Thesis (doctoral)--Universität, Giessen, 2001.

Rumination is a maladaptive coping style that has been found to be associated with several negative outcomes, including depression and anxiety. In particular, rumination has been found to be associated with deficits in inhibiting irrelevant information. This study examined the relationship of rumination to depression, anxiety, and stress and examined gender differences in these relationships. It also examined inhibitory deficits in rumination using a negative priming task with both short- and long-term components and evaluated the efficacy of a negative priming paradigm which utilised single presentations of stimuli that were not confounded by stimulus-response bindings. The results found that rumination was associated with higher levels of depression, anxiety, and stress, in line with the classification of rumination as maladaptive. It was also discovered that the predictors of rumination differed between males and females, with rumination being predicted by stress and depression for females and by anxiety for males, indicating possible gender differences in the explanation of rumination. The negative priming paradigm used in this study failed to produce any significant negative priming, and indeed produced significant positive priming meaning that no conclusions could be drawn from the data about inhibitory deficits and rumination. The results did however highlight the importance of the probe distractor in negative priming as it appears that a lack of competition between the probe distractor and the probe target may be a possible reason for the failure to observe negative priming.

　　Temporal preparation and impulsivity are sharing two common cognitive processes: time perception and response inhibition. Rhythmic synchronization can be regarded as a specific paradigm of temporal preparation. The major purpose of the present study is to examine the relationship between rhythmic synchronization and response inhibition. Results indicated a significant correlation between rhythmic synchronization and response inhibition. Number of years of formal music training was not significantly correlated with rhythmic synchronization. No relationship was found between response inhibition and general intelligence. Regression analysis revealed that number of commission errors was the best predictor for rhythmic synchronization, followed by reaction time of interference. Time perception is anticipatory in nature and should be better examined with a proactive stopping paradigm. Response style was not found to have a statistical significant role in the present study. Further research may further examine the clinical effectiveness of rhythmic synchronization on alleviating impulsivity via its effect on response inhibition. proactive stopping paradigm. Response style was not found to have a statistical significant role in the present study. Further research may further examine the clinical effectiveness of rhythmic synchronization on alleviating impulsivity via its effect on response inhibition. / published_or_final_version / Clinical Psychology / Doctoral / Doctor of Psychology

The focus of the thesis is the investigation of the causal nature of the established association between rumination and that ability to resolve interference from task-irrelevant information, and prepotent responses. Rumination is a term used to refer to both unhelpful dwelling on negative moods and depressive symptoms (e.g., Nolen-Hoeksema, 1991), and repetitive intrusive thoughts around the theme of unresolved personal goals (Martin & Tesser, 1996). It has been proposed that rumination occupies working memory resources, thereby depleting cognitive control capabilities necessary for the performance of concurrent effortful tasks (Hartlage, Alloy, Vasquez, & Dykman, 1993; Hertel, 2004; Watkins & Brown, 2002). This model constitutes one possible account of the considerable data demonstrating an association between depressive rumination and deficits on tasks invoking inhibitory processes (Joormann, Yoon, & Gotlib, 2007). An inhibition construct is invoked to account for the empirical observation of interference; however there are few instances where inhibition is unambiguously driving interference (MacLeod, 2007). Moreover, there is evidence that inhibition is not a unitary construct (Friedman & Miyake, 2004). Five experiments manipulated rumination on depressive symptoms and on personal goals in dysphoric and unselected samples in order to test Watkins and Brown’s (2002) hypothesis that state rumination impairs interference control capabilities. The causal impact of state rumination was examined on interference control tasks that implicate different inhibitory sub-types: resistance to proactive interference from positive and negative material (Studies One, Two, and Five), and prepotent response inhibition on a go/no-go paradigm (Studies Three and Four). No evidence was found to support the prediction that state rumination about depressed mood (Studies One and Two) or on-going personal goal discrepancies (Study Five) causes difficulties resolving interference from irrelevant emotional material relative to non-ruminative control conditions in both dysphoric (Studies One and Two) and unselected (Study Five) samples. No evidence was found to support the prediction that state rumination about personal goal discrepancies impairs prepotent response inhibition relative to non-ruminative control conditions (Studies Three and Four). There was some tentative evidence to suggest that ruminating on personal goal discrepancies increased efficiency in holding a single goal active in working memory without reinforcement (Study Four). The implications of these findings for existing models of the causal nature of the relationship between rumination and interference control processes is discussed (Chapter Nine). It is concluded that models proposing a causal impact of state rumination on available working memory capacity are insufficient to fully account for the established association between the trait tendency to ruminate and increased susceptibility to interference from irrelevant material.

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Neuronal activity and subsequent calcium influx activates a signaling cascade that causes transcription factors in the nucleus to rapidly induce an early-response program of gene expression. This early-response program is composed of transcriptional regulators that in turn induce transcription of late-response genes, which are enriched for regulators of synaptic development and plasticity that act locally at the synapse.

Drosophila is a simple and genetically tractable model system for studying neural circuits. This dissertation consists of two studies, with the broad goal of understanding sensory processing in neural circuits using Drosophila as a model system.

Recent conceptualizations of procrastination suggest that procrastination is akin to self-regulatory failure wherein the effect of good intentions is attenuated for individuals who tend to procrastinate. Some researchers speculate that this effect is due to subtle neurological deficits that make it more difficult for procrastinators to follow through with completing tasks. The present work examines this claim while also investigating two factors that should theoretically weaken the effect of intentions for engaging unpleasant, but important, tasks – namely habitual avoidance and the executive function of inhibition. Study 1 investigated the question of whether chronic avoidance patterns may become so entrenched that they take on the qualities of a habit. This is important because habits are known to be less reliant on intentions because they are triggered in a relatively automatic fashion. Habit indices were created which assessed the degree to which the experience of avoiding particular tasks was automatic and self-descriptive in nature (Verplanken & Orbell, 2003). The results confirmed the expectation that more frequent avoidance patterns are experienced as occurring relatively automatically. Habit-like avoidance can be measured reliably and is related to other constructs in expected ways. For example, habit-level predicts reduced task quality and lower rates of task completion above-and-beyond motivational variables (e.g. intentions). Finally, habit-like avoidance patterns were more often associated with stable features identified by participants as being present in the environment. Using a prospective design, Study 2 assessed the degree to which existing habitual-avoidance patterns weakened the effect of good intentions to carry out unpleasant tasks over the course of a week. Several computer tasks at Time 1 were also used to assess inhibitory control or the degree to which participants could inhibit prepotent responses. In addition to personality traits which purportedly moderate the intention-behaviour relation (e.g. trait procrastination), the moderating effects of habitual avoidance and inhibitory control were also tested. Trait-level procrastination did not weaken the effect of one’s intentions to carry out unpleasant tasks. However, habitual avoidance and inhibitory control jointly moderated the effect of intentions on behaviour such that poor inhibitors had difficulty overcoming previous avoidance habits in order to complete unpleasant tasks during the week. In contrast, good inhibitors were able to behave according to their intentions irrespective of habit-like avoidance patterns. These findings point to the importance of recognizing the joint influence of avoidance patterns and regulatory capacities involved in self-control when understanding procrastination behaviour.

Inhibition, an important cognitive skill relying on frontal lobe function, is often deficient in individuals with autism spectrum disorders (ASD). Spatiotemporal measures of brain activity were acquired using magnetoencephalography during a Go/No-go task with adolescents and adults with ASD and matched controls. During the task, participants responded to Go stimuli and withheld their response to No-go stimuli. Typical inhibitory network development was investigated in study 1. Adolescents displayed a distributed activity pattern, recruiting temporal and parietal regions, in addition to frontal areas, unlike adults. In study 2, inhibition was compared between individuals with and without ASD. Lateralization differences were found: adults with ASD activated the left and control adults recruited the right inferior prefrontal cortex. Adolescents with ASD recruited predominantly frontal regions, unlike their controls. Implications include immature inhibitory networks in typical adolescence and deficits in adolescents with ASD in recruiting distal cortical regions to supplement poor frontal lobe function.

Inhibition, an important cognitive skill relying on frontal lobe function, is often deficient in individuals with autism spectrum disorders (ASD). Spatiotemporal measures of brain activity were acquired using magnetoencephalography during a Go/No-go task with adolescents and adults with ASD and matched controls. During the task, participants responded to Go stimuli and withheld their response to No-go stimuli. Typical inhibitory network development was investigated in study 1. Adolescents displayed a distributed activity pattern, recruiting temporal and parietal regions, in addition to frontal areas, unlike adults. In study 2, inhibition was compared between individuals with and without ASD. Lateralization differences were found: adults with ASD activated the left and control adults recruited the right inferior prefrontal cortex. Adolescents with ASD recruited predominantly frontal regions, unlike their controls. Implications include immature inhibitory networks in typical adolescence and deficits in adolescents with ASD in recruiting distal cortical regions to supplement poor frontal lobe function.