RESUMEN
Current research and theory support the position that there are diurnal changes in the relative functional dominance of the hemispheres in the "normal" population. In one example of this position, Bakan (1978) has stated that REM sleep allows for right hemisphere dominance with a relative absence of left hemisphere interference. The present study involved pre- and postREM deprivation visual presentation of cognitive/perceptual performance tasks that had previously been demonstrated to have lateralizing value. Ten right-handed adult males each spent three nights in a sleep laboratory completing these tasks and a variety of questionnaires. After REM deprivation, performance decreased on right hemisphere tasks presented to the right hemisphere first. However, left-hemisphere-first presentation of one of the right hemisphere tasks (facial recognition) actually resulted in performance improvement after REM deprivation. This improvement was attributed to a suppression or diminution of capacity of the primary processing style of the left hemisphere. Results are further discussed in terms of Bakan's theory, the different processing "styles" of the two hemispheres, possible functions of REM and relationships of the biological cycles to possible shifts in cerebral laterality.