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Deliberation entails the sequential, serial search through possible options. This means that deliberation requires a mechanism to represent the structure of the world, from which predictions can be generated concerning these options and the expectations of the consequences of taking those options. Deliberation requires a mechanism to move mentally through those predictions as well as a mechanism to evaluate and compare those predictions. Neural signals for each of these factors have been found in the rat.

This chapter examines dynamic states in which brain systems differentially express their involvement in conscious versus nonconscious representation. Given the evidence for a role of corticothalamic systems in consciousness, in what kind of state should they be to do so? Reviewing the neurophysiology of sleep, anaesthesia and wakefulness, a diverse picture of brain dynamics emerges in association with conscious processing. Comparing sleep with wakefulness, we see evidence for the primary role of so-called Up states in the neocortex, featuring high levels of depolarization, irregular firing, and desynchronized EEG. Pathophysiological and computational studies emphasize the importance of having decorrelated activity rather than global synchrony. Studies on "replay" during sleep or wakefulness show that this phenomenon unlikely corresponds to conscious processing, challenging simple implementations of “neural coalitions” embodying consciousness. Findings on anesthesia highlight the prominence of sustaining long-range rather than local interactions between distributed cell assemblies. On the fast time scale of perception, recurrent interactions from higher to lower cortical levels are probably important, yet more work is needed to find out which connectivity components are essential for perception or behavioral reporting. In EEG research on perception, alpha oscillations are emerging in regulating the phasing of stimulus perceptibility.

The hippocampal system provides a beautiful example of how different classes of neuronal network in the brain work together as a system to implement episodic memory, the memory for particular recent events. The hippocampus contains spatial view neurons in primates including humans, which provide a representation of locations in viewed space. These representations can be combined with object and temporal representations to provide an episodic memory about what happened where and when. A key part of the system is the CA3 system with its recurrent collateral connections that provide a single attractor network for these associations to be learned. The computational generation of time, encoded by time cells in the hippocampus, is described, and this leads to a theory of hippocampal replay and reverse replay. The computational operation of a key part of the architecture, the recall of memories to the neocortex, is described.

Chapter 4 shows that repeated watching of movies gave rise to their reenactment, with music conjuring up memorable scenes and spurring attempts by habitual spectators to replay them in real life. Film music catalyzed mnemonic innervation—a variant of the "mimetic innervation" Walter Benjamin saw as a vital effect of cinema by turning viewers' minds and bodies into audiovisual recording and playback devices. Case studies focus on a subgenre of films in which canonical movies have become part of people's lives by supplying them with plot elements, dialogue, and music: Play it Again, Sam (1972) as inspired by "As Time Goes By" from Casablanca (1942); The Purple Rose of Cairo (1985) as framed by "Cheek to Cheek" from Top Hat (1935); and Sleepless in Seattle (1993) as cued by Hugo Friedhofer score from An Affair to Remember (1957). The phenomenon of such music-driven auratic replay supports to Benjamin’s claim that cinema reconfigured the experience of reality by activating viewers' mimetic and mnemonic capabilities (Miriam Hansen). Amid a rapidly growing consumption of movies, film music has thus come to fulfill an important role in linking cultural and individual memory by blurring the boundary between soundtracks of films and the soundtracks of life.

This introduction establishes the core concepts of the book, setting the stage for the chapters that follow. It describes the significance of replaying both in video games and in classical music and introduces the concept of replay value. The chapter offers some instances of classical music appearing in 1980s video games, such as the opening theme of the Toccata and Fugue in D Minor by J. S. Bach, which is used in a key moment in the game The Battle of Olympus. It then sketches an outline of the organization of the book, including a brief description of each of the later chapters.

This chapter argues that the three primary methods for making machinima during its brief history—code, capture, and compositing—match up neatly with three ways to document the history of virtual worlds—replay, POV recording, and asset extraction. These linkages are provocative for thinking about what we can do to save and preserve the history of virtual worlds in their early days. They also suggest how we might begin to think about machinima as a documentary medium.

A prime example of internally organized patterns is observed during sleep. The best studied of these is the sharp wave ripple in the hippocampus. Neuronal sequences during ripple events reach back to the past to replay snippets of waking experience at times when the brain is disengaged from the outside world. This process may consolidate episodic memories and stitch together discontiguous experiences, thereby giving rise to creative thoughts. In addition, neuronal assembly sequences during ripples also act as internalized, vicarious, trial-and-error mechanisms that can assist with subconscious optimization of future plans. Because the same neuronal substrate can perform both retrospective and prospective operations, it is not clear whether the traditional separation of postdiction (i.e., memory) from prediction (i.e., planning) is justified.