203 research outputs found

    Economic choices can be made using only stimulus values

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    Decision-making often involves choices between different stimuli, each of which is associated with a different physical action. A growing consensus suggests that the brain makes such decisions by assigning a value to each available option and then comparing them to make a choice. An open question in decision neuroscience is whether the brain computes these choices by comparing the values of stimuli directly in goods space or instead by first assigning values to the associated actions and then making a choice over actions. We used a functional MRI paradigm in which human subjects made choices between different stimuli with and without knowledge of the actions required to obtain the different stimuli. We found neural correlates of the value of the chosen stimulus (a postdecision signal) in ventromedial prefrontal cortex before the actual stimulus–action pairing was revealed. These findings provide support for the hypothesis that the brain is capable of making choices in the space of goods without first transferring values into action space

    Lack of effect of citalopram on magnetic resonance spectroscopy measures of glutamate and glutamine in frontal cortex of healthy volunteers

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    Magnetic resonance spectroscopy (MRS) is a non-invasive imaging technique that can provide localised measures of brain chemistry in vivo. We previously found that healthy volunteers receiving the selective serotonin reuptake inhibitor, citalopram, daily for 1 week showed higher levels of a combined measure of glutamate and glutamine (Glx) in occipital cortex than those receiving placebo. The aim of this study was to assess if a similar effect could be detected in the frontal brain region. Twenty-three healthy volunteers randomised to receive either citalopram 20 mg or a placebo capsule daily for 7–10 days were studied and scanned using a 3T Varian INOVA system before and at the end of treatment. Standard short-TE (echo time) PRESS (Point-resolved spectroscopy) (TE = 26 ms) and PRESS-J spectra were acquired from a single 8-cm3 voxel in a frontal region incorporating anterior cingulate cortex. Glutamate and total Glx levels were quantified both relative to creatine and as absolute levels. Relative to placebo, citalopram produced no change in Glx or glutamate alone at the end of the study. Similarly, no effect was seen on other MRS measures studied: myo-inositol, choline, N-acetylaspartate and creatine. These data suggest that the effects of serotonin reuptake to modify cortical glutamatergic MRS measures may be regionally specific. This supports the potential for MRS in assessing neuroanatomically specific serotonin-glutamate interactions in the human brain

    Impulsive choice in hippocampal but not orbitofrontal cortex-lesioned rats on a nonspatial decision-making maze task

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    Orbitofrontal cortical (OFC) and hippocampal (HPC) lesions in primates and rodents have been associated with impulsive behaviour. We showed previously that OFC- or HPC-lesioned rats chose the immediate low-reward (LR) option in preference to the delayed high-reward (HR) option, where LR and HR were associated with different spatial responses in a uniform grey T-maze. We now report that on a novel nonspatial T-maze task in which the HR and LR options are associated with patterned goal arms (black-and-white stripes vs. gray), OFC-lesioned rats did not show impulsive behaviour, choosing the delayed HR option, and were indistinguishable from controls. In contrast, HPC-lesioned rats exhibited impulsive choice in the nonspatial decision-making task, although they chose the HR option on the majority of trials when there was a 10-s delay associated with both goal arms. The previously reported impairment in OFC-lesioned rats on the spatial version of the intertemporal choice task is unlikely to reflect a general problem with spatial learning, because OFC lesions were without effect on acquisition of the standard reference memory water-maze task and spatial working memory performance (nonmatching-to-place) on the T-maze. The differential effect of OFC lesions on the two versions of the intertemporal choice task may be explained instead in terms of the putative role of OFC in using associative information to represent expected outcomes and generate predictions. The impulsivity in HPC-lesioned rats may reflect impaired temporal information processing, and emphasizes a role for the hippocampus beyond the spatial domain

    Inferring brain-wide interactions using data-constrained recurrent neural network models

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    Behavior arises from the coordinated activity of numerous anatomically and functionally distinct brain regions. Modern experimental tools allow unprecedented access to large neural populations spanning many interacting regions brain-wide. Yet, understanding such large-scale datasets necessitates both scalable computational models to extract meaningful features of inter-region communication and principled theories to interpret those features. Here, we introduce Current-Based Decomposition (CURBD), an approach for inferring brain-wide interactions using data-constrained recurrent neural network models that directly reproduce experimentally-obtained neural data. CURBD leverages the functional interactions inferred by such models to reveal directional currents between multiple brain regions. We first show that CURBD accurately isolates inter-region currents in simulated networks with known dynamics. We then apply CURBD to multi-region neural recordings obtained from mice during running, macaques during Pavlovian conditioning, and humans during memory retrieval to demonstrate the widespread applicability of CURBD to untangle brain-wide interactions underlying behavior from a variety of neural datasets

    Physicians' messages in problematic sickness certification: a narrative analysis of case reports

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    <p>Abstract</p> <p>Background</p> <p>Many physicians find sickness certification tasks problematic. There is some knowledge about situations that are experienced as problematic, whereas less is understood about how physicians respond to the problems they face. One way to acquire such knowledge is to consider "reflection-in-action", aspects of which are expressed in the physician's interpretation of the patient's story. The aim of this study was to gain knowledge about the meaning content of case reports about problematic sickness certification. Specifically, we looked for possible messages to the colleagues intended to read the reports.</p> <p>Methods</p> <p>A narrative approach was used to analyse reports about problematic sickness certification cases that had been written by GPs and occupational health service physicians as part of a sickness insurance course. The analysis included elements from both thematic and structural analysis. Nineteen case reports were used in the actual analysis and 25 in the validation of the results. Main narrative qualities and structural features of the written case reports were explored.</p> <p>Results</p> <p>Five types of messages were identified in the case reports, here classified as "a call for help", "a call for understanding", "hidden worries", "in my opinion", and "appearing neutral". In the reports, the physicians tried to achieve neutrality in their writing, and the patients' stories tended to be interpreted within a traditional biomedical framework. In some cases there was an open request for help, in others it was not obvious that the physician had any problems. Overall, the messages were about having problems as such, rather than the specific features of the problems.</p> <p>Conclusions</p> <p>The case reports clearly demonstrated different ways of writing about problems that arise during sickness certification, from being neutral and not mentioning the problems to being emotionally involved and asking for help. The general character of the messages suggests that they are also relevant for case reports in problematic areas other than sickness certification. If pertinent relationships can be found between reflection-in-practice and the narrative writing about practice, they will provide an approach to further research concerning consultations perceived as problematic and also to medical education.</p

    Clinical development innovation in rare diseases: lessons learned and best practices from the DevelopAKUre consortium

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    New opportunities have arisen for development of therapies for rare diseases with the increased focus and progress in the field. However, standardised framework integrating individual initiatives has not been formed. We present lessons learned and best practice from a collaborative success case in developing a treatment for a rare genetic disease. Our unique consortium model incorporated several of the identified developments under one project, DevelopAKUre, truly bringing together academia, industry and patient organisations in clinical drug development. We found that the equal partnership between all parties in our consortium was a key success factor creating a momentum based on a strong organisational culture where all partners had high engagement and taking ownership of the entire programme. With an agreed mutual objective, this provided synergies through connecting the strengths of the individual parties. Another key success factor was the central role of the patient organisation within the management team, and their unique study participants’ advocacy role securing the understanding and meeting the needs of the clinical study participants in real-time. This resulted in an accelerated enrolment into the clinical studies with a high retention rate allowing for delivery of the programme with significantly improved timelines. Our project was partly funded through an external EU research grant, enabling our model with equal partnership. Further attention within the community should be given to establishing a functional framework where sustainable funding and risk sharing between private and public organisations allow for our model to be replicated

    Satisfaction is not all – patients' perceptions of outcome of general practice consultations, a qualitative study

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    BACKGROUND: Evaluation of outcome in general practice can be seen from different viewpoints. In this study we focus on the concepts patients use to describe the outcome of a consultation with a GP. METHOD: Patients were interviewed within a week after a consultation with a GP. The interviews were made with 20 patients in 5 focus groups and 8 individually. They were analysed with a phenomenographic research approach. RESULTS: From the patient's perspective, the outcome of a consultation is about cure or symptom relief, understanding, confirmation, reassurance, change in self-perception and satisfaction. CONCLUSION: General practice consultations are often more important for patients than generally supposed. Understanding is the most basic concept

    To make a difference – how GPs conceive consultation outcomes. A phenomenographic study

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    <p>Abstract</p> <p>Background</p> <p>Outcomes from GPs' consultations have been measured mainly with disease specific measures and with patient questionnaires about health, satisfaction, enablement and quality. The aim of this study was to explore GPs' conceptions of consultation outcomes.</p> <p>Methods</p> <p>Interviews with 17 GPs in groups and individually about consultation outcomes from recently performed consultations were analysed with a phenomenographic research approach.</p> <p>Results</p> <p>The GPs conceived outcomes in four ways: patient outcomes, GPs' self-evaluation, relationship building and change of surgery routines.</p> <p>Conclusion</p> <p>Patient outcomes, as conceived by the GPs, were generally congruent with those that had been taken up in outcome studies. Relationship building and change of surgery routines were outcomes in preparation for consultations to come. GPs made self-assessments related to internalized norms, grounded on a perceived collegial professional consensus. Considerations of such different aspects of outcomes can inspire professional development.</p

    Comparing the Phenylalanine/Tyrosine Pathway and Related Factors between Keratopathy and No-Keratopathy Groups as Well as between Genders in Alkaptonuria during Nitisinone Treatment

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    Nitisinone (NIT) causes tyrosinaemia and corneal keratopathy (KP), especially in men. However, the adaptation within the phenylalanine (PHE)/tyrosine (TYR) catabolic pathway during KP is not understood. The objective of this study is to assess potential differences in the PHE/TYR pathway during KP and the influence of gender in NIT-induced tyrosinaemia in alkaptonuria (AKU). Samples of serum and 24 h urine collected from patients treated with NIT during a 4-year randomized study in NIT vs. no-treatment controls (SONIA 2; Suitability Of Nitisinone In Alkaptonuria 2; EudraCT no. 2013-001633-41) at months 3 (V2), 12 (V3), 24 (V4), 36 (V5) and 48 (V6) were included in these analyses. Homogentisic acid (HGA), TYR, PHE, hydroxyphenylpyruvate (HPPA), hydroxyphenyllactate (HPLA) and sNIT were analysed at all time-points in serum and urine in the NIT-group. All statistical analyses were post hoc. Keratopathy occurred in 10 out of 69 AKU patients, eight of them male. Thirty-five sampling points (serum and 24 h urine) were analysed in patients experiencing KP and 272 in those with no-KP (NKP) during NIT therapy. The KP group had a lower HPLA/TYR ratio and a higher TYR/PHE ratio compared with the NKP group (p &lt; 0.05 for both). There were 24, 45, 100 and 207 sampling points (serum and 24 h urine) in the NIT group which were pre-NIT female, pre-NIT male, NIT female and NIT male, respectively. The PHE/TYR ratio and the HPLA/TYR ratio were lower in males (p &lt; 0.001 and p &lt; 0.01, respectively). In the KP group and in the male group during NIT therapy, adaptive responses to minimise TYR formation were impaired compared to NKP group and females, respectively
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