An identical sensory stimulus may or may not be incorporated into perceptual experience, depending on the behavioral and cognitive state of the organism. What determines whether a sensory stimulus will be perceived? While different behavioral and cognitive states may share a similar profile of electrophysiology, metabolism, and early sensory responses, neuromodulation is often different and therefore may constitute a key mechanism enabling perceptual awareness. Specifically, noradrenaline improves sensory responses, correlates with orienting toward behaviorally relevant stimuli, and is markedly reduced during sleep, while experience is largely "disconnected" from external events. Despite correlative evidence hinting at a relationship between noradrenaline and perception, causal evidence remains absent. Here, we pharmacologically down- and upregulated noradrenaline signaling in healthy volunteers using clonidine and reboxetine in double-blind placebo-controlled experiments, testing the effects on perceptual abilities and visually evoked electroencephalography (EEG) and fMRI responses. We found that detection sensitivity, discrimination accuracy, and subjective visibility change in accordance with noradrenaline (NE) levels, whereas decision bias (criterion) is not affected. Similarly, noradrenaline increases the consistency of EEG visually evoked potentials, while lower noradrenaline levels delay response components around 200 ms. Furthermore, blood-oxygen-level-dependent (BOLD) fMRI activations in high-order visual cortex selectively vary along with noradrenaline signaling. Taken together, these results point to noradrenaline as a key factor causally linking visual awareness to external world events. VIDEO ABSTRACT.

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We have designed an immersive video experience providing participants with theexperience of an intimate encounter with themselves using immersive video. Seventy three participants (35 men, 38 women) ages 22-65 (M = 37.82, SD = 8.1) were randomly assigned to one of two conditions: meeting Self (n=38) and meeting Stranger (n=35), and the experience was carefully designed to increase self-compassion. The participants in the Self condition found the experience significantly more meaningful than those in the control condition (t(72)=-3.923, p<0.001) and reported higher active positive affect (t(72)=-2.353, p=0.021). However, our results indicate that the experience (interacting with self) negatively affected self-esteem, self-kindness and self-isolation (reverse coded) as compared to the control group (interacting with a stranger). Furthermore, the results indicate that older individuals may benefit more from the experience than younger individuals, and suggest that BMI is also an important moderating variable. Overall, our conclusion is that meeting yourself in VR can be a very powerful experience, but further studies are necessary in order to understand the contribution of experience design decisions and moderating variables,if this is intended as a positive experience.