Rem sleep without atonia--from cats to humans.

Basic science research observations often lead to unexpected surprises. It is likely that in 1965 when Dr. Michel Jouvet placed bilateral peri-locus coeruleus lesions in cats and observed REM sleep without atonia (RWA) and "oneiric" behavior that could only be explained by "acting out dreams" (or "dreaming out acts"), he recognized that it was an important observation, but had little inkling of its true significance. Nor could he even imagine that it would lead to such greater understanding of wake/sleep phenomena in humans. Likely also, the first observation of REM sleep behavior disorder (RBD) in humans was felt to be interesting and novel - again with no true appreciation of what this seemingly simple observation would lead to important clinical relationships with numerous neurodegenerative disorders. The identification of RBD in humans also buttressed the concept of state dissociation, which has served to explain many previously unexplainable human behavioral phenomena.