1,366 research outputs found

    Psychopathy and Attachment: The Effect of Security Priming on Psychopathy in a College Student Sample

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    Psychopathy has been defined as a pattern of negative behaviors, social interactions, and affective features, including impoverishment of emotion, unethical and manipulative actions, and impulsivity (Neumann & Hare, 2008). It is estimated that between 15 to 30 percent of incarcerated adults meet the criteria for psychopathy (Hare, 1991, 1996; Salekin, Rogers, Ustad, & Sewell, 1998). Because psychopathy is linked with deviant behaviors and a significant portion of incarcerated adults are high in psychopathy, methods of reducing psychopathy are needed. The current longitudinal study sought to reduce state psychopathy levels through secure attachment priming. It was first hypothesized that the mean of state levels of psychopathy would correlate with trait measures of psychopathy. Secondly, it was hypothesized that participants primed with secure attachment would report higher levels of state secure attachment and lower levels of state avoidant and anxious attachment. Finally, it was hypothesized that participants primed with secure attachment would report lower levels of state psychopathy than participants primed with a neutral concept. Forty undergraduate students (33 women and 7 men) participated in the experiment. Results indicated that the mean of state levels of psychopathy were positively associated with trait measures of psychopathy. Contrary to hypotheses, however, the secure attachment prime did not significantly affect levels of state security, anxiety, or avoidance, and the security prime did not reduce state levels of psychopathy over time. These findings provide initial support for a measure of state psychopathy, and call for further research to better understand the relationship between attachment and psychopathy

    Tonic inhibition of accumbal spiny neurons by extrasynaptic 4 GABAA receptors modulates the actions of psychostimulants

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    Within the nucleus accumbens (NAc), synaptic GABAA receptors (GABAARs) mediate phasic inhibition of medium spiny neurons (MSNs) and influence behavioral responses to cocaine. We demonstrate that both dopamine D1- and D2-receptor-expressing MSNs (D-MSNs) additionally harbor extrasynaptic GABAARs incorporating α4, β, and δ subunits that mediate tonic inhibition, thereby influencing neuronal excitability. Both the selective δ-GABAAR agonist THIP and DS2, a selective positive allosteric modulator, greatly increased the tonic current of all MSNs from wild-type (WT), but not from δ−/− or α4−/− mice. Coupling dopamine and tonic inhibition, the acute activation of D1 receptors (by a selective agonist or indirectly by amphetamine) greatly enhanced tonic inhibition in D1-MSNs but not D2-MSNs. In contrast, prolonged D2 receptor activation modestly reduced the tonic conductance of D2-MSNs. Behaviorally, WT and constitutive α4−/− mice did not differ in their expression of cocaine-conditioned place preference (CPP). Importantly, however, mice with the α4 deletion specific to D1-expressing neurons (α4D1−/−) showed increased CPP. Furthermore, THIP administered systemically or directly into the NAc of WT, but not α4−/− or α4D1−/− mice, blocked cocaine enhancement of CPP. In comparison, α4D2−/− mice exhibited normal CPP, but no cocaine enhancement. In conclusion, dopamine modulation of GABAergic tonic inhibition of D1- and D2-MSNs provides an intrinsic mechanism to differentially affect their excitability in response to psychostimulants and thereby influence their ability to potentiate conditioned reward. Therefore, α4βδ GABAARs may represent a viable target for the development of novel therapeutics to better understand and influence addictive behaviors

    Compound-specific Carbon Isotope Compositions of Aldehydes and Ketones in the Murchison Meteorite

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    Compoundspecific carbon isotope analysis (13C) of meteoritic organic compounds can be used to elucidate the abiotic chemical reactions involved in their synthesis. The soluble organic content of the Murchison carbonaceous chondrite has been extensively investigated over the years, with a focus on the origins of amino acids and the potential role of Streckercyanohydrin synthesis in the early solar system. Previous 13C investigations have targeted amino acid and hydroxy acid Strecker products and reactant HCN; however, 13C values for meteoritic aldehydes and ketones (Strecker precursors) have not yet been reported. As such, the distribution of aldehydes and ketones in the cosmos and their role in prebiotic reactions have not been fully investigated. Here, we have applied an optimized O(2,3,4,5,6pentafluorobenzyl)hydroxylamine (PFBHA) derivatization procedure to the extraction, identification, and 13C analysis of carbonyl compounds in the Murchison meteorite. A suite of aldehydes and ketones, dominated by acetaldehyde, propionaldehyde, and acetone, were detected in the sample. 13C values, ranging from 10.0 to +66.4, were more 13Cdepleted than would be expected for aldehydes and ketones derived from the interstellar medium, based on interstellar 12C/13C ratios. These relatively 13Cdepleted values suggest that chemical processes taking place in asteroid parent bodies (e.g., oxidation of the IOM) may provide a secondary source of aldehydes and ketones in the solar system. Comparisons between 13C compositions of meteoritic aldehydes and ketones and other organic compound classes were used to evaluate potential structural relationships and associated reactions, including Strecker synthesis and alterationdriven chemical pathways

    The application of mHealth to mental health: opportunities and challenges

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    Recent advances in smartphones and wearable biosensors enable the gathering of ‘real-time’ psychological, behavioural and physiological data, in increasingly precise and unobtrusive ways. It is therefore now possible to collect moment-to-moment information about an individuals’ moods, cognitions and activities, as well as automated data about their whereabouts, behaviour and physiological states. In this paper, we discuss the potential of these new mobile digital technologies for transforming mental health research and clinical practice. By drawing on a recent research project, we illustrate how traditional boundaries between research and clinical practice are becoming increasingly blurred and how in turn, this is leading to exciting new developments in the assessment and management of common mental disorders. The potential risks and key challenges associated with applying mobile technology to mental health are also discussed

    Parent Body Influences on Amino Acids in the Tagish Lake Meteorite

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    The Tagish Lake meteorite is a primitive C2 carbonaceous chondrite with a mineralogy, oxygen isotope, and bulk chemical. However, in contrast to many CI and CM carbonaceous chondrites, the Tagish Lake meteorite was reported to have only trace levels of indigenous amino acids, with evidence for terrestrial L-amino acid contamination from the Tagish Lake meltwater. The lack of indigenous amino acids in Tagish Lake suggested that they were either destroyed during parent body alteration processes and/or the Tagish Lake meteorite originated on a chemically distinct parent body from CI and CM meteorites where formation of amino acids was less favorable. We recently measured the amino acid composition of three different lithologies (11h, 5b, and 11i) of pristine Tagish Lake meteorite fragments that represent a range of progressive aqueous alteration in order 11h < 5b < 11i as inferred from the mineralogy, petrology, bulk isotopes, and insoluble organic matter structure. The distribution and enantiomeric abundances of the one- to six-carbon aliphatic amino acids found in hot-water extracts of the Tagish Lake fragments were determined by ultra performance liquid chromatography fluorescence detection and time of flight mass spectrometry coupled with OPA/NAC derivatization. Stable carbon isotope analyses of the most abundant amino acids in 11h were measured with gas chromatography coupled with quadrupole mass spectrometry and isotope ratio mass spectrometry

    Castelvecchio and Castiglione del Lago: Two new Italian iron meteorites

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    Martian low-temperature alteration materials in shock-melt pockets in Tissint: Constraints on their preservation in shergottite meteorites

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    We apply an array of in situ analytical techniques, including electron and Raman microscopy, electron and ion probe microanalysis, and laser ablation mass spectrometry to the Tissint martian meteorite in order to find and elucidate a geochemical signature characteristic of low-temperature alteration at or near the martian surface. Tissint contains abundant shock-produced quench-crystallized melt pockets containing water in concentrations ranging from 73 to 1730 ppm; water content is positively correlated with Cl content. The isotopic composition of hydrogen in the shock-produced glass ranges from δD = 2559 to 4422 ‰. Water is derived from two distinct hydrogen reservoirs: the martian near-surface (>500 ‰) and the martian mantle (-100 ‰). In one shock melt pocket comprising texturally homogeneous vesiculated glass, the concentration of H in the shock melt decreases while simultaneously becoming enriched in D, attributable to the preferential loss of H over D to the vesicle while the pocket was still molten. While igneous sulfides are pyrrhotite in composition (Fe_(0.88-0.90)S), the iron to sulfur ratios of spherules in shock melt pockets are elevated, up to Fe_(1.70)S, which we attribute to shock-oxidation of igneous pyrrhotite and the formation of hematite at high temperature. The D- and Cl-enrichment, and higher oxidation of the pockets (as indicated by hematite) support a scenario in which alteration products formed within fractures or void spaces within the rock; the signature of these alteration products is preserved within shock melt (now glass) which formed upon collapse of these fractures and voids during impact shock. Thermal modeling of Tissint shock melt pockets using the HEAT program demonstrates that the shock melt pockets with the greatest potential to preserve a signature of aqueous alteration are small, isolated from other regions of shock melt, vesicle-free, and glassy

    Tolerance in Internet gaming disorder: a need for increasing gaming time or something else?

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    Background and aims The criterion of tolerance in DSM-5 Internet gaming disorder (IGD) refers to a need for increasing time spent gaming. However, this focus on "need for gaming time" may overlook some of the broader motivations, outcomes, or effects of gaming that underlie excessive play. This study aimed to explore regular and problematic gamers' experiences and perceptions of tolerance in IGD. Methods An online survey of 630 adult gamers yielded 1,417 text responses to open-ended questions. A thematic analysis of 23,373 words was conducted to extract dominant themes. Results Participants reported that they increasingly desired game items, status, or story progress as they became more involved or invested in games. As players develop higher standards of play in games, an increasing number of potential reward outcomes may have diminishing mood-modifying effects. None of the participants, including those with self-reported IGD, explicitly referred to a need for increasing time spent gaming. Discussion and conclusions These results suggest that players may be motivated by preferences for specific goals or reinforcers in games rather than wanting an amount of time spent gaming. Thus, problematic gaming may involve a need for completion of increasingly intricate, time-consuming, or difficult goals to achieve satisfaction and/or reduce fears of missing out. Further research is needed to determine whether these cognitive and motivational factors related to gaming stimuli should extend or replace the concept of tolerance in IGD or be considered as separate but related processes in disordered gaming.King Daniel L., Madeleine C. E. Herd, Paul H. Delfabbr

    An analysis of the dependence of saccadic latency on target position and target characteristics in human subjects

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    BACKGROUND: Predictions from conduction velocity data for primate retinal ganglion cell axons indicate that the conduction time to the lateral geniculate nucleus for stimulation of peripheral retina should be no longer than for stimulation of central retina. On this basis, the latency of saccadic eye movements should not increase for more peripherally located targets. However, previous studies have reported relatively very large increases, which has the implication of a very considerable increase in central processing time for the saccade-generating system. RESULTS: In order to resolve this paradox, we have undertaken an extended series of experiments in which saccadic eye movements were recorded by electro-oculography in response to targets presented in the horizontal meridian in normal young subjects. For stationary or moving targets of either normal beam intensity or reduced red intensity, with the direction of gaze either straight ahead with respect to the head or directed eccentrically, the saccadic latency was shown to remain invariant with respect to a wide range of target angular displacements. CONCLUSIONS: These results indicate that, irrespective of the angular displacement of the target, the direction of gaze or the target intensity, the saccade-generating system operates with a constant generation time
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