The insular cortex is an area of the human brain that plays a large role in cognition and consciousness. Though part of the cerebral cortex, its location within the cortex's folds makes it hidden from the outside. It processes information about one's physiology and can even affect some physiological functions. For example, it pairs appropriate emotions with outside events. Medical research has linked the cortex with cravings associated with psychological addiction.
Part of the cerebral cortex, the insular cortex is the folded layers of gray matter that cover most of the brain. Its exact location is the deep groove that separates the frontal and temporal lobes. It is adjacent to the thalamus, a structure of the brain that receives all sensory input data expect one's sense of smell. This proximity is important due to how the insular cortex processes information related to sensation.
Once the thalamus receives sensory information, the insular cortex processes the data into a perceived sensation. One's idea of physical self-awareness comes largely from this process. A benefit of this system is one's ability to judge different levels of pain. This ability goes further than direct sensations. Research subjects asked to view images of other humans in pain experienced similar neural impulses in the insular cortex as if they were the ones in pain; some researchers have interpreted this physiological response as the cause of human empathy.
Besides empathy, the connection between the insular cortex and human emotion is better understood. In many cases, it is the cortex's responsibility to pair an appropriate emotion with a sensory stimulus. This pairing creates conscious feelings. With the advent of spoken language roughly 100,000 years ago, human beings have had the ability to categorize and define these feelings, leading to further self-awareness.
The insular cortex also controls some motor functions such as hand-eye coordination, swallowing and certain parts of speaking. One is not conscious of its role in raising heart rate and blood pressure during exercise. As of 2011, medical research is investigating how the cortex regulates the immune system and other autonomic bodily functions.
One of the possible negative aspects of the insular cortex is its role in addiction. For example, if one is attempting to quit smoking, environmental cues such as seeing others smoke act as a trigger in the cortex. One's desire to smoke rises because the cortex expects smoking to follow certain sensory stimulation. This trigger applies to any number of drugs and can make abstaining extremely difficult.
