From Architecture to Evolution: Multisensory Evidence of Decentralized Emotion

Emotional appraisal in humans is often considered a centrally mediated process by which sensory signals, void of emotional meaning, are assessed by integrative brain structures steps removed from raw sensation. We review emerging evidence that the emotional value of the environment is coded by nonvisual sensory systems as early as the sensory receptors and that these signals inform the emotional state of an organism independent of sensory cortical processes. We further present evidence for cross-species conservation of sensory projections to central emotion-processing brain regions. Based on this, we argue not only that emotional appraisal is a decentralized process, but that all human emotional experience may reflect the sensory experience of our ancestors.