Fig. 1.

Photographs of the touch screen operant chamber system and depictions of trial types used in the a object-location paired-associates learning (dPAL) and b context-disambiguated paired-associate learning (cdPAL) tasks. In the trial type figures, positive sign denotes the correct object and negative sign denotes the incorrect object in each trial type. In cdPAL, a vertical barrier is inserted to divide the arena into two spatial contexts with a connecting central zone at the rear of the chamber