The effects of caffeine (250 mg) and placebo on healthy controls were studied in a double-blind, cross over study on 24 healthy subjects who performed a working memory n-back task. Reaction time and accuracy levels were tested using the n-back working memory measure in cognitive neuroscience. An experimental study tested on the 1, 2 and 3-back tasks under the placebo/coffee condition. Based on the empirical results obtained in this thesis it can be concluded that changes produced by caffeine ingestion support the hypothesis that caffeine acts as a stimulant. However, it cannot be proven that the stimulant translates into enhanced motor processes with an improvement in performance.

This paper explores the effect of color on working memory performance. Interest in Baker-Miller pink surged with the finding by Schauss (1979) that it reduced aggression in aggravated detainees. However, research behind Baker-Miller pink has been influenced by biases and methodological errors. Its effects are likely overstated. Red and blue have also been studied for their effects on creativity, approach-avoidance conflict, detail-orientation, and most importantly, stress. Further research has been conducted on the effects of relaxation on cognition, with the conclusion that increased relaxation leads to improvements in working memory performance. This paper tests the effect of color on working memory performance. Accuracy on the n-back was compared across 4 colors: pink, red, blue, and black. No significant differences in accuracy were found in any of the color conditions, though the main effect of load was significant. Future research can increase the sample size and utilize a cognitive task that is inherently stressful.

The intent of this thesis was to test if one of the many fitness-tracking devices, Microsoft’s Band 2 (MSB2), is accurate and reliable in detecting changes in Heart Rate (HR) and R-R intervals, during the repeated trial of two conditions of a working-memory test known as the N-Back. A 2 (devices: ECG, MSB2) × 4 (epochs: baseline 1, 1-back task, baseline 2, 3-back task) repeated measures factorial design was conducted. The participants were simultaneously equipped to the MSB2 and an electrocardiogram (ECG). The results of this study validated the MSB2 for the use in a cognitive task. The study suggests that fitness-tracking devices with similar sampling rates and features are candidates for further exploration as alternatives to ECG, in hope of making the inclusion of physiological data in psychological research more available and accessible. .

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Type 1 diabetes (T1D) is a chronic disease that is due to the dysregulation of glucose in the blood when insulin is not made endogenously. Patients rely on a combination of exogenic insulin, medications, blood glucose monitoring, and healthy lifestyle activities such as dietary control and exercise to manage their blood glucose levels. T1D typically begins its onset during childhood or adolescence, where it may also affect the development of executive function (EF) processes which are also relevant for self-regulation, or goal-directed behavior. This in turn may affect individuals’ adherence to their T1D management regimens, which can result in severe short- and long-term complications. Despite evidence for the plasticity of EF during childhood, previous research has not frequently focused on EF or self-regulation (SR) as a possible mechanism for improving health outcomes in adolescents with T1D. This study focused on the dosage of EF training and its possible effects on both cognitive and health outcomes for 47 adolescents (M= 15.4, SD =1.45) with T1D undergoing a larger adherence intervention. EF was measured by the Digit Span and Go/No-Go tests, while composite measures of T1D treatment adherence were aggregated via separate parent and adolescent reports. It was hypothesized that both cognitive measures and treatment adherence would have a dose-dependent relationship with n-back training. However, no association was found between training dosage and EF outcomes or treatment adherence. The study’s limitations include a relatively small sample size along with low participant compliance for the EF training. It also might be that the relationship between EF, SR, and health behaviors is more nuanced than previously suggested and that there are a variety of reasons why dosage of training was not linked to differential outcomes. As such, further investigation is required to better understand this relationship in the search for effective interventions for health behavior. / M.S. / Adolescents with Type 1 Diabetes often demonstrate difficulty following their diabetes management plans. One potential reason for these challenges may be that their self-regulation (the ability to intentionally direct their behavior towards a goal) is still developing. This study examined whether there was a dose-response relationship between a cognitive intervention aimed at increasing cognition/self-regulation as well as adherence to diabetes management regimens. The sample included 47 adolescents whose mean age was 15 years. Overall, no effect of dosage of cognitive training was observed on the adolescents' cognitive performance or diabetes management adherence. Reasons for this finding include the study's small sample size, low participation in the cognitive training, or a more nuanced relationship between self-regulation and health behavior.

Nearly all functional magnetic resonance imaging (fMRI) studies are conducted in the supine body posture, which has been discussed as a potential confounder of such examinations. The literature suggests that cognitive functions, such as problem solving or perception, differ between supine and upright postures. However, the effect of posture on many cognitive functions is still unknown. Therefore, the aim of the present study was to investigate the effects of body posture (supine vs. sitting) on one of the most frequently used paradigms in the cognitive sciences: the N-back working memory paradigm. Twenty-two subjects were investigated in a randomized within-subject design. Subjects performed the N-back task on two consecutive days in either the supine or the upright posture. Subjective sleep quality and chronic stress were recorded as covariates. Furthermore, changes in mood dimensions and heart rate variability (HRV) were assessed during the experiment. Results indicate that the quality of sleep strongly affects reaction times when subjects performed a working memory task in a supine posture. These effects, however, could not be observed in the sitting position. The findings can be explained by HRV parameters that indicated differences in autonomic regulation in the upright vs. the supine posture. The finding is of particular relevance for fMRI group comparisons when group differences in sleep quality cannot be ruled out.

Nearly all functional magnetic resonance imaging (fMRI) studies are conducted in the supine body posture, which has been discussed as a potential confounder of such examinations. The literature suggests that cognitive functions, such as problem solving or perception, differ between supine and upright postures. However, the effect of posture on many cognitive functions is still unknown. Therefore, the aim of the present study was to investigate the effects of body posture (supine vs. sitting) on one of the most frequently used paradigms in the cognitive sciences: the N-back working memory paradigm. Twenty-two subjects were investigated in a randomized within-subject design. Subjects performed the N-back task on two consecutive days in either the supine or the upright posture. Subjective sleep quality and chronic stress were recorded as covariates. Furthermore, changes in mood dimensions and heart rate variability (HRV) were assessed during the experiment. Results indicate that the quality of sleep strongly affects reaction times when subjects performed a working memory task in a supine posture. These effects, however, could not be observed in the sitting position. The findings can be explained by HRV parameters that indicated differences in autonomic regulation in the upright vs. the supine posture. The finding is of particular relevance for fMRI group comparisons when group differences in sleep quality cannot be ruled out.

Les Troubles Obsessionnels Compulsifs (TOC) sont composés de compulsions, qui sont des comportements répétés, et d'obsessions, qui sont des pensées intrusives. Leurs impacts sur le fonctionnement socio-professionnel handicapent et isolent considérablement les patients. Les traitements efficaces pour ces patients sont médicamenteux ou les thérapies cognitives et comportementales. Néanmoins, un nombre élevé de patients ne voient pas leurs symptômes diminuer suffisamment avec l'un ou l'autre des traitements ou en les combinant. Il est donc nécessaire de développer des traitements intermédiaires afin d'améliorer la palette de traitements des TOC. Une alternative thérapeutique utilisée en psychiatrie pour la dépression est la Stimulation Magnétique Transcrânienne répétée (TMS). Néanmoins, son efficacité reste difficile à démontrer dans le TOC, dû à une multitude de facteurs à prendre en compte, et peut nécessiter d'étudier le fonctionnement de la rTMS sur une population de sujets sains. Lors de notre première étude, nous avons évalué l'impact d'un protocole de rTMS sur les fonctions cognitives de sujets sains. Nous avons donc pu observer, indépendamment de la pathologie, l'effet de deux semaines de TMS sur les performances cognitives et sur l'activité cérébrale. Malgré une absence d'effet comportemental, une modification du réseau cortico-sous-cortical lié à une tâche de mémoire de travail a pu être montrée. Ces résultats orientent les recherches futures à modifier l'approche méthodologique, améliorer l'approche clinique des TOC, et changer l'approche neurophysiologique de la TMS dans le but de proposer un traitement complémentaire pour améliorer l'état clinique des patients. / Obsessive Compulsive Disorder (OCD) is a mental illness defined by the presence of compulsions which are repetitive behaviors and obsessions which are intrusive thoughts. OCD may have a dramatic impact on the social and professional lifes of patients. The treatments for OCD are medication and cognitive-behavioral therapy. Nevertheless, symptoms remain in 25 to 40% of patients. Repeated Transcranial Magnetic Stimulation (rTMS) represent a novel therapeutic option for OCD patients however its effectiveness has been difficult to prove partly due to a multitude of factors involving the rTMS technique itself. The first study evaluated the impact of a two-week rTMS protocol on cognitive functions in healthy subjects using fMRI during a working-memory task. In the absence of behavioral modification, we observed that compared to sham, rTMS induced changes at multiple nodes of the cerebral network activated by the task beyond the stimulation site. This result represents an encouraging perspective for rTMS intervention on pathological brain network in OCD because hyperactive regions in this disorder (orbitofrontal cortex and anterior cingulate cortex) are too deep to be directly stimulated by rTMS. Our second study targeted the supplementary motor area (SMA), which had been suggested as candidate target region lying near the anterior cingulate cortex. We used for four week rTMS in a group of OCD patients while pre- and post-treatment fMRI was acquired during performance of a cognitive inhibition task. Stimulation of the SMA did not result in significant clinical improvement. These results shall guide future research to address the methodological challenges and the neurophysiological mechanisms of rTMS to improve its clinical efficacy for OCD.