The concepts of arousal, vigilance, and selective attention are all tightly related aspects of our brain’s ability to bring certain pieces of information into conscious awareness and maintain that information over time. When considering selective attention more closely, we start to see the complexities involved in shifting the focus of our awareness, and to appreciate how those shifts involve a number of factors, including the degree…

Attentional mechanisms exist across much of the brain, including brainstem and subcortical structures involved in general arousal, cortical networks for voluntary and reflexive shifts of attention in the dorsal and… Unattended sources of information do not benefit from the same enhanced processing as attended sources, but they are nevertheless processed by the relevant sensory systems in the brain.