Search for: All records

The transition to motherhood in mammals is marked by changes in females’ perception of and responsiveness to sensory stimuli from infants. Our understanding of maternally induced sensory plasticity relies most heavily on studies in uniparental, promiscuous house mice and rats, which may not be representative of rodent species with different life histories. We exposed biparental, monogamous California mouse (Peromyscus californicus) mothers and ovariectomized virgin females to one of four acoustic and olfactory stimulus combinations (Control: clean cotton and white noise; Call: clean cotton and pup vocalizations; Odor: pup-scented cotton and white noise; Call + Odor: pup-scented cotton and pup vocalizations) and quantified females’ behavior and Fos expression in select brain regions. Behavior did not differ between mothers and ovariectomized virgins. Among mothers, however, those exposed to the Control condition took the longest to sniff the odor stimulus, and mothers exposed to the Odor condition were quicker to sniff the odor ball compared to those in the Call condition. Behavior did not differ among ovariectomized virgins exposed to the different conditions. Fos expression differed across conditions only in the anterior hypothalamic nucleus (AHN), which responds to aversive stimuli: among mothers, the Control condition elicited the highest AHN Fos and Call + Odor elicited the lowest. Among ovariectomized virgin fe- males, Call elicited the lowest Fos in the AHN. Thus, reproductive status in California mice alters females’ behavioral responses to stimuli from pups, especially odors, and results in the inhibition of defense circuitry in response to pup stimuli. 

An animal's umwelt, comprising its perception of the sensory environment, which is inherently subjective, can change across the lifespan in accordance with major life events. In mammals, the onset of motherhood, in particular, is associated with a neural and sensory plasticity that alters a mother's detection and use of sensory information such as infant-related sensory stimuli. Although the literature surrounding mammalian mothers is well established, very few studies have addressed the effects of parenthood on sensory plasticity in mammalian fathers. In this review, we summarize the major find- ings on the effects of parenthood on behavioural and neural responses to sensory stim- uli from pups in rodent mothers, with a focus on the olfactory, auditory, and somatosensory systems, as well as multisensory integration. We also review the avail- able literature on sensory plasticity in rodent fathers. Finally, we discuss the importance of sensory plasticity for effective parental care, hormonal modulation of plasticity, and an exploration of temporal, ecological, and life-history considerations of sensory plastic- ity associated with parenthood. The changes in processing and/or perception of sensory stimuli associated with the onset of parental care may have both transient and long- lasting effects on parental behaviour and cognition in both mothers and fathers; as such, several promising areas of study, such as on the molecular/genetic, neurochemical, and experiential underpinnings of parenthood-related sensory plasticity, as well as determi- nants of interspecific variation, remain potential avenues for further exploration.