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.