What is insula?
The insula (or insular cortex) is a region of the cerebral cortex folded deep within the lateral sulcus. Its name means "island" in Latin. It is a key region for interoceptive processing — handling signals about heartbeat, breathing, the gut and other internal states (Craig, 2002; Schulz, 2016).
Functions
- •Interoceptive processing — receiving and integrating signals about heartbeat, breath and the gut
- •Emotion — active when people report feelings; influential models propose it links body signals to felt emotion
- •Self-awareness — Craig's model places a sense of the bodily self in the anterior insula; this is a model, not an established fact
- •Salience and choice — involved in pain, craving, uncertainty and decision-making
Anterior vs. Posterior Insula
| Region | Function | ONDA Relevance | |--------|----------|---------------| | Posterior | More direct body signals | Level 1: Primary interoception | | Anterior | Integration with emotion and decision regions | Level 2: Emotional awareness |
"Insula" and "insular cortex" are two names for the same structure. ONDA does not measure insula activity.
Why does the insula matter?
The insula matters because it helps link what is happening inside the body with decisions and behavior. Brain imaging shows it is active in pain, thirst, disgust, craving, and uncertainty, and it is considered a key part of the salience network, which helps shift attention toward what matters in the moment.
The insula is not one uniform area. Its back portion receives more direct body-signal information, while the front portion connects more with emotion and decision-making regions. How these signals become subjective feelings is complex, and researchers still debate how much the insula creates feelings versus integrates them.
What happens when the insula goes wrong?
When the insula is damaged or works differently, people can have trouble with body awareness, emotion, and craving. Strokes affecting the insula can change heart rhythm control and taste perception. In one well-known study, smokers with insula damage were more likely to quit easily, suggesting a role in addictive urges.
Altered insula activity has been reported in anxiety, depression, eating disorders, and chronic pain. These findings come mostly from imaging studies showing associations, so they do not establish that the insula causes these conditions.
Scientific Basis
Sources: Craig, Nat Rev Neurosci (2002); Craig, Nat Rev Neurosci (2009) — the anterior insula and awareness (a model). See Interoception for the full evidence.