“…Dream scenes mainly occur in the REM sleep and include mental images, thoughts, sounds, and other sensory experiences in various sequences that may be episodically disturbed by discontinuous shifts in dream narratives ( Kahn and Hobson, 1993 ; Faw, 1997 ; Kahn et al, 1997 , 2000 , 2002 ; Stickgold et al, 2001 ; Hobson and Pace-Schott, 2002 ; Kahn, 2013 ). According to some findings neural correlates of these discontinuous shifts in a dream scenery are rapid shifts in neural patterns related to self-organized neural activities, mainly associated with activities of cholinergic pontogeniculoocipital (PGO) systems ( Hobson and McCarley, 1977 ; Quattrochi et al, 1989 ; Hobson, 1990 ; Kahn and Hobson, 1993 ; Stickgold et al, 1994 , 2001 ; Kahn et al, 1997 , 2000 , 2002 ; Kahn, 2013 ). In addition, there is also evidence that the PGO activity is correlated with increased firings in the visual cortex and lateral geniculate bodies participating in formation of images ( Callaway et al, 1987 ; Singer, 1989 ; Kahn and Hobson, 1993 ; Porte and Hobson, 1996 ; Stickgold et al, 2001 ; Kahn, 2013 ).…”