The experiment employed explicitly unpaired controls (UP). These animals were also subjected to the 10 min habituation and weighing procedure. Adolescents unpaired controls were exposed to the CS1 either 5 (Early unpaired group) or 30 min (Late unpaired group) after having been weighted. This procedure aimed at equating the interval between habituation and conditioning across groups. Since interval between habituation and conditioning failed to affect responsiveness at test in adolescent controls (see data analysis section), only early unpaired controls were employed when examining adult animals. These animals were habituated to the chambers, weighed and 5 min later exposed to the intraoral CS1. All unpaired animals were returned to their holding chambers immediately after CS1 exposure. Ethanol administration (0.5 or 2.0 g/kg) in UP animals took place in these holding chambers 240 min following CS1 exposure. Volume of EtOH administration was calculated using the weight measurement obtained earlier during the day (i.e., immediately after the habituation phase).
