Fredrich August von Kekule, a famous German chemist, was attempting to determine the shape of the benzene molecule, which was known to have six carbon atoms. In 1865, reflecting upon his discovery of the hexagonal-ring like structure, he asserted that the solution came to him in a dream1; however, it is not clear if he was in rapid eye movement (REM) sleep dreaming or if he was in non-REM (NREM) sleep imagery. It is possible to think of this type of discoveries as an expression of creativity, i.e. the ability to use existing pieces of information and combine them in novel patterns leading to greater understanding and new solutions. Preliminary support of the role of sleep in creative thinking comes from a recent study by Wagner et al.2; these authors asked normal participants to perform a cognitive task, the Number Reduction Task. In this task, participants are required to understand a set of stimulus-response sequences and supply a single representative numerical answer. Improvement in task performance may be gradual (i.e., by slowly increasing response speed), or abrupt (after insight into an abstract rule underlying all sequences). They found that 59% of the participants that were allowed to sleep were able to perform the task in a time that was 70% shorter than the other group that did not sleep and suggested that sleep may facilitate insight-related problem solving. Here we report the results of the first study showing a direct complex correlation between sleep architecture or microstructure and creativity in normal controls
