380 research outputs found

    The motivational drive to natural rewards is modulated by prenatal glucocorticoid exposure

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    Exposure to elevated levels of glucocorticoids (GCs) during neurodevelopment has been identified as a triggering factor for the development of reward-associated disorders in adulthood. Disturbances in the neural networks responsible for the complex processes that assign value to rewards and associated stimuli are critical for disorders such as depression, obsessive–compulsive disorders, obesity and addiction. Essential in the understanding on how cues influence behavior is the Pavlovian–instrumental transfer (PIT), a phenomenon that refers to the capacity of a Pavlovian stimulus that predicts a reward to elicit instrumental responses for that same reward. Here, we demonstrate that in utero exposure to GCs (iuGC) impairs both general and selective versions of the PIT paradigm, suggestive of deficits in motivational drive. The iuGC animals presented impaired neuronal activation pattern upon PIT performance in cortical and limbic regions, as well as morphometric changes and reduced levels of dopamine in prefrontal and orbitofrontal cortices, key regions involved in the integration of Pavlovian and instrumental stimuli. Normalization of dopamine levels rescued this behavior, a process that relied on D2/D3, but not D1, dopamine receptor activation. In summary, iuGC exposure programs the mesocorticolimbic dopaminergic circuitry, leading to a reduction in the attribution of the incentive salience to cues, in a dopamine-D2/D3-dependent manner. Ultimately, these results are important to understand how GCs bias incentive processes, a fact that is particularly relevant for disorders where differential attribution of incentive salience is critical.We thank Pedro Morgado for discussions and help in the technical aspects of PIT procedure. This project was supported by a grant of Institute for the Study of Affective Neuroscience (ISAN) and by Janssen Neuroscience Prize. CS-C, SB, MMC and AJR are recipients of Fundacao para a Ciencia e Tecnologia (FCT) fellowships (CS-C: SFRH/BD/51992/2012; SB: SFRH/BD/89936/2012; MMC: SRFH/BD/51061/2010; AJR: SFRH/BPD/33611/2009)

    Differential Effects of Migration and Deportation on HIV Infection among Male and Female Injection Drug Users in Tijuana, Mexico

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    HIV prevalence is rising, especially among high risk females in Tijuana, Baja California, a Mexico-US border city situated on major migration and drug trafficking routes. We compared factors associated with HIV infection among male and female injection drug users (IDUs) in Tijuana in an effort to inform HIV prevention and treatment programs. IDUs aged ≥18 years were recruited using respondent-driven sampling and underwent testing for HIV, syphilis and structured interviews. Logistic regression identified correlates of HIV infection, stratified by gender. Among 1056 IDUs, most were Mexican-born but 67% were born outside Tijuana. Reasons for moving to Tijuana included deportation from the US (56% for males, 29% for females), and looking for work/better life (34% for females, 15% for males). HIV prevalence was higher in females versus males (10.2% vs. 3.5%, p = 0.001). Among females (N = 158), factors independently associated with higher HIV prevalence included younger age, lifetime syphilis infection and living in Tijuana for longer durations. Among males (N = 898), factors independently associated with higher HIV prevalence were syphilis titers consistent with active infection, being arrested for having ‘track-marks’, having larger numbers of recent injection partners and living in Tijuana for shorter durations. An interaction between gender and number of years lived in Tijuana regressed on HIV infection was significant (p = 0.03). Upon further analysis, deportation from the U.S. explained the association between shorter duration lived in Tijuana and HIV infection among males; odds of HIV infection were four-fold higher among male injectors deported from the US, compared to other males, adjusting for all other significant correlates (p = 0.002). Geographic mobility has a profound influence on Tijuana's evolving HIV epidemic, and its impact is significantly modified by gender. Future studies are needed to elucidate the context of mobility and HIV acquisition in this region, and whether US immigration policies adversely affect HIV risk

    Correction to: Assessing genotype-phenotype associations in three dorsal colour morphs in the meadow spittlebug Philaenus spumarius (L.) (Hemiptera: Aphrophoridae) using genomic and transcriptomic resources.

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    Following publication of the original article [1], it has been brought to the authors' attention that in their paper (Rodrigues et al. 2016) they reported the genome size based on 2C values (diploid genome) when it is more common to present it as 1C value

    Fungal infestation boosts fruit aroma and fruit removal by mammals and birds

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    For four decades, an influential hypothesis has posited that competition for food resources between microbes and vertebrates selects for microbes to alter these resources in ways that make them unpalatable to vertebrates. We chose an understudied cross kingdom interaction to experimentally evaluate the effect of fruit infection by fungi on both vertebrate (mammals and birds) fruit preferences and on ecologically relevant fruit traits (volatile compounds, toughness, etc). Our well-replicated field experiments revealed that, in contrast to previous studies, frugivorous mammals and birds consistently preferred infested over intact fruits. This was concordant with the higher level of attractive volatiles (esters, ethanol) in infested fruits. This investigation suggests that vertebrate frugivores, fleshyfruited plants, and microbes form a tripartite interaction in which each part could interact positively with the other two (e.g. both orange seeds and fungal spores are likely dispersed by mammals). Such a mutualistic view of these complex interactions is opposed to the generalized idea of competition between frugivorous vertebrates and microorganisms. Thus, this research provides a new perspective on the widely accepted plant evolutionary dilemma to make fruits attractive to mutualistic frugivores while unattractive to presumed antagonistic microbes that constrain seed dispersalinfo:eu-repo/semantics/publishedVersio
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