Primal emotional-affective expressive foundations of human facial expression

Emotional facial expressions provide important insights into various valenced feelings of humans. Recent cross-species neuroscientific advances offer insights into molecular foundations of mammalian affects and hence, by inference, the related emotional/affective facial expressions in humans. This is premised on deep homologies based on affective neuroscience studies of valenced primary emotional systems across species. Thus, emerging theoretical perspectives suggest that ancient cross-species emotional systems are intimately linked not only to emotional action patterns evident in all mammals, but also, by inference, distinct emotional facial expressions studied intensively in humans. Thus, the goal of the present theoretical work was to relate categories of human emotional facial expressions—e.g. especially of anger fear, joy and sadness—to respective underlying primary cross-mammalian emotional circuits. This can potentially provide coherent theoretical frameworks for the eventual molecular study of emotional facial expressions in humans.