UC Berkeley

Experiences, both in early life and adulthood, can profoundly modify brain and behavior in mammals. In the Long-Evans rat, two salient components of early life experiences are i) the quality of maternal care received and ii) environmental housing parameters/conditions, both of which are capable of modifying numerous components of the developing CNS, including stress or hypothalamic pituitary adrenal axis (HPA) functioning. The following studies address modifications to both brain and behavior (i.e. stress physiology and behavior, executive function, and reproduction) in Long-Evans rat offspring due to variation in the aforementioned parameters. Understanding how basic environmental variables are capable of influencing brain and behavior is important not just in the study of basic neurobiology but also for the exploration of potential sources of psychopathology. Section 2 of this dissertation provides a review of HPA axis regulation, while Sections 3 and 4 discuss relevant primate and rodent models of early life stress axis calibration. Section 6 addresses how early life maternal care is capable of differentially programing sexual behavior and the underlying hypothalamic pituitary gonadal axis (HPG). Section 7 focuses on early life maternal care and developmental programming of stress physiology and executive function. Finally, Section 8 investigates the role of housing parameters, specifically the role of animal bedding, in regulating stress sensitive behaviors. All the studies demonstrate the powerful effect of early life experience and developmental programming of brain and behavior in the rodent.