Sleep has been identified as a state that optimizes the consolidation of newly acquired information in memory, depending on the specific conditions of learning and the timing of sleep. Consolidation during sleep promotes both quantitative and qualitative changes of memory representations.” (Diekelmann & Born).
Stress shapes memory. Depending on the timing of the stress exposure facilitating and impairing effects of stress are reported on how much is learned and remembered. Beyond such stress-induced changes in the quantity of memory, recent research suggests that stress also affects the contribution of multiple memory systems to performance. Under stress, rigid ‘habit’ memory gets favored over more flexible ‘cognitive’ memory. Thus, stress has an impact on the way we learn and remember, that is the quality of memory. This shift between different behavioral strategies on “environmental demands” may facilitate adaptive responses. Here, we review stress effects on both quantity and quality of memory and address possible implications of these effects for the understanding of stress-related psychiatric disorders(Schwabe, Wolf & Oitzl).