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Forschungsdatenbank PMU-SQQUID

Comparison between reverse shoulder arthroplasty and Humerusblock in three- and four-part proximal humerus fractures in elderly patients.
Ortmaier, R; Mattiassich, G; Pumberger, M; Hitzl, W; Moroder, P; Auffarth, A; Resch, H;
Int Orthop. 2015; 39(2):335-342
Originalarbeiten (Zeitschrift)


Auffarth Alexander
Hitzl Wolfgang
Mattiassich Georg
Moroder Philipp
Ortmaier Reinhold
Resch Herbert


Dopamine plays a key role in learning; however, its exact function in decision making and choice remains unclear. Recently, we proposed a generic model based on active (Bayesian) inference wherein dopamine encodes the precision of beliefs about optimal policies. Put simply, dopamine discharges reflect the confidence that a chosen policy will lead to desired outcomes. We designed a novel task to test this hypothesis, where subjects played a "limited offer" game in a functional magnetic resonance imaging experiment. Subjects had to decide how long to wait for a high offer before accepting a low offer, with the risk of losing everything if they waited too long. Bayesian model comparison showed that behavior strongly supported active inference, based on surprise minimization, over classical utility maximization schemes. Furthermore, midbrain activity, encompassing dopamine projection neurons, was accurately predicted by trial-by-trial variations in model-based estimates of precision. Our findings demonstrate that human subjects infer both optimal policies and the precision of those inferences, and thus support the notion that humans perform hierarchical probabilistic Bayesian inference. In other words, subjects have to infer both what they should do as well as how confident they are in their choices, where confidence may be encoded by dopaminergic firing. © The Author 2014. Published by Oxford University Press.

Find related publications in this database (Keywords)

Reverse shoulder arthroplasty
Proximal humeral fractures