Research master thesis | Psychology (research) (MSc)
closed access
Introduction: The default mode network (DMN) is a large intrinsic network in the brain, which seems to be affected in depressed patients. Also, aberrant heart rate variability (HRV) is often found...Show moreIntroduction: The default mode network (DMN) is a large intrinsic network in the brain, which seems to be affected in depressed patients. Also, aberrant heart rate variability (HRV) is often found in this population. Ketamine is thought to be a fast-acting antidepressant and has shown to have an effect on HRV and intrinsic brain connectivity. In this study, the effect of HRV on resting-state functional connectivity of the DMN and brain activity of areas within the DMN that were significantly correlated with HRV was examined. Also, it was investigated whether ketamine moderated this relationship. Method: Twelve healthy men received an intravenous ketamine or placebo infusion on two occasions. Resting-state functional connectivity and HRV were measured before, during, and after infusion. Dual-regression was used to obtain DMN connectivity scores, while a whole brain analysis was done to determine which brain areas were correlated with HRV. Raw digitized electrocardiogram (EKG), obtained with a pulse oximeter, was analyzed in order to extract HRV data. Multilevel analysis was used to determine the effect of HRV and ketamine on resting-state functional connectivity in the DMN and brain activity in the subgenual anterior cingulate cortex (sgACC), right dorsolateral prefrontal cortex (dlPFC), and the left postcentral gyrus. Results: DMN connectivity strength was negatively related to HRV, but positively related to activity of the right dlPFC and the left postcentral gyrus for the placebo condition. Ketamine was associated with a more profound effect of HRV on DMN connectivity and brain activity within the postcentral gyrus. Discussion: The present results complement recent studies that show that HRV is associated with connectivity strength in the DMN. Implications for the relevance of using ketamine in depressed patients are discussed. Initial increases of DMN connectivity are followed by a decrease in the DMN, which may be beneficial for depressed patients who generally show hyperconnectivity within the DMN. Results thus imply that ketamine has a moderating role in this.Show less
Research master thesis | Psychology (research) (MSc)
open access
In public areas, people often encounter situations of close proximity to others where it is likely that an individual’s personal space (PS) gets intruded. PS is the area surrounding an individual...Show moreIn public areas, people often encounter situations of close proximity to others where it is likely that an individual’s personal space (PS) gets intruded. PS is the area surrounding an individual that includes the intimate and personal domain (within 1.50 meters of a person). We aimed to investigate the role of PS in seating behavior and to extend previous research by distinguishing an immediate PS consideration (i.e., considering PS in the immediate situation) from an anticipated PS consideration (i.e., considering PS also in a possible future situation). We conducted an observational study (N = 237), an open-ended question study (N = 40), and an experimental online study using a mixed-design (N = 325) in the context of choosing a seat in a railway station concourse. The results revealed that most participants chose a seat outside their intimate and personal domain. We concluded that people try to safeguard their PS. Furthermore, immediate and anticipated PS considerations both play a role in seating behavior; however, both are merely facets of PS rather than two exclusive concepts. With our results, we hope to extend the theory of PS as well as inform and possibly influence the design of seating arrangements to optimize people’s well-being in public areas.Show less
Research master thesis | Psychology (research) (MSc)
closed access
Socially anxious individuals are known to avoid many forms of social interaction. Since understanding emotions is essential for smooth social interaction, alterations in emotion recognition were...Show moreSocially anxious individuals are known to avoid many forms of social interaction. Since understanding emotions is essential for smooth social interaction, alterations in emotion recognition were previously assumed as one potential reason for this avoidance. Furthermore, this altered emotion recognition might be mediated by altered facial mimicry. However, metacognitive perspectives became more popular in psychopathology and might also be related to confidence in emotions recognition. In this study, we aimed to differentiate between alterations in emotion recognition (behavioral model) and alterations in self-evaluation (metacognitive model) in high socially anxious individuals compared to low socially anxious individuals. Participants completed both a facial mimicry and emotion recognition task with the addition of a confidence rating to measure self-evaluation. We hypothesized that, according to the behavioral model, high socially anxious individuals show altered emotion recognition and facial mimicry performance. In contrast, according to our metacognitive model, there should be no differences in emotion recognition and facial mimicry performance between groups, but high socially anxious individuals should score lower on confidence. The current study found support for the metacognitive model, namely that social anxiety does not seem to affect the ability to recognize and mimic emotions accurately. However, high socially anxious individuals feel less confident about this ability than less socially anxious individuals. Thus, lowered confidence in socially anxious individuals might affect the fear for social situations and therefore play an important role in the avoidance of social interactions.Show less
Research master thesis | Psychology (research) (MSc)
closed access
Depression and social anxiety are among the most prevalent and co-occurring mental-health problems related to difficulties in social decision-making and aberrant responses to social reward and...Show moreDepression and social anxiety are among the most prevalent and co-occurring mental-health problems related to difficulties in social decision-making and aberrant responses to social reward and punishment. Processing social feedback and integrating information from negative and positive outcomes are important for adapting behaviors and cognitions accordingly. Thus, in order to better understand the mechanisms underlying affective problems such as depression and social anxiety, it is crucial to investigate how they relate to differences in social feedback processing and learning through social evaluative feedback. This study aimed to investigate whether depressive and social anxiety symptoms in healthy young adults were differentially associated with how individuals learned through positive and negative peer feedback and electrocortical responses to social feedback which would help elucidate the underlying mechanisms of the aforementioned affective problems. Nineteen participants (18-25 years old) took part in a novel social probabilistic learning task while concurrent EEG was being recorded. In this task, participants believed that they received acceptance and rejection feedback from actual peers. In reality, each of the four peers provided computerized feedback with assigned probabilities of 85%, 70%, 30%, and 15% acceptance. The participants showed positive expectancy and positive memory biases. Social anxiety symptoms predicted a lower positive memory bias. The participants learned the probabilities in the expected direction for each peer through trial-and-error over the course of the task. No differences in learning were observed in relation to depression and social anxiety. As expected, the time-frequency theta (4- 7 Hz) power was larger following unexpected rejection, particularly, in comparison to expected acceptance. However, delta power (1-4 Hz) was largest for both expected acceptance and unexpected rejection. There were no interactions between time-frequency responses and individual differences in depression and social anxiety. Our findings demonstrate that healthy young adults show positive expectancy and memory biases for social evaluative situations with peers which can be reduced by the level of social anxiety one experiences. These could be informative for professionals practicing in mental health such that they can target the way socially anxious individuals recall events in treatment. This study also shows that individuals use positive and negative social evaluative feedback to adapt their feedback expectations from others.Show less
Research master thesis | Psychology (research) (MSc)
closed access
Patients that suffer from posttraumatic stress disorder (PTSD) may respond less well to existing PTSD therapies if their PTSD was caused by childhood trauma. A relatively novel treatment, Narrative...Show morePatients that suffer from posttraumatic stress disorder (PTSD) may respond less well to existing PTSD therapies if their PTSD was caused by childhood trauma. A relatively novel treatment, Narrative Exposure Therapy (NET), has shown promising outcomes for refugee and veteran PTSD patients that suffered from multiple and continuous trauma, as is often the case for those with childhood trauma-related PTSD (CTR-PTSD). We aimed to investigate whether NET could be effective for the treatment of CTR-PTSD. Methods: We followed the treatment trajectories of nine adult CTR-PTSD patients in an outpatient setting. A non-concurrent multiple baseline design was used, with a baseline of 4 weeks before treatment started. Participants responded to weekly online questionnaires that assessed their PTSD symptoms (i.e., the Posttraumatic Diagnostic Scale; PDS) and their experienced quality of life (QOL; i.e. the Manchester Short Assessment of quality of life; MANSA). Data were analyzed using visual inspection and a mixed model analysis. Results: Results revealed no significant reduction of PTSD symptoms during NET treatment, nor an increase in QOL, as compared to baseline. Of the nine participants, one lost her PTSD diagnosis after treatment with NET. During the procedure, several participants dropped out due to medical, practical or unknown reasons. Conclusion: Results of this study indicate that NET is not effective for the treatment of CTR-PTSD, in contrast to previous literature.Show less
