Brain mechanisms of self-control: A neurocognitive investigation of reward-based action control and error awareness

Motivation and the ability to detect errors are critical for the interaction with our environment. They provide us with the opportunity to engage in purposive, persistent and corrective behavior, and to take the consequences of our actions into account. Diminished motivation and error awareness have been linked to decreased goal directed behavior and reduced insight in certain types of brain injury and particular psychiatric syndromes. How the brain processes motivation and awareness is still largely unknown. This dissertation used behavioral and neuroimaging methods to examine how cognitive control is shaped by what we expect (motivational incentive) and what we are aware of (insight in our actions). The findings emphasize, that the positive impact of motivational incentive on cognitive control appears intact with advancing age and in Parkinson’s disease. Individual differences in white matter pathways between cortex and striatum translated into individual differences in the efficacy which with older adults improved their behavior by motivational incentive. The findings on error awareness suggest that local fluctuations in brain activation during awareness are interacting globally with distant brain areas, and that these fluctuations and interactions are related to physiological arousal, indexed by pupil dilation. The value of the current approach lies in the fact that it provides a framework to embed the local activity of brain structures into larger functional systems, and that it sheds light on factors that help to improve decline in cognitive control among healthy older adults and in older adults with Parkinson’s disease

Short-term and long-term effects of United Nations peace operations

Earlier studies have shown that United Nations peace operations make a positive contribution to peacebuilding efforts after civil wars. But do these effects carry over to the period after the peacekeepers leave? And how do the effects of UN peace operations interact with other determinants of peacebuilding in the long run? The author addresses these questions using a revised version of the Doyle and Sambanis dataset and applying different estimation methods to estimate the short-term and long-term effects of UN peace missions. He finds that UN missions have robust, positive effects on peacebuilding in the short term. UN missions can help parties implement peace agreements but the UN cannot fight wars, and UN operations contribute more to the quality of the peace where peace is based on participation, than to the longevity of the peace, where peace is simply the absence of war. The effects of UN missions are also felt in the long run, but they dissipate over time. What is missing in UN peacebuilding is a strategy to foster the self-sustaining economic growth that could connect increased participation with sustainable peace.Post Conflict Reintegration,Peace&Peacekeeping,International Affairs,Post Conflict Reconstruction,Politics and Government

Error blindness and motivational significance: Shifts in networks centering on anterior insula co-vary with error awareness and pupil dilation

This investigation aims to further our understanding of the brain mechanisms underlying the awareness of one's erroneous actions. While all errors are registered as such in the rostral cingulate zone, errors enter awareness only when the anterior insula cortex is activated. Aware but not unaware errors elicit autonomic nervous system reactivity. Our aim is to investigate the hypothesis that activation in the insula during error awareness is related to autonomic arousal and to inter-regional interactions with other areas of the brain. To examine the role of the anterior insula in error awareness, we assessed its functional connectivity to other brain regions along with autonomic nervous system reactivity in young healthy participants who underwent simultaneous pupil-diameter and functional magnetic resonance imaging measurements while performing a complex and error-prone task. Error blindness was associated with failures to engage sufficient autonomic reactivity. During aware errors increased pupil-diameter along with increased task-related activation within, and increased connectivity between anterior insula and task-related networks suggested an increased capacity for action-control information transfer. Increased pupil-diameter during aware errors was furthermore associated with decreased activation of the default-mode network along with decreased insular connectivity with regions of the default mode system, possibly reflecting decreased task-irrelevant information processing. This shifting mechanism may be relevant to a better understanding of how the brain and the autonomic nervous system interact to enable efficient adaptive behavior during cognitive challenge

How the aging brain translates motivational incentive into action: the role of individual differences in striato-cortical white matter pathways

ABSTRACTThe anticipation of reward enhances actions that lead to those rewards, but individuals differ in how effectively motivational incentives modulate their actions. Such individual differences are particularly prominent in aging. In order to account for such inter-individual variability among older adults, we approach the neurobiological mechanisms of motivated behavior from an individual differences perspective focusing on white matter pathways in the aging brain. Using analyses of probabilistic tractography seeded in the striatum, we report that the estimated strength of cortico-striatal and intra-striatal white matter pathways among older adults correlated with how effectively motivational incentives modulated their actions. Specifically, individual differences in the extent to which elderly participants utilized reward cues to prepare and perform more efficient antisaccades predicted structural connectivity of the striatum with cortical areas involved in reward anticipation and oculomotor control. These striatal connectivity profiles endow us with a network account for individual differences in motivated behavior among older adults. More generally, the data suggest that capturing individual differences may be crucial to better understand developmental trajectories in motivated behavior

Error awareness and salience processing in the oddball task: shared neural mechanisms

A body of work suggests similarities in the way we become aware of an error and process motivationally salient events. Yet, evidence for a shared neural mechanism has not been provided. A within subject investigation of the brain regions involved in error awareness and salience processing has not been reported. While the neural response to motivationally salient events is classically studied during target detection after longer target-to-target intervals in an oddball task and engages a widespread insula-thalamo-cortical brain network, error awareness has recently been linked to, most prominently, anterior insula cortex. Here we explore whether the anterior insula activation for error awareness is related to salience processing, by testing for activation overlap in subjects undergoing two different task settings. Using a within subjects design, we show activation overlap in six major brain areas during aware errors in an antisaccade task and during target detection after longer target-to-target intervals in an oddball task: anterior insula, anterior cingulate, supplementary motor area, thalamus, brainstem, and parietal lobe. Within subject analyses shows that the insula is engaged in both error awareness and the processing of salience, and that the anterior insula is more involved in both processes than the posterior insula. The results of a fine-grained spatial pattern overlap analysis between active clusters in the same subjects indicates that even if the anterior insula is activated for both error awareness and salience processing, the two types of processes might tend to activate non-identical neural ensembles on a finer-grained spatial level. Together, these outcomes suggest a similar functional phenomenon in the two different task settings. Error awareness and salience processing share a functional anatomy, with a tendency toward subregional dorsal and ventral specialization within the anterior insula