Off-line replay of waking experience-dependent activity has been also observed in the neocortex (Figure 7C; Euston et al., 2007; Hoffmann and McNaughton, 2002; Huber et al., 2004; Johnson et al., 2010; Takehara-Nishiuchi and McNaughton, 2008) and striatum (Lansing et al., 2008; Pennarz et al., 2004), as well as across structures (Ji and Wilson, 2007; Lansing et al., 2009), illustrating that it is a general phenomenon in the brain. Sleep-related assembly sequences are perhaps the strongest evidence for the occurrence of complex self-organized patterns in the brain independent from the influence of the environment. However, in contrast to the internally generated neuronal sentences underlying cognitive operations, such as recall, imagination, decision making or action planning, which occur in real (clock) time, assembly replay during rest and sleep occurs in snippets and is faster, often compressed by at least a factor of ten compared to the behavioral time scale of neuronal activation (Davidson et al., 2009; Diba and Buzsáki, 2007; Euston et al., 2007; Foster and Wilson, 2006; Nádasdy et al., 1999). Although this time compression is only slightly faster than that
