Dream bizarreness and the activation-synthesis hypothesis.

The unusual aspect of dream consciousness which has been called "dream bizarreness" may be defined as impossibility or improbability in the domains of dream plot, cognition and affect. The bizarre features of dreams may be divided into three broad categories: discontinuities, incongruities and uncertainties. Discontinuities are interruptions in orientational stability; incongruities are inappropriate syntheses of mismatching plot elements; uncertainties are confusions of distinct conceptions. Dream bizarreness appears to be the manifestation of some state-dependent cognitive process which is probably rooted in REM sleep neurophysiology. In the waking state, our brain/minds are capable of remaining focused on the normal flow of ongoing information, and such features of life as plot and time unfold in a linear sequence. In REM sleep/dreaming, this function appears to be interfered with, and disparate elements of consciousness are suddenly interjected as the brain/mind cannot maintain its orientational focus in the usual way.