125 research outputs found

    Slow and steady? Strategic adjustments in response caution are moderately reliable and correlate across tasks.

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    Speed-accuracy trade-offs are often considered a confound in speeded choice tasks, but individual differences in strategy have been linked to personality and brain structure. We ask whether strategic adjustments in response caution are reliable, and whether they correlate across tasks and with impulsivity traits. In Study 1, participants performed Eriksen flanker and Stroop tasks in two sessions four weeks apart. We manipulated response caution by emphasising speed or accuracy. We fit the diffusion model for conflict tasks and correlated the change in boundary (accuracy – speed) across session and task. We observed moderate test-retest reliability, and medium to large correlations across tasks. We replicated this between-task correlation in Study 2 using flanker and perceptual decision tasks. We found no consistent correlations with impulsivity. Though moderate reliability poses a challenge for researchers interested in stable traits, consistent correlation between tasks indicates there are meaningful individual differences in the speed-accuracy trade-off

    Low and variable correlation between reaction time costs and accuracy costs explained by accumulation models: Meta-analysis and simulations.

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    The underpinning assumption of much research on cognitive individual differences (or group differences) is that task performance indexes cognitive ability in that domain. In many tasks performance is measured by differences (costs) between conditions, which are widely assumed to index a psychological process of interest rather than extraneous factors such as speed–accuracy trade-offs (e.g., Stroop, implicit association task, lexical decision, antisaccade, Simon, Navon, flanker, and task switching). Relatedly, reaction time (RT) costs or error costs are interpreted similarly and used interchangeably in the literature. All of this assumes a strong correlation between RT-costs and error-costs from the same psychological effect. We conducted a meta-analysis to test this, with 114 effects across a range of well-known tasks. Counterintuitively, we found a general pattern of weak, and often no, association between RT and error costs (mean r = .17, range −.45 to .78). This general problem is accounted for by the theoretical framework of evidence accumulation models, which capture individual differences in (at least) 2 distinct ways. Differences affecting accumulation rate produce positive correlation. But this is cancelled out if individuals also differ in response threshold, which produces negative correlations. In the models, subtractions between conditions do not isolate processing costs from caution. To demonstrate the explanatory power of synthesizing the traditional subtraction method within a broader decision model framework, we confirm 2 predictions with new data. Thus, using error costs or RT costs is more than a pragmatic choice; the decision carries theoretical consequence that can be understood through the accumulation model framework

    Inability to improve performance with control shows limited access to inner states

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    Any repeatedly performed action is characterized by endogenous variability, affecting both speed and accuracy—for a large part presumably caused by fluctuations in underlying brain and body states. The current research questions concerned (a) whether such states are accessible to us and (b) whether we can act upon this information to reduce variability. For example, when playing a game of darts, there is an implicit assumption that people can wait to throw until they are in the right perceptual-attentional state. If this is true, taking away the ability to self-pace the game should worsen performance. We first tested precisely this assumption asking participants to play darts in a self-paced and a fixed-paced condition. There was no benefit of self-pacing, showing that participants were unable to use such control to improve their performance and reduce their variability. Next, we replicated these findings in 2 computer-based tasks, in which participants performed a rapid action-selection and a visual detection task in 1 self-paced and 3 forced-paced conditions. Over 4 different empirical tests, we show that the self-paced condition did not lead to improved performance or reduced variability, nor to reduced temporal dependencies in the reaction time (RT) series. Overall, it seems that, if people have any access to their fluctuating performance-relevant inner states, this access is limited and not relevant for upcoming performance

    Neo/adjuvant chemotherapy does not improve outcome in resected primary synovial sarcoma: a study of the French Sarcoma Group

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    Background: There are only scarce data about the benefit of adjunctive chemotherapy in patients with localized synovial sarcoma (SS). Patients and methods: Data from 237 SS patients recorded in the database of the French Sarcoma Group were retrospectively analyzed. The respective impact of radiotherapy, neo-adjuvant chemotherapy and adjuvant chemotherapy on overall survival (OS), local recurrence-free survival (LRFS) and distant recurrence-free survival (DRFS) were assessed after adjustment to prognostic factors. Results: The median follow-up was 58 months (range 1-321). Adjuvant, neo-adjuvant chemotherapy and postoperative radiotherapy were administered in 112, 45 and 181 cases, respectively. In all, 59% of patients treated with chemotherapy received an ifosfamide-containing regimen. The 5-year OS, LRFS and DRFS rates were 64.0%, 70% and 57%, respectively. On multivariate analysis, age >35 years old, grade 3 and not-R0 margins were highly significant independent predictors of worse OS. After adjustment to prognostic factors, radiotherapy significantly improved LRFS but not DRFS or OS. Neither neo-adjuvant nor adjuvant chemotherapy had significant impact on OS, LRFS or DRFS. Conclusion: As for other high-grade soft-tissue sarcomas, well-planned wide surgical excision with adjuvant radiotherapy remains the cornerstone of treatment for SS. Neo-adjuvant or adjuvant chemotherapy should not be delivered outside a clinical trial settin

    More GABA, less distraction: a neurochemical predictor of motor decision speed

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    People vary markedly in the efficiency with which they can resolve competitive action decisions, even simple ones such as shifting gaze to one stimulus rather than another. We found that an individual's ability to rapidly resolve such competition is predicted by the concentration of GABA, the main inhibitory neurotransmitter, in a region of frontal cortex that is relevant for eye movements, but not in a control region (occipital cortex)

    Long-term efficacy of imatinib mesylate in patients with advanced Tenosynovial Giant Cell Tumor

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    Tenosynovial giant cell tumors (TGCT), are rare colony stimulating factor-1(CSF-1)-driven proliferative disorders affecting joints. Diffuse-type TGCT often causes significant morbidity due to local recurrences necessitating multiple surgeries. Imatinib mesylate (IM) blocks the CSF-1 receptor. This study investigated the long term effects of IM in TGCT. We conducted an international multi-institutional retrospective study to assess the activity of IM: data was collected anonymously from individual patients with locally advanced, recurrent or metastatic TGCT. Sixty-two patients from 12 institutions across Europe, Australia and the United States were identified. Four patients with metastatic TGCT progressed rapidly on IM and were excluded for further analyses. Seventeen of 58 evaluable patients achieved complete response (CR) or partial response (PR). One- and five-year progression-free survival rates were 71% and 48%, respectively. Thirty-eight (66%) patients discontinued IM after a median of 7 (range 1-80) months. Reported adverse events in 45 (78%) patients were among other edema (48%) and fatigue (50%), mostly grade 1-2 (89%). Five patients experienced grade 3-4 toxicities. This study confirms, with additional follow-up, the efficacy of IM in TGCT. In responding cases we confirmed prolonged IM activity on TGCT symptoms even after discontinuation, but with high rates of treatment interruption and additional treatments

    Dietary Education Provision Within a Cardiac Rehabilitation Programme in the UK: A Pilot Study Evaluating Nutritional Intakes Alongside Physical Activity Levels

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    Background/aims: The primary aim of this study was to evaluate the effectiveness of two 30-minute dietary education sessions, within cardiac rehabilitation (CR), as a means to optimise nutrient and energy intakes (EI). A secondary aim was to evaluate patients’ habitual physical activity (PA) levels. Methods: Thirty patients (males: n = 24, 61.8 ± 11.2 years; females: n = 6, 66.7 ± 8.5 years) attended a six-week early outpatient CR programme in the UK and received two 30-minute dietary education sessions emphasising Mediterranean diet principles. EI and nutrient intakes were measured through completion of three-day food diaries in weeks one and six (before and after the dietary education sessions) to assess the impact of these sessions on nutrient intakes. At the same time-points, a sub-group (n = 13) of patients had their PA levels assessed via accelerometery to assess the impact of the CR programme on PA. Findings: Estimated energy requirements (EER) at week one (1988 ± 366 kcal . d -1 ) were not matched by actual EI (1785 ± 561 kcal . d -1 ) ( P = 0.047, d = -0.36). EI reduced to 1655 ± 470 kcal . d -1 at week six ( P = 0.66, d = -0.33) whereas EER increased as a function of increased activity (CR sessions). Nutrient intakes remained suboptimal, while no significant increases were observed in healthy fats and fibre, which consist core elements of a Mediterranean diet. Statistically significant increases were not observed in PA however patients decreased sedentary time by 11 ± 12% in week six compared to week one ( P = 0.009; d = -0.54). Conclusion : The present study findings suggest that two 30-minute dietary education sessions did not positively influence EI and nutrient intakes, while habitual PA levels were not significantly increased as a result of the CR programme. Future research should explore means of optimising nutrition and habitual PA within UK CR
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