Figure 14.

Blocking NMDAR activity in the dorsal hippocampus during the retention interval prevents the decay of long‐term object location memories. (a) During sampling, animals were exposed to two copies of a junk objects for 10 min a day for the seven consecutive days that remained at the same locations. This protocol leads to long‐term object location memories lasting for about 8 days (Migues et al., 2016). Twenty‐four hours after the last sampling session, animals were infused with AP5 or Veh into the dorsal hippocampus twice daily for 13−days. The following day, 14−days after the end of sampling, animals were returned to the open field for the probe trial, where one of the original objects was moved to a novel location. (b) Animals infused with AP5 preferred to explore the relocated object, thus expressing memory for the original object locations, while animals infused with vehicle explored both objects the same. (c) Both groups expressed the same overall exploratory activity during the probe trial. (d) Using the same behavioral protocol, animals were infused with Ro25‐6981 during the memory retention interval. (e) Only animals that received the GluN2B‐selective antagonist Ro25‐6981 preferred exploring the object at the novel location. (f) There were no differences in overall exploratory activity. *p−<−.05, **p−<−.01