We hypothesized that representations of social interactions in REM and non-REM (NREM) dreams would reflect differing regional brain activation patterns associated with the two sleep states, and that levels of aggressive interactions would be higher in REM than in NREM dreams. One hundred REM, 100 NREM, and 100 wake reports were collected in the home from 8 men and 7 women using the Nightcap sleep-wake mentation-monitoring system and scored for number and variety of social interactions. We found that (a) social interactions were more likely to be depicted in dream than in wake reports, (b) aggressive social interactions were more characteristic of REM than NREM or wake reports, and (c) dreamer-initiated friendliness was more characteristic of NREM than REM reports. We conclude that processing of, or simulations about, selected social interactions is preferentially performed while "off-line" during the dream state, with the REM state specializing in simulation of aggressive interactions and the NREM state specializing in simulation of friendly interactions.
Bibliographical noteFunding Information:
This material is based on work supported in part by the Office of Research and Development, Medical Research Service, Department of Veterans Affairs, and by National Institutes of Health grants (MH 48,832; MH 65,292; DA 11,744). We would like to thank Adam Schneider and Bill Domhoff for providing us with very helpful advice on how best to use DreamSat, as well as how to interpret its statistical output.