Figure 15.

Enhancing NMDAR activity in the dorsal hippocampus with D‐Serine, but not D‐Cyloserine accelerates the natural forgetting of long‐term object location memories. (a) We used the same protocol as in Figure 14 with the difference that the retention interval was only 7 days. Animals were infused with the partial NMDAR agonist D‐Cycloserine during each day of this 6‐day memory retention interval. Animals were tested 7 days after the end of sampling, at a time when they naturally express long‐term object location memory in this paradigm (Migues et al., 2016). (b) At all doses tested, animals infused with D‐Cycloserine preferred to explore the object at the novel location, just like animals that had received Veh. Group differences were absent. (c) Overall exploratory activity during the probe trial was the same for all groups. (d) Instead of D‐Cycloserine, animals were infused with the NMDAR co‐agonist D‐Serine during the 6‐day memory retention interval. (e) Animals that had received D‐Serine showed no object location preference during the probe trial, while animals infused with Veh preferred to explore the moved object. (f) There were no differences in overall exploratory activity. *p−<−.05, **p−<−.01