Objective Pattern completion, the ability to retrieve complete memories initiated by partial cues, is a critical feature of the memory.Present study investigates the role of dopamine in memory recall.Methods We have analyzed dopamine transporter heterozygous knockout mice (DAT+/2).Results (1) While these mice possess normal learning, consolidation, and memory recall under full cue conditions, they exhibit specific deficits in pattern completion under partial cue condition; (2) This form of memory recall deficit in the dopamine transporter heterozygous knockout mice can be reversed by a low dose of the dopamine antagonist haloperidol, further confirming that the inability to retrieve memory patterns is a result of dopamine imbalance.Conclusion Our results reveal that a delicate control of the brain's dopamine level is critical for pattern completion during associative memory recall.