Summary
This is a resubmission of the R01 grant proposal entitled “Roles of Non-REM and REM sleep in facilitating
visual perceptual learning”. Visual perceptual learning (VPL) refers to long-term performance enhancement on
a visual task as a result of visual experience. VPL not only provides substantial insight into visual and brain
plasticity but can also help in the development of an effective clinical tool to improve vision that is damaged or
declining due to disease or other causes. Thus, it is crucial to examine what factors facilitate VPL. Although a
number of studies have developed effective methods to facilitate VPL during training, much less is known about
the role that sleep plays in facilitating VPL (sleep facilitation). A better understanding of the roles and
mechanisms of sleep facilitation may be of enormous potential in improving visual training methods.
Our pilot study identified 3 types of facilitatory effects of sleep in VPL: offline performance gains, stabilization,
and post-sleep learning promotion. Aim 1 will investigate the underlying mechanism of these 3 sleep facilitation
effects by testing: H(ypothesis)1-1: The dorsolateral prefrontal cortex (dlPFC) and early visual areas (EVAs)
play a role in inducing offline performance gains during NREM sleep, H1-2: The ventromedial PFC (vmPFC) and
EVAs play a role in inducing stabilization during REM sleep, and H1-3: The vmPFC and EVAs play a role in
inducing postsleep learning promotion during REM sleep. This will be done by measuring the E/I ratio changes
in the retinotopically-defined EVAs, dlPFC, and vmPFC during NREM and REM sleep monitored by
polysomnography (PSG) and the correlation between the E/I ratio changes and each sleep facilitation effect. If
the results support these hypotheses, we will test whether the dlPFC and/or vmPFC plays a similar or different
role from EVAs in inducing sleep facilitation. To do so, we will compare the E/I ratio changes and the correlation
between each sleep facilitation effect and the E/I ratio changes in the dlPFC or vmPFC with those in EVAs.
Our other pilot study indicates that reward provided during training and posttraining sleep interact with each
other to enhance offline performance gains. This suggests that reward process is fundamentally involved in sleep
facilitation. Aim 2 will examine whether and how reward interacts with sleep to enhance sleep facilitation effects.
First, we will examine the other two sleep facilitation effects by testing H2-1: Reward and sleep interact with each
other and enhance stabilization, and H2-2: Reward and sleep interact with each other and enhance postsleep
learning promotion. Next, we will examine the mechanism underlying the interaction effect by testing H2-3: Sleep
facilitation effects, which may involve the dlPFC, vmPFC and EVAs during NREM and REM sleep, interact with
and are enhanced by reward. To test H2-1 to H-2-3, we will measure psychophysical performance for each sleep
facilitation effect as well as the E/I ratio changes in EVAs, vmPFC and dlPFC during NREM and REM sleep
monitored by PSG.