48 research outputs found

    A role of the claustrum in auditory scene analysis by reflecting sensory change

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    The biological function of the claustrum remains speculative, despite many years of research. On the basis of its widespread connections it is often hypothesized that the claustrum may have an integrative function mainly reflecting objects rather than the details of sensory stimuli. Given the absence of a clear demonstration of any sensory integration in claustral neurons, however, we propose an alternative, data-driven, hypothesis: namely that the claustrum detects the occurrence of novel or salient sensory events. The detection of new events is critical for behavior and survival, as suddenly appearing objects may require rapid and coordinated reactions. Sounds are of particular relevance in this regard, and our conclusions are based on the analysis of neurons in the auditory zone of the primate claustrum. Specifically, we studied the responses to natural sounds, their preference to various sound categories, and to changes in the auditory scene. In a test for sound-category preference claustral neurons responded to but displayed a clear lack of selectivity between monkey vocalizations, other animal vocalizations or environmental sounds (Esnd). Claustral neurons were however able to detect target sounds embedded in a noisy background and their responses scaled with target signal to noise ratio (SNR). The single trial responses of individual neurons suggest that these neurons detected and reflected the occurrence of a change in the auditory scene. Given its widespread connectivity with sensory, motor and limbic structures the claustrum could play the essential role of identifying the occurrence of important sensory changes and notifying other brain areas—hence contributing to sensory awareness

    Ventromedial hypothalamic neurons control a defensive emotion state

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    Defensive behaviors reflect underlying emotion states, such as fear. The hypothalamus plays a role in such behaviors, but prevailing textbook views depict it as an effector of upstream emotion centers, such as the amygdala, rather than as an emotion center itself. We used optogenetic manipulations to probe the function of a specific hypothalamic cell type that mediates innate defensive responses. These neurons are sufficient to drive multiple defensive actions, and required for defensive behaviors in diverse contexts. The behavioral consequences of activating these neurons, moreover, exhibit properties characteristic of emotion states in general, including scalability, (negative) valence, generalization and persistence. Importantly, these neurons can also condition learned defensive behavior, further refuting long-standing claims that the hypothalamus is unable to support emotional learning and therefore is not an emotion center. These data indicate that the hypothalamus plays an integral role to instantiate emotion states, and is not simply a passive effector of upstream emotion centers

    Scalable control of mounting and attack by Esr1^+ neurons in the ventromedial hypothalamus

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    Social behaviours, such as aggression or mating, proceed through a series of appetitive and consummatory phases that are associated with increasing levels of arousal. How such escalation is encoded in the brain, and linked to behavioural action selection, remains an unsolved problem in neuroscience. The ventrolateral subdivision of the murine ventromedial hypothalamus (VMHvl) contains neurons whose activity increases during male–male and male–female social encounters. Non-cell-type-specific optogenetic activation of this region elicited attack behaviour, but not mounting. We have identified a subset of VMHvl neurons marked by the oestrogen receptor 1 (Esr1), and investigated their role in male social behaviour. Optogenetic manipulations indicated that Esr1^+ (but not Esr1^−) neurons are sufficient to initiate attack, and that their activity is continuously required during ongoing agonistic behaviour. Surprisingly, weaker optogenetic activation of these neurons promoted mounting behaviour, rather than attack, towards both males and females, as well as sniffing and close investigation. Increasing photostimulation intensity could promote a transition from close investigation and mounting to attack, within a single social encounter. Importantly, time-resolved optogenetic inhibition experiments revealed requirements for Esr1^+ neurons in both the appetitive (investigative) and the consummatory phases of social interactions. Combined optogenetic activation and calcium imaging experiments in vitro, as well as c-Fos analysis in vivo, indicated that increasing photostimulation intensity increases both the number of active neurons and the average level of activity per neuron. These data suggest that Esr1^+ neurons in VMHvl control the progression of a social encounter from its appetitive through its consummatory phases, in a scalable manner that reflects the number or type of active neurons in the population

    Internal States and Behavioral Decision-Making: Toward an Integration of Emotion and Cognition

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    Social interactions, such as an aggressive encounter between two conspecific males or a mating encounter between a male and a female, typically progress from an initial appetitive or motivational phase, to a final consummatory phase. This progression involves both changes in the intensity of the animals’ internal state of arousal or motivation and sequential changes in their behavior. How are these internal states, and their escalating intensity, encoded in the brain? Does this escalation drive the progression from the appetitive/motivational to the consummatory phase of a social interaction and, if so, how are appropriate behaviors chosen during this progression? Recent work on social behaviors in flies and mice suggests possible ways in which changes in internal state intensity during a social encounter may be encoded and coupled to appropriate behavioral decisions at appropriate phases of the interaction. These studies may have relevance to understanding how emotion states influence cognitive behavioral decisions at higher levels of brain function

    Experiencing fear appeals as a challenge or a threat influences attainment value and academic self-efficacy

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    © 2015 Elsevier Ltd. Fear appeals are persuasive messages that highlight the negative consequences of a particular course of action. Studies have shown that attainment value and academic self-efficacy predict how fear appeals are appraised. In this study we examined how the appraisal of fear appeals might also influence subsequent attainment value and academic self-efficacy. Self-report data were collected from 1433 students in their final two years of secondary education over three waves. Findings revealed that when students saw fear appeals as a challenge attainment value and academic self-efficacy were higher. When students saw fear appeals as a threat, attainment value and academic self-efficacy were lower. These results highlight the functional importance of how fear appeals are appraised. Challenge and threat appraisals were not mere by products of attainment value or academic self-efficacy but impacted on attainment value and academic self-efficacy; variables that are likely to make a critical impact on educational progress and attainment. We conclude that initial teacher education and teacher professional development programs would benefit from enhanced interpersonal and relational-skills training to enable teachers to judge more effectively how fear appeals are appraised

    Supporting international medical graduates’ transition to their host-country: realist synthesis

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    Context Many health services and systems rely on the contribution of international medical graduates (IMGs) to the workforce. However, concern has grown around their regulation and professional practice. There is a need, in the absence of strong evidence and a robust theoretical base, for a deeper understanding of the efficacy of interventions used to support IMGs’ transition to their host countries. This study seeks to explore and synthesise evidence relating to interventions developed for IMGs. It aims to provide educators and policy makers with an understanding of how interventions should be developed to support IMGs in their transition to the workplace, particularly looking to identify how and why they are effective. Methods The realist synthesis involved an initial systematic search of the literature for the period January 1990 to April 2015. Secondary searches were conducted throughout the review in order to inform and test the developing programme theory. The context, mechanism and outcome data were extracted from all sources meeting the inclusion criteria. Fourteen case studies were included to further aid theory refinement. Results Sixty-two articles were identified, describing diverse interventions of varying intensity. A further 26 articles were identified through a secondary search. The findings illustrate that, alongside a developed programme, ongoing support and cultural awareness at organisational and training levels are crucial. Individual differences must also be taken into consideration. This will ensure that IMGs engage in transformative learning, increase their levels of self-efficacy and cultural health capital, and reduce feelings of stress and anxiety. These factors will have an impact on work, interactions and cultural adjustment. Conclusions Organisational, training and individual contexts all play a role in IMGs’ adjustment during the transition process. Establishing ongoing support is critical. A list of recommendations for implementation is given

    Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

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    Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

    Monkey drumming reveals common networks for perceiving vocal and nonvocal communication sounds

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    Remedios R, Logothetis NK, Kayser C. Monkey drumming reveals common networks for perceiving vocal and nonvocal communication sounds. Proc Natl Acad Sci U S A. 2009;106(42):18010-5
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