Major depressive disorder (MDD) has been linked to aberrant functional connectivity in large scale neural networks, such as reduced salience network (SN) functional connectivity, as well as...Show moreMajor depressive disorder (MDD) has been linked to aberrant functional connectivity in large scale neural networks, such as reduced salience network (SN) functional connectivity, as well as decreased resting heart rate variability (HRV). It is unknown whether these features are present in depressed patients, as a consequence of MDD, or also present in healthy individuals at risk for depression, which would indicate their playing a broader role in the development of MDD. The current study aimed to investigate this in a healthy sample at risk for depression, using a cross-sectional, between-subject experimental design. To select a healthy sample at risk, individuals were screened for having a general tendency to ruminate. The intention was to include individuals with high scores on rumination’s facet of brooding, which is a pertinent risk factor for depression. Nevertheless, this screening was unsuccessful in selecting a sample at risk, since analyses revealed healthy levels of brooding. However, the present sample (N = 29) did display reduced HRV and elevated cognitive reactivity to sadness. Against prediction, no significant negative relationship was found between SN connectivity and brooding trait scores. As expected, SN connectivity was positively linked to HRV. Exploratory correlational analyses revealed connectivity within the right anterior insula to be positively linked to HRV. Given the healthy levels of brooding, no inferences can be made regarding this risk factor for depression development. Nonetheless, the results replicate the coupling of SN and HRV in a healthy sample, thereby providing further evidence of the SN’s role in autonomic modulation.Show less
Recent research has only shown little evidence for a relationship between patient characteristics and treatment outcome. It is proposed that patients with a higher need of Mental Health Care due to...Show moreRecent research has only shown little evidence for a relationship between patient characteristics and treatment outcome. It is proposed that patients with a higher need of Mental Health Care due to higher psychopathologic complexity receive more treatment compared to others to reach a comparatively good treatment result. The treatment dose in more complex patients might therefore be significantly higher than in less complex patients. According to that, treatment dose should mediate the relationship between complexity and outcome. Thereby, the main purpose of this study is the investigation of a proposed mediation effect by treatment dose, operationalized as treatment duration in minutes and treatment length in days. Clinical Complexity was based on the degree of psychopathological severity and treatment outcome was measured with the self-report questionnaire Outcome Questionnaire-45. This investigation is based on a sample of patients in ambulatory treatment, who suffer from anxiety disorders, originated from the GGZ institution Arkin, an MHC provider in the Netherlands. Finally, no mediation effect has been shown and no evidence for an existent triadic relationship between complexity, outcome and treatment dose has been found. Besides, treatment duration correlated positively with complexity. Patients with higher complexity also tend to have a less favorable treatment outcome compared with patients of lower complexity. The results of this study should be interpreted and dealt with caution due to potential threats to internal and external validity. In future research alternative complexity and treatment dose indicators need further investigation to assess the prognostic value of patient characteristics for treatment outcome.Show less
Research master thesis | Psychology (research) (MSc)
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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
Background: Emotion regulation is part of our everyday executive functioning. Mood disorders such as bipolar disorder or depression are associated with dysfunctional emotion regulation. A...Show moreBackground: Emotion regulation is part of our everyday executive functioning. Mood disorders such as bipolar disorder or depression are associated with dysfunctional emotion regulation. A physiological measure of emotion regulation is heart rate (HR). People tend to show HR decrease to emotional stimuli, this is called bradycardia. Frontal-Theta/Beta-ratio (TBR) has shown to be a potential biomarker for multiple executive functions. In most frontal-TBR studies, a reversed correlation between frontal-TBR and level of executive functioning is found. Objective: The current study investigated if frontal-TBR plays a moderating role for emotion regulation of negative and positive stimuli. It was expected that low frontal-TBR would correlate with less fear-bradycardia and that low frontal-TBR would lead to better regulation of negative and positive stimuli. Methods: An emotion regulation task was used to induce physiological responses in participants. Participants (n=56) viewed 40 negative, 40 neutral and 40 positive pictures and were asked to attend or upregulate their emotional affect. Their physiological response was measured using ECG. Frontal-TBR was measured using EEG. Results: Against the hypotheses, results showed no moderating role for frontal-TBR on physiological reaction to positive or negative stimuli. There was a weaker fear-bradycardia than expected and no positive-bradycardia was found. Discussion: The absence of strong bradycardia in our sample blocks possibilities for a moderating role of frontal-TBR on emotion regulation. The results can be due to factors such as data collection method, stimuli selection or male/female distribution. Future studies should focus on replicating the frontal-TBR effects on emotion regulation of negative stimuli.Show less
