Open field with objects. Effects of donepezil pre-treatment and 192-IgG-saporin (Sap) lesions on open field with objects contact time with objects during spatial change in session 5 (S5) (a), S6 (b) and novelty (S7) (c). Cholinergic depletion per se (Sal-Sap group) significantly affected spatial discrimination abilities in S5 and S6, and donepezil pre-treatment (Don-Sap group) prevented spatial memory deficits. In S7, all rats detected the presence of the novel object. Behavioral data are expressed as means ± SEM, and asterisks indicate post hoc comparisons between groups. DO, Displaced object; Don-Sap, donepezil-treated Sap-lesioned rats; Don-Sham, donepezil-treated sham-lesioned rats; FO, familiar object; NDO, non-displaced objects; NO, novel object; Sal-Sap, saline-treated Sap-lesioned rats; Sal-Sham, saline-treated sham-lesioned rats. **P < 0.01, ***P < 0.001.