Project Summary Emotional dysfunction is at the core of many psychiatric disorders, in particular fear, anxiety, post-traumatic, and mood disorders. Describing the neural mechanisms associated with emotional processing is therefore a critical issue in mental health care. Previous attempts to define the neurophysiology of human emotions in the cognitive neuroscience laboratory have been hampered by the unavailability of conceptual and methodological frameworks for studying complex emotional responses in context and with conflicting information present. The proposed research establishes a novel technique for combining electrophysiological recordings, high in temporal precision, with functional brain imaging, which is high in spatial precision. This approach, called steady-state potential frequency-tagging, achieves stimulus specificity, temporal, and spatial resolution across the whole brain. It is unique in that it allows researchers to identify distinct brain networks selectively activated by different elements of a complex visual scene—even when the elements are spatially overlapping and accompanied by stimulation in other sensory modalities. We combine this innovative approach with a novel conceptual framework that considers changes in visual perception an active part of an observer’s emotional response, to address the following Aims: (1) We characterize the large-scale brain dynamics mediating the emotional response to an element that is embedded in a complex visual array. (2) We determine how conflicting appetitive and aversive information, visual and auditory, affects these brain dynamics. (3) Finally, we translate this novel method to socially anxious observers, testing mechanistic hypotheses regarding the interactive effects of trait anxiety and chronic stress on short-term reactivity to emotional challenge. The long-term clinical implications of the proposed research are manifold: For diagnostic assessment and for monitoring treatment efficacy, a quantitative brain-based marker of emotional engagement opens avenues for objectively evaluating pre- to post-treatment changes in appetitive/aversive neural reactivity. It also enables measuring neural circuit function to enable quantitative measurements of specific psychopathology and for identifying treatment targets in a personalized medicine framework.