According to neuroscientists who study it, the insula is a long-neglected brain region that has emerged as crucial to understanding what it feels like to be human.
They say it is the wellspring of social emotions, things like lust and disgust, pride and humiliation, guilt and atonement. It helps give rise to moral intuition, empathy and the capacity to respond emotionally to music.
Its anatomy and evolution shed light on the profound differences between humans and other animals.
The insula also reads body states like hunger and craving and helps push people into reaching for the next sandwich, cigarette or line of cocaine. So insula research offers new ways to think about treating drug addiction, alcoholism, anxiety and eating disorders.
Of course, so much about the brain remains to be discovered that the insula’s role may be a minor character in the play of the human mind. It is just now coming on stage.
The activity of the insula in so many areas is something of a puzzle. “People have had a hard time conceptualizing what the insula does,” said Dr. Martin Paulus, a psychiatrist at the University of California, San Diego.
If it does everything, what exactly is it that it does?
For example, the insula “lights up” in brain scans when people crave drugs, feel pain, anticipate pain, empathize with others, listen to jokes, see disgust on someone’s face, are shunned in a social settings, listen to music, decide not to buy an item, see someone cheat and decide to punish them, and determine degrees of preference while eating chocolate.
Damage to the insula can lead to apathy, loss of libido and an inability to tell fresh food from rotten.