Semester of Graduation

Summer 2023


Master of Arts (MA)



Document Type



Second-generation antipsychotics (SGAs), such as risperidone, are widely prescribed to children, but the long-term effects of SGA treatment are not well understood. This study investigated the impact of early-life risperidone treatment on sucrose demand in mice in adulthood. Mice were administered risperidone or vehicle from postnatal day (PND) 33 to 60 and trained in adulthood (>PND 120) to nose poke for a sucrose solution reinforcer. The fixed ratio (FR) value (the number of responses required to produce sucrose delivery; the “price” of sucrose) was varied from 1 to 45, and the resulting consumption versus FR value data were analyzed using a mathematical model of demand. This model includes two key parameters, Q0 and α, which represent estimated consumption at zero price and the rate of decline in consumption, respectively. Once training was complete and demand curves for 5% sucrose were obtained, the sucrose concentration was varied (1%, 15%, 5% replication, & 0%) and demand curves were obtained at each concentration. The study had two primary objectives: first, to determine whether mice treated with risperidone during early life exhibited differences in sucrose demand compared to control mice, and second, to evaluate whether the theory proposed by Hursh and Silberberg (2008), which suggests that α measures the essential value of a reinforcer regardless of its scalar value, is supported. We found minimal behavioral differences between groups in that one of the five conditions were better represented by a model that varied between groups. Our findings did not support Hursh and Silberberg’s (2008) theory; in both groups the data was best represented by a model that allowed α to vary between concentrations, while Hursh and Silberberg (2008) would have predicted a consistent α across concentration.



Committee Chair

Soto, Paul



Available for download on Wednesday, May 08, 2024