Insula · Grey Matter

The insula is a lobe of cortex hidden inside the lateral fissure that tells the brain how the body feels from the inside: it receives taste and the signals of the heart, lungs, gut, temperature and pain, and turns them into felt states such as hunger, nausea, disgust or a racing heart.

Insula. The insula is a lobe of cortex hidden inside the lateral fissure that tells the brain how the body feels from the inside: it receives taste and the signals of the heart, lungs, gut, temperature and pain, and turns them into felt states such as hunger, nausea, disgust or a racing heart.

It is covered by the frontal, parietal and temporal lobes (the opercula) and is seen only when they are pulled apart. Its back part receives body signals relayed through the thalamus, and the front part re-represents them combined with context, motivation and emotion, which is why Craig proposed the anterior insula as the place where bodily states become feelings. The front of the insula also holds the primary taste cortex.

Interoception is its specialty. People who are better at counting their own heartbeat without touching their pulse show more anterior insula activity, and the region is active in almost every emotion studied by imaging.

Together with the anterior cingulate cortex it forms the salience network, which flags what in the body or the world needs attention now.

It is part of the emotional memory system with the amygdala and the ventromedial prefrontal cortex, and of the rule of thumb on the cerebral cortex card for where the senses arrive.

Questions: How does a racing heart become the feeling of being anxious? Signals from the heart, lungs and gut travel through the brainstem and thalamus to the back of the insula, which maps the body's inner state the way the somatosensory cortex maps the skin. The anterior insula re-represents that map together with context and emotion, and Craig proposed that this is where a bodily state becomes a felt state. Together with the anterior cingulate cortex it forms the salience network, which flags the change as something that needs attention and recruits the control needed to respond.