Right Cerebral Activation in REM Sleep: Evidence from a Unilateral Tactile Recognition Test

Several authors have advanced the hypothesis that the right cerebral hemisphere predominates during REM sleep. This hypothesis was tested by giving a newly‐devised unilateral tactile recognition test to 16 right‐handed male subjects during waking and upon awakenings from REM and NREM sleep. A two‐way analysis of variance revealed both a main effect for hand (the left hand being superior to the right) and a condition (waking‐REM‐NREM) X hand interaction. Consistent with the hypothesis of right‐hemisphere activation during REM, left‐hand superiority upon awakenings from REM was greater than that during waking; in the NREM condition, no between‐hand difference was observed. The latter result, as well as previous findings by Gordon, Frooman, and Lavie (1982), seems to point to the presence of left‐hemisphere activation during NREM and, more generally, to the link between hemispheric functional alternation and the REM‐NREM cycle.