Thirty min following phase 2, animals were tested in a 12 min locational preference test. This procedure represents a variant of the widely-employed conditioned place preference test. During this phase, barriers separating the compartments were absent, hence animals could freely explore the three-chamber test box. Position of the test box during testing was the same as in phase 2 of conditioning, so as to keep constant potential distal spatial cues that could have signaled CS1 delivery. Spatial location of the target compartment affects expression of ethanol-mediated place preference when the procedure involves visual CSs (Cunningham et al., 2006). Preference assessment started by placing the animal in the central portion of the neutral compartment. Time spent over each end compartment of the apparatus was recorded in real time by two experimenters who were blind in regard to the training conditions of the animals. A subject was considered to be in a particular compartment when two paws and the head were over that section. The middle section of the apparatus (i.e., the start box) was considered as a neutral area. In this as well as in the previous experimental phases, the apparatus was cleaned with distilled water after each animal was tested.
