The idea that perception is a direct reflection of the outer world has been challenged by the notion that information is integrated at all levels of processing, including perceptual levels. Affect... Show moreThe idea that perception is a direct reflection of the outer world has been challenged by the notion that information is integrated at all levels of processing, including perceptual levels. Affect has been suggested to be a powerful source of information. This thesis explored affective influences on auditory perception and processing and what such influences may imply about penetrability of perception. The presented studies found that listeners in a sad mood more frequently judged ambiguous pitch changes as going downwards than in a happy mood. Furthermore, auditory sensitivity in noise was related to the affective reactivity of the listener, but its relation with mood remained inconclusive and should be further explored. Finally, this thesis demonstrated that evaluative conditioning changed affective quality of sounds without changing low-level stimulus features, which future studies into auditory processing of affective sounds can utilize. Together the findings suggest that aspects of auditory perception are subject to affective influence. This is consistent with the notion that perceptual and non-perceptual information is integrated, allowing listeners to form percepts from often noisy, incomplete, or ambiguous auditory input. The findings provide a basis and stimulation to further investigate where in the brain and through which mechanisms this integration occurs. Show less
Adaptive behavioral control involves a balance between top-down persistence and flexible updating of goals under changing demands. According to the metacontrol state model (MSM), this balance... Show moreAdaptive behavioral control involves a balance between top-down persistence and flexible updating of goals under changing demands. According to the metacontrol state model (MSM), this balance emerges from the interaction between the frontal and the striatal dopaminergic system. The attentional blink (AB) task has been argued to tap into the interaction between persistence and flexibility, as it reflects overpersistence—the too-exclusive allocation of attentional resources to the processing of the first of two consecutive targets. Notably, previous studies are inconclusive about the association between the AB and noninvasive proxies of dopamine including the spontaneous eye blink rate (sEBR), which allegedly assesses striatal dopamine levels. We aimed to substantiate and extend previous attempts to predict individual sizes of the AB in two separate experiments with larger sample sizes (N = 71 & N = 65) by means of noninvasive behavioral and physiological proxies of dopamine (DA), such as sEBR and mood measures, which are likely to reflect striatal dopamine levels, and color discrimination, which has been argued to tap into the frontal dopamine levels. Our findings did not confirm the prediction that AB size covaries with sEBR, mood, or color discrimination. The implications of this inconsistency with previous observations are discussed. Show less
Individuals suffering from depression often have difficulty trusting others. Previous research has shown a relationship between trust formation and pupil mimicry - the synchronization of pupil... Show moreIndividuals suffering from depression often have difficulty trusting others. Previous research has shown a relationship between trust formation and pupil mimicry - the synchronization of pupil sizes between individuals. The current study therefore examined whether pupil mimicry is weaker in depressed individuals and an underlying factor of their low levels of trust. Forty-two patients with major depressive disorder (MDD) and 40 healthy control subjects played trust games with virtual partners. Images of these partners' eye regions were presented to participants before they had to make a monetary investment decision. Partners' pupils either dilated, constricted, or remained static over the course of 4-s interactions. During the task, participants' pupil sizes were recorded with eye-tracking equipment to assess mimicry. The results confirm that patients with MDD were somewhat less trusting than controls and used another's pupillary cues differently when deciding to trust. Specifically, whereas healthy controls trusted partners with dilating pupils more than partners with constricting pupils, patients with MDD particularly trusted partners whose pupils changed in size less, regardless of whether partners' pupils were dilating or constricting. This difference in investment behavior was unrelated to differences in pupil mimicry, which was equally apparent in both groups and fostered trust to the same extent. Whereas lower levels of trust observed in patients with MDD could not be explained by differences in pupil mimicry, our data show that pupil dilation mimicry might help people to trust. These findings provide further evidence for the important role of pupil size and pupil mimicry in interpersonal trust formation and shed light on the pathophysiology of clinically low trust in patients with MDD. Show less
To assess (feasibility) of adherence to treatment guidelines among outpatients with common mental disorders in a routine Dutch clinical outpatient setting for common mental disorders with clinical... Show moreTo assess (feasibility) of adherence to treatment guidelines among outpatients with common mental disorders in a routine Dutch clinical outpatient setting for common mental disorders with clinical treatment data. Also,we studied patient- and therapistfactors influencing guideline-adherence in clinical practice.We established certain characteristics that might hamper tretamnet according to guidelines and more research is needed to assess whether patient in clinical practice do benefit from guidelines. Show less
The studies described in this thesis aimed to investigate how affect and motivation impact cognitive control, in terms of both behavior and brain activation. Six out of the eight empirical studies... Show moreThe studies described in this thesis aimed to investigate how affect and motivation impact cognitive control, in terms of both behavior and brain activation. Six out of the eight empirical studies found support for indirect effects on cognitive control, as measured with sequential trial-to-trial adaptations in cognitive control tasks. Only two studies resulted in evidence for a direct modulation of cognitive control (Chapter 4 and 9). Indirect effects occurred on trial-to-trial adaptation in cognitive control tasks involving a random presentation of compatible and incompatible trials. We found that conflict adaptation, the transient improvement of behavioral control after incompatible in comparison to compatible trials, was subject to affective regulation. In particular, we found that after incompatible trials, positive emotional states reduced and negative emotional states increased adaptation. These effects occurred for both short-term (Chapters 2 and 3) and long-term affect manipulations (Chapters 5, 6, and 7). Motivation and task difficulty also interacted with conflict adaptation (Chapter 8). The neuroimaging studies described in Chapter 3 and 6 demonstrate the role of fronto-striatal interactions in this affective regulation of cognitive control. Taken together, this thesis demonstrates the role that positive and negative emotions play in the adaptation of behavior and mental effort. Show less
This thesis focuses on patients with Binge Eating Disorder. The thesis consists of three parts. In the first part the validity of the diagnosis of BED will be discussed. The results of two... Show moreThis thesis focuses on patients with Binge Eating Disorder. The thesis consists of three parts. In the first part the validity of the diagnosis of BED will be discussed. The results of two literature reviews and an empirical cross-sectional study suggested that BED is a distinct eating disorder and should be added to a next version of the DSM. In the second part results of a randomized controlled trial were described. The effectiveness of cognitive behavioural therapy was compared to a waiting list control group. As expected, objective binge eating frequency, eating disordered psychopathology, and comorbid psychopathology decreased significantly in the CBT group whereas no reduction was found in the control (WLC) group. Mediator analyses indicated that abstinence from binge eating at post treatment was fully mediated by changes in weight concerns and marginally by changes in concerns about shape and eating, depressive symptoms, and more general psychopathological symptoms. In the third and last part the results of two experimental studies were presented. The purpose of the studies was to investigate the causal relationship between negative mood and binge eating. Both experimental studies found evidence for the fact that in individuals with BED depressive symptoms and caloric intake are positively related. Show less
In Chapter 2, results of a study are reported in which remitted depressed patients are compared to healthy controls to investigate possible residual cognitive impairments that persist into the... Show moreIn Chapter 2, results of a study are reported in which remitted depressed patients are compared to healthy controls to investigate possible residual cognitive impairments that persist into the euthymic phase. Chapter 3 will describe the effects of an alpha-lactalbumin enriched diet on cognitive performance in unmedicated recovered depressed patients and healthy controls. In Chapter 4 the effects of alpha-lactalbumin on mood and stress-induced cortisol response in unmedicated recovered depressed patients and healthy controls are reported. Chapter 5 describes the effects of low-dose and high-dose ATD on mood and neutral as well as emotional information processing in medicated remitted depressed patients. In Chapter 6, the effects of low-dose and high-dose tryptophan depletion on individual plasma tryptophan levels and the ratio tryptophan/LNAA will be discussed. In Chapter 7 the effects of ATD on heart rate variability in medicated remitted depressed patients are reported. A literature overview of studies investigating the effects of serotonin manipulations on emotional information processing and mood is given in Chapter 8. Also, evidence for a possible sequential link between serotonin induced changes in emotional information processing and mood is evaluated. Chapter 9 contains a summary and integration of the main findings, as well as methodological strengths and limitations, directions for future research and clinical implications of the findings reported in this thesis Show less
