Marieke G.N. Bos

Bio: Marieke G.N. Bos is an academic researcher from Leiden University. The author has contributed to research in topics: Memory consolidation & Extinction (psychology). The author has an hindex of 17, co-authored 33 publications receiving 724 citations. Previous affiliations of Marieke G.N. Bos include University of Amsterdam.

Emerging depression in adolescence coincides with accelerated frontal cortical thinning.

Abstract: Background Adolescence is a transition period characterized by heightened emotional reactivity, which for some sets the stage for emerging depressive symptoms. Prior studies suggest that adolescent depression is associated with deviant cortical and subcortical brain structure. Longitudinal studies are, however, currently scarce, but critical to detect which adolescents are at risk for developing depressive symptoms. Methods In this longitudinal study, a community sample of 205 participants underwent magnetic resonance imaging (MRI) in three biennial waves (522 scans) spanning 5 years across ages 8-25 years. Depressive symptomatology was assessed using self-report at the third time point. Mixed models were used to examine the relations between structural brain development, specifically regional change in cortical thickness, surface area and subcortical volumes (hippocampus and amygdala), and depressive symptoms. Results Accelerated frontal lobe cortical thinning was observed in adolescents who developed depressive symptoms at the third time point. This effect remained after controlling for parent-reported affective problems at the first time point. Moreover, the effect was driven by specific lateral orbitofrontal and precentral regions. In addition, differential developmental trajectories of parietal cortical thickness and surface area in several regions were found for participants reporting higher depressive symptomatology, but these results did not survive correction for multiple comparisons. Volumes or developmental volume changes in hippocampus or amygdala were not related to depressive symptoms. Conclusions This study showed that emerging depression is associated with cortical thinning in frontal regions within individuals. These findings move beyond detecting cross-sectional correlations and set the stage for early detection, which may inform future intervention.

Noradrenergic blockade of memory reconsolidation: a failure to reduce conditioned fear responding.

Abstract: Upon recall, a memory can enter a labile state in which it requires new protein synthesis to restabilize. This two-phased reconsolidation process raises the prospect to directly target excessive fear memory as opposed to the formation of inhibitory memory following extinction training. In our previous studies, we convincingly demonstrated that 40 mg propranolol HCl administration before or after memory reactivation eliminated the emotional expression of fear memory indexed by the fear-potentiated startle reflex. To apply this procedure in clinical practice it is important to understand the optimal and boundary conditions of this procedure. As part of a large project aimed at unraveling putative boundary conditions of disrupting reconsolidation of associative fear memory with propranolol HCl, we again tested our memory reconsolidation procedure. Participants (N = 44) underwent a three-day differential fear conditioning procedure. Twenty-four hours after fear acquisition, participants received 40 mg propranolol HCl prior to memory reactivation. The next day, participants were subjected to extinction training and reinstatement testing. In sharp contrast to our previous findings, propranolol HCl before memory reactivation did not attenuate the startle fear response. Remarkably, the startle fear response even persisted during extinction training and did not show the usually observed gradual decline in conditioned physiological responding (startle potentiation and skin conductance) upon repeated unreinforced trials. We discuss these unexpected findings and propose some potential explanations. It remains however unclear why we observed a resistance to reduce conditioned fear responding by either disrupting reconsolidation or extinction training. The present results underscore that the success of human fear conditioning research may depend on subtle manipulations and instructions.

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Applied Longitudinal Data Analysis Modeling Change And Event Occurrence

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An opportunity cost model of subjective effort and task performance.

Abstract: Why does performing certain tasks cause the aversive experience of mental effort and concomitant deterioration in task performance? One explanation posits a physical resource that is depleted over time. We propose an alternative explanation that centers on mental representations of the costs and benefits associated with task performance. Specifically, certain computational mechanisms, especially those associated with executive function, can be deployed for only a limited number of simultaneous tasks at any given moment. Consequently, the deployment of these computational mechanisms carries an opportunity cost-that is, the next-best use to which these systems might be put. We argue that the phenomenology of effort can be understood as the felt output of these cost/benefit computations. In turn, the subjective experience of effort motivates reduced deployment of these computational mechanisms in the service of the present task. These opportunity cost representations, then, together with other cost/benefit calculations, determine effort expended and, everything else equal, result in performance reductions. In making our case for this position, we review alternative explanations for both the phenomenology of effort associated with these tasks and for performance reductions over time. Likewise, we review the broad range of relevant empirical results from across sub-disciplines, especially psychology and neuroscience. We hope that our proposal will help to build links among the diverse fields that have been addressing similar questions from different perspectives, and we emphasize ways in which alternative models might be empirically distinguished.