Sensory Plasticity in Fathers

University Of California-Riverside, Riverside CA

Investigators

Abstract

In order for their infants to survive, mammalian parents, including humans, must engage in specific types of behavior toward infants, such as feeding, transporting, and protecting them. To do so, parents must respond appropriately to sensory cues from infants, such as odors and cries. Behavioral responses to these cues often differ between mothers and females without offspring, with mothers being more attracted to these cues and more likely to engage in caregiving behaviors. Mothers in some species also show changes in how the brain responds to infant-related sensory cues, so that mothers are better able to detect and identify these stimuli. However, almost nothing is known about how fathers’ brains respond to specific types of sensory information from infants. This research will evaluate whether fathers show different behavioral and brain responses to odors and cries from infants, compared to males without infants, and whether this difference is influenced by the hormone oxytocin, which plays a role in infant care and social bonding. The results will provide new information about how being a father affects males’ brains and changes how males respond to infants, which might ultimately improve understanding of interactions between human fathers and their children. These studies will provide training for graduate and undergraduate students, including students from underrepresented populations, and will be used as the basis for outreach activities in the local community and in schools for special-needs students. Mammalian parents must alter their behavior to meet the needs of their offspring. This behavioral plasticity is mediated by plasticity in neural processes influencing parents’ motivational, cognitive, and affective responses to offspring-related stimuli. Sensory processing, too, can undergo plastic changes in parents, enhancing their ability to detect and discriminate infant-related sensory cues. In mothers, changes in sensory function may be mediated by the pronounced hormonal shifts that occur during pregnancy and lactation; however, the mechanisms of parenthood-related sensory plasticity are only beginning to be understood. Coordinated plasticity in multiple parts of individual sensory pathways has received scant attention, for example, and little is known about how stimuli in different sensory modalities interact to determine neural and behavioral responses. Moreover, almost nothing is known about sensory plasticity in fathers. This research will use biparental California mice (Peromyscus californicus) to test the hypotheses that 1) fatherhood alters males’ behavioral and neural responses to stimuli from infants, 2) these effects are enhanced by simultaneous exposure to stimuli in multiple modalities, and 3) oxytocin plays a key role in mediating sensory plasticity in fathers.¬¬ Pup odors and vocalizations will be presented, both separately and simultaneously, to fathers and non-breeding males, and neural responses will be quantified using immunohistochemistry for the immediate-early gene product Fos in numerous brain regions as well as electrophysiological recordings in the auditory cortex. Oxytocin signaling will be manipulated pharmacologically to determine its role in fatherhood-induced sensory plasticity. Results will provide unique insights into plasticity of the paternal brain. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.