VESTIBULAR DREAMS - THE EFFECT OF ROCKING ON DREAM MENTATION

The study investigates the proposed link between vestibular activation and dream lucidity. In the experiment, subjects spent two consecutive nights sleeping in a hammock in the sleep lab. For each night, during the second, third, and fourth REM sleep periods, the hammock was eith er stationary (control condition), or rocked at a constant frequency ( experimental condition) stimulating the subject's vestibular system. I n all conditions the subject was awakened after ten minutes of REM sle ep and asked to provide a mentation report. Each report was later anal yzed on a number of scales (total word count, vestibular imagery self- reflectiveness categorization on a mentation continuum, and bizarrenes s). Physiological measures such as REM density and EEG power were also analyzed. A rocking by time interaction was found: rocking increased lucid mentation during early morning REM periods, but had little effec t on the already high degree of lucid mentation during late morning RE M periods. Physiological measures showed little differentiation betwee n conditions, with the exception of a significantly high incidence of nystagmoid-like compensatory phasic eye-movements in the rocking condi tion. These results suggest that vestibular activation during REM slee p can influence dream mentation, specifically, dream self-reflectivene ss and vestibular imagery.