With a life-time prevalence of 25%, anxiety disorders are the most frequent psychiatric disorders and alone accounted for 147 billion Euros EU health care costs in 2004.The aim of this Marie Curie collaborative research project is to combine and share scientific expertise and shed more light on the dysfunctional neurocircuitry of anxiety disorders.Our current understanding has largely benefited from research on fear and fear learning. Indeed, it has been proposed that disturbed prefrontal cortex (PFC) functions as consequence upon a hyperresponsive amygdala (bottom-up) or/and a lack of PFC-amygdala top-down control are main reasons for affective disorders.In the present project we plan to further identify and disentangle underlying structures and temporal dynamics of both mechanisms using the integration of peripheral and central psychophysiological measures that allow for a millisecond resolution. Firstly, we will concentrate on the role of the PFC in early sensory processing of fear-relevant stimuli using an implicit fear learning paradigm. We propose that the PFC does not only play a part in late, but also in very early modulation of the neuronal fear response. Secondly, we will study how contingency awareness influences the strength of the CS-UCS association in fear conditioning. Using an explicit learning paradigm, both psychophysiological and neuronal correlates of fear learning will be investigated. At last, we will explore the biological basis of extinction learning and reappraisal, two approaches that play a major role in cognitive-behavioral therapy of anxiety disorders. We will study correlates of these processes in implicit and explicit learning tasks in order to study short- and long-term effects of therapeutic interventions.The basic hypothesis is that apart from an impaired top-down control also alterations in bottom-up affective regulation are important for the pathogenesis of anxiety disorders and a successful therapy thereof.