Reward does not facilitate visual perceptual learning until sleep occurs | PNAS

“First, we demonstrated a significantly larger offline performance gain over a 12-h interval including sleep in a reward group than that in a no-reward group. However, the offline performance gains over the 12-h interval without sleep were not significantly different with or without reward during training, indicating a crucial interaction between reward and sleep in VPL.”

https://www.pnas.org/content/early/2019/12/30/1913079117