Adolescents expressed ethanol-induced conditioning not only in terms of CS2 preference but also via conditioned behavioral activation, expressed in response to CS1 during the second-order conditioning phase. After pairings of 2.0 g/kg ethanol and CS1, adolescents exhibited more wall-climbing than unpaired controls when briefly re-exposed to CS1. Conditioned wall-climbing is often observed in response to tastants previously paired with the aversive postingestive effects of emetic agents (Pautassi et al., 2008) or drugs of abuse, including ethanol (Arias & Chotro, 2006). Hence, the increased wall-climbing observed in paired animals might reflect aversive effects of ethanol. However, this finding seems to be better explained in terms of an ethanol-mediated conditioned motor response, as reported in 14-day olds by Molina et al. (2006), with conditioning procedures similar to those of the present study. Specifically, (Molina et al. (2006; 2007) also found greater wall-climbing during the second-order conditioning phase in paired animals than in unpaired controls, believed to represent an ethanol-mediated conditioned motor response that had become conditioned to CS1. Cunningham & Noble (1992) provided support for this hypothesis. These authors found that the
