversive event, and sensitivity to task magnitude, task difficulty, and delay to task completion were measured. The effects of manipulating values of those parameters on self-control then were assessed. For all participants, self-control increased as a function of one or more changes in task parameter values. In Study 2, the effects of a commitment response on self-control was assessed. Results indicated that for all participants, levels of self-control were higher when the opportunity to commit to the immediate aversive event was available. PMID:22844138

  18. Reappraising striatal D1- and D2-neurons in reward and aversion.

    PubMed

    Soares-Cunha, Carina; Coimbra, Barbara; Sousa, Nuno; Rodrigues, Ana J

    2016-09-01

    The striatum has been involved in complex behaviors such as motor control, learning, decision-making, reward and aversion. The striatum is mainly composed of medium spiny neurons (MSNs), typically divided into those expressing dopamine receptor D1, forming the so-called direct pathway, and those expressing D2 receptor (indirect pathway). For decades it has been proposed that these two populations exhibit opposing control over motor output, and recently, the same dichotomy has been proposed for valenced behaviors. Whereas D1-MSNs mediate reinforcement and reward, D2-MSNs have been associated with punishment and aversion. In this review we will discuss pharmacological, genetic and optogenetic studies that indicate that there is still controversy to what concerns the role of striatal D1- and D2-MSNs in this type of behaviors, highlighting the need to reconsider the early view that they mediate solely opposing aspects of valenced behaviour. PMID:27235078

  19. Aversive workplace conditions and absenteeism: taking referent group norms and supervisor support into account.

    PubMed

    Biron, Michal; Bamberger, Peter

    2012-07-01

    Past research reveals inconsistent findings regarding the association between aversive workplace conditions and absenteeism, suggesting that other, contextual factors may play a role in this association. Extending contemporary models of absence, we draw from the social identity theory of attitude-behavior relations to examine how peer absence-related norms and leader support combine to explain the effect of aversive workplace conditions on absenteeism. Using a prospective design and a random sample of transit workers, we obtained results indicating that perceived job hazards and exposure to critical incidents are positively related to subsequent absenteeism, but only under conditions of more permissive peer absence norms. Moreover, this positive impact of peer norms on absenteeism is amplified among employees perceiving their supervisor to be less supportive and is attenuated to the point of nonsignificance among those viewing their supervisor as more supportive. PMID:22390387

  20. Approximate kernel competitive learning.

    PubMed

    Wu, Jian-Sheng; Zheng, Wei-Shi; Lai, Jian-Huang

    2015-03-01

    Kernel competitive learning has been successfully used to achieve robust clustering. However, kernel competitive learning (KCL) is not scalable for large scale data processing, because (1) it has to calculate and store the full kernel matrix that is too large to be calculated and kept in the memory and (2) it cannot be computed in parallel. In this paper we develop a framework of approximate kernel competitive learning for processing large scale dataset. The proposed framework consists of two parts. First, it derives an approximate kernel competitive learning (AKCL), which learns kernel competitive learning in a subspace via sampling. We provide solid theoretical analysis on why the proposed approximation modelling would work for kernel competitive learning, and furthermore, we show that the computational complexity of AKCL is largely reduced. Second, we propose a pseudo-parallelled approximate kernel competitive learning (PAKCL) based on a set-based kernel competitive learning strategy, which overcomes the obstacle of using parallel programming in kernel competitive learning and significantly accelerates the approximate kernel competitive learning for large scale clustering. The empirical evaluation on publicly available datasets shows that the proposed AKCL and PAKCL can perform comparably as KCL, with a large reduction on computational cost. Also, the proposed methods achieve more effective clustering performance in terms of clustering precision against related approximate clustering approaches. PMID:25528318

  1. Competitiveness among Japanese, Chinese, and American undergraduate students.

    PubMed

    Houston, John M; Harris, Paul B; Moore, Robert; Brummett, Rebecca; Kametani, Hideki

    2005-08-01

    Although research indicates that competitiveness, defined as the desire to win in interpersonal situations, is an important individual difference that influences a range of social interactions, little research has focused on competitiveness in cultures outside the United States. This study investigated competitiveness in three cultures by comparing Chinese (n=61), Japanese (n=232), and American (n=161) undergraduate college students. Nationality and sex were compared on two scales of the revised Competitiveness Index. Analysis indicated that American students scored higher on Enjoyment of Competitiveness than Chinese and Japanese students, but no difference was found on Contentiousness. Men scored higher than women on Enjoyment of Competition but not on Contentiousness. The findings indicate that sex and cultural patterns influence some but not all aspects of competitiveness. PMID:16279327

  2. Suboptimal nutrient balancing despite dietary choice in glucose-averse German cockroaches, Blattella germanica.

    PubMed

    Jensen, Kim; Schal, Coby; Silverman, Jules

    2015-10-01

    Insects have evolved fine-tuned gustatory and post-ingestive physiological mechanisms that enable them to self-select an optimal composition of macronutrients. Their ability to forage optimally among multiple food sources and maximize fitness parameters depends on their ability not only to taste and perceive the nutritional value of potential foods but also to avoid deleterious components; the strength of such avoidance should reflect the severity of the perceived hazard. In German cockroaches (Blattella germanica), glucose aversion has evolved in some populations in response to anthropogenic selection with glucose-containing insecticidal baits. In four feeding treatments, we gave newly eclosed glucose-averse female cockroaches free choice to feed from two artificial, nutritionally complementary foods varying in protein and carbohydrate composition, with glucose or fructose as the sole carbohydrate source in either food. After 6days of feeding, we measured diet consumption and the length of basal oocytes as an estimate of sexual maturation. The females did not compromise on their aversion to glucose in order to balance their protein and carbohydrate intake, and experienced lower sexual maturation rates as a consequence. Nutrient specific hunger via feedback mechanisms, and adjustments to gustatory sensitivity thus do not override the deterrence of glucose, likely due to strong selection against ingesting even small amounts of toxin associated with glucose in baits. In the absence of baits, glucose aversion would be expected to incur a fitness cost compared to wild-type individuals due to lower overall food availability but also to larger difficulty in attaining a nutritionally balanced diet. PMID:26145203

  3. Overshadowing of a context aversion by a novel incentive in operant conditioning.

    PubMed

    Meachum, C L

    1990-05-01

    Two experiments examined the processes underlying the suppression of instrumental behaviours by lithium in rats, as reported by Meachum (1988 and this issue). Experiment 1 examined whether presenting a novel sucrose solution prior to lithium chloride administration would overshadow aversion learning to either the stimuli of the operant chamber or to familiar food pellets. After lever pressing had been established, and in the absence of responding, animals received free deliveries of a novel sucrose solution, familiar food pellets, or both, or they were exposed to only the cues of the operant chamber, prior to lithium injections. Lever pressing for food pellets was then assessed. It was found that the animals receiving the novel sucrose, either alone or with the familiar food pellets, pressed more for pellets than either the group receiving only food pellets or the group exposed to only the context. In addition, there was no appreciable difference in the response rates between the context-only group and the group that received the familiar food pellets. These outcomes were interpreted in terms of the novel sucrose overshadowing aversion learning to the context. Experiment 2 investigated whether in fact aversive contextual conditioning could be obtained using the present parameters. This was accomplished by directly manipulating the contexts. In this experiment animals were trained to lever press in two distinctive contexts. Subsequently, one context was paired with the novel sucrose, and the second was experienced in the absence of reinforcement prior to toxicosis. During a subsequent non-reinforced test it was found that responding in the context paired with the novel sucrose was considerably higher than responding in the context that was experienced alone. These findings stand in contrast to the taste-mediated contextual potentiation observed when a consumatory response is used to assess aversive contextual conditioning. PMID:2164239

  4. Overloaded elution band profiles of ionizable compounds in reversed-phase liquid chromatography: Influence of the competition between the neutral and the ionic species

    SciTech Connect

    Gritti, Fabrice; Guiochon, Georges A

    2008-01-01

    The parameters that affect the shape of the band profiles of acido-basic compounds under moderately overloaded conditions (sample size less than 500 nmol for a conventional column) in RPLC are discussed. Only analytes that have a single pK{sub a} are considered. In the buffer mobile phase used for their elution, their dissociation may, under certain conditions, cause a significant pH perturbation during the passage of the band. Two consecutive injections (3.3 and 10 {micro}L) of each one of three sample solutions (0.5, 5, and 50 mM) of ten compounds were injected on five C{sub 18}-bonded packing materials, including the 5 {micro}m Xterra-C{sub 18} (121 {angstrom}), 5 {micro}m Gemini-C{sub 18} (110 {angstrom}), 5 {micro}m Luna-C{sub 18}(2) (93 {angstrom}), 3.5 {micro}m Extend-C{sub 18} (80 {angstrom}), and 2.7 {micro}m Halo-C{sub 18} (90 {angstrom}). The mobile phase was an aqueous solution of methanol buffered at a constant {sub W}{sup W}pH of 6, with a phosphate buffer. The total concentration of the phosphate groups was constant at 50 mM. The methanol concentration was adjusted to keep all the retention factors between 1 and 10. The compounds injected were phenol, caffeine, 3-phenyl 1-propanol, 2-phenyl butyric acid, amphetamine, aniline, benzylamine, p-toluidine, procainamidium chloride, and propranololium chloride. Depending on the relative values of the analyte pK{sub a} and the buffer solution pH, these analytes elute as the neutral, the cationic, or the anionic species. The influence of structural parameters such as the charge, the size, and the hydrophobicity of the analytes on the shape of its overloaded band profile is discussed. Simple but general rules predict these shapes. An original adsorption model is proposed that accounts for the unusual peak shapes observed when the analyte is partially dissociated in the buffer solution during its elution.

  5. Instructed knowledge shapes feedback-driven aversive learning in striatum and orbitofrontal cortex, but not the amygdala

    PubMed Central

    Atlas, Lauren Y; Doll, Bradley B; Li, Jian; Daw, Nathaniel D; Phelps, Elizabeth A

    2016-01-01

    Socially-conveyed rules and instructions strongly shape expectations and emotions. Yet most neuroscientific studies of learning consider reinforcement history alone, irrespective of knowledge acquired through other means. We examined fear conditioning and reversal in humans to test whether instructed knowledge modulates the neural mechanisms of feedback-driven learning. One group was informed about contingencies and reversals. A second group learned only from reinforcement. We combined quantitative models with functional magnetic resonance imaging and found that instructions induced dissociations in the neural systems of aversive learning. Responses in striatum and orbitofrontal cortex updated with instructions and correlated with prefrontal responses to instructions. Amygdala responses were influenced by reinforcement similarly in both groups and did not update with instructions. Results extend work on instructed reward learning and reveal novel dissociations that have not been observed with punishments or rewards. Findings support theories of specialized threat-detection and may have implications for fear maintenance in anxiety. DOI: http://dx.doi.org/10.7554/eLife.15192.001 PMID:27171199

  6. Aversive viscerally referred states and thirst accompanying the sating of hunger motivation by rapid digestion of glucosaccharides.

    PubMed

    Booth, David A; O'Leary, Gemma; Li, Lixiang; Higgs, Suzanne

    2011-03-01

    Associative conditioning of satiety indicates that concentrated maltodextrin (cMD) may induce a mildly aversive visceral signal within 20 min of its ingestion, as well as satiating normally. Individuals' awareness of this adverse state was tested on ratings of statistically distinct descriptions of factors liable to suppress hunger, whether distressing or comfortably satisfying. Wanted amount of a food and the pleasantness of eating it correlated highly for each of five foods, once again refuting the widespread presumption that "pleasant" refers to sensory pleasure; hence, as in previous reports, suppression of hunger was measured as a reduction of the averaged pleasantness of functionally related foods. At 20 min after the start of ingestion of a small meal on a near-empty stomach, cMD reliably reduced hunger. The greatest influence on hunger, besides normal sating, was thirst, but there were also tendencies to nausea and bloat, although all less than after a full sized meal. Visceral processes shortly after a meal can create dissociable conscious states, only one of which is satiety for food. PMID:21118700

  7. Histaminergic modulation of cholinergic release from the nucleus basalis magnocellularis into insular cortex during taste aversive memory formation.

    PubMed

    Purón-Sierra, Liliana; Miranda, María Isabel

    2014-01-01

    The ability of acetylcholine (ACh) to alter specific functional properties of the cortex endows the cholinergic system with an important modulatory role in memory formation. For example, an increase in ACh release occurs during novel stimulus processing, indicating that ACh activity is critical during early stages of memory processing. During novel taste presentation, there is an increase in ACh release in the insular cortex (IC), a major structure for taste memory recognition. There is extensive evidence implicating the cholinergic efferents of the nucleus basalis magnocellularis (NBM) in cortical activity changes during learning processes, and new evidence suggests that the histaminergic system may interact with the cholinergic system in important ways. However, there is little information as to whether changes in cholinergic activity in the IC are modulated during taste memory formation. Therefore, in the present study, we evaluated the influence of two histamine receptor subtypes, H1 in the NBM and H3 in the IC, on ACh release in the IC during conditioned taste aversion (CTA). Injection of the H3 receptor agonist R-α-methylhistamine (RAMH) into the IC or of the H1 receptor antagonist pyrilamine into the NBM during CTA training impaired subsequent CTA memory, and simultaneously resulted in a reduction of ACh release in the IC. This study demonstrated that basal and cortical cholinergic pathways are finely tuned by histaminergic activity during CTA, since dual actions of histamine receptor subtypes on ACh modulation release each have a significant impact during taste memory formation. PMID:24625748

  8. Nurses and subordination: a historical study of mental nurses’ perceptions on administering aversion therapy for ‘sexual deviations’

    PubMed Central

    Dickinson, Tommy; Cook, Matt; Playle, John; Hallett, Christine

    2014-01-01

    Nurses and subordination: a historical study of mental nurses’ perceptions on administering aversion therapy for ‘sexual deviations’ This study aimed to examine the meanings that nurses attached to the ‘treatments’ administered to cure ‘sexual deviation’ (SD) in the UK, 1935–1974. In the UK, homosexuality was considered a classifiable mental illness that could be ‘cured’ until 1992. Nurses were involved in administering painful and distressing treatments. The study is based on oral history interviews with fifteen nurses who had administered treatments to cure individuals of their SD. The interviews were transcribed for historical interpretation. Some nurses believed that their role was to passively follow any orders they had been given. Other nurses limited their culpability concerning administering these treatments by adopting dehumanising and objectifying language and by focussing on administrative tasks, rather than the human beings in need of their care. Meanwhile, some nurses genuinely believed that they were acting beneficently by administering these distinctly unpleasant treatments. It is envisaged that this study might act to reiterate the need for nurses to ensure their interventions have a sound evidence base and that they constantly reflect on the moral and value base of their practice and the influence that science and societal norms can have on changing views of what is considered ‘acceptable practice’. PMID:23876127

  9. The role of the glucocorticoid receptor gene (NR3C1) for the processing of aversive stimuli.

    PubMed

    Schneider, Katja Kerstin; Frings, Christian; Meyer, Jobst; Schote, Andrea B

    2016-06-01

    The glucocorticoid receptor (GR) is a crucial component of the hypothalamus-pituitary-adrenal (HPA) axis and as such a part of the stress response system. An impairment of the GR not only alters the level of glucocorticoids, but also modulates cognitive functions and the processing of emotional stimuli. We tested the effects of functional polymorphisms of the GR-encoding gene (NR3C1) on the processing of emotional stimuli on a basal level. In a sample of n=182 participants, we found a haplotype (NR3C1-CTGGACA) to modulate the performance in an emotional reaction time task. Compared to non-carriers, participants who carried the haplotype were quicker to react after aversive stimuli had been presented. In contrast, the presence of the haplotype had no effect on the processing of neutral stimuli. We conclude that properties of the glucocorticoid receptor contribute to the processing of emotional stimuli and influence the intensity of their processing even in the absence of acute stressors. PMID:26689331

  10. Dopamine Receptor Blockade Modulates the Rewarding and Aversive Properties of Nicotine via Dissociable Neuronal Activity Patterns in the Nucleus Accumbens

    PubMed Central

    Sun, Ninglei; Laviolette, Steven R

    2014-01-01

    The mesolimbic pathway comprising the ventral tegmental area (VTA) and projection terminals in the nucleus accumbens (NAc) has been identified as a critical neural system involved in processing both the rewarding and aversive behavioral effects of nicotine. Transmission through dopamine (DA) receptors functionally modulates these effects directly within the NAc. Nevertheless, the neuronal mechanisms within the NAc responsible for these bivalent behavioral effects are presently not known. Using an unbiased conditioned place preference procedure combined with in vivo neuronal recordings, we examined the effects of nicotine reward and aversion conditioning on intra-NAc neuronal sub-population activity patterns. We report that intra-VTA doses of nicotine that differentially produce rewarding or aversive behavioral effects produce opposite effects on sub-populations of fast-spiking interneurons (FSIs) or medium spiny neurons (MSNs) within the shell region of the NAc (NAshell). Thus, while the rewarding effects of intra-VTA nicotine were associated with inhibition of FSI and activation of MSNs, the aversive effects of nicotine produced the opposite pattern of NAshell neuronal population activity. Blockade of DA transmission with a broad-spectrum DA receptor antagonist, α-flupenthixol, strongly inhibited the spontaneous activity of NAshell FSIs, and reversed the conditioning properties of intra-VTA nicotine, switching nicotine-conditioned responses from aversive to rewarding. Remarkably, DA receptor blockade switched intra-NAshell neuronal population activity from an aversion to a reward pattern, concomitant with the observed switch in behavioral conditioning effects. PMID:24896614

  11. Age differences in (±) 3,4-methylenedioxymethamphetamine (MDMA)-induced conditioned taste aversions and monoaminergic levels.

    PubMed

    Cobuzzi, Jennifer L; Siletti, Kayla A; Hurwitz, Zachary E; Wetzell, Bradley; Baumann, Michael H; Riley, Anthony L

    2014-05-01

    Preclinical work indicates that adolescent rats appear more sensitive to the rewarding effects and less sensitive to the aversive effects of abused drugs. The present investigation utilized the conditioned taste aversion (CTA) design to measure the relative aversive effects of (±)3,4-methylenedioxymethamphetamine (MDMA; 0, 1.0, 1.8, or 3.2 mg/kg) in adolescent and adult Sprague-Dawley rats. After behavioral testing was complete, monoamine and associated metabolite levels in discrete brain regions were quantified using high-performance liquid chromatography coupled to electrochemical detection (HPLC-ECD) to determine if adolescent animals displayed a different neurochemical profile than did adult animals after being exposed to subcutaneous low doses of MDMA. Adolescent rats displayed less robust MDMA-induced taste aversions than adults during acquisition and on a final two-bottle aversion test. MDMA at these doses had no consistent effect on monoamine levels in either age group, although levels did vary with age. The relative insensitivity of adolescents to MDMA's aversive effects may engender an increased vulnerability to MDMA abuse in this specific population. PMID:23775255

  12. VTA glutamatergic inputs to nucleus accumbens drive aversion by acting on GABAergic interneurons.

    PubMed

    Qi, Jia; Zhang, Shiliang; Wang, Hui-Ling; Barker, David J; Miranda-Barrientos, Jorge; Morales, Marisela

    2016-05-01

    The ventral tegmental area (VTA) is best known for its dopamine neurons, some of which project to nucleus accumbens (nAcc). However, the VTA also has glutamatergic neurons that project to nAcc. The function of the mesoaccumbens glutamatergic pathway remains unknown. Here we report that nAcc photoactivation of mesoaccumbens glutamatergic fibers promotes aversion. Although we found that these mesoaccumbens glutamatergic fibers lack GABA, the aversion evoked by their photoactivation depended on glutamate- and GABA-receptor signaling, and not on dopamine-receptor signaling. We found that mesoaccumbens glutamatergic fibers established multiple asymmetric synapses on single parvalbumin GABAergic interneurons and that nAcc photoactivation of these fibers drove AMPA-mediated cellular firing of parvalbumin GABAergic interneurons. These parvalbumin GABAergic interneurons in turn inhibited nAcc medium spiny output neurons, thereby controlling inhibitory neurotransmission in nAcc. To our knowledge, the mesoaccumbens glutamatergic pathway is the first glutamatergic input to nAcc shown to mediate aversion instead of reward, and the first pathway shown to establish excitatory synapses on nAcc parvalbumin GABAergic interneurons. PMID:27019014

  13. Aversive Learning and Appetitive Motivation Toggle Feed-Forward Inhibition in the Drosophila Mushroom Body.

    PubMed

    Perisse, Emmanuel; Owald, David; Barnstedt, Oliver; Talbot, Clifford B; Huetteroth, Wolf; Waddell, Scott

    2016-06-01

    In Drosophila, negatively reinforcing dopaminergic neurons also provide the inhibitory control of satiety over appetitive memory expression. Here we show that aversive learning causes a persistent depression of the conditioned odor drive to two downstream feed-forward inhibitory GABAergic interneurons of the mushroom body, called MVP2, or mushroom body output neuron (MBON)-γ1pedc>α/β. However, MVP2 neuron output is only essential for expression of short-term aversive memory. Stimulating MVP2 neurons preferentially inhibits the odor-evoked activity of avoidance-directing MBONs and odor-driven avoidance behavior, whereas their inhibition enhances odor avoidance. In contrast, odor-evoked activity of MVP2 neurons is elevated in hungry flies, and their feed-forward inhibition is required for expression of appetitive memory at all times. Moreover, imposing MVP2 activity promotes inappropriate appetitive memory expression in food-satiated flies. Aversive learning and appetitive motivation therefore toggle alternate modes of a common feed-forward inhibitory MVP2 pathway to promote conditioned odor avoidance or approach. PMID:27210550

  14. Diet specialization in an extreme omnivore: nutritional regulation in glucose-averse German cockroaches.

    PubMed

    Shik, J Z; Schal, C; Silverman, J

    2014-10-01

    Organisms have diverse adaptations for balancing dietary nutrients, but often face trade-offs between ingesting nutrients and toxins in food. While extremely omnivorous cockroaches would seem excluded from such dietary trade-offs, German cockroaches (Blattella germanica) in multiple populations have rapidly evolved a unique dietary specialization - an aversion to glucose, the phagostimulant in toxic baits used for pest control. We used factorial feeding experiments within the geometric framework to test whether glucose-averse (GA) cockroaches with limited access to this critical metabolic fuel have compensatory behavioural and physiological strategies for meeting nutritional requirements. GA cockroaches had severely constrained intake, fat and N mass, and performance on glucose-based diets relative to wild-type (WT) cockroaches and did not appear to exhibit digestive strategies for retaining undereaten nutrients. However, a GA × WT 'hybrid' had lower glucose aversion than GA and greater access to macronutrients within glucose-based diets - while still having lower intake and survival than WT. Given these intermediate foraging constraints, hybrids may be a reservoir for this maladaptive trait in the absence of positive selection and may account for the rapid evolution of this trait following bait application. PMID:25078384

  15. Time-dependent effects of treadmill exercise on aversive memory and cyclooxygenase pathway function.

    PubMed

    Lovatel, Gisele Agustini; Bertoldi, Karine; Elsner, Viviane Rostirola; Vanzella, Cláudia; Moysés, Felipe Dos Santos; Spindler, Christiano; Funck, Vinicius Rafael; Pereira, Leticia Meier; de Oliveira, Clarissa Vasconcelos; Oliveira, Mauro Schneider; Netto, Carlos Alexandre; Siqueira, Ionara Rodrigues

    2012-09-01

    Exercise induces brain function adaptations and improves learning and memory; however the time window of exercise effects has been poorly investigated. Studies demonstrate an important role for cyclooxygenase-2 (COX-2) pathway function in the mechanisms underlying memory formation. The aim of present work was to investigate the effects of treadmill exercise on aversive memory and COX-2, PGE(2) and E-prostanoid receptors contents in the rat hippocampus at different time points after exercise has ended. Adult male Wistar rats were assigned to non-exercised (sedentary) and exercised (running daily for 20min, for 2weeks) groups. The inhibitory avoidance task was used to assess aversive memory and the COX-2, PGE(2) and E-prostanoid receptors (EP1, EP2, EP3 and EP4) levels were determined 1h, 18h, 3days or 7days after the last training session of treadmill exercise. The step down latency in the inhibitory avoidance, COX-2 and EP4 receptors levels were acutely increased by exercise, with a significant positive correlation between aversive memory performance and COX-2 levels. Increased EP2 content decreased PGE(2) levels were observed 7days after the last running session. The treadmill exercise protocol facilitates inhibitory avoidance memory and induces time-dependent changes on COX-2 pathways function (COX-2, PGE(2) and EP receptors). PMID:22728946

  16. Emotion regulation reduces loss aversion and decreases amygdala responses to losses

    PubMed Central

    Sokol-Hessner, Peter; Camerer, Colin F.

    2013-01-01

    Emotion regulation strategies can alter behavioral and physiological responses to emotional stimuli and the neural correlates of those responses in regions such as the amygdala or striatum. The current study investigates the brain systems engaged when using an emotion regulation technique during financial decisions. In decision making, regulating emotion with reappraisal-focused strategies that encourage taking a different perspective has been shown to reduce loss aversion as observed both in choices and in the relative arousal responses to actual loss and gain outcomes. In the current study, we find using fMRI that behavioral loss aversion correlates with amygdala activity in response to losses relative to gains. Success in regulating loss aversion also correlates with the reduction in amygdala responses to losses but not to gains. Furthermore, across both decisions and outcomes, we find the reappraisal strategy increases baseline activity in dorsolateral and ventromedial prefrontal cortex and the striatum. The similarity of the neural circuitry observed to that seen in emotion regulation, despite divergent tasks, serves as further evidence for a role of emotion in decision making, and for the power of reappraisal to change assessments of value and thereby choices. PMID:22275168

  17. Strain-dependent differences in corticolimbic processing of aversive or rewarding stimuli

    PubMed Central

    Andolina, Diego; Puglisi-Allegra, Stefano; Ventura, Rossella

    2015-01-01

    Aberrations in the elaboration of both aversive and rewarding stimuli characterize several psychopathologies including anxiety, depression and addiction. Several studies suggest that different neurotrasmitters, within the corticolimbic system, are critically involved in the processing of positive and negative stimuli. Individual differences in this system, depending on genotype, have been shown to act as a liability factor for different psychopathologies. Inbred mouse strains are commonly used in preclinical studies of normal and pathological behaviors. In particular, C57BL/6J (C57) and DBA/2J (DBA) strains have permitted to disclose the impact of different genetic backgrounds over the corticolimbic system functions. Here, we summarize the main findings collected over the years in our laboratory, showing how the genetic background plays a critical role in modulating amminergic and GABAergic neurotransmission in prefrontal-accumbal-amygdala system response to different rewarding and aversive experiences, as well as to stress response. Finally, we propose a top-down model for the response to rewarding and aversive stimuli in which amminergic transmission in prefrontal cortex (PFC) controls accumbal and amygdala neurotransmitter response. PMID:25698940

  18. Reacquisition, reinstatement, and renewal of a conditioned taste aversion in preweanling rats.

    PubMed

    Revillo, D A; Castello, S; Paglini, G; Arias, C

    2014-05-01

    Pavlovian extinction is defined as a reduction of the conditioned response (CR) as a consequence of repeated and nonreinforced presentations of the conditioned stimulus (CS). This phenomenon has been explained through two nonexclusive associative hypotheses. One of them proposes that the CS-unconditioned stimulus (US) association is weakened during extinction, while the second one explains extinction by the formation of a new inhibitory association between the CS, and the US (CS-noUS) which competes with the excitatory one acquired at conditioning (CS-US). Research supporting this second hypothesis is based on the demonstration that the CR can be recovered after extinction. However, in preweanling rats, renewal, and reinstatement treatments have failed to recover a conditioned fear response, suggesting that extinction during this ontogenetic period may involve erasure of the CS-US association. The goal of the present study was to explore whether this conclusion can be extended to the extinction of a conditioned taste aversion by evaluating infant rats in three different procedures (reacquisition, ABA renewal, and reinstatement). The results are consistent with the idea that extinction of a taste aversive memory during infancy involves relearning about the relationship between the CS and the US, with the initial CS-US association remaining relatively intact. Extinction of a taste aversive memory and a fear memory may involve different biological mechanisms during infancy. The conclusion that the only psychological mechanism for extinction during infancy is unlearning should be confined to a particular type of memory. PMID:23765264

  19. Evidence for involvement of endogenous acetylcholine in emotional-aversive response in the cat.

    PubMed

    Brudzynski, S M; Eckersdorf, B; Golebiewski, H

    1990-01-01

    1. The purpose of the present study was to provide evidence for involvement of endogenous acetylcholine in naturally as well as pharmacologically induced emotional behaviour in the cat. 2. Emotional-aversive responses of 10 cats were naturally evoked by presentation of a dog or the responses were pharmacologically induced by intracerebral injections of cholinomimetics. 3. Naturally evoked emotional behaviour was abolished by i.p. pretreatment with atropine sulfate (1 mg/kg), but not by atropine methyl nitrate, or it was significantly decreased by bilateral intracerebral injection of atropine sulfate (5 micrograms/microliter). 4. On the other hand, intracerebral injections of physostigmine (100 micrograms/microliter), an acetylcholinesterase inhibitor which elevates the level of endogenous acetylcholine, induced the fully developed emotional-aversive response comparable with natural behaviour and with responses induced by carbachol (10 micrograms/microliter). 5. The results demonstrate that the endogenous acetylcholine in the basal forebrain and diencephalic areas play a role in naturally occurring emotional aversive behaviour in cats. PMID:2293258

  20. Effects of Aversive Stimuli on Prospective Memory. An Event-Related fMRI Study

    PubMed Central

    Rea, Massimiliano; Kullmann, Stephanie; Veit, Ralf; Casile, Antonino; Braun, Christoph; Belardinelli, Marta Olivetti; Birbaumer, Niels; Caria, Andrea

    2011-01-01

    Prospective memory (PM) describes the ability to execute a previously planned action at the appropriate point in time. Although behavioral studies clearly showed that prospective memory performance is affected by the emotional significance attributed to the intended action, no study so far investigated the brain mechanisms subserving the modulatory effect of emotional salience on PM performance. The general aim of the present study was to explore brain regions involved in prospective memory processes when PM cues are associated with emotional stimuli. In particular, based on the hypothesised critical role of the prefrontal cortex in prospective memory in the presence of emotionally salient stimuli, we expected a stronger involvement of aPFC when the retrieval and execution of the intended action is cued by an aversive stimulus. To this aim BOLD responses of PM trials cued by aversive facial expressions were compared to PM trials cued by neutral facial expressions. Whole brain analysis showed that PM task cued by aversive stimuli is differentially associated with activity in the right lateral prefrontal area (BA 10) and in the left caudate nucleus. Moreover a temporal shift between the response of the caudate nucleus that preceded that of aPFC was observed. These findings suggest that the caudate nucleus might provide an early analysis of the affective properties of the stimuli, whereas the anterior lateral prefrontal cortex (BA10) would be involved in a slower and more deliberative analysis to guide goal-directed behaviour. PMID:22022589

  1. Egr-1 induction provides a genetic response to food aversion in zebrafish

    PubMed Central

    Boyer, Brigitte; Ernest, Sylvain; Rosa, Frédéric

    2013-01-01

    As soon as zebrafish larvae start eating, they exhibit a marked aversion for bitter and acidic substances, as revealed by a consumption assay, in which fluorescent Tetrahymena serve as a feeding basis, to which various stimuli can be added. Bitter and acidic substances elicited an increase in mRNA accumulation of the immediate-early response gene egr-1, as revealed by in situ hybridization. Conversely, chemostimulants that did not induce aversion did not induce egr-1 response. Maximum labeling was observed in cells located in the oropharyngeal cavity and on the gill rakers. Gustatory areas of the brain were also labeled. Interestingly, when bitter tastants were repeatedly associated with food reward, zebrafish juveniles learned to ingest food in the presence of the bitter compound. After habituation, the acquisition of acceptance for bitterness was accompanied by a loss of egr-1 labeling. Altogether, our data indicate that egr-1 participates specifically in food aversion. The existence of reward-coupled changes in taste sensitivity in humans suggests that our results are relevant to situations in humans. PMID:23720615

  2. Assessing appetitive, aversive, and negative ethanol-mediated reinforcement through an immature rat model

    PubMed Central

    Pautassi, Ricardo M.; Nizhnikov, Michael E.; Spear, Norman E.

    2009-01-01

    The motivational effects of drugs play a key role during the transition from casual use to abuse and dependence. Ethanol reinforcement has been successfully studied through Pavlovian and operant conditioning in adult rats and mice genetically selected for their ready acceptance of ethanol. Another model for studying ethanol reinforcement is the immature (preweanling) rat, which consumes ethanol and exhibits the capacity to process tactile, odor and taste cues and transfer information between different sensorial modalities. This review describes the motivational effects of ethanol in preweanling, heterogeneous non-selected rats. Preweanlings exhibit ethanol-mediated conditioned taste avoidance and conditioned place aversion. Ethanol's appetitive effects, however, are evident when using first- and second-order conditioning and operant procedures. Ethanol also devalues the motivational representation of aversive stimuli, suggesting early negative reinforcement. It seems that preweanlings are highly sensitive not only to the aversive motivational effects of ethanol but also to its positive and negative (anti-anxiety) reinforcement potential. The review underscores the advantages of using a developing rat to evaluate alcohol's motivational effects. PMID:19428502

  3. Neural mechanisms of the nucleus accumbens circuit in reward and aversive learning.

    PubMed

    Hikida, Takatoshi; Morita, Makiko; Macpherson, Tom

    2016-07-01

    The basal ganglia are key neural substrates not only for motor function, but also cognitive functions including reward and aversive learning. Critical for these processes are the functional role played by two projection neurons within nucleus accumbens (NAc); the D1- and D2-expressing neurons. Recently, we have developed a novel reversible neurotransmission blocking technique that specifically blocks neurotransmission from NAc D1- and D2-expressing neurons, allowing for in vivo analysis. In this review, we outline the functional dissociation of NAc D1- and D2-expressing neurons of the basal ganglia in reward and aversive learning, as well as drug addiction. These studies have revealed the importance of activation of NAc D1 receptors for reward learning and drug addiction, and inactivation of NAc D2 receptors for aversive learning and flexibility. Based on these findings, we propose a neural mechanism, in which dopamine neurons in the ventral tegmental area that send inputs to the NAc work as a switch between D1- and D2-expressing neurons. These basal ganglia neural mechanisms will give us new insights into the pathophysiology of neuropsychiatric diseases. PMID:26827817

  4. Reward salience and risk aversion underlie differential ACC activity in substance dependence

    PubMed Central

    Alexander, William H.; Fukunaga, Rena; Finn, Peter; Brown, Joshua W.

    2015-01-01

    The medial prefrontal cortex, especially the dorsal anterior cingulate cortex (ACC), has long been implicated in cognitive control and error processing. Although the association between ACC and behavior has been established, it is less clear how ACC contributes to dysfunctional behavior such as substance dependence. Evidence from neuroimaging studies investigating ACC function in substance users is mixed, with some studies showing disengagement of ACC in substance dependent individuals (SDs), while others show increased ACC activity related to substance use. In this study, we investigate ACC function in SDs and healthy individuals performing a change signal task for monetary rewards. Using a priori predictions derived from a recent computational model of ACC, we find that ACC activity differs between SDs and controls in factors related to reward salience and risk aversion between SDs and healthy individuals. Quantitative fits of a computational model to fMRI data reveal significant differences in best fit parameters for reward salience and risk preferences. Specifically, the ACC in SDs shows greater risk aversion, defined as concavity in the utility function, and greater attention to rewards relative to reward omission. Furthermore, across participants risk aversion and reward salience are positively correlated. The results clarify the role that ACC plays in both the reduced sensitivity to omitted rewards and greater reward valuation in SDs. Clinical implications of applying computational modeling in psychiatry are also discussed. PMID:26106528

  5. Dexamethasone: a potent blocker for radiation-induced taste aversion in rats

    SciTech Connect

    Cairnie, A.B.; Leach, K.E.

    1982-08-01

    Rats, trained to drink water during a single 30-min period each day, were then given 0.1% saccharin twice a week and water on other days for 30 min. If 20 rad of radiation (0.2 Gy) were given each time 30 to 40 min after the saccharin the rats developed a profound aversion to saccharin during the course of three weeks, whereas control groups failed to do so. This paradigm was then used to test the ability of drugs, given twice weekly immediately after the saccharin, to prevent the development during three weeks of an aversion when 20 rad was given, 30 to 40 min later. Insulin, domperidone, haloperidol, acetylsalicylic acid, naloxone, chlorpheniramine, cimetidine, and dimethyl sulphoxide were tested without notable success. However dexamethasone, at doses ranging from 0.013 mg/kg to 1.3 mg/kg, significantly attenuated the conditioned taste aversion by up to 60 percent. The results are discussed in terms of a search for an antinauseant and antiemetic drug effective against radiation in man.

  6. Brain-derived neurotrophic factor into adult neocortex strengthens a taste aversion memory.

    PubMed

    Martínez-Moreno, Araceli; Rodríguez-Durán, Luis F; Escobar, Martha L

    2016-01-15

    Nowadays, it is known that brain derived neurotrophic-factor (BDNF) is a protein critically involved in regulating long-term memory related mechanisms. Previous studies from our group in the insular cortex (IC), a brain structure of the temporal lobe implicated in acquisition, consolidation and retention of conditioned taste aversion (CTA), demonstrated that BDNF is essential for CTA consolidation. Recent studies show that BDNF-TrkB signaling is able to mediate the enhancement of memory. However, whether BDNF into neocortex is able to enhance aversive memories remains unexplored. In the present work, we administrated BDNF in a concentration capable of inducing in vivo neocortical LTP, into the IC immediately after CTA acquisition in two different conditions: a "strong-CTA" induced by 0.2M lithium chloride i.p. as unconditioned stimulus, and a "weak-CTA" induced by 0.1M lithium chloride i.p. Our results show that infusion of BDNF into the IC converts a weak CTA into a strong one, in a TrkB receptor-dependent manner. The present data suggest that BDNF into the adult insular cortex is sufficient to increase an aversive memory-trace. PMID:26433146

  7. The involvement of nucleus accumbens dopamine in appetitive and aversive motivation.

    PubMed

    Salamone, J D

    1994-04-18

    In recent years, considerable emphasis has been placed upon the putative role of nucleus accumbens dopamine systems in appetitive motivation and positive reinforcement. However, considerable evidence indicates that brain dopamine in general, and nucleus accumbens dopamine in particular, is involved in aspects of aversive motivation. Administration of dopamine antagonists or localized interference with nucleus accumbens dopamine systems has been shown to disrupt active avoidance behavior. In addition, accumbens dopamine release and metabolism is activated by a wide variety of stressful conditions. A review of the literature indicates that there are substantial similarities between the characteristics of dopaminergic involvement in appetitive and aversive motivation. There is conflicting evidence about the role of dopamine in emotion, and little evidence to suggest that the profound and consistent changes in instrumental behavior produced by interference with DA systems are due to direct dopaminergic mediation of positive affective responses such as hedonia. It is suggested that nucleus accumbens dopamine is involved in aspects of sensorimotor functions that are involved in both appetitive and aversive motivation. PMID:8037860

  8. Prostaglandin-dependent modulation of dopaminergic neurotransmission elicits inflammation-induced aversion in mice

    PubMed Central

    Fritz, Michael; Klawonn, Anna M.; Nilsson, Anna; Singh, Anand Kumar; Zajdel, Joanna; Björk Wilhelms, Daniel; Lazarus, Michael; Löfberg, Andreas; Jaarola, Maarit; Örtegren Kugelberg, Unn; Billiar, Timothy R.; Hackam, David J.; Sodhi, Chhinder P.; Breyer, Matthew D.; Jakobsson, Johan; Schwaninger, Markus; Schütz, Günther; Rodriguez Parkitna, Jan; Saper, Clifford B.; Blomqvist, Anders; Engblom, David

    2015-01-01

    Systemic inflammation causes malaise and general feelings of discomfort. This fundamental aspect of the sickness response reduces the quality of life for people suffering from chronic inflammatory diseases and is a nuisance during mild infections like common colds or the flu. To investigate how inflammation is perceived as unpleasant and causes negative affect, we used a behavioral test in which mice avoid an environment that they have learned to associate with inflammation-induced discomfort. Using a combination of cell-type–specific gene deletions, pharmacology, and chemogenetics, we found that systemic inflammation triggered aversion through MyD88-dependent activation of the brain endothelium followed by COX1-mediated cerebral prostaglandin E2 (PGE2) synthesis. Further, we showed that inflammation-induced PGE2 targeted EP1 receptors on striatal dopamine D1 receptor–expressing neurons and that this signaling sequence induced aversion through GABA-mediated inhibition of dopaminergic cells. Finally, we demonstrated that inflammation-induced aversion was not an indirect consequence of fever or anorexia but that it constituted an independent inflammatory symptom triggered by a unique molecular mechanism. Collectively, these findings demonstrate that PGE2-mediated modulation of the dopaminergic motivational circuitry is a key mechanism underlying the negative affect induced by inflammation. PMID:26690700

  9. Social anxiety and cognitive expectancy of aversive outcome in avoidance conditioning.

    PubMed

    Ly, Verena; Roelofs, Karin

    2009-10-01

    Fear conditioning studies have shown that social anxiety is associated with enhanced expectancy of aversive outcome. However, the relation between cognitive expectancy and social anxiety has never been tested in avoidance conditioning paradigms. We compared 48 low (LSA) and high socially anxious individuals (HSA) on subjective expectancy of aversive outcome during an avoidance conditioning task. Displays of neutral faces were coupled with an aversive outcome (US): a shout and a shock. Participants could avoid the US by pressing a correct button from a button box. First, HSA showed higher US expectancy than LSA during the initial phase of avoidance conditioning, supporting the view that socially anxious individuals have an expectancy bias when social situations are ambiguous. Second, when the avoidance response became unavailable, LSA showed lower US expectancy than HSA, suggesting that low socially anxious individuals are prone to a positive bias when perceived threat is high. A lack of such positive bias in socially anxious individuals may lead to higher susceptibility to safety behavior interpretations. Together, these findings support the role of cognitive processes in avoidance conditioning and underscore the relevance to encounter avoidance learning when studying social anxiety. PMID:19625013

  10. The influence of competition between lichen colonization and erosion on the evolution of soil surfaces in the Tabernas badlands (SE Spain) and its landscape effects

    NASA Astrophysics Data System (ADS)

    Lázaro, R.; Cantón, Y.; Solé-Benet, A.; Bevan, J.; Alexander, R.; Sancho, L. G.; Puigdefábregas, J.

    2008-12-01

    often greater in north to east facing orientations because of the higher slope stability and the longer duration of moisture. However, the increase of the whole biological soil crust can depend more on species composition and previous cover and less or not at all on the aspect, although certain species do grow faster in particular orientations. Within the plots cleared in 2004 the greatest increase occurred in the pioneering brown crust, which reached an average of 26% cover after one year, in spite of it receiving the most insolation. Significant microclimatic differences exist among the communities, mainly in radiation, soil moisture and thallus surface temperature. Terricolous lichen crusts, primary colonizers of bare, sufficiently stable areas, can grow quickly and, by increasing soil stability and development and modifying surface hydrology, they can influence surface dynamics and ultimately landform dynamics. Crust growth rate probably decreases as its cover increases and it probably also oscillates with microclimatic oscillations. However, the high potential growth rate recorded allows detection not only of climatic changes but also short term (possibly seasonal) periods of stability. Extensive lichen crusts indicate low erosion rates and particular climatic conditions; variations of crust cover could indicate climatic (or land use) variations.

  11. Four paths of competition

    SciTech Connect

    Studness, C.M.

    1995-05-01

    The financial community`s focus on utility competition has been riveted on the proceedings now in progress at state regulatory commissions. The fear that something immediately damaging will come out of these proceedings seems to have diminished in recent months, and the stock market has reacted favorably. However, regulatory developments are only one of four paths leading to competition; the others are the marketplace, the legislatures, and the courts. Each could play a critical role in the emergence of competition.

  12. Intramural Gymnastics Competition.

    ERIC Educational Resources Information Center

    Cornelius, William L.

    1981-01-01

    An intramural gymnastic competition, if properly organized, can foster student and community interest in gymnastics. Aspects of organization and essential preplanning include: directing, judging, scoring, and managing. (JN)

  13. Kappa Opioid Receptor-Induced Aversion Requires p38 MAPK Activation in VTA Dopamine Neurons

    PubMed Central

    Ehrich, Jonathan M.; Messinger, Daniel I.; Knakal, Cerise R.; Kuhar, Jamie R.; Schattauer, Selena S.; Bruchas, Michael R.; Zweifel, Larry S.; Kieffer, Brigitte L.; Phillips, Paul E.M.

    2015-01-01

    The endogenous dynorphin-κ opioid receptor (KOR) system encodes the dysphoric component of the stress response and controls the risk of depression-like and addiction behaviors; however, the molecular and neural circuit mechanisms are not understood. In this study, we report that KOR activation of p38α MAPK in ventral tegmental (VTA) dopaminergic neurons was required for conditioned place aversion (CPA) in mice. Conditional genetic deletion of floxed KOR or floxed p38α MAPK by Cre recombinase expression in dopaminergic neurons blocked place aversion to the KOR agonist U50,488. Selective viral rescue by wild-type KOR expression in dopaminergic neurons of KOR−/− mice restored U50,488-CPA, whereas expression of a mutated form of KOR that could not initiate p38α MAPK activation did not. Surprisingly, while p38α MAPK inactivation blocked U50,488-CPA, p38α MAPK was not required for KOR inhibition of evoked dopamine release measured by fast scan cyclic voltammetry in the nucleus accumbens. In contrast, KOR activation acutely inhibited VTA dopaminergic neuron firing, and repeated exposure attenuated the opioid response. This adaptation to repeated exposure was blocked by conditional deletion of p38α MAPK, which also blocked KOR-induced tyrosine phosphorylation of the inwardly rectifying potassium channel (GIRK) subunit Kir3.1 in VTA dopaminergic neurons. Consistent with the reduced response, GIRK phosphorylation at this amino terminal tyrosine residue (Y12) enhances channel deactivation. Thus, contrary to prevailing expectations, these results suggest that κ opioid-induced aversion requires regulation of VTA dopaminergic neuron somatic excitability through a p38α MAPK effect on GIRK deactivation kinetics rather than by presynaptically inhibiting dopamine release. SIGNIFICANCE STATEMENT Kappa opioid receptor (KOR) agonists have the potential to be effective, nonaddictive analgesics, but their therapeutic utility is greatly limited by adverse effects on mood

  14. Imagery Rescripting: The Impact of Conceptual and Perceptual Changes on Aversive Autobiographical Memories

    PubMed Central

    Slofstra, Christien; Nauta, Maaike H.; Holmes, Emily A.; Bockting, Claudi L. H.

    2016-01-01

    Background Imagery rescripting (ImRs) is a process by which aversive autobiographical memories are rendered less unpleasant or emotional. ImRs is thought only to be effective if a change in the meaning-relevant (semantic) content of the mental image is produced, according to a cognitive hypothesis of ImRs. We propose an additional hypothesis: that ImRs can also be effective by the manipulation of perceptual features of the memory, without explicitly targeting meaning-relevant content. Methods In two experiments using a within-subjects design (both N = 48, community samples), both Conceptual-ImRs—focusing on changing meaning-relevant content—and Perceptual-ImRs—focusing on changing perceptual features—were compared to Recall-only of aversive autobiographical image-based memories. An active control condition, Recall + Attentional Breathing (Recall+AB) was added in the first experiment. In the second experiment, a Positive-ImRs condition was added—changing the aversive image into a positive image that was unrelated to the aversive autobiographical memory. Effects on the aversive memory’s unpleasantness, vividness and emotionality were investigated. Results In Experiment 1, compared to Recall-only, both Conceptual-ImRs and Perceptual-ImRs led to greater decreases in unpleasantness, and Perceptual-ImRs led to greater decreases in emotionality of memories. In Experiment 2, the effects on unpleasantness were not replicated, and both Conceptual-ImRs and Perceptual-ImRs led to greater decreases in emotionality, compared to Recall-only, as did Positive-ImRs. There were no effects on vividness, and the ImRs conditions did not differ significantly from Recall+AB. Conclusions Results suggest that, in addition to traditional forms of ImRs, targeting the meaning-relevant content of an image during ImRs, relatively simple techniques focusing on perceptual aspects or positive imagery might also yield benefits. Findings require replication and extension to clinical

  15. Competition promotes the persistence of populations in ecosystems.

    PubMed

    Wang, Tao; Duan, Jinqiao; Liu, Tong

    2016-01-01

    Competition is one of the most common form in ecological systems, which plays important roles in population dynamics. However, the influences of competition on persistence of populations remain unclear when space effect is included. In this paper, we investigated a predator-prey model with competition and spatial diffusion. Based on pattern formations and time series of populations, we found that competitions induce the persistence of populations, which denies competitive exclusion principle. Moreover, we testify the robustness of these effects. Our results also suggest that space may lead to the emergence of new phenomenon in ecosystems. PMID:27460143

  16. Competition promotes the persistence of populations in ecosystems

    NASA Astrophysics Data System (ADS)

    Wang, Tao; Duan, Jinqiao; Liu, Tong

    2016-07-01

    Competition is one of the most common form in ecological systems, which plays important roles in population dynamics. However, the influences of competition on persistence of populations remain unclear when space effect is included. In this paper, we investigated a predator-prey model with competition and spatial diffusion. Based on pattern formations and time series of populations, we found that competitions induce the persistence of populations, which denies competitive exclusion principle. Moreover, we testify the robustness of these effects. Our results also suggest that space may lead to the emergence of new phenomenon in ecosystems.

  17. Competition promotes the persistence of populations in ecosystems

    PubMed Central

    Wang, Tao; Duan, Jinqiao; Liu, Tong

    2016-01-01

    Competition is one of the most common form in ecological systems, which plays important roles in population dynamics. However, the influences of competition on persistence of populations remain unclear when space effect is included. In this paper, we investigated a predator-prey model with competition and spatial diffusion. Based on pattern formations and time series of populations, we found that competitions induce the persistence of populations, which denies competitive exclusion principle. Moreover, we testify the robustness of these effects. Our results also suggest that space may lead to the emergence of new phenomenon in ecosystems. PMID:27460143

  18. Distinct Contributions of Ventromedial and Dorsolateral Subregions of the Human Substantia Nigra to Appetitive and Aversive Learning

    PubMed Central

    Larsen, Tobias; Collette, Sven; Tyszka, Julian M.; Seymour, Ben; O'Doherty, John P.

    2015-01-01

    The role of neurons in the substantia nigra (SN) and ventral tegmental area (VTA) of the midbrain in contributing to the elicitation of reward prediction errors during appetitive learning has been well established. Less is known about the differential contribution of these midbrain regions to appetitive versus aversive learning, especially in humans. Here we scanned human participants with high-resolution fMRI focused on the SN and VTA while they participated in a sequential Pavlovian conditioning paradigm involving an appetitive outcome (a pleasant juice), as well as an aversive outcome (an unpleasant bitter and salty flavor). We found a degree of regional specialization within the SN: Whereas a region of ventromedial SN correlated with a temporal difference reward prediction error during appetitive Pavlovian learning, a dorsolateral area correlated instead with an aversive expected value signal in response to the most distal cue, and to a reward prediction error in response to the most proximal cue to the aversive outcome. Furthermore, participants' affective reactions to both the appetitive and aversive conditioned stimuli more than 1 year after the fMRI experiment was conducted correlated with activation in the ventromedial and dorsolateral SN obtained during the experiment, respectively. These findings suggest that, whereas the human ventromedial SN contributes to long-term learning about rewards, the dorsolateral SN may be particularly important for long-term learning in aversive contexts. SIGNIFICANCE STATEMENT The role of the substantia nigra (SN) and ventral tegmental area (VTA) in appetitive learning is well established, but less is known about their contribution to aversive compared with appetitive learning, especially in humans. We used high-resolution fMRI to measure activity in the SN and VTA while participants underwent higher-order Pavlovian learning. We found a regional specialization within the SN: a ventromedial area was selectively engaged

  19. Utah Mock Trial Competition.

    ERIC Educational Resources Information Center

    Oswald, Linda, Comp.

    Background materials and guidelines for secondary students and educators in Utah who wish to participate in the state-wide mock trial competition are provided. Many parts of the publication can be used by educators in other states who are using mock trials in their classrooms or who are developing a state-wide mock trial competition. The manual…

  20. Competition: Was Kohn Right?

    ERIC Educational Resources Information Center

    Shields, David Light; Bredemeier, Brenda Light

    2010-01-01

    Alfie Kohn made the case for competition being destructive to education. The truth may be that there are two separate ways to contest: true competition, which is a healthy desire to excel, and decompetition, which is the unhealthy desire merely to beat the opponent. Decompetition leads to the ills that Kohn enumerated. Educators should teach their…

  1. Competitiveness, Technology and Skills.

    ERIC Educational Resources Information Center

    Lall, Sanjaya

    This document examines competitiveness in the developing world. Chapters 1 through 3, which are largely conceptual, examine the following topics: the concept of competitiveness and why it is important; market-stimulating technology policies in developing countries, and the relationship between import liberalization and industrial performance.…

  2. Serotonin Transporter Gene Polymorphism Modulates Activity and Connectivity within an Emotional Arousal Network of Healthy Men during an Aversive Visceral Stimulus

    PubMed Central

    Labus, Jennifer S.; Gupta, Arpana; Hamaguchi, Toyohiro; Mizuno, Tomoko; Komuro, Hazuki; Kano, Michiko; Kanazawa, Motoyori; Aoki, Masashi; Fukudo, Shin

    2015-01-01

    Background and Aims The 5-hydroxytryptamine transporter gene-linked polymorphic region (5-HTTLPR) has been linked to increased stress responsiveness and negative emotional states. During fearful face recognition individuals with the s allele of 5-HTTLPR show greater amygdala activation. We aimed to test the hypothesis that the 5-HTTLPR polymorphism differentially affects connectivity within brain networks during an aversive visceral stimulus. Methods Twenty-three healthy male subjects were enrolled. DNA was extracted from the peripheral blood. The genotype of 5-HTTLPR was determined using polymerase chain reaction. Subjects with the s/s genotype (n = 13) were compared to those with the l allele (genotypes l/s, l/l, n = 10). Controlled rectal distension from 0 to 40 mmHg was delivered in random order using a barostat. Radioactive H2[15-O] saline was injected at time of distension followed by positron emission tomography (PET). Changes in regional cerebral blood flow (rCBF) were analyzed using partial least squares (PLS) and structural equation modeling (SEM). Results During baseline, subjects with s/s genotype demonstrated a significantly increased negative influence of pregenual ACC (pACC) on amygdala activity compared to l-carriers. During inflation, subjects with s/s genotype demonstrated a significantly greater positive influence of hippocampus on amygdala activity compared to l-carriers. Conclusion In male Japanese subjects, individuals with s/s genotype show alterations in the connectivity of brain regions involved in stress responsiveness and emotion regulation during aversive visceral stimuli compared to those with l carriers. PMID:25893242

  3. Plant functional traits have globally consistent effects on competition.

    PubMed

    Kunstler, Georges; Falster, Daniel; Coomes, David A; Hui, Francis; Kooyman, Robert M; Laughlin, Daniel C; Poorter, Lourens; Vanderwel, Mark; Vieilledent, Ghislain; Wright, S Joseph; Aiba, Masahiro; Baraloto, Christopher; Caspersen, John; Cornelissen, J Hans C; Gourlet-Fleury, Sylvie; Hanewinkel, Marc; Herault, Bruno; Kattge, Jens; Kurokawa, Hiroko; Onoda, Yusuke; Peñuelas, Josep; Poorter, Hendrik; Uriarte, Maria; Richardson, Sarah; Ruiz-Benito, Paloma; Sun, I-Fang; Ståhl, Göran; Swenson, Nathan G; Thompson, Jill; Westerlund, Bertil; Wirth, Christian; Zavala, Miguel A; Zeng, Hongcheng; Zimmerman, Jess K; Zimmermann, Niklaus E; Westoby, Mark

    2016-01-14

    Phenotypic traits and their associated trade-offs have been shown to have globally consistent effects on individual plant physiological functions, but how these effects scale up to influence competition, a key driver of community assembly in terrestrial vegetation, has remained unclear. Here we use growth data from more than 3 million trees in over 140,000 plots across the world to show how three key functional traits--wood density, specific leaf area and maximum height--consistently influence competitive interactions. Fast maximum growth of a species was correlated negatively with its wood density in all biomes, and positively with its specific leaf area in most biomes. Low wood density was also correlated with a low ability to tolerate competition and a low competitive effect on neighbours, while high specific leaf area was correlated with a low competitive effect. Thus, traits generate trade-offs between performance with competition versus performance without competition, a fundamental ingredient in the classical hypothesis that the coexistence of plant species is enabled via differentiation in their successional strategies. Competition within species was stronger than between species, but an increase in trait dissimilarity between species had little influence in weakening competition. No benefit of dissimilarity was detected for specific leaf area or wood density, and only a weak benefit for maximum height. Our trait-based approach to modelling competition makes generalization possible across the forest ecosystems of the world and their highly diverse species composition. PMID:26700807

  4. Fitness Costs Predict Inbreeding Aversion Irrespective of Self-Involvement: Support for Hypotheses Derived from Evolutionary Theory

    PubMed Central

    Antfolk, Jan; Lieberman, Debra; Santtila, Pekka

    2012-01-01

    It is expected that in humans, the lowered fitness of inbred offspring has produced a sexual aversion between close relatives. Generally, the strength of this aversion depends on the degree of relatedness between two individuals, with closer relatives inciting greater aversion than more distant relatives. Individuals are also expected to oppose acts of inbreeding that do not include the self, as inbreeding between two individuals posits fitness costs not only to the individuals involved in the sexual act, but also to their biological relatives. Thus, the strength of inbreeding aversion should be predicted by the fitness costs an inbred child posits to a given individual, irrespective of this individual’s actual involvement in the sexual act. To test this prediction, we obtained information about the family structures of 663 participants, who reported the number of same-sex siblings, opposite-sex siblings, opposite-sex half siblings and opposite-sex cousins. Each participant was presented with three different types of inbreeding scenarios: 1) Participant descriptions, in which participants themselves were described as having sex with an actual opposite-sex relative (sibling, half sibling, or cousin); 2) Related third-party descriptions, in which participants’ actual same-sex siblings were described as having sex with their actual opposite-sex relatives; 3) Unrelated third-party descriptions, in which individuals of the same sex as the participants but unrelated to them were described as having sex with opposite-sex relatives. Participants rated each description on the strength of sexual aversion (i.e., disgust-reaction). We found that unrelated third-party descriptions elicited less disgust than related third-party and participant descriptions. Related third-party and participant descriptions elicited similar levels of disgust suggesting that the strength of inbreeding aversion is predicted by inclusive fitness costs. Further, in the related and unrelated

  5. Stackelberg Game of Buyback Policy in Supply Chain with a Risk-Averse Retailer and a Risk-Averse Supplier Based on CVaR

    PubMed Central

    Zhou, Yanju; Chen, Qian; Chen, Xiaohong; Wang, Zongrun

    2014-01-01

    This paper considers a decentralized supply chain in which a single supplier sells a perishable product to a single retailer facing uncertain demand. We assume that the supplier and the retailer are both risk averse and utilize Conditional Value at Risk (CVaR), a risk measure method which is popularized in financial risk management, to estimate their risk attitude. We establish a buyback policy model based on Stackelberg game theory under considering supply chain members' risk preference and get the expressions of the supplier's optimal repurchase price and the retailer's optimal order quantity which are compared with those under risk neutral case. Finally, a numerical example is applied to simulate that model and prove related conclusions. PMID:25247605

  6. Stackelberg game of buyback policy in supply chain with a risk-averse retailer and a risk-averse supplier based on CVaR.

    PubMed

    Zhou, Yanju; Chen, Qian; Chen, Xiaohong; Wang, Zongrun

    2014-01-01

    This paper considers a decentralized supply chain in which a single supplier sells a perishable product to a single retailer facing uncertain demand. We assume that the supplier and the retailer are both risk averse and utilize Conditional Value at Risk (CVaR), a risk measure method which is popularized in financial risk management, to estimate their risk attitude. We establish a buyback policy model based on Stackelberg game theory under considering supply chain members' risk preference and get the expressions of the supplier's optimal repurchase price and the retailer's optimal order quantity which are compared with those under risk neutral case. Finally, a numerical example is applied to simulate that model and prove related conclusions. PMID:25247605

  7. Sperm competition and the evolution of gamete morphology in frogs.

    PubMed

    Byrne, Phillip G; Simmons, Leigh W; Roberts, J Dale

    2003-10-01

    Despite detailed knowledge of the ultrastructure of spermatozoa, there is a paucity of information on the selective pressures that influence sperm form and function. Theoretical models for both internal and external fertilizers predict that sperm competition could favour the evolution of longer sperm. Empirical tests of the external-fertilization model have been restricted to just one group, the fishes, and these tests have proved equivocal. We investigated how sperm competition affects sperm morphology in externally fertilizing myobatrachid frogs. We also examined selection acting on egg size, and covariation between sperm and egg morphology. Species were ranked according to probability of group spawning and hence risk of sperm competition. Body size, testis size and oviposition environment may also influence gamete traits and were included in our analyses. After controlling for phylogenetic relationships between the species examined, we found that an increased risk of sperm competition was associated with increased sperm head and tail lengths. Path analysis showed that sperm competition had its greatest direct effect on sperm tail length, as might be expected under selection resulting from competitive fertilization. Sperm competition did not influence egg size. Oviposition location had a strong influence on egg size and a weak influence on sperm length, with terrestrial spawners having larger gametes than aquatic spawners. Our analysis revealed significant correlated evolution between egg morphology and sperm morphology. These data provide a conclusive demonstration that sperm competition selects for increased sperm length in frogs, and evidence for evolutionary covariance between aspects of male and female gamete morphology. PMID:14561298

  8. SEX-RATIO MEIOTIC DRIVE AND INTERSPECIFIC COMPETITION

    PubMed Central

    Unckless, Robert L.; Clark, Andrew G.

    2014-01-01

    It has long been known that processes occurring within a species may impact the interactions between species. For example, since competitive ability is sensitive to parameters including reproductive rate, carrying capacity and competition efficiency, the outcome of interspecific competition may be influenced by any process that alters these attributes. While several such scenarios have been discussed, the influence of selfish genetic elements within one species on competition between species has not received theoretical treatment. We show that, with strong competition, sex-ratio meiotic drive systems can result in a significant shift in community composition because the effective birth rate in the population may be increased by a female-biased sex-ratio. Using empirical data we attempt to estimate the magnitude of this effect in several Drosophila species. We infer that meiotic drive elements, selfish genetic elements within species, can provide a substantial competitive advantage to that species within a community. PMID:24835887

  9. Mediated overshadowing and potentiation of long-delay taste aversion learning: Two versus six cue-taste pairings.

    PubMed

    Kwok, Dorothy W S; Sun, Qian; Boakes, Robert A

    2016-01-01

    Mediated overshadowing occurs when an evoked representation of one stimulus interferes with the formation of an association between two other stimuli. This study tested whether such an effect can be found in long-delay taste aversion learning. The general methodology was to pair a cue with a sour taste (hydrochloric acid [HCl]) and then introduce the cue during the delay between the target taste, sucrose, and injection with lithium chloride (LiCl). Either 2 or 6 cue-HCl pairings were given. In Experiment 1, introduction of the cue, an almond flavor, produced overshadowing of the sucrose aversion in the group given 2 cue-HCl pairings (Paired-2), relative to an unpaired control, but potentiation of the sucrose aversion in the group given 6 cue-HCl pairings (Paired-6). This confirms that few pairings can be better than many in determining whether representation-mediated effects occur (Holland, 1990). A possible explanation for the Paired-6 results is that almond evoked an aversive response rather than memory of the sour HCl and that this added to the aversion produced by the sucrose-lithium pairing. Experiment 2 obtained similar results when a context was used as the cue intended to evoke an HCl representation. PMID:26752235

  10. The influence of negative stimulus features on conflict adaption: evidence from fluency of processing.

    PubMed

    Fritz, Julia; Fischer, Rico; Dreisbach, Gesine

    2015-01-01

    Cognitive control enables adaptive behavior in a dynamically changing environment. In this context, one prominent adaptation effect is the sequential conflict adjustment, i.e., the observation of reduced response interference on trials following conflict trials. Increasing evidence suggests that such response conflicts are registered as aversive signals. So far, however, the functional role of this aversive signal for conflict adaptation to occur has not been put to test directly. In two experiments, the affective valence of conflict stimuli was manipulated by fluency of processing (stimulus contrast). Experiment 1 used a flanker interference task, Experiment 2 a color-word Stroop task. In both experiments, conflict adaptation effects were only present in fluent, but absent in disfluent trials. Results thus speak against the simple idea that any aversive stimulus feature is suited to promote specific conflict adjustments. Two alternative but not mutually exclusive accounts, namely resource competition and adaptation-by-motivation, will be discussed. PMID:25767453

  11. The influence of negative stimulus features on conflict adaption: evidence from fluency of processing

    PubMed Central

    Fritz, Julia; Fischer, Rico; Dreisbach, Gesine

    2015-01-01

    Cognitive control enables adaptive behavior in a dynamically changing environment. In this context, one prominent adaptation effect is the sequential conflict adjustment, i.e., the observation of reduced response interference on trials following conflict trials. Increasing evidence suggests that such response conflicts are registered as aversive signals. So far, however, the functional role of this aversive signal for conflict adaptation to occur has not been put to test directly. In two experiments, the affective valence of conflict stimuli was manipulated by fluency of processing (stimulus contrast). Experiment 1 used a flanker interference task, Experiment 2 a color-word Stroop task. In both experiments, conflict adaptation effects were only present in fluent, but absent in disfluent trials. Results thus speak against the simple idea that any aversive stimulus feature is suited to promote specific conflict adjustments. Two alternative but not mutually exclusive accounts, namely resource competition and adaptation-by-motivation, will be discussed. PMID:25767453

  12. What are the elements of motivation for acquisition of conditioned taste aversion?

    PubMed

    Mita, Koichi; Okuta, Akiko; Okada, Ryuichi; Hatakeyama, Dai; Otsuka, Emi; Yamagishi, Miki; Morikawa, Mika; Naganuma, Yuki; Fujito, Yutaka; Dyakonova, Varvara; Lukowiak, Ken; Ito, Etsuro

    2014-01-01

    The pond snail Lymnaea stagnalis is capable of being classically conditioned to avoid food and to consolidate this aversion into a long-term memory (LTM). Previous studies have shown that the length of food deprivation is important for both the acquisition of taste aversion and its consolidation into LTM, which is referred to as conditioned taste aversion (CTA). Here we tested the hypothesis that the hemolymph glucose concentration is an important factor in the learning and memory of CTA. One-day food deprivation resulted in the best learning and memory, whereas more prolonged food deprivation had diminishing effects. Five-day food deprivation resulted in snails incapable of learning or remembering. During this food deprivation period, the hemolymph glucose concentration decreased. If snails were fed for 2days following the 5-day food deprivation, their glucose levels increased significantly and they exhibited both learning and memory, but neither learning nor memory was as good as with the 1-day food-deprived snails. Injection of the snails with insulin to reduce glucose levels resulted in better learning and memory. Insulin is also known to cause a long-term enhancement of synaptic transmission between the feeding-related neurons. On the other hand, injection of glucose into 5-day food-deprived snails did not alter their inability to learn and remember. However, if these snails were fed on sucrose for 3min, they then exhibited learning and memory formation. Our data suggest that hemolymph glucose concentration is an important factor in motivating acquisition of CTA in Lymnaea and that the action of insulin in the brain and the feeding behavior are also important factors. PMID:24176925

  13. Inequity Aversion Negatively Affects Tolerance and Contact-Seeking Behaviours towards Partner and Experimenter.

    PubMed

    Brucks, Désirée; Essler, Jennifer L; Marshall-Pescini, Sarah; Range, Friederike

    2016-01-01

    Inequity aversion has been proposed to act as a limiting factor for cooperation, thus preventing subjects from disadvantageous cooperative interactions. While a recent study revealed that also dogs show some sensitivity to inequity, the underlying mechanisms of this behaviour are still unclear. The aim of the current study was threefold: 1) to replicate the study by Range et al. (2009, PNAS, 106, 340-345); 2) to investigate the emotional mechanisms involved in the inequity response by measuring the heart rate and 3) to explore the link between inequity aversion and cooperation in terms of behaviours shown towards the partner dog and towards the experimenter who caused the inequity. Dog tested in dyads were alternately asked to give their paw and were either equally or unequally rewarded by the experimenter. After each social test condition, we conducted food tolerance tests and free interaction tests in which the subjects' social behaviour towards the partner and the experimenter were observed. As in the previous study, subjects refused to continue giving their paw when only the partner was rewarded, but not when both dogs were rewarded with rewards of different quality. Although subjects did not react to this quality inequity during the test, we did find reduced durations of food sharing in the subsequent tolerance test, indicating that dogs perceived the inequity but were not able to react to it in the test context. Moreover, subjects avoided their partner and the experimenter more during the free interaction time following unequal compared to equal treatment. Despite the clear behavioural reactions to inequity, we could not detect any changes in heart rate. Results suggest that inequity aversion might in fact be mediated by simple emotional mechanisms: sharing a negative experience, like inequity, might reduce future cooperation by decreasing the likelihood of proximity being maintained between partners. PMID:27081852

  14. Inequity Aversion Negatively Affects Tolerance and Contact-Seeking Behaviours towards Partner and Experimenter

    PubMed Central

    Brucks, Désirée; Essler, Jennifer L.; Marshall-Pescini, Sarah; Range, Friederike

    2016-01-01

    Inequity aversion has been proposed to act as a limiting factor for cooperation, thus preventing subjects from disadvantageous cooperative interactions. While a recent study revealed that also dogs show some sensitivity to inequity, the underlying mechanisms of this behaviour are still unclear. The aim of the current study was threefold: 1) to replicate the study by Range et al. (2009, PNAS, 106, 340–345); 2) to investigate the emotional mechanisms involved in the inequity response by measuring the heart rate and 3) to explore the link between inequity aversion and cooperation in terms of behaviours shown towards the partner dog and towards the experimenter who caused the inequity. Dog tested in dyads were alternately asked to give their paw and were either equally or unequally rewarded by the experimenter. After each social test condition, we conducted food tolerance tests and free interaction tests in which the subjects’ social behaviour towards the partner and the experimenter were observed. As in the previous study, subjects refused to continue giving their paw when only the partner was rewarded, but not when both dogs were rewarded with rewards of different quality. Although subjects did not react to this quality inequity during the test, we did find reduced durations of food sharing in the subsequent tolerance test, indicating that dogs perceived the inequity but were not able to react to it in the test context. Moreover, subjects avoided their partner and the experimenter more during the free interaction time following unequal compared to equal treatment. Despite the clear behavioural reactions to inequity, we could not detect any changes in heart rate. Results suggest that inequity aversion might in fact be mediated by simple emotional mechanisms: sharing a negative experience, like inequity, might reduce future cooperation by decreasing the likelihood of proximity being maintained between partners. PMID:27081852

  15. Do sex and age affect strategic behavior and inequity aversion in children?

    PubMed

    Bueno-Guerra, Nereida; Leiva, David; Colell, Montserrat; Call, Josep

    2016-10-01

    The ultimatum game is commonly used to explore fairness in adults in bargaining situations. Although the changes in responses that occur during development have been investigated in children, the results have been mixed. Whereas some studies show that proposers offer more when they grow older, others indicate the opposite. Moreover, these studies are outcome-based and leave intentions out of the scene, although intentions play a relevant role in daily life. The mini-ultimatum game offers the opportunity to test both outcomes and intentions, but one major obstacle for accurately pinpointing developmental transitions in strategic behavior and inequity aversion so far has been the multiple confounds that have plagued previous studies, including different methods, small sample sizes, and reduced age differences. We administered an anonymous direct-method one-shot mini-ultimatum game to 478 6- and 10-year-old children. Strategic behavior was present at 10 years of age; older participants matched more accurately what responders would accept than younger participants. However, this was true only for older girls. No sex differences were detected in younger children. No age group seemed to consider the proposer's intentions given that the rejections of the default option were not significant across conditions. Both disadvantageous and advantageous inequity aversions were present in 6-year-olds. However, older children exhibited significantly more disadvantageous inequity aversion than younger children. This contrast made the pattern of rejection of 6-year-olds look more similar to the pattern of rejection found in adults. No sex differences were found in responders' behavior. PMID:27372561

  16. Transdiagnostic Psychiatric Symptoms and Event-Related Potentials following Rewarding and Aversive Outcomes

    PubMed Central

    Bedwell, Jeffrey S.; Potts, Geoffrey F.; Gooding, Diane C.; Trachik, Benjamin J.; Chan, Chi C.; Spencer, Christopher C.

    2016-01-01

    There is a need for a better understanding of transdiagnostic psychiatric symptoms that relate to neurophysiological abnormalities following rewarding and aversive feedback in order to inform development of novel targeted treatments. To address this need, we examined a transdiagnostic sample of 44 adults (mean age: 35.52; 57% female), which consisted of individuals with broadly-defined schizophrenia-spectrum disorders (n = 16), bipolar disorders (n = 10), other mood and anxiety disorders (n = 5), and no history of a psychiatric disorder (n = 13). Participants completed a Pavlovian monetary reward prediction task during 32-channel electroencephalogram recording. We assessed the event-related potentials (ERPs) of feedback-related negativity (FRN), feedback-related positivity (FRP), and the late positive potential (LPP), following better and worse than expected outcomes. Examination of symptom relationships using stepwise regressions across the entire sample revealed that an increase in the clinician-rated Negative Symptoms factor score from the Positive and Negative Syndrome Scale, was related to a decreased LPP amplitude during better than expected (i.e., rewarding) outcomes. We also found that increased self-reported scores on the Schizotypal Personality Questionnaire (Brief-Revised) Disorganized factor related to an increased FRN amplitude during worse than expected (i.e., aversive) outcomes. Across the entire sample, the FRP component amplitudes did not show significant relationships to any of the symptoms examined. Analyses of the three diagnostic groups of schizophrenia-spectrum disorders, bipolar disorders, and nonpsychiatric controls did not reveal any statistically significant differences across the ERP amplitudes and conditions. These findings suggest relationships between specific neurophysiological abnormalities following rewarding and aversive outcomes and particular transdiagnostic psychiatric symptoms. PMID:27299996

  17. Variant BDNF Val66Met polymorphism affects extinction of conditioned aversive memory.

    PubMed

    Yu, Hui; Wang, Yue; Pattwell, Siobhan; Jing, Deqiang; Liu, Ting; Zhang, Yun; Bath, Kevin G; Lee, Francis S; Chen, Zhe-Yu

    2009-04-01

    Brain-derived neurotrophic factor (BDNF) plays important roles in activity-dependent plasticity processes, such as long-term potentiation, learning, and memory. The recently reported human BDNF Val66Met (BDNF(Met)) polymorphism has been shown to lead to altered hippocampal volume and impaired hippocampal-dependent memory and is associated with a variety of neuropsychiatric disorders. There are few studies, however, that investigate the effect of the BDNF(Met) polymorphism on hippocampal-independent memory processes. A conditioned taste aversion (CTA) task was used for studying the mechanisms of long-term, hippocampal-independent, nondeclarative memory in the mammalian brain. Using the CTA paradigm, we found a novel impairment in extinction learning, but not acquisition or retention, of aversive memories resulting from the variant BDNF(Met). BDNF(Met) mice were slower to extinguish an aversive CTA memory compared with wild-type counterparts. Moreover, the BDNF(Met) was associated with smaller volume and decreased neuronal dendritic complexity in the ventromedial prefrontal cortex (vmPFC), which plays a significant role in extinction of CTA. Finally, this delay in extinction learning could be rescued pharmacologically with a cognitive enhancer, d-cycloserine (DCS). To our knowledge, this is the first evidence that the BDNF(Met) polymorphism contributes to abnormalities in memory extinction. This abnormality in extinction learning may be explained by alterations in neuronal morphology, as well as decreased neural activity in the vmPFC. Importantly, DCS was effective in rescuing this delay in extinction, suggesting that when coupled with behavior therapy, DCS may be an effective treatment option for anxiety disorders in humans with this genetic variant BDNF. PMID:19339601

  18. Age-related striatal BOLD changes without changes in behavioral loss aversion

    PubMed Central

    Viswanathan, Vijay; Lee, Sang; Gilman, Jodi M.; Kim, Byoung Woo; Lee, Nick; Chamberlain, Laura; Livengood, Sherri L.; Raman, Kalyan; Lee, Myung Joo; Kuster, Jake; Stern, Daniel B.; Calder, Bobby; Mulhern, Frank J.; Blood, Anne J.; Breiter, Hans C.

    2015-01-01

    Loss aversion (LA), the idea that negative valuations have a higher psychological impact than positive ones, is considered an important variable in consumer research. The literature on aging and behavior suggests older individuals may show more LA, although it is not clear if this is an effect of aging in general (as in the continuum from age 20 and 50 years), or of the state of older age (e.g., past age 65 years). We also have not yet identified the potential biological effects of aging on the neural processing of LA. In the current study we used a cohort of subjects with a 30 year range of ages, and performed whole brain functional MRI (fMRI) to examine the ventral striatum/nucleus accumbens (VS/NAc) response during a passive viewing of affective faces with model-based fMRI analysis incorporating behavioral data from a validated approach/avoidance task with the same stimuli. Our a priori focus on the VS/NAc was based on (1) the VS/NAc being a central region for reward/aversion processing; (2) its activation to both positive and negative stimuli; (3) its reported involvement with tracking LA. LA from approach/avoidance to affective faces showed excellent fidelity to published measures of LA. Imaging results were then compared to the behavioral measure of LA using the same affective faces. Although there was no relationship between age and LA, we observed increasing neural differential sensitivity (NDS) of the VS/NAc to avoidance responses (negative valuations) relative to approach responses (positive valuations) with increasing age. These findings suggest that a central region for reward/aversion processing changes with age, and may require more activation to produce the same LA behavior as in younger individuals, consistent with the idea of neural efficiency observed with high IQ individuals showing less brain activation to complete the same task. PMID:25983682

  19. Age-related striatal BOLD changes without changes in behavioral loss aversion.

    PubMed

    Viswanathan, Vijay; Lee, Sang; Gilman, Jodi M; Kim, Byoung Woo; Lee, Nick; Chamberlain, Laura; Livengood, Sherri L; Raman, Kalyan; Lee, Myung Joo; Kuster, Jake; Stern, Daniel B; Calder, Bobby; Mulhern, Frank J; Blood, Anne J; Breiter, Hans C

    2015-01-01

    Loss aversion (LA), the idea that negative valuations have a higher psychological impact than positive ones, is considered an important variable in consumer research. The literature on aging and behavior suggests older individuals may show more LA, although it is not clear if this is an effect of aging in general (as in the continuum from age 20 and 50 years), or of the state of older age (e.g., past age 65 years). We also have not yet identified the potential biological effects of aging on the neural processing of LA. In the current study we used a cohort of subjects with a 30 year range of ages, and performed whole brain functional MRI (fMRI) to examine the ventral striatum/nucleus accumbens (VS/NAc) response during a passive viewing of affective faces with model-based fMRI analysis incorporating behavioral data from a validated approach/avoidance task with the same stimuli. Our a priori focus on the VS/NAc was based on (1) the VS/NAc being a central region for reward/aversion processing; (2) its activation to both positive and negative stimuli; (3) its reported involvement with tracking LA. LA from approach/avoidance to affective faces showed excellent fidelity to published measures of LA. Imaging results were then compared to the behavioral measure of LA using the same affective faces. Although there was no relationship between age and LA, we observed increasing neural differential sensitivity (NDS) of the VS/NAc to avoidance responses (negative valuations) relative to approach responses (positive valuations) with increasing age. These findings suggest that a central region for reward/aversion processing changes with age, and may require more activation to produce the same LA behavior as in younger individuals, consistent with the idea of neural efficiency observed with high IQ individuals showing less brain activation to complete the same task. PMID:25983682

  20. Transdiagnostic Psychiatric Symptoms and Event-Related Potentials following Rewarding and Aversive Outcomes.

    PubMed

    Bedwell, Jeffrey S; Potts, Geoffrey F; Gooding, Diane C; Trachik, Benjamin J; Chan, Chi C; Spencer, Christopher C

    2016-01-01

    There is a need for a better understanding of transdiagnostic psychiatric symptoms that relate to neurophysiological abnormalities following rewarding and aversive feedback in order to inform development of novel targeted treatments. To address this need, we examined a transdiagnostic sample of 44 adults (mean age: 35.52; 57% female), which consisted of individuals with broadly-defined schizophrenia-spectrum disorders (n = 16), bipolar disorders (n = 10), other mood and anxiety disorders (n = 5), and no history of a psychiatric disorder (n = 13). Participants completed a Pavlovian monetary reward prediction task during 32-channel electroencephalogram recording. We assessed the event-related potentials (ERPs) of feedback-related negativity (FRN), feedback-related positivity (FRP), and the late positive potential (LPP), following better and worse than expected outcomes. Examination of symptom relationships using stepwise regressions across the entire sample revealed that an increase in the clinician-rated Negative Symptoms factor score from the Positive and Negative Syndrome Scale, was related to a decreased LPP amplitude during better than expected (i.e., rewarding) outcomes. We also found that increased self-reported scores on the Schizotypal Personality Questionnaire (Brief-Revised) Disorganized factor related to an increased FRN amplitude during worse than expected (i.e., aversive) outcomes. Across the entire sample, the FRP component amplitudes did not show significant relationships to any of the symptoms examined. Analyses of the three diagnostic groups of schizophrenia-spectrum disorders, bipolar disorders, and nonpsychiatric controls did not reveal any statistically significant differences across the ERP amplitudes and conditions. These findings suggest relationships between specific neurophysiological abnormalities following rewarding and aversive outcomes and particular transdiagnostic psychiatric symptoms. PMID:27299996