Nusbaum, H.
Center for Cognitive and Social Neuroscience, Department of Psychology, The University of Chicago, Chicago, IL USA
Language learning is marked by two broad characteristics: (1) Learning generalizes to new patterns and situations, and (2) learning is robust, showing little performance variability over time. There is substantial plasticity in adult learning phonetic patterns, and there is evidence of both of these characteristics. Recently we investigated how sleep contributes to the long-term stability of phonetic learning through consolidation (Fenn et al., 2003). The basic paradigm compares posttest to pretest recognition performance after a single training session. By varying duration of a retention interval and inclusion of sleep (immediate, 12 hours awake, 12 hours with sleep), we can assess the effect of sleep on consolidating phonetic learning. Moreover, by examining training and testing at different points in a day, we can control for circadian contributions. We found that after a 12 hour waking retention interval, there is a significant loss of performance compared to a posttest right after training. However, sleep restores this loss of performance. Moreover, sleep after training prevents subsequent loss the next day. We have subsequently demonstrated that this sleep consolidation is not specific to phonetic learning; sleep consolidates generalization learning in a complex sensorimotor task using videogames (Brawn et al., 2008). Using a nap paradigm, we have investigated how much sleep is necessary to consolidate learning. We have also examined how sleep consolidation may differ in rote and generalized learning of phonetic patterns. We have also developed an animal model using an auditory classification task for vocal communication (Brawn et al., 2010). This has provided the first behavioral evidence for sleep consolidation in non-human animals, showing a very similar pattern of consolidation to humans. Using this animal model, we have begun to investigate the nature of the loss of performance over a waking retention interval and how sleep may restore performance.