All posts filed under: Papers

Myelin-related growth during adolescence related to compulsivity and impulsivity traits

In a recent paper that we recently published in Nature Neuroscience, we present data from a longitudinal cohort study (the NSPN project). We repeatedly acquired MRI scans from over 300 adolescents and followed them over time. Using a specific marked (magentization transfer saturation) that indexes myelination (the insulation of brain connections), we show that adolescence undergoes fundamental reorganisation during adolescence. A wide-spread myelin-related growth is thereby present in both white and gray matter. Looking at traits of impulsivity and compulsivity, we then show that scoring high on these dimensions is related to a reduced growth in prefrontal brain areas. Our study thus links adolescent brain development to prychiatric traits during a periode when many mental health problems emerge. More information can be found here: Ziegler G*, Hauser TU*, Moutoussis M, Bullmore ET, Goodyer IM, Fonagy P, Jones PB, NSPN Consortium, Lindenberger U & Dolan RJ (2019). Compulsivity and impulsivity are linked to distinct developmental trajectories of fronto-striatal myelinatioCompulsivity and impulsivity traits linked to attenuated developmental frontostriatal myelination trajectoriesn. Nature Neuroscience

Papers on exploration and model-free behaviour

I had the pleasure to co-author two papers that provide substantial new insight nto the mechanisms underlying cognition. In a recent paper by Nitzan Shahar, he assesses the reliability of the famous ‘two-step task’ and describes how to improve the reliability of this test. This is critical if we want to adequately capture the functioning of multiple reasoning-systems in health and disorder. In a second paper by Philipp Schwartenbeck, he uses computational modelling to describe to forms of goal-directed exploration. While one of them is to learn environmental contingencies, the other form helps determine in which state an agent is. These forms of goal-directed exploration thus serve different functions and are believed to be important contributors to decision making. Schwartenbeck P, Passecker J, Hauser TU, FitzGerald THB, Kronbichler M & Friston K (2019). Computational mechanisms of curiosity and goal-directed exploration. eLife doi:10.1101/589713 Shahar N, Hauser TU, Moutoussis M, Moran R, Keramati M, NSPN Consortium & Dolan RJ (2019). Improving the reliability of model-based decision-making estimates in the two-stage decision task with reaction-times and drift-diffusion modeling. …

Propranolol modulates Information Gathering

In a recent paper that we have just published in Journal of Neuroscience, we show that Information Gathering can be modulated using the noradrenergic Beta-Receptorblocker Propranolol. Upon a single dose propranolol, we found a reduction in information gathering. Computational modelling revealed that this is due to an earlier rise of an internal urgency signal, which promotes timely decisions. This could be interesting in the context of OCD, because we found a delay in this urgency signal in patients with OCD. Hauser TU, Moutoussis M, Purg N, Dayan P* & Dolan RJ* (2018). Beta-blocker propranolol modulates decision urgency during sequential information gathering. J Neurosci 38 (32) 7170-7178

Information Gathering in Compulsivity

We just published a new paper in Translational Psychiatry, where we investigate information gathering behaviour across a compulsivity spectrum. Crucially, we recruited subjects with high or low obsessive-compulsive symptoms, but which were matched for other psychiatric dimensions, such as depressive symptoms. We found that these subjects differed in the extent that they gathered information before making a decision. We thus expend our previous findings in which we show a similar difference in juvenile OCD patients. Our findings thus speak for an increased information gathering being a marker for a compulsive dimensions, which exceeds a mere clinical distinction. further reading: Hauser TU, Moutoussis M, Iannaccone R, Brem S, Walitza S, Drechsler R*, Dayan P* & Dolan RJ* (2017). Increased decision thresholds enhance information gathering performance in juvenile obsessive-compulsive disorder (OCD). PLoS Comput Biol 13(4): e1005440. Hauser TU, Moutoussis M, NSPN Consortium, Dayan P* & Dolan RJ* (2017). Increased decision thresholds trigger extended information gathering across the compulsivity spectrum. Nat Translat Psychiatry 7(12):1296