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Terry E. Robinson - One of the best experts on this subject based on the ideXlab platform.
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neurobiological basis of Individual Variation in stimulus reward learning
Current opinion in behavioral sciences, 2017Co-Authors: Shelly B Flagel, Terry E. RobinsonAbstract:Cues in the environment can guide behavior in adaptive ways, leading one towards valuable resources such as food, water, or a potential mate. However, cues in the environment may also serve as powerful motivators that lead to maladaptive patterns of behavior, such as addiction. Importantly, and central to this article, there is considerable Individual Variation in the extent to which reward cues gain motivational control over behavior. Here we describe an animal model that captures this Individual Variation, allowing us to better understand the psychological and neurobiological processes that contribute to cue-evoked behaviors. When a discrete cue is paired with a food reward in a Pavlovian manner it acquires greater control over motivated behavior in some rats ("sign-trackers, STs) than in others ("goal-trackers", GTs). We review studies that have exploited this animal model to parse the neurobiological mechanisms involved in learning associations between stimuli vs. those involved in attributing incentive salience to those same stimuli. The latter seems to be dependent on dopamine and subcortical circuits, whereas the former may engage more cortical "top-down" mechanisms.
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Individual Variation in incentive salience attribution and accumbens dopamine transporter expression and function
European Journal of Neuroscience, 2016Co-Authors: Bryan F Singer, Bipasha Guptaroy, Curtis J Austin, Isabella Wohl, Jillian L Seiler, Vedran Lovic, Roxanne A Vaughan, Terry E. Robinson, Margaret E. Gnegy, Brandon J AragonaAbstract:Cues (conditioned stimuli; CSs) associated with rewards can come to motivate behavior, but there is considerable Individual Variation in their ability to do so. For example, a lever-CS that predicts food reward becomes attractive and wanted, and elicits reward-seeking behavior, to a greater extent in some rats (‘sign-trackers’; STs) than others (‘goal-trackers’; GTs). Variation in dopamine (DA) neurotransmission in the nucleus accumbens (NAc) core is thought to contribute to such Individual Variation. Given that the DA transporter (DAT) exerts powerful regulation over DA signaling, we characterized the expression and function of the DAT in the accumbens of STs and GTs. STs showed greater DAT surface expression in ventral striatal synaptosomes than GTs, and ex vivo fast-scan cyclic voltammetry recordings of electrically evoked DA release confirmed enhanced DAT function in STs, as indicated by faster DA uptake, specifically in the NAc core. Consistent with this, systemic amphetamine (AMPH) produced greater inhibition of DA uptake in STs than in GTs. Furthermore, injection of AMPH directly into the NAc core enhanced lever-directed approach in STs, presumably by amplifying the incentive value of the CS, but had no effect on goal-tracking behavior. On the other hand, there were no differences between STs and GTs in electrically-evoked DA release in slices, or in total ventral striatal DA content. We conclude that greater DAT surface expression may facilitate the attribution of incentive salience to discrete reward cues. Investigating this variability in animal sub-populations may help explain why some people abuse drugs while others do not.
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quantifying Individual Variation in the propensity to attribute incentive salience to reward cues
PLOS ONE, 2012Co-Authors: Paul J Meyer, Shelly B Flagel, Lindsay M Yager, Vedran Lovic, Benjamin T Saunders, Jonathan D Morrow, Terry E. RobinsonAbstract:If reward-associated cues acquire the properties of incentive stimuli they can come to powerfully control behavior, and potentially promote maladaptive behavior. Pavlovian incentive stimuli are defined as stimuli that have three fundamental properties: they are attractive, they are themselves desired, and they can spur instrumental actions. We have found, however, that there is considerable Individual Variation in the extent to which animals attribute Pavlovian incentive motivational properties (‘‘incentive salience’’) to reward cues. The purpose of this paper was to develop criteria for identifying and classifying Individuals based on their propensity to attribute incentive salience to reward cues. To do this, we conducted a meta-analysis of a large sample of rats (N=1,878) subjected to a classic Pavlovian conditioning procedure. We then used the propensity of animals to approach a cue predictive of reward (one index of the extent to which the cue was attributed with incentive salience), to characterize two behavioral phenotypes in this population: animals that approached the cue (‘‘sign-trackers’’) vs. others that approached the location of reward delivery (‘‘goal-trackers’’). This Variation in Pavlovian approach behavior predicted other behavioral indices of the propensity to attribute incentive salience to reward cues. Thus, the procedures reported here should be useful for making comparisons across studies and for assessing Individual Variation in incentive salience attribution in small samples of the population, or even for classifying single animals.
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Individual Variation in the Motivational Properties of Cocaine
Neuropsychopharmacology, 2011Co-Authors: Benjamin T Saunders, Terry E. RobinsonAbstract:Cues in the environment associated with drug use draw the attention of addicts, elicit approach, and motivate drug-seeking and drug-taking behavior, making abstinence difficult. However, preclinical studies have identified large Individual differences in the extent to which reward cues acquire these incentive motivational properties. For example, only in some rats does a spatially discrete food cue become attractive, eliciting approach and engagement with it, and acts as an effective conditioned reinforcer. Moreover, a discrete cocaine cue also acquires greater motivational control over behavior in rats prone to attribute incentive salience to a food cue. In this study, we asked whether there is similar Individual Variation in the extent to which interoceptive cues produced by cocaine itself instigate cocaine-seeking behavior. After quantifying Individual Variation in the propensity to attribute incentive salience to a food cue, rats were trained to self-administer cocaine in the absence of an explicit conditional stimulus. We then assessed motivation for cocaine by: (1) performance on a progressive ratio schedule, and (2) the degree to which a cocaine ‘prime’ reinstated cocaine-seeking following extinction of self-administration behavior. We found that rats prone to attribute incentive salience to a food cue worked harder for cocaine, and showed more robust cocaine-induced reinstatement. We conclude that there is considerable Individual Variation in the motivational properties of cocaine itself, and this can be predicted by the propensity to attribute incentive salience to reward cues.
Jonathan D Morrow - One of the best experts on this subject based on the ideXlab platform.
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Individual Variation in the attribution of incentive salience to social cues
Scientific Reports, 2020Co-Authors: Christopher J Fitzpatrick, Jonathan D MorrowAbstract:Research on the attribution of incentive salience to drug cues has furthered our understanding of drug self-administration in animals and addiction in humans. The influence of social cues on drug-seeking behavior has garnered attention recently, but few studies have investigated how social cues gain incentive-motivational value. In the present study, a Pavlovian conditioned approach (PCA) procedure was used to identify rats that are more (sign-trackers; STs) or less (goal-trackers; GTs) prone to attribute incentive salience to food reward cues. In Experiment 1, a novel procedure employed social ‘peers’ to compare the tendency of STs and GTs to attribute incentive salience to social reward cues as well as form a social-conditioned place preference. In Experiment 2, social behavior of STs and GTs was compared using social interaction and choice tests. Finally, in Experiment 3, levels of plasma oxytocin were measured in STs and GTs seven days after the last PCA training session, because oxytocin is known to modulate the mesolimbic reward system and social behavior. Compared to GTs, STs attributed more incentive salience to social-related cues and exhibited prosocial behaviors (e.g., social-conditioned place preference, increased social interaction, and social novelty-seeking). No group differences were observed in plasma oxytocin levels. Taken together, these experiments demonstrate Individual Variation in the attribution of incentive salience to both food- and social-related cues, which has important implications for the pathophysiology of addiction.
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Individual Variation in the attribution of incentive salience to social cues
bioRxiv, 2019Co-Authors: Christopher J Fitzpatrick, Jonathan D MorrowAbstract:Abstract Research on the attribution of incentive salience to drug cues has furthered our understanding of drug self-administration in animals as well as drug relapse and craving in humans. The influence of peers and other social cues on drug-seeking has garnered more attention recently, but few studies have investigated the ability of social cues to gain incentive-motivational value. In the present study, a Pavlovian conditioned approach procedure was used to identify rats that are more (sign-trackers) or less (goal-trackers) prone to attribute incentive salience to food reward cues. A novel procedure then employed social ‘peers’ to compare the tendency of sign-trackers and goal-trackers to attribute incentive salience to social reward cues. Social behavior of sign-trackers and goal-trackers was also compared using social interaction and choice tests. Finally, basal levels of plasma oxytocin were measured in sign-trackers and goal-trackers, because oxytocin is known to modulate the mesolimbic reward system and social behavior. Compared to goal-trackers, sign-trackers attributed more incentive salience to social cues and exhibited more prosocial behaviors. No group differences were observed in baseline plasma oxytocin levels. Taken together, these experiments demonstrate a concordance of Individual Variation in social behavior, the attribution of incentive salience to social cues following peer interaction, and attribution of incentive salience to food cues. This general tendency to attribute motivational value to reward cues has important implications for the pathophysiology of addiction and other disorders of reward learning.
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quantifying Individual Variation in the propensity to attribute incentive salience to reward cues
PLOS ONE, 2012Co-Authors: Paul J Meyer, Shelly B Flagel, Lindsay M Yager, Vedran Lovic, Benjamin T Saunders, Jonathan D Morrow, Terry E. RobinsonAbstract:If reward-associated cues acquire the properties of incentive stimuli they can come to powerfully control behavior, and potentially promote maladaptive behavior. Pavlovian incentive stimuli are defined as stimuli that have three fundamental properties: they are attractive, they are themselves desired, and they can spur instrumental actions. We have found, however, that there is considerable Individual Variation in the extent to which animals attribute Pavlovian incentive motivational properties (‘‘incentive salience’’) to reward cues. The purpose of this paper was to develop criteria for identifying and classifying Individuals based on their propensity to attribute incentive salience to reward cues. To do this, we conducted a meta-analysis of a large sample of rats (N=1,878) subjected to a classic Pavlovian conditioning procedure. We then used the propensity of animals to approach a cue predictive of reward (one index of the extent to which the cue was attributed with incentive salience), to characterize two behavioral phenotypes in this population: animals that approached the cue (‘‘sign-trackers’’) vs. others that approached the location of reward delivery (‘‘goal-trackers’’). This Variation in Pavlovian approach behavior predicted other behavioral indices of the propensity to attribute incentive salience to reward cues. Thus, the procedures reported here should be useful for making comparisons across studies and for assessing Individual Variation in incentive salience attribution in small samples of the population, or even for classifying single animals.
Ben Dantzer - One of the best experts on this subject based on the ideXlab platform.
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how does Individual Variation in sociality influence fitness in prairie voles
Animal Behaviour, 2020Co-Authors: Anne C Sabol, Connor T Lambert, Brian Keane, Nancy G Solomon, Ben DantzerAbstract:Comparative studies aid in our understanding of specific conditions favouring the initial evolution of different types of social behaviours, yet there is much unexplained intraspecific Variation in the expression of social behaviour that comparative studies have not yet addressed. The proximate causes of this Individual Variation in social behaviour within a species have been examined in some species but its fitness consequences have been less frequently investigated. In this study, we quantified the fitness consequences of Variation in the sociality of prairie voles, Microtus ochrogaster. We characterized sociality of voles in seminatural enclosures using an automated behavioural tracking system paired with social network analyses to quantify the degree of spatial and temporal co-occurrence of different voles. We then assessed the relationship between sociality and both mating success (number of different conspecifics with which an Individual produced offspring) and reproductive success (total number of offspring surviving to first capture). We measured the number of social connections each Individual had with all voles and with only opposite-sex voles (unweighted degree) through social network analyses. Both female and male voles varied in the number of social connections they had with all conspecifics and with opposite-sex conspecifics. In both analyses, females and males with an intermediate number of social connections had higher mating success overall and, for the analysis with all connections, produced more offspring. Males with many or few social connections also had the lowest average body mass. Overall, our results suggest some limit on the fitness benefits of sociality. Although there was substantial Individual Variation in our measure of vole social behaviour, intermediate levels of social connections may be most favourable.
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how does Individual Variation in sociality influence fitness in prairie voles
bioRxiv, 2019Co-Authors: Anne C Sabol, Connor T Lambert, Brian Keane, Nancy G Solomon, Ben DantzerAbstract:Comparative studies aid in our understanding of specific conditions favoring the initial evolution of different types of social behaviors, yet there is much unexplained intraspecific Variation in the expression of social behavior that comparative studies have not yet addressed. The proximate causes of this Individual Variation in social behavior within a species have been examined in some species but its fitness consequences have been less frequently investigated. In this study, we quantified the fitness consequences of Variation in the sociality of prairie voles (Microtus ochrogaster). We characterized sociality of voles in semi-natural enclosures using an automated behavioral tracking system paired with social network analyses to quantify the degree of spatial and temporal co-occurrence of different voles. We then assessed the relationship between sociality with mating success (number of different conspecifics with which an Individual produced offspring) and reproductive success (total number of offspring surviving to first capture). We measured the number of social connections each Individual had with all voles and only with opposite-sex voles by calculating unweighted degree through social network analyses. Both female and male voles varied in the number of social connections they had with all conspecifics and with opposite-sex conspecifics. Voles with an intermediate number of social connections with voles of both sexes had higher mating success overall. In our analyses that considered all social connections with voles of both sexes, voles with an intermediate number of social connections produced more offspring. Males with a very high or low number of social connections also had the lowest average body mass. Overall, our results suggest some limit on the fitness benefits of sociality. Although there was substantial Individual-Variation in our measure of vole social behavior, intermediate levels of social connections may be most favorable.
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Individual Variation in phenotypic plasticity of the stress axis
bioRxiv, 2019Co-Authors: Sarah Guindreparker, Andrew G Mcadam, Freya Van Kesteren, Rupert Palme, Rudy Boonstra, Stan Boutin, Jeffrey E Lane, Ben DantzerAbstract:ABSTRACT Phenotypic plasticity—one Individual’s capacity for phenotypic Variation under different environments—is critical for organisms facing fluctuating conditions within their lifetime. North American red squirrels (Tamiasciurus hudsonicus) experience drastic among-year fluctuations in conspecific density. This shapes juvenile competition over vacant territories and overwinter survival. To help young cope with competition at high densities, mothers can increase offspring growth rates via a glucocorticoid-mediated maternal effect. However, this effect is only adaptive under high densities, and faster growth often comes at a cost to longevity. While experiments have demonstrated that red squirrels can adjust hormones in response to fluctuating density, the degree to which mothers differ in their ability to regulate glucocorticoids across changing densities remains unknown—little is known about within-Individual plasticity in endocrine traits relative to among-Individual Variation. Findings from our reaction norm approach revealed significant Individual Variation not only in a female red squirrel’s mean endocrine phenotype, but also in endocrine plasticity in response to changes in local density. Future work on the proximate and ultimate drivers of Variation in the plasticity of endocrine traits and maternal effects is needed, particularly in free-living animals experiencing fluctuating environments.
Marjo Saastamoinen - One of the best experts on this subject based on the ideXlab platform.
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landscape permeability and Individual Variation in a dispersal linked gene jointly determine genetic structure in the glanville fritillary butterfly
Evolution letters, 2018Co-Authors: Michelle F Dileo, Arild Husby, Marjo SaastamoinenAbstract:There is now clear evidence that species across a broad range of taxa harbor extensive heritable Variation in dispersal. While studies suggest that this Variation can facilitate demographic outcomes such as range expansion and invasions, few have considered the consequences of intraspecific Variation in dispersal for the maintenance and distribution of genetic Variation across fragmented landscapes. Here, we examine how landscape characteristics and Individual Variation in dispersal combine to predict genetic structure using genomic and spatial data from the Glanville fritillary butterfly. We used linear and latent factor mixed models to identify the landscape features that best predict spatial sorting of alleles in the dispersal-related gene phosphoglucose isomerase (Pgi). We next used structural equation modeling to test if Variation in Pgi mediated gene flow as measured by Fst at putatively neutral loci. In a year when the population was recovering following a large decline, Individuals with a genotype associated with greater dispersal ability were found at significantly higher frequencies in populations isolated by water and forest, and these populations showed lower levels of genetic differentiation at neutral loci. These relationships disappeared in the next year when metapopulation density was high, suggesting that the effects of Individual Variation are context dependent. Together our results highlight that (1) more complex aspects of landscape structure beyond just the configuration of habitat can be important for maintaining spatial Variation in dispersal traits and (2) that Individual Variation in dispersal plays a key role in maintaining genetic Variation across fragmented landscapes.
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landscape permeability and Individual Variation in a dispersal linked gene jointly determine genetic structure in the glanville fritillary butterfly
bioRxiv, 2018Co-Authors: Michelle F Dileo, Arild Husby, Marjo SaastamoinenAbstract:There is now clear evidence that species across a broad range of taxa harbour extensive heritable Variation in dispersal. While studies suggest that this Variation can facilitate demographic outcomes such as range expansion and invasions, few have considered the consequences of intraspecific Variation in dispersal for the maintenance and distribution of genetic Variation across fragmented landscapes. Here we examine how landscape characteristics and Individual Variation in dispersal combine to predict genetic structure using genomic and spatial data from the Glanville fritillary butterfly. We used linear and latent factor mixed models to identify the landscape features that best predict spatial sorting of alleles in the dispersal-related gene phosphoglucose isomerase (Pgi). We next used structural equation modeling to test if Variation in Pgi mediated gene flow as measured by Fst at putatively neutral loci. In a year when the population was expanding following a large decline, Individuals with a genotype associated with greater dispersal ability were found at significantly higher frequencies in populations isolated by water and forest, and these populations showed lower levels of genetic differentiation at neutral loci. These relationships disappeared in the next year when metapopulation density was high, suggesting that the effects of Individual Variation are context dependent. Together our results highlight that 1) more complex aspects of landscape structure beyond just the configuration of habitat can be important for maintaining spatial Variation in dispersal traits, and 2) that Individual Variation in dispersal plays a key role in maintaining genetic Variation across fragmented landscapes.
Anne C Sabol - One of the best experts on this subject based on the ideXlab platform.
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how does Individual Variation in sociality influence fitness in prairie voles
Animal Behaviour, 2020Co-Authors: Anne C Sabol, Connor T Lambert, Brian Keane, Nancy G Solomon, Ben DantzerAbstract:Comparative studies aid in our understanding of specific conditions favouring the initial evolution of different types of social behaviours, yet there is much unexplained intraspecific Variation in the expression of social behaviour that comparative studies have not yet addressed. The proximate causes of this Individual Variation in social behaviour within a species have been examined in some species but its fitness consequences have been less frequently investigated. In this study, we quantified the fitness consequences of Variation in the sociality of prairie voles, Microtus ochrogaster. We characterized sociality of voles in seminatural enclosures using an automated behavioural tracking system paired with social network analyses to quantify the degree of spatial and temporal co-occurrence of different voles. We then assessed the relationship between sociality and both mating success (number of different conspecifics with which an Individual produced offspring) and reproductive success (total number of offspring surviving to first capture). We measured the number of social connections each Individual had with all voles and with only opposite-sex voles (unweighted degree) through social network analyses. Both female and male voles varied in the number of social connections they had with all conspecifics and with opposite-sex conspecifics. In both analyses, females and males with an intermediate number of social connections had higher mating success overall and, for the analysis with all connections, produced more offspring. Males with many or few social connections also had the lowest average body mass. Overall, our results suggest some limit on the fitness benefits of sociality. Although there was substantial Individual Variation in our measure of vole social behaviour, intermediate levels of social connections may be most favourable.
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how does Individual Variation in sociality influence fitness in prairie voles
bioRxiv, 2019Co-Authors: Anne C Sabol, Connor T Lambert, Brian Keane, Nancy G Solomon, Ben DantzerAbstract:Comparative studies aid in our understanding of specific conditions favoring the initial evolution of different types of social behaviors, yet there is much unexplained intraspecific Variation in the expression of social behavior that comparative studies have not yet addressed. The proximate causes of this Individual Variation in social behavior within a species have been examined in some species but its fitness consequences have been less frequently investigated. In this study, we quantified the fitness consequences of Variation in the sociality of prairie voles (Microtus ochrogaster). We characterized sociality of voles in semi-natural enclosures using an automated behavioral tracking system paired with social network analyses to quantify the degree of spatial and temporal co-occurrence of different voles. We then assessed the relationship between sociality with mating success (number of different conspecifics with which an Individual produced offspring) and reproductive success (total number of offspring surviving to first capture). We measured the number of social connections each Individual had with all voles and only with opposite-sex voles by calculating unweighted degree through social network analyses. Both female and male voles varied in the number of social connections they had with all conspecifics and with opposite-sex conspecifics. Voles with an intermediate number of social connections with voles of both sexes had higher mating success overall. In our analyses that considered all social connections with voles of both sexes, voles with an intermediate number of social connections produced more offspring. Males with a very high or low number of social connections also had the lowest average body mass. Overall, our results suggest some limit on the fitness benefits of sociality. Although there was substantial Individual-Variation in our measure of vole social behavior, intermediate levels of social connections may be most favorable.
