The consolidation hypothesis for REM sleep function: stress and other confounding factors--a review

One commonly held hypothesis about the function of REM sleep (RS) concerns the consolidation of plastic processes, particularly those relating to learning and memory. The majority of the experimental data apparently supporting this hypothesis come from RS deprivation (RSD) studies. However, this review points out that: (i) there are several shortcomings with the methodology of animal RSD investigations, (ii) RSD seems to produce arousal and stereotyped behaviour which may interfere with learning etc., and consequently give artificial support to the hypothesis. The review then examines evidence outside the field of RSD, relating to the hypothesis, which seems further to confound or contradict it. Whilst the hypothesis is not rejected, these problems need to be addressed further by its supporters.