Kristina Smiley
Parental care is essential for offspring survival and requires coordinated interactions between neural and hormonal systems to support the onset and maintenance of caregiving behavior. My research investigates how prolactin, a hormone best known for its role in lactation, promotes parental behavior across species. I will present evidence showing that prolactin is necessary for the onset of parenting in both male and female songbirds and that prolactin receptors are widely expressed throughout brain regions involved in parental care. In mammals, I further demonstrate that a specific population of prolactin-responsive neurons in the medial preoptic area (MPOA) of the hypothalamus is critical for paternal behavior in male mice, revealing a conserved role for prolactin in parenting across vertebrates. In addition to hormonal changes, sensory cues from dependent offspring are also crucial for eliciting parental behavior, yet how these cues are encoded in the brain—and how hormones may shape their perception—remains poorly understood. My current work examines neural responses to offspring auditory cues in biparental songbirds and shows that parents exhibit enhanced and increasingly selective responses to begging calls, particularly in females. Finally, I will outline future directions of my research program aimed at understanding how parental hormones shape sensory processing, how offspring cues influence hormonal state, and how these bidirectional interactions are implemented within parenting-related neural circuits.
Dr. Smiley is a new Assistant Professor in the Department of Psychology at the University of Michigan and an affiliate member of the Michigan Neuroscience Institute as of January 2025. Her research lies at the intersection of behavioral neuroendocrinology and sensory neuroscience, with a central focus on the neural mechanisms underlying parental behavior.
During her PhD at Cornell University, Dr. Smiley investigated the role of prolactin—a hormone best known for its function in mammalian lactation—in the onset of parenting behavior in male and female songbirds. Her work revealed that prolactin serves a more evolutionarily conserved role in promoting offspring-directed behavior across sexes, extending beyond its traditional association with maternal physiology.
For her postdoctoral training, Dr. Smiley moved to the University of Otago in New Zealand, where she examined how prolactin regulates paternal care in mammals. There, she identified the medial preoptic area of the hypothalamus as a critical brain region through which prolactin promotes male parental behavior in rodents, providing the first causal evidence for prolactin’s role in mammalian fatherhood. She then returned to the United States for a second postdoctoral position at UMass Amherst, where she shifted focus to how parents use sensory cues—such as offspring vocalizations—to guide caregiving behavior. Using a songbird model, she discovered that auditory processing regions of the brain differ markedly between parents and non-parents in their responses to offspring vocal signals.
In her new research program at the University of Michigan, Dr. Smiley integrates these lines of work to investigate how the hormonal changes accompanying parenthood reshape auditory neural processing to support adaptive caregiving. Her lab aims to uncover how sensory cortical plasticity influences broader parenting circuits and, ultimately, parental behavior. Because individuals with postpartum depression show both altered neuroendocrine profiles and reduced neural responses to infant cues, Dr. Smiley’s work also has important implications for understanding the healthy parental brain and identifying potential targets for treating mental health disorders unique to parents.