Facial expression conveys complex and nuanced emotions. How facial expressions are produced and adapted, and how these processes change in mental disorders remains unknown, largely due to the complexity of the behavior in humans, and a lack of cellular-level understanding of the underlying neurobiology. In The Expression of the Emotions in Man and Animals, Darwin explored the connection of emotional states to organization of movements, and characterized the universal nature of facial expression and its anatomical and musculature origin, such as lifting of the eyebrow in surprise. Underlying the rich tapestry of facial expressions is a group of facial muscles, directly controlled by motor neurons in the facial nucleus in the brainstem. Many of the machineries of facial expression are highly conserved in mammals including rodents.
My lab studies how the brain orchestrates motor control in natural innate behaviors, specifically the neural mechanisms underlying the dynamic control of facial expression using rodents as a model. To solve this puzzle, we start by studying how complexity arises from ‘simple’ neural structures: evolutionarily conserved integration nodes in the brainstem where all information must funnel through to guide behavior.