Twenty years ago we knew very little about the insula. It tucked way deep inside the brain and went largely unnoticed.[I] In fact, ‘insula’ literally means ‘island’.[ii]

However, developments in neuroimaging (pictures of the brain) and case studies of brain damage how shown that the insula plays an important role in everyday life.[iii]

Photo by haydenbird/iStock / Getty Images

Despite this, it still remains one of this least understood brain areas.[iv]

What does it do?

Today, the insula has been implicated in more that just disgust.

It has been linked with

Self-awareness,
Interoception (a perception of how we feel),
Pain processing,
Addiction,
Motivation and
Salience detection.[v]

Self-awareness

The anterior insula (the front part of the insula) has been thought to play a core role in how we feel and providing a sense of ‘self’. There are several theories that the insula gives us an awareness of out physical self as a sentient (feeling) entity.[vi]

Interoception

The insula has been implicated in the process of interoception.[vii] This is how we monitor the internal state of our body. Neuroimaing studies have fond that the insula is often activated when people are shown arousaling stimuli such as scary, happy, sad or disgusting imagines.[viii]

Photo by Martin Keiler/iStock / Getty Images

This role in interception also affects the ability to empathise. For us to empathise, we need interoception and self-awareness to relate to how someone else is feeling.[ix] Neuroimaing has shown the insula as activated in response to the pain of others and to their expressions of fear, anxiety, happiness and disgust.[x]

Motivation

The insula has also been thought to be vital to motivation. It does this by evaluating and encoding stimuli so that rewarding things make us feel pleasure and bad things make us feel pain.[xi]

Addiction

While many parts of the brain have been examined when looking at addiction, the insula has only recently been implicated. One study found that smokers who had acquired damage to their insula found it easy to quit smoking and remain abstinent.[xii] They were able to quit easily and immediately without relapsing and without cravings.[xiii] This suggests that the insula is key to understanding addiction.

A flow on of this is the link between the insula and risky decision making. Neuroimaging has found it lights up during gambling as well.[xiv]

Conclusion

Until recently the insula has been a little known, largely unnoticed part of the brain tucked deep within the cortex. However, with the advancement of neuroimaging techniques, its vital roles have slowly been uncovered. It is a window into our self and others. It is key to self-awareness, motivation and addiction and empathy. Still, much is still unknown about this vital island buried deep inside our brains.

[i] https://www.neuroscientificallychallenged.com/blog/2013/05/what-is-insula

[ii] Ward, J. (2015).

[iii] https://www.neuroscientificallychallenged.com/blog/2013/05/what-is-insula

[iv] Uddin, Lucina Q et al. “Structure and Function of the Human Insula.” Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society vol. 34,4 (2017): 300-306. doi:10.1097/WNP.0000000000000377

[v] Multiple sources cited in Namkung, H., Kim, S. H., & Sawa, A. (2017). The Insula: An Underestimated Brain Area in Clinical Neuroscience, Psychiatry, and Neurology. Trends in neurosciences, 40(4), 200–207. https://doi.org/10.1016/j.tins.2017.02.002

[vi] Seth (2013) cited in Namkung, H., Kim, S. H., & Sawa, A. (2017).

[vii] Ward, J.

[viii] Pugnaghi, M. et al. (2011) cited in Uddin, Lucina Q et al. “Structure and Function of the Human Insula.” Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society vol. 34,4 (2017): 300-306. doi:10.1097/WNP.0000000000000377

[ix] Uddin, Lucina Q et al. “Structure and Function of the Human Insula.” Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society vol. 34,4 (2017): 300-306. doi:10.1097/WNP.0000000000000377

[x] Uddin, Lucina Q et al. “Structure and Function of the Human Insula.” Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society vol. 34,4 (2017): 300-306. doi:10.1097/WNP.0000000000000377

[xi] Dolan (2002) cited in Namkung, H., Kim, S. H., & Sawa, A. (2017).

[xii] Naqvi, N. H., Rudrauf, D., Damasio, H., & Bechara, A. (2007). Damage to the insula disrupts addiction to cigarette smoking. Science (New York, N.Y.), 315(5811), 531–534. https://doi.org/10.1126/science.1135926

[xiii] Naqvi, N. H., Rudrauf, D., Damasio, H., & Bechara, A. (2007).

[xiv] Uddin, Lucina Q et al. (2017)

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