Cortical attention plays a crucial role in how mammals process sensory information, with 70% of cortical activity linked to outer-world cognition and 30% to inner-world cognition. This balance allows the brain to switch focus between external stimuli and internal states like pain or thirst. The late exhalation phase is particularly vital for generating internal attention and emotional responses, which help form associative memories. Understanding this attentional switching enhances our grasp of how emotional experiences shape cognition and behavior.
When awake and relaxed, spontaneous activation of memory engrams brings various memory-scenes to mind, and the present self may long for them. Odorants are strong cues for remembering associated memories. Associative learning of odor signals and object cognition allows prediction of cognitive imagery of an environmental object. The neural network connecting olfactory cortices to higher cognitive areas dynamically switches processing from feedforward to top-down, correlated with the respiratory cycle. During inhalation, feedforward odor signals drive burst firings of specific pyramidal cells in the olfactory cortex; during late exhalation, top-down cognitive scene-signals reactivate the same cells, potentially inducing plastic changes that form associative-learning memory.