CONICET | Buscador de Institutos y Recursos Humanos

In Pavlovian conditioning training an organism is given conditional stimulus-unconditional stimulus (i.e., CS-US) pairings. Subsequent re-exposure to the target CS causes a conditioned response (CR), similar to the response initially associated with the US. Memories derived from CS-US pairings can be modified, however, by pre- or post-training CS-CS or US-US pairings. These procedures are known as high-order conditioning procedures, and encompass sensory preconditioning, US devaluation/inflation and second-order conditioning (SOC). High-order conditioning is expressed early in the development of the rat and it has been employed to assess the motivational (appetitive, aversive and anxiolytic) effects of ethanol and neurobiological underpinnings of early sensitivity to ethanol. Studies indicate that ethanol can devalue the expression of an avoidance memory. In this study (Pautassi et al., 2006) animals were given pairings of lemon odor (CS) and a highly aversive citric taste (US). Posttraining pairing of this US and ethanol?s (0.5 g/kg) effects resulted in an ameliorated CR, a result likely explained by anxiolytic effects of ethanol. Another set of experiment (Molina et al., 2006; 2007; Pautassi et al., 2008, 2011; 2012) employed the second-order conditioning technique (SOC). In a SOC, the memory resulting from CS1-US pairings is assessed by analyzing the capability of CS1 to transfer information to another stimulus (CS2). This technique helped circumvent several problems associated with the analysis of ethanolinduced reinforcement, such as the cofounding effect of competing conditioned motor responses. SOC has allowed detection of age-dependent, motivational effects of ethanol that may explain the enhanced propensity of adolescents to engage and escalate in alcohol drinking.