A visual paired associate learning (vPAL) paradigm to study memory consolidation during sleep

Sleep improves memory consolidation, including hippocampus-dependent declarative memory. It is thought that by associating multiple aspects of an experience, the hippocampus enables its transformation into an enduring memory. Most research on human sleep and declarative memory uses exhaustive learning of word-pair associations. Here we present the visual paired association learning (vPAL) paradigm, in which participants learn new associations between images of celebrities and animals. vPAL associations are based on a one-shot exposure that resembles learning in natural conditions. Furthermore, vPAL is an engaging short paradigm that does not require rehearsal or reading, making it valuable for clinical settings. We tested if vPAL can reveal a role for sleep in memory consolidation by assessing the specificity of memory recognition, and the cued recall performance, before and after sleep. We found that a daytime nap improved the stability of recognition memory (decay was minimized) compared to identical intervals of wakefulness. By contrast, cued recall of associations did not exhibit significant sleep-dependent effects. Investigating memory consolidation during sleep with the vPAL paradigm opens up new avenues for future research across ages and heterogeneous populations in health and disease.