Sleep Helps Preserve Declarative Memories
Study shows that sleep consolidates memories and protects them from interference
WEDNESDAY, July 12 (HealthDay News) -- Sleep protects declarative (hippocampus-mediated) memories from associative interference, according to a study published in the July 11 issue of Current Biology.
Jeffrey M. Ellenbogen, M.D., of Harvard Medical School in Boston, and colleagues assigned 60 participants to four groups: sleep before testing, wake before testing, sleep before testing with interference, or wake before testing with interference. All participants learned 20 paired words and were tested for recall 12 hours later.
The researchers found that the wake-before-testing group had only a small (13 percent) relative reduction in recall compared to the sleep-before-testing group. But they found that the wake-before-testing with interference group had a robust (58 percent) relative reduction in recall compared to the sleep-before-testing with interference group.
"Our study provides a source of convergence for investigations of declarative memory consolidation between human behavior, animal research, computational models and neuroimaging studies," the authors conclude. "While further research is needed to define the empirical limits and physiological correlates of this sleep and memory interaction, our study provides a new framework for considering the effects of sleep on human memory: sleep helps consolidate declarative memories, rendering them resistant to associative interference."