Efeitos do Isolamento Social durante a Adolescência na Escolha por Taxas e Concentrações de Sacarose: Um Estudo a partir da Lei da Igualação Generalizada

Abstract

Adolescent social isolation has been associated with several behavioral changes, including increased stress response and vulnerability to drug addiction. Despite extensive preclinical research reporting changes in reward sensitivity in isolated subjects, the effects of isolation on seeking for natural reinforcers and choice behavior remain unclear. This study evaluated the impact of adolescent social isolation on sucrose consumption and choice, based on the generalized matching law. After weaning, rats were allocated to isolation (GI, n = 12) or social (GS, n = 12) groups. In adulthood, the following were assessed: (a) consumption of 10% sucrose in a two-bottle test with water as an alternative; (b) choice between different delivery rates of 10% sucrose in competing VI–VI schedules; and (c) choice between three sucrose concentrations (3%, 8%, and 15%) in two-bottle tests. Isolation increased consumption of 10% sucrose under limited access (2 h), but not under free access (24 h). Furthermore, in choice tests, parameters of reinforcement sensitivity and bias did not differ between groups, both in VI–VI concurrent schedules and in the choice between concentrations. These results extend, for concurrent choice, previous findings indicating no effects of isolation on operant behavior for sucrose in simple schedules. Differences restricted to the short test suggest that the effects of isolation may be transient and masked in long-term assessments.