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Concious states and brain networks
Attention and consciousness are related. We solve problems by directing attention to them and shift our attention to unrelated thoughts when our mind wonders. These circumstances can represent different conscious states. Research shows that adults activate two distinct brain networks when directing attention to a task (i.e., fronto-parietal or executive network) and when mind wondering (i.e., default mode or resting-state network). There is general agreement that a relation exists between these networks, however this relation is not semantically explained. This paper will present functional magnetic resonance imaging (fMRI) data that examine the relation among brain regions associated with the executive and default mode networks. Results reveal a set of areas that gradually increase in activity with increases in attentional load and a decrease in activity with increases in attentional load. Importantly these changes in fMRI signal are linear and graded across many levels of difficulty, revealing a mutually competing activation pattern in the prefrontal cortex(1). Moreover, additional data from adults (N = 23) show that this relation is modulated by mental-attentional capacity (i.e., the ability to maintain and manipulate information in mind). Specifically, linear pattern persists as long as the mental demand of the task is within the mental-attentional capacity of the individual. When task demand exceeds the individuals mental-attentional capacity fMRI signal reverts to signal related to the default mode network. Conclusions are discussed in terms of the protracted development of the prefrontal cortex and speculate on the how shifts between states of consciousness develop in children.