573 research outputs found

    The interaction between gaze and facial expression in the amygdala and extended amygdala is modulated by anxiety

    Get PDF
    Behavioral evidence indicates that angry faces are seen as more threatening, and elicit greater anxiety, when directed at the observer, whereas the influence of gaze on the processing of fearful faces is less consistent. Recent research has also found inconsistent effects of expression and gaze direction on the amygdala response to facial signals of threat. However, such studies have failed to consider the important influence of anxiety on the response to signals of threat; an influence that is well established in behavioral research and recent neuroimaging studies. Here, we investigated the way in which individual differences in anxiety would influence the interactive effect of gaze and expression on the response to angry and fearful faces in the human extended amygdala. Participants viewed images of fearful, angry and neutral faces, either displaying an averted or direct gaze. We found that state anxiety predicted an increased response in the dorsal amygdala/substantia innominata (SI) to angry faces when gazing at, relative to away from the observer. By contrast, high state anxious individuals showed an increased amygdala response to fearful faces that was less dependent on gaze. In addition, the relationship between state anxiety and gaze on emotional intensity ratings mirrored the relationship between anxiety and the amygdala/SI response. These results have implications for understanding the functional role of the amygdala and extended amygdala in processing signals of threat, and are consistent with the proposed role of this region in coding the relevance or significance of a stimulus to the observer

    One-pot multi-reaction processes: synthesis of natural products and drug-like scaffolds

    Get PDF
    One-pot multi-reaction processes involving Overman rearrangements, metathesis cyclizations, and Diels–Alder reactions have been developed for the rapid and efficient synthesis of amino-substituted carbocyclic and heterocyclic compounds. This account describes the development and optimization of these processes, as well as their applications in the synthesis of natural products and drug-like scaffolds

    Self priming in face recognition

    Get PDF
    Recently Burton, Bruce and Johnston (1990) have presented an interactive activation and competition model of face recognition. They have shown that this IAC model presents a parsimonious account of semantic and repetition priming effects with faces. In addition, a number of new predictions are evident from the model's structure. One such prediction is highlighted by Burton et al. themselves - that for short prime-target stimulus onset asynchronies (SOAs) a face should prime the recognition of a target name (or vice versa), 'self priming'. This thesis examined this prediction and found that it held for a design in which items were repeated across prime type conditions (same, associated, neutral and unrelated). Further, cross (face prime/name target) and within-domain (name prime/name target) designs were found to produce equivalent degrees of self and semantic priming (Experiments 1 and 2). Closer examination of the Burton et al. model suggested that the effect of domain equivalence for self priming should not hold for a design in which the stimulus items are not repeated across prime type conditions (i.e. subjects are presented with each item only once). This prediction was confirmed in Experiments 3, 4, 5 and 6.The time courses of self and semantic priming were investigated in two experiments where the interstimulus interval (ISI) between prime and target, and prime presentation times were varied. The results proved difficult to accommodate within the Burton et al. model, but it is argued that they did not provide a sufficient basis on which to reject the model. Finally, the self priming paradigm was applied to the study of distinctiveness effects. Faces judged to be distinctive in appearance were found to produce more facilitation than faces judged to be typical in appearance. Similarly, caricatured representation of faces were found to produce more facilitation than veridical or anticaricatured representations. The results of the distinctiveness studies are discussed in terms of the Valentine's (1991a; 1991b) exemplar-based coding model and Burton, Bruce and Johnston's (1990) IAC implementation. It is concluded that the results of these experiments lend support to the Burton et al. model

    One-pot synthesis of 5-amino-2,5-dihydro-1-benzoxepines: access to pharmacologically active heterocyclic scaffolds

    Get PDF
    A one-pot multibond-forming process involving a thermally mediated Overman rearrangement and a ring closing metathesis reaction of allylic trichloroacetimidates bearing a 2-allyloxyaryl group has been developed for the synthesis of 5-amino-substituted 2,5-dihydro-1-benzoxepines. Chemoselective reduction and functionalization of these compounds allowed access to a range of pharmacologically active 5-amino-2,3,4,5-tetrahydro-1-benzoxepine scaffolds

    Responsiveness of bovine cumulus-oocyte-complexes (COC) to porcine and recombinant human FSH, and the effect of COC quality on gonadotropin receptor and Cx43 marker gene mRNAs during maturation in vitro

    Get PDF
    Substantially less development to the blastocyst stage occurs in vitro than in vivo and this may be due to deficiencies in oocyte competence. Although a large proportion of bovine oocytes undergo spontaneous nuclear maturation, less is known about requirements for proper cytoplasmic maturation. Commonly, supraphysiological concentrations of FSH and LH are added to maturation media to improve cumulus expansion, fertilization and embryonic development. Therefore, various concentrations of porcine FSH (pFSH) and recombinant human FSH (rhFSH) were investigated for their effect on bovine cumulus expansion in vitro. Expression of FSHr, LHr and Cx43 mRNAs was determined in cumulus-oocyte complexes to determine whether they would be useful markers of oocyte competence. In serum-free media, only 1000 ng/ml pFSH induced marked cumulus expansion, but the effect of 100 ng/ml pFSH was amplified in the presence of 10% serum. In contrast, cumulus expansion occurred with 1 ng/ml rhFSH in the absence of serum. FSHr mRNA was highest at 0–6 h of maturation, then abundance decreased. Similarly, Cx43 mRNA expression was highest from 0–6 h but decreased by 24 h of maturation. However, the relative abundance of LHr mRNA did not change from 6–24 h of maturation. Decreased levels of FSHr, LHr and Cx43 mRNAs were detected in COCs of poorer quality. In conclusion, expansion of bovine cumulus occurred at low doses of rhFSH in serum-free media. In summary, FSHr, LHr and Cx43 mRNA abundance reflects COC quality and FSHr and Cx43 mRNA expression changes during in vitro maturation; these genes may be useful markers of oocyte developmental competence

    The "where" of social attention: Head and body direction aftereffects arise from representations specific to cue type and not direction alone.

    Get PDF
    Human beings have remarkable social attention skills. From the initial processing of cues, such as eye gaze, head direction, and body orientation, we perceive where other people are attending, allowing us to draw inferences about the intentions, desires, and dispositions of others. But before we can infer why someone is attending to something in the world we must first accurately represent where they are attending. Here we investigate the "where" of social attention perception, and employ adaptation paradigms to ascertain how head and body orientation are visually represented in the human brain. Across two experiments we show that the representation of two cues to social attention (head and body orientation) exists at the category-specific level. This suggests that aftereffects do not arise from "social attention cells" discovered in macaques or from abstract representations of "leftness" or "rightness.

    Accessing Five- and Seven-Membered Phosphorus-Based Heterocycles via Cycloaddition Reactions of Azophosphines

    Get PDF
    Heterocycles containing both phosphorus and nitrogen have seen increasing use in recent years in luminescent materials, coordination chemistry and building blocks for inorganic polymers, yet their chemistry is currently dominated by five- and six-memberd derivatives. Seven-membered P/N heterocycles are comparatively scarce and lack general, high yielding syntheses. We explore the synthesis and characterisation of 1,2,5-diazaphosphepines from azophosphines. The mechanism has been probed in detail with both computational and experimental studies supporting a stepwise mechanism to form a five-membered ring, and subsequent ring expansion to the diazaphosphepine. Regioselective synthesis of five- and seven-membered rings is possible using asymmetric alkynes. The Lewis acidic borane B(C6F5)3 could either catalyse the formation of the seven-membered ring (iPr derivative) or trap out a key intermediate via a frustrated Lewis pair (FLP) mechanism (tBu derivative)

    The Scottish Contribution to the Development of Obstetrics

    Get PDF
    Among the many things in which the Scots nation can take pride our contribution to medical science has been of a very high order. This perhaps reached its acme in the 18th and 19th centuries when Scotland in general and Edinburgh in particular represented the magnet for medical trainees from across the globe. The catalogue of Scottish contributions to developments in medicine is enormous but perhaps in no branch of medicine is it greater than in obstetrics. It could be reasonably claimed that in compiling a list of those obstetricians from the British Isles who have made the most telling contributions to the advancement of this clinical discipline the first half dozen names would probably be Scots. This short article will highlight some of the famous obstetricians who have helped to bring the art and science of obstetrics out of the mists of obscurity to the highly developed clinical science of today

    Mitogen-activated protein kinase (MAPK) blockade of bovine preimplantation embryogenesis requires inhibition of both p38 and extracellular signal-regulated kinase (ERK) pathways.

    Get PDF
    Blastocyst formation, as a critical period during development, is an effective indicator of embryonic health and reproductive efficiency. Out of a number of mechanisms underlying blastocyst formation, highly conserved mitogen-activated protein kinase (MAPK) signaling has emerged as a major mechanism involved in regulating murine preimplantation embryo development. The objective of our study was to ascertain the role of MAPK signaling in regulating bovine development to the blastocyst stage. Using reverse transcriptase PCR and immunohistochemical staining procedures we have demonstrated that mRNA transcripts and polypeptides encoding p38 MAPK pathway constituents are detectable in preimplantation bovine embryos from the one-cell to the blastocyst stage. Further, the effects on bovine embryo development following inhibition of p38 alpha/beta and extracellular signal-regulated kinase (ERK) signaling by treatment with SB220025 and U0126, respectively, were investigated. Eight-cell bovine embryos (50 per group; three replicates) were placed into treatments consisting of synthetic oviductal fluid (SOF) medium: SOF + SB202474 (inactive analogue), SOF + SB220025, SOF + U0124 (inactive analogue), SOF + U0126, and SOF + SB220025 + U0126. Inhibition of p38 MAPK or ERK signaling individually did not affect development to the blastocyst stage. However, when both pathways were blocked simultaneously there was a significant reduction (P \u3c 0.05) in blastocyst formation, cell number and immunofluorescence of phosphorylated downstream pathway constituents. We have determined that, in variance to what was observed during murine preimplantation development, bovine early embryos progress at normal frequencies to the blastocyst stage in the presence of p38 MAPK inhibitors
    • …
    corecore