Brain & body: The little insula that could
Welcome to this week’s brain buzz. Last week we discussed the brainstem and how the brain connects to areas all over the body and what this means for your health. A simple click here and you can learn more.
This week we’re going to talk about another player that tends to sit on the sidelines too much in our textbooks: the insula. The insula is like that kid that never got picked for the dodgeball team.
He seemed liked a loser at first, but then you got to know him and realized, “this kid is cool.”
Why? Because the insula plays a huge role in a primary difference between us and other animals: emotions. In particular, social emotions such as empathy and compassion.
The insula is the little lobe that changed the whole game.
If you’ve done any reading or studying of the brain, you might’ve heard about the “4 lobes:” the frontal lobe, temporal lobe, parietal lobe, and occipital lobe.
But there’s another!
The insular lobe, the unsung hero lobe of the brain.
It’s tucked deep into the sylvian fissure, the sulcus that separates the temporal, frontal, and parietal lobes.
It looks a bit like this:
This lobe doesn’t get much recognition because it’s hidden underneath the others, but it does A LOT of incredible things. It detects very basic physiological changes in temperature and pain, and also contributes to “higher level” functions like consciousness.
But there’s another crucial role that the insula plays, and that’s one of converting our sensations into emotions.
In order to explain how this happens we have to dive into our evolution and talk about the “reptilian brain” versus the “new brain.”
The reptilian brain takes care of the essential survival mechanisms, like breathing, eating, reflexes, and sex. The new brain, otherwise called the neocortex, is comprised of the big squishy lobes and is responsible for all of the things we consider to be very human: thinking, decision-making, feeling, and being creative and rational.
The neocortex has only recently evolved and is thought to be the reason why we can live, think, and thrive like we do as human beings in society.
But what’s the bridge between the reptilian brain and the neocortex? It’s unlikely that out of the reptilian brain sprang up the neocortex all of a sudden.
Could the insula be the brain part that allowed for the great evolutionary leap to the neocortex? Science says yes.
It’s specifically proposed that the anterior insula is responsible for the step that transformed bodily sensations from the reptilian brain into emotions that induce behavior in the new brain (X. Gu et al.).
If you look at the anatomical location of the insula you’ll see that it sits between the subcortical structures (ei the reptilian brain) and the cortical structures (ei the neocortex). The projections from the insula run all throughout both parts of the brain.
In this way, the insula is unlike any other structure in the brain! It’s involved in both systems of “reptilian-ness” and new world thinking!
Dr. Antonio Damasio at the center for Brain and Creativity puts it like this: the insula reads and translates the signals from the body and then sends the signals to the conscious brain for further translation into an understandable emotion.
Sounds great, but what does this actually mean?
As Dr. Martin Paulus at the University of California, San Diego says, it means the integration of the body and the mind, the integration of our physiology with our mental experiences.
This isn’t just a profound finding, this has real-world, practical applications.
Two of which include
- understanding addictions
- pain tolerance
Let’s start with addictions:
Addictions are the integration of a physical sensation with a mental and emotional state. People become addicted to certain drugs or behaviors, not only because the substance or behavior is addictive, but because the physical cues that accompany the drug or behavior evoke an emotional memory. This is the job of the insula – to use physical cues to create an emotion that then puts you into action. So, during an addictive episode, the insula goes crazy.
Recently, more evidence for the insula’s involvement in addiction has come forth. There is evidence that comes from a small population: smoker’s with damage to their insula. We normally think damage equals bad, but in this case, damage to the insula completely halts a smoker’s addiction. After the insula has acquired a couple of bruises and scratches, smokers no longer have cravings to light up that cigarette (Naqvi et al., 2007).
The physical cues of the cigarette pack, the time of day, and the bodily state, no longer evoke the emotion that prompted the ex-addict to pull out a cigarette.
It makes sense why addictions are so hard to shake; they start first in the physical, in the deep, unshakable unconscious part of the brain. This physical foundation then builds up to an emotional resonance that consumes the conscious brain.
But, with damage to the insula, the root from the unconscious no longer has its power.
So, what do we do now? Go and damage all of the addicts insulas?
Not quite. Scientists have come up with a more clever way to change the insula.
Introducing, real-time fMRI feedback (rtfMRI).
Sounds complicated, but it’s actually quite simple and innovative. This technique puts a person in an fMRI machine where they watch their brain in real-time and figure out how to activate or deactivate a certain area of the brain. A similar technique to this is NeuroFeedBack.
Here’s an example: healthy volunteers were put into an fMRI machine and told to watch brain regions responsible for pain sensation while they felt physical pain from a hot instrument on their palm. The volunteers then learned how to change the neural activity of the brain by watching the brain image and trying to get the pain region to be less active (Chapin, 2012).
What an amazing feat! This is controlling the brain from the top, down; this is using the mind and perception to change something physical and tangible.
So, scientist are thinking, is there a way to deactivate the insula of addicts? Can we use neurofeedback to help addicts understand what mental state they need to be in in order to change the neural activity of their brain and calm down the insula?
This would be a much more effective treatment than damaging the insula. No medication or surgery required. Just a little brain training.
Let’s move on to the second practical application…
In addictions, deactivating the insula seems to be useful, but for pain tolerance and emotional awareness, the opposite is true.
It’s important to note that even though the insula is small, it has many different parts. The part that is damaged for the addicts is a different region than the area that is increased for those who have greater emotional awareness and pain tolerance.
The posterior part of the insula is responsible for the physical sensations of the body, while the anterior is responsible for the emotional and mental side. There is also a difference from side to side. The left side of the insula has involvement with the parasympathetic nervous system, the system that calms you down, and the right insula plays a role with the sympathetic system, the fear and stress system.
As we know, the insula integrates physical sensations with emotional responses. Often times those physical sensations are painful. We also know that some people tolerate pain better than others, why could that be?
There’s one population in particular who seems to have this increase in pain tolerance and subsequently a difference in their insulas: people who practice yoga.
A 2013 study found that yogis tend to have an increase in the white matter connections of the left insula. Not only that, but there is an overall increase in the size of the left insula. Remember the left insula is the part of the brain that regulates the parasympathetic nervous system, aka relax mode.
Yoga does this “by teaching different ways to deal with sensory inputs and the potential emotional reactions attached to those inputs leading to a change in insular brain anatomy and connectivity (Villemure, 2013).”
No wonder yogis are happier and more emotionally aware, they’re training not only their bodies, but also their brains.
Often times people in great physical pain from illnesses like cancer find relief in the practice of yoga. It isn’t because they’re reducing the amount of pain coming in. It’s because they’re changing their emotional reaction to the pain, making the pain feel less intense; they’re strengthening the left anterior insula and changing the connection between the physical pain and the evoked emotion.
So, the takeaway message from this article: start spending time with your insula. There are many ways that it can help you. If you give it some attention, it may just return you the gifts of calmness and emotional intelligence.
Here are some actions you can take today to enhance your insula:
- Consciously notice the connection between a physical sensation or cue and the emotion that goes with it. For example, if you’re a smoker, and you normally have a smoke when you exit a building, next time notice the sensations in your body when you’re leaving a building and notice the emotion that goes with it. That’s your insula working. Becoming aware of it is the first step
- Look into neurofeedback or rtfMRI. You don’t have to be an addict to experience it.
- Sign up for a yoga or meditation class!
As always, I’m like the neuron, waiting to connect with others, so feel free to contact me at any time!
And for more information about how yoga betters the brain visit www.neuroyogini.com.
From my heart & brain to yours,
I’m a brain enthusiast and yoga fanatic. I work as a researcher at the University of California, San Diego while also running a yoga business on the side.
I use brain research and yoga as a springboard to blog about lifestyle, health, happiness, and how it all relates to your brain.
Just like the nerve cells in our brains, I love making new connections. So, feel free to reach out.For more info on yoga and the brain, take some time to explore neuroyogini.com.