Self Comes to Mind

PMCs), and it does show that all three are depressed.
    Consciousness is also depressed during rapid eye movement (REM) sleep, during which dreams are most prevalent. But REM sleep allows dream contents to enter consciousness, either via learning and subsequent recall or via so-called paradoxical consciousness. The brain regions whose activity is most markedly decreased during REM are the dorsolateral prefrontal cortex and the lateral parietal cortex; predictably, the decrease in activity of the PMCs is far less marked. 6
    In brief, the level of activity in the PMCs is highest during wakefulness and lowest during slow-wave sleep. During REM sleep the PMCs operate at intermediate levels. This makes some sense. Consciousness is mostly suspended during slow-wave sleep; in dream sleep, things do happen to a “self.” The dream self is not the normal self, of course, but the brain state that goes with it appears to recruit the PMCs.
THE PMCS’ INVOLVEMENT IN THE DEFAULT NETWORK
    In a series of functional imaging studies using both positron-emission tomography and functional magnetic resonance, Marcus Raichle called attention to the fact that when subjects are at rest, not engaging in a task requiring focused attention, a selective subset of brain regions appears consistently active; when attention is directed to a specific task, the activity of these regions decreases slightly, but never to the degree noted in anesthesia, for example. 7 The subset of regions includes the medial prefrontal cortex; the temporoparietal junction, structures in the medial and anterior temporal cortex, and the PMCs, all regions that we now know to be extensively interconnected. Most of the attention focused on the PMCs has actually come from their membership in this club of regions.

     
Figure 9.5: The PMCs, along with other CDRegions, are prominently activated in a variety of functional imaging tasks involving self-reference. Such tasks include recalling autobiographical memory, anticipating future events, and making moral judgments.
    Raichle has suggested that the activity of this network represents a “default mode” of operation, a mode that is disrupted by tasks requiring externally directed attention. In tasks requiring internally directed and self-oriented attention, such as in the retrieval of autobiographical information and in certain emotional states, we and others have demonstrated that the decrease of activity in the PMCs is less pronounced or may fail to appear. In fact, in such conditions, there may be an actual increase. 8 Examples are the recall of autobiographical memories, the recall of plans made for a possible future, a number of theory-of-mind tasks, and a host of tasks that involve judgments of people or situations within a moral framework. 9 In all those tasks, there tends to be one more significant site of activity, albeit not as extensive: another medial territory, located anteriorly in the prefrontal cortex. We know that neuroanatomically this is also a convergence-divergence region.
…
    Raichle has emphasized the intrinsic aspect of the default mode of operation and has related it, quite sensibly, to the very high energy consumption associated with intrinsic brain activity, as opposed to activity driven by external stimulation—in all probability, the PMCs are the most highly metabolic region of the entire cerebral cortex. 10 This too is compatible with the role I am proposing for the PMCs in consciousness, that of an important integrator/coordinator that would remain active at all times, attempting to hold highly disparate sets of background activity in a coherent pattern. How does the seesaw pattern of the default mode of operation fit with the idea that a region such as the PMCs would serve consciousness? It possibly reflects the background-foreground dance played by the self within the conscious mind. When we need to attend to external stimuli, our conscious mind brings the object under scrutiny into the foreground and lets the self retreat into the background. When we are unsolicited by the outside world, our self moves closer to center stage and may even move further forward when the object under scrutiny is our own person, alone or in its social setting.
RESEARCH ON NEUROLOGICAL CONDITIONS
    The list of neurological conditions in which consciousness is compromised is mercifully short: coma and vegetative states, certain kinds of epileptic state, and the so-called akinetic mute states that may be caused