"Imagine what might be possible if you can turn fear on and off. In exploring the contribution of bodily arousal to emotions, we uncovered a specific mechanism whereby the brain’s processing of threatening / fear stimuli is ‘gated’ by the occurrence of heartbeats: Fear stimuli presented when the heart has just made a beat are processed more effectively than at other times, modulating their emotional impact. We term this effect the Cardiac Control of Fear in Brain (CCFIB). Specifically, I wish to refine, develop and exploit CCFIB as; 1) a clinical screening tool for drugs and patients; 2) as the basis of an intervention to accelerate unlearning of fear, e.g. for treatment of anxiety disorders; 3) as a means to optimise and enrich human-machine interactions, in anticipation of the rapid development of virtual or augmented reality (VR/AR) as a therapeutic tool, and to open possibilities for improving machine operation. This ground-breaking project will have impact in many areas, notably in the clinical management of anxiety disorders, which affect 69.1 million European Union citizens at an annual cost of €74.4 billion, and in the educational, recreational and occupational realms of human-machine interaction. The proposal 1) will refine knowledge about the neurochemistry and stimulus-specificity of CCFIB for implementation as a clinical screening tool, using pharmacological and neuroimaging methods. 2) Test in clinical anxiety patients the power of CCFIB to predict symptom profile and response to psychological and pharmacological treatment. 3) Optimize CCFIB to augment psychological and behavioural treatments and validate this in phobic individuals. 4) Instantiate CCFIB in VR/AR settings to enhance engagement with virtual environments, develop VR/AR as a ‘training platform’ in clinical and recreational contexts and to demonstrate how reactions to rapid threats fluctuate with cardiac cycle, motivating corresponding changes in sensitivity of user interfaces (e.g. brakes)."