State Dependence of Character Perception.

Dreaming consciousness can be quite different from waking consciousness and this difference must depend upon the underlying neurobiology. Our approach is to infer the underlying brain basis for this difference by studying dream reports and comparing them with waking. In this study we investigated mentation during dreaming by asking subjects to provide us with dream reports and by asking them to create a dream log. In the dream log, the subjects recorded all implausibility, illogicality or inappropriateness of character during the dream narrative when compared to the character's real-life waking counterpart. Thus, the dream acted as its own control in comparing waking and dreaming mentation. Our results showed that recognition of the implausibility of a character occurred far less often during the dream than outside of the dream when the subject compared the dream character to its real-life waking counterpart. Further, not all kinds of implausibility were equally likely to occur in the dream. The most common implausibility both during the dream and when compared to the character's real-life counterpart was a character's behaviour. Calling on existing imaging data of the brain in REM sleep, we speculate on the brain-basis of these results in terms of the inaccessibility of episodic memory during dreaming and the diminished role of the dorsal lateral prefrontal cortex during REM sleep. [ABSTRACT FROM AUTHOR]