When we turn our attention to the role of qualia played within the brain's system, "communication" also surfaces as a major theme. The functional role of qualia in facilitating communication within the brain is a fundamental one. In order to understand the essense of communicative qualia, one needs to study the phenomenology of subjectivity.
Qualia are tightly coupled with subjectivity. After all, it is "I" that perceive the redness of red. A quale does not exist as an objective entity like an electron or a nucleus. A quale does not float in the mid-air. A quale exists only in reference to a subject such as "I", and makes sense only to that person.
Studies of sensory perception, for example visual perception, have made it clear that in order for a subject to "perceive" a quale, two networks in the brain need to match. One is the sensory network that receives the input from the sensory peripherals (such as the retina in the case of vision). The other is the "intentional" network that is centered in the prefrontal area of the brain, and supports the self-consciousness. The sensory network provides the basic material for the qualia, while the intentional network provides the infrastructure for subjectivity. When these networks meet, the subject "I" perceive the qualia coded by activities of neurons in the sensory network ("sensori-intentional" matching).