INFLUENCE OF MK-801 ON RECONSOLIDATION OF SPATIAL MEMORY IN 8-ARM RADIAL MAZE DEPENDS ON CONDITIONS OF ITS REACTIVATION

The spatial memory about food reinforcement in 4-arms of an 8-arm radial maze in rats underwent reconsolidation by reactivation with one unreinforced trial, and did not undergo to it by reactivation with three consecutive unreinforced trials or with three trials with more intensive and preferred reinforcement. The reactivated rats remembered an omission of a single reinforcement and increased reinforcement which was reflected in the change in the number of errors and time of food collection at testing stage. The intraperitoneal injection of NMDA-receptor antagonist, MK-801 (0.1mg/kg) immediately after a reactivation trial prevented the appearance of memory reconsolidation. In 24 hours after reactivation trial the reactivated rats committed the same amount of errors as they did before reactivation and about the same amount as did the other control groups. The data obtained are discussed in the light of a role of memory update and reinforcement prediction error in the processes of memory reconsolidation and extinction.