The effects of apomorphine and haloperidol on memory consolidation in the day-old chick

Apomorphine was found to disrupt memory consolidation in a dose-dependent m anner on chicks trained on a 1-trial passive avoidance task with a strong a versant experience. Chicks injected with 4.0 mg/kg apomorphine displayed me mory deficits at 180 min after learning and showed marked behavioral distur bances, including increased locomotion and increased pecking at the feet of conspecifics. Pretreatment with the dopamine antagonist haloperidol elimin ated the memory disturbance induced by apomorphine and facilitated consolid ation of memory in chicks given a weak (20% vol/vol methyl anthralinate) tr aining experience. Time-of-retention data suggested that the memory disrupt ion occurred from 120 min after learning, leading to the suggestion that do pamine-related modulation of the training experience may be involved in lat e-memory formation processes.