Efeito da submissão ao chronic mild stress (CMS) sobre o valor reforçador do estímulo

• Autor(a) principal: Thomaz, Cássia Roberta da Cunha
• Data de Publicação: 2001
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da PUC_SP
• Texto Completo: https://tede2.pucsp.br/handle/handle/16811
• topic: Modelos animais; Modelos experimentais; Estresse; Depressão; Valor reforçador do estímulo; Esquemas concorrentes; Psicologia experimental; Animal model; Experimental model; Chronic mild stress; Depression; Reinforcing value; Concurrent schedules of reinforcement; CNPQ::CIENCIAS HUMANAS::PSICOLOGIA::PSICOLOGIA EXPERIMENTAL

Chronic Mild Stress (CMS) is an experimental model for depression: Rats are submitted to a set of stressing conditions and as a result their consumption of water and water with sucrose, as well as the animals previous preference for water and water and sucrose also drops. It is argued that the stress changes the organism and, consequently, changes the reinforcing properties of water and water with sucrose. Therefore the stress would make the subjects insensible to reward. The present study investigated if what has been called sensitivity to reward could be described as a drop in the reinforcing value of a reinforcer. In other words, one of this study's goals was to evaluate if a protocol of mild stress diminished the reinforcing value of a known reinforcer, here, water with sucrose. Four male rats were submitted to a stress protocol of six weeks (as described by Willner, Towell, Sampson, Sophokleus e Muscat (1987). Two of them were also submitted to operant sessions of a FR-FR concurrent schedule of reinforcement, with responses followed either by water or water with sucrose prior and after the stress protocol. Results showed that all four subjects diminished their overall liquid consumption while the stress protocol was in effect. Results also showed the two subjects preferred water with sucrose on the FRFR condition (with higher rates of responses on the lever associated with water with sucrose), and that these subjects recovered their overall consumption and their preference for water with sucrose faster than the two subjects not submitted to the operant condition