▸ We examine memory consolidation, reconsolidation, and state dependency in adolescent rats. ▸ Post-training NMDA antagonism with MK-801 disrupted both consolidation and reconsolidation. ▸ Disruption of reconsolidation was shown to be state dependent using a modified state dependent retention paradigm.
The characteristics of memory consolidation, reconsolidation, and state dependency have received considerable attention for many years. Three experiments examined the effects of the NMDA antagonist MK-801 on these phenomena in adolescent rats using passive avoidance conditioning. Experiment 1demonstrated that immediate post-training administration of MK-801 produced a consolidation impairment at postnatal day 37. Experiment 2 extended this result, showing that MK-801 administered immediately following memory reactivation disrupted reconsolidation. Experiment 3 employed a state dependent reconsolidation design, where saline or MK-801 was administered immediately following memory reactivation, and again 20 min prior to the retention test. Retention by the training/testing matched groups (saline/saline and MK-801/MK-801) was comparable and better than the mismatched groups (saline/MK-801 and MK-801/saline) providing evidence of state dependency. These results extend the consolidation/reconsolidation literature to adolescent animals and provide evidence that some deficits described as reconsolidation impairments may be more aptly considered state dependent retention deficits.