Dans de nombreuses activités physiques et sportives, la performance dépend de l’efficacité des processus physiologiques et cognitifs sollicités dans l’action. Plus précisément, il semblerait que celle-ci soit fréquemment influencée par l’efficacité des processus décisionnels qui s’effectuent sous pression temporelle. A ce titre, ce travail de thèse s’intéresse à l’effet de l’administration de trois supplémentations nutritionnelles classiquement consommées par les athlètes (hydrates de carbone, caféine et guarana) sur le fonctionnement cognitif au cours d’un exercice. Nos résultats indiquent que l’ingestion isolée de ces trois composés améliore la vitesse du traitement de l’information lors d'une tâche décisionnelle dès la fin d’un exercice. Par ailleurs, l’utilisation de la caféine en rinçage de bouche semble aussi pertinente, puisque nos résultats suggèrent une amélioration probable de l’efficacité des processus relatifs à la gestion d’un conflit au cours de l’exercice. Enfin, une diminution de la perception de l’effort est aussi rapportée lors de l’ingestion de caféine et de guarana, ou de l’utilisation d’hydrates de carbone en rinçage de bouche. L’ensemble de ces résultats indique une potentialisation de l’effet de l’exercice sur la performance cognitive. Il suggère aussi que la mise en place de supplémentations nutritionnelles lors d’un exercice améliore l’efficacité de processus cognitifs qui s’avèrent être essentiels à la performance sportive. / In sport and exercise activities, successful performances strongly depend on the ability to simultaneously carry out cognitive and physical demands. More precisely, it would seem that performance is frequently influenced by the efficacy of decision-making realized under strong temporal pressure. The aim of this thesis work is to assess the effect of nutritional supplements that is carbohydrate, caffeine and guarana on cognitive functions during an acute exercise. Overall, our results suggest that ingestion of these three supplements enhance speed of information processing during a decision-making task at the end of exercise. Additionally, caffeine mouth rinsing seems worthwhile since a likely enhancement of inhibition processes has been reported after use during exercise. Finally, a decrease of perceived exertion has been reported with caffeine and guarana ingestion along with carbohydrate mouth rinsing. In conclusion, our results indicate the potentiation of exercise effects on cognitive function. Furthermore, they suggest nutritional supplements could enhance cognitive processes during exercise in what may be a predictive factor of performance enhancement.

A multitude of sensory inputs needs to be processed during sensorimotor integration. A crucial factor for detecting relevant information is its complexity, since information content can be conflicting at a perceptual level. This may be central to executive control processes, such as response inhibition. This EEG study aims to investigate the system neurophysiological mechanisms behind effects of perceptual conflict on response inhibition. We systematically modulated perceptual conflict by integrating a Global-local task with a Go/Nogo paradigm. The results show that conflicting perceptual information, in comparison to non-conflicting perceptual information, impairs response inhibition performance. This effect was evident regardless of whether the relevant information for response inhibition is displayed on the global, or local perceptual level. The neurophysiological data suggests that early perceptual/ attentional processing stages do not underlie these modulations. Rather, processes at the response selection level (P3), play a role in changed response inhibition performance. This conflict-related impairment of inhibitory processes is associated with activation differences in (inferior) parietal areas (BA7 and BA40) and not as commonly found in the medial prefrontal areas. This suggests that various functional neuroanatomical structures may mediate response inhibition and that the functional neuroanatomical structures involved depend on the complexity of sensory integration processes.

There are large overlaps in cognitive deficits occurring in attention deficit disorder (ADD) and neurodevelopmental disorders like neurofibromatosis type 1 (NF1). This overlap is mostly based on clinical measures and not on in-depth analyses of neuronal mechanisms. However, the consideration of such neuronal underpinnings is crucial when aiming to integrate measures that can lead to a better understanding of the underlying mechanisms. Inhibitory control deficits, for example, are a hallmark in ADD, but it is unclear how far there are similar deficits in NF1. We thus compared adolescent ADD and NF1 patients to healthy controls in a Go/Nogo task using behavioural and neurophysiological measures. Clinical measures of ADD-symptoms were not different between ADD and NF1. Only patients with ADD showed increased Nogo errors and reductions in components reflecting response inhibition (i.e. Nogo-P3). Early perceptual processes (P1) were changed in ADD and NF1. Clinically, patients with ADD and NF1 thus show strong similarities. This is not the case in regard to underlying cognitive control processes. This shows that in-depth analyses of neurophysiological processes are needed to determine whether the overlap between ADD and NF1 is as strong as assumed and to develop appropriate treatment strategies.

There have recently been considerable advances in our understanding of the neuronal mechanisms underlying multitasking, but the role of multimodal integration for this faculty has remained rather unclear. We examined this issue by comparing different modality combinations in a multitasking (stop-change) paradigm. In-depth neurophysiological analyses of event-related potentials (ERPs) were conducted to complement the obtained behavioral data. Specifically, we applied signal decomposition using second order blind identification (SOBI) to the multi-subject ERP data and source localization. We found that both general multimodal information integration and modality-specific aspects (potentially related to task difficulty) modulate behavioral performance and associated neurophysiological correlates. Simultaneous multimodal input generally increased early attentional processing of visual stimuli (i.e. P1 and N1 amplitudes) as well as measures of cognitive effort and conflict (i.e. central P3 amplitudes). Yet, tactile-visual input caused larger impairments in multitasking than audio-visual input. General aspects of multimodal information integration modulated the activity in the premotor cortex (BA 6) as well as different visual association areas concerned with the integration of visual information with input from other modalities (BA 19, BA 21, BA 37). On top of this, differences in the specific combination of modalities also affected performance and measures of conflict/effort originating in prefrontal regions (BA 6).

Background. Seasonal allergic rhinitis (SAR) is a chronic disease affecting about 23% of the European population with increasing prevalence rates. Beside classical symptoms (i.e. sneezing, nasal congestion), patients frequently complain about subjective impairments in cognitive functioning during periods of acute allergic inflammation. However, objective evidence for such deficits or the role of potential modulators and underlying mechanisms is limited. The present study aimed to investigate the effect of SAR on attention-related cognitive processes. In addition, relationships between attention performance, sleep and mood disturbances as well as specific disease characteristics as potential modulators of this link were explored. Method. SAR patients (n = 41) and non-allergic healthy controls (n = 42) completed a set of attention tasks during a symptomatic allergy period and during a non-symptomatic period. Influences of sleep, mood, total immunoglobulin E (IgE) levels and individual allergy characteristics on cognitive performance were evaluated. Results. Compared to healthy controls, SAR patients had a slower processing speed during both symptomatic and nonsymptomatic allergy periods. Additionally, they showed a more flexible adjustment in attention control, which may serve as a compensatory strategy. Reduction in processing speed was positively associated with total IgE levels whereas flexible adjustment of attention was linked with anxious mood. No association was found between SAR-related attention deficits and allergy characteristics or sleep. Conclusions. SAR represents a state that is crucially linked to impairments in information processing and changes in attentional control adjustments. These cognitive alterations are more likely to be influenced by mood and basal inflammatory processes than sleep impairments or subjective symptom severity.

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The dynamic adaptation of cognitive control in the face of competition from conflicting response tendencies is one of the hallmarks of flexible human action control. Here, we suggest an alternative framework that places conflicttriggered control adaptation into the broader context of affect regulation. Specifically, we review evidence showing that (a) conflicts are inherently aversive, that (b) aversive stimuli in the absence of conflict also trigger behavioral adjustments, and, finally, that (c) conflict stimuli do trigger processes of affective counter-regulation. Together with recent findings showing that conflict-triggered control adaptation depends on the subjective experience of the conflict, we suggest that it is the subjective aversive conflict experience that originally motivates control adaptations. Such a view offers new perspectives for investigating and understanding intra- and interindividual differences in the regulation of cognitive control by differentiating between the individual sensitivity to experience and the individual ability to utilize the aversive signal.

<p>Cognitive control is accomplished by a set of higher-order cognitive processes that are recruited to aid in the completion of various tasks. A popular proposed mechanism is the Dual Mechanisms of Control (Braver, Gray, & Burgess, 2007), proposing proactive and reactive mechanisms. While neuroscience studies provide evidence that these are two distinct processes, it remains unclear whether the processes are competing, or whether they can be used together. That is, are the two processes able to both be enacted to some degree? Further, whether these mechanisms can be titrated to produce a gradient-like use of control on a trial-level basis is unknown. These are the two primary pursuits of this dissertation. Experiment 1 shows the titrated pattern of control use, indicating (a) sensitivity to task demands, and (b) dynamic use of proactive and reactive control at the trial level, in a new task. Further, a novel contribution is the observation of ability to titrate the use of control. Additional experiments relate performance on this task to working memory (Experiment 2), replicate the findings in an online format (Experiment 3), and differentiate performance from distance effects commonly seen in relative judgment tasks (Experiment 4). This work has implications for the understanding of how cognitive control functions and how dynamically the use of these mechanisms can be adjusted.</p>

Objective: The present study investigated, for the first time, event- and time-based prospective memory (PM) in the same sample of adults with ADHD within one paradigm using parallel task constraints. Method: A total of 25 individuals with ADHD and 25 matched neurotypical controls completed a computerized version of the Dresden Breakfast Task, which required participants to prepare breakfast following a set of rules and time restrictions. Results: Although groups did not differ in event-based PM, results demonstrated a large-sized impairment in individuals with ADHD in time-based PM. Conclusion: Findings suggest a task-specific impairment in PM functioning and are discussed in an executive control framework of neurocognitive functioning in ADHD. (J. of Att. Dis. 2014; 18(7) 617-624)