I discuss how the work in Walker's article adds to the considerable body of research on dreaming, sleep, and memory that appeared in the early days of modern sleep research. I also consider the issue of REM-independent and REM-dependent kinds of learning. This requires including emotional issues in our discussion, and therefore emphasizes the importance of studying and understanding dreams.

In this commentary I discuss the importance of considering the isomorphism between the full richness of dreams and the great body of information about REM sleep that is amply documented in the five target articles. With this inclusive mode I point out the importance of looking at REM sleep as involving both pontine and cortical activity in an integrated network. We cannot have a full appreciation of sleep and dreaming (view of the forest) without taking both physiology and mental activity (...) seriously. [Hobson et al., Nielsen, Revonsuo, Solms, Vertes & Eastman]. (shrink)