ECSS Paris 2023: CP-SH12
Introduction Imagine an athlete who must analyse a dynamic environment in a fraction of a second, make a decision, and execute a precise action. Such performance relies not only on physical preparation but also on cognitive abilities -to perceive, process, interpret, and select relevant information while coping the disruptive effects of intense exertion. Yet, our understanding remains limited of how athletes monitor and adjust their own cognitive processes, especially when evaluating the confidence in their decisions -a critical aspect of metacognition. By integrating behavioral and physiological measurements, this study investigates how high-intensity intermittent exercise (HIIE) influences information processing, affects perceptual decision-making and modulates the efficiency of self-assessment regarding one’s own actions. Methods Sixteen active young adults (22.3 ± 2.5 years, 6 women) completed two sessions on separate days: a HIIE session consisting of 8 × 3min bouts above the lactate threshold, interspersed with 5min recovery periods, and a control session involving video watching. During each 5min recovery period, participants performed a visual discrimination task. Confidence judgments -the evaluation of the accuracy of a decision just made- were collected during the first and the last blocks of each session. Capillary blood lactate and glucose levels, heart rate, RPE and rate of perceived fatigue were measured throughout the protocol. Two cognitive measures were analysed using mixed-effects models (i) Reaction Time (RT) performance and (ii) metacognitive sensitivity, which quantifies the trial-by-trial relationship between confidence and response accuracy. Results Results indicated that exercise induced significant physiological stress, with lactate levels rising to 4.75 ± 1.8 mmol/L during the HIIE session compared to 0.99 ± 0.53 mmol/L in the control condition. Analyses revealed that HIIE exercise impaired information processing in terms of speed, with no effect on accuracy (p=0.58). Mean RT was significantly longer in the HIIE condition than in the control condition (HIIE: 965 ± 334 ms; REST: 952 ± 366 ms) (p<0.001). Metacognitive sensitivity was quantified using the area under the curve (AUC) for the type-2 Receiver Operating Characteristic (ROC), calculated separately for each participant. Results showed a trend toward lower AUC values in the HIIE session compared to control session, indicating potential reduced metacognitive sensitivity (p=0.08). Conclusion The current study demonstrates that HIIE slows information processing without compromising accuracy, it also tends to reduce metacognitive sensitivity -suggesting that intense exercise may impair athlete's ability to accurately evaluate their own decisions. These findings highlight the need for further investigation into the exercise-cognition interaction, particularly the underlying mechanisms of information processing and metacognitive abilities.
Read CV Lucas GUILBAUDECSS Paris 2023: CP-SH12
INTRODUCTION Placebo and nocebo effects can substantially influence motor performance measures such as strength and fatigue resistance. However, the underlying neurophysiological mechanisms remain poorly understood. This study used a randomised controlled design with high-density electroencephalography (EEG) to characterise the temporal and spatial dynamics of cortical activity associated with placebo- and nocebo-induced modulation of motor performance. METHODS Fifty-six healthy participants were randomly assigned to one of four groups: placebo, nocebo, control, or natural history. At baseline, all participants underwent high-density EEG recordings during an isometric knee-extension task on an isokinetic dynamometer and completed validated questionnaires assessing expectancy, optimism, anxiety, and additional psychological measures. After 48–72 hours from baseline, participants in the experimental groups received one of three interventions: (1) a positive-expectation manipulation (placebo), (2) a negative-expectation manipulation (nocebo), or (3) neutral instructions (control). In the placebo and nocebo groups, an inert substance was described as either performance-enhancing or performance-impairing, respectively. Expectancy was further reinforced using EEG-guided presentations of positive, negative, or neutral adjectives matched to each condition. Baseline measurements were then repeated. Participants in the natural history group received no intervention and simply repeated baseline testing. RESULTS Collected Data is currently being analysed. Primary neurophysiological outcomes focus on the contingent negative variation (CNV), complemented by exploratory source localisation analysis. Behavioural outcomes include maximal and mean peak torque and force production during isometric leg extensions and time-to-failure at 60% of maximal voluntary contraction. Data are analysed with a 2 × 4 mixed-design ANOVA, with condition (baseline vs. test) as the within-subject factor and group (placebo, nocebo, control, natural history) as the between-subject factor. Questionnaire data are being analysed for potential correlations and regressions with objective measures. Significant interactions are followed by post hoc comparisons corrected for multiple testing. Statistical significance is set at p < 0.05. DISCUSSION This study will provide insight into when (temporal dynamics), where (cortical sources), and how placebo and nocebo effects influence motor performance. Improved understanding of these mechanisms has direct implications for sport and exercise contexts, informing ethical and evidence-based approaches to placebo and nocebo modulation in performance enhancement. Preregistration Trial registration number: NCT06835777.
Read CV Janina HanssenECSS Paris 2023: CP-SH12