Shift in cognitive asymmetries between wakings from REM and NREM sleep

Twelve subjects were awakened from REM and NREM sleep and tested on three tests designed to measure functions attributed to the left cerebral hemisphere and three tests designed to measure right hemisphere function. A significant shift in cognitive profile was found in the direction of tasks attributed to left hemisphere performance following waking from NREM sleep relative to waking from REM sleep. These results are consistent with the observed reciprocal oscillations between left and right functions during the waking period and imply that performance of these specialized functions may be controlled by some of the same mechanisms that govern biorhythms.