Introduction
We all live with our bodies every day, but do we truly experience them? Does this experience of the body have a broader consequence on our interpretation of life and our experience of well-being? The ability to experience the sensations of the body is known as interoception, and mindfulness meditation seems to be a powerful way of enhancing this ability. Enhanced interoception may not just result in a better understanding of the body, but may lead to a general increase in subjective well-being. Furthermore, it also may be indicative of a broader truth about how we can reach a more profound level of consciousness.
In a previous post, I began an exploration into possible reasons why those who meditate claim to achieve an altered form of consciousness. I mentioned that across enlightenment-related research, there is a common experience and interpretation of being one with everything during these altered or heightened states. I proposed that this interpretation of reality was achieved through an improved capability of the brain to process incoming information. The argument stems from the idea that the brain is constantly receiving signals from internal and external stimuli, trying to interpret those signals using previous experiences and predicted models (Seth, 2013). The interpretation created, in part, manifests itself as our conscious reality. I used an analogy of a calm pond to describe a possible consequence of this neuroscientific idea: imagine the brain as this pond, where incoming signals can be thought of as raindrops. When a single raindrop falls upon a pond, the ripples created are distinct. It is incredibly easy to determine how big the raindrop was, where it dropped, and came from, etc. However, if there is a massive rainstorm, then it is almost impossible to interpret all the intersecting ripples, and it is very hard to understand the “information” of each raindrop. This is analogous to how our brains work. The busier the incoming signals, the more difficult it is to interpret the reality of what is happening. This would also be true for the signals within the brain manifested by our thoughts and ruminations. Therefore, the calmer the pond/brain, the clearer and more accurate understanding of our world, and ourselves, is achieved. Meditation may be a method to achieve this heightened state of awareness. I find this idea profoundly interesting, and so my goal is to further explore this idea using scientific evidence as support.
To further explore and verify this idea, I felt it was important to research interoception. If this idea holds water, then it should be observed that meditation allows an individual to achieve a better understanding of incoming stimuli, both internal and external. In this post, I will explore the ability to interpret internal stimuli, which is known as interoception.
A quick note before I continue: As I began researching this topic, I found that the study of interoception was quite complex. The research is constantly evolving, and previous notions are quickly dismissed as the research progresses. Therefore, much of the research presented is speculative, and surely not indicative of definitive truth. Nothing you ever read is definitive of course, but I find that this is especially true here. Regardless, it will adequately depict the fascinating nature of our bodies and the processes involved in interpreting ourselves and reality, hopefully highlighting how important interoception is, and how poorly it is understood.
Understanding the Different Senses
To begin, an outline of our body’s senses is required. Classically speaking, the senses are defined as teloreception (vision and hearing), proprioception (limb position), exteroception (touch), chemoreception (smell and taste), and interoception (sensations from the internal organs)(A. D. Craig, 2002). In this classical definition, sensations of pain, temperature, and itches belonged to the family of touch/exteroception (A. D. Craig, 2002). Therefore, the line between the stimuli from the outside world is clearly defined and separated from the stimuli coming from inside the body. However, more recent findings suggest that temperature, pain, and itch are distinct from touch because they are associated with different neuronal pathways, and the experiences of these sensations seem to rely upon post-processing (A. D. Craig, 2002, 2003). In other words, the experience of these stimuli is more related to the mind than pure touch is. Additionally, interoception is also being redefined. The lamina I spinothalamocortical system is one of the major neuronal pathways that provide the brain with interoceptive signals (A. D. Craig, 2002, 2003). This nerve, across multiple studies, has been shown to not just send signals regarding the organs, but a sense of the condition of the entire body as well (A. D. Craig, 2002). Therefore, interoception encompasses the general feelings we have about the body’s state of being including, but not limited to, thirst, hunger, penile stimulation, exercise/exhaustion, and the condition of our organs such as bladder, stomach, etc. (A. D. B. Craig, 2009). To further complicate things, some researchers have attempted to distinguish between different aspects of interoception (Garfinkel et al., 2015):
• interoceptive accuracy – “Objective accuracy in detecting internal bodily sensations”
• interoceptive sensibility – “Self-perceived dispositional tendency to be internally self-focused and interoceptively cognizant”
• interoceptive awareness – “Metacognitive awareness of interoceptive accuracy”
Here, the ability to accurately detect signals and the subjective belief of one’s accuracy is differentiated. The interoceptive awareness evaluates if your subjective confidence in your ability to sense the signals coincides with the true ability. Therefore, the mind and our subjective evaluation of our signals are incredibly related to our perceived understanding. For this reason, the neuroscience of interoception should be explored, to gain a better understanding of how it works. The two brain areas that are involved in interoception and that will be discussed here are: the insula and the anterior cingulate cortex (ACC).
Insula
The insula is located deep within the cerebral cortex, and likely plays the most important role in interoception. The insula, especially the anterior portion of the insula, is thought to be involved in bodily and emotional awareness (Giuliani et al., 2011). It plays a major role in interoception and the sensations of internal physical states (Fox et al., 2014; Wolf E. Mehling et al., 2012). Not only is it integral to generating mental images of the internal state, but it is required for the motivation to make reactions based upon the interpretation, which subsequently affect the quality of life and survival (Craig, 2002). Consequentially, it plays a predictive role in awareness and decision-making (Craig, 2009). Therefore, falling in line with the idea that consciousness is the product of the predictive model generating nature of the brain to understanding and interpret incoming stimuli, the insula is thought to be a major seat of human consciousness and awareness of self-hood (Craig, 2009; Fox et al., 2014; Seth, 2013). Already, there is a clear connection between interoception, body awareness, and consciousness within the scientific literature.
Anterior Cingulate Cortex (ACC)
The other brain region heavily involved in interoception is the ACC. Where the insula largely is involved in the processing of the signal, the ACC is more involved with the response to the signal (Craig, 2002). In other words, the insula is related to the limbic sensory cortex, whereas the ACC is associated with the limbic motor cortex (Craig, 2002). Most recent studies have also shown that the ACC and insula are co-activated when a person experiences feelings (Craig, 2002, 2009). For example, both brain regions are involved in the sensation of the intensity and unpleasantness of pain (Grant et al., 2011). This provides further evidence that interoception is both a feeling and a motivation (Craig, 2009). Additionally, this enhances the argument that our interpretations and feelings from our internal environment are there for survival. It supports the idea that our brain is organized in a way that makes predictions, generates a conscious experience, that then elicits a reaction for the continuation of life.
Meditation and Interoception
Interoception involves more than just sensory information. It influences our feelings, and our understanding of our body, self, and the surrounding world. This understanding and experience of the self are seemingly influenced by the practice of meditation. Not only is this idea espoused in the east, but recent research has also indicated that increased mindfulness is correlated with increase interoceptive awareness (de Jong et al., 2016; Farb et al., 2010; Hanley et al., 2017). The exact mechanisms to how this occurs are still unclear. However, fMRI studies have shown that mindfulness meditation seems to increase activation in the insula (Farb et al., 2010). This may indicate that mindfulness promotes neurogenesis in areas that promote interoception. On that same note, the cognitive practices of mindfulness meditation may promote a mental framework that is helpful towards interoception. Mindfulness meditation involves orienting one’s attention to their immediate experience and becoming aware of all incoming stimuli with an open, curious, non-reactive, and non-judgmental interpretation (Bishop et al., 2004). This process helps generate a feeling of safety within the body, and the individual learns to interpret thoughts not as concrete objects of reality, but simply as thoughts that come and go within the mind. Researchers have found evidence to suggest that the non-reactivity obtained through meditation practice is closely linked to the ability to sustain attention towards bodily sensations (Hanley et al., 2017). This concept closely links to the idea that the calmer the mind is, the better the brain can process incoming information. This article brings forward evidence that the brain, with a calmer mind, can process interoceptive information better.
Consciousness
An interesting observation amongst interoceptive research is that an increase in interoceptive awareness is negatively correlated with emotional distress, hence an increase in subjective well-being is achieved (Hanley et al., 2017; W E Mehling et al., 2012). This is further supported by the observation that sadness is correlated with decreased activation of the insula and ACC, the brain regions involved in interoception (Farb et al., 2010). The relationship between the ability to be aware of the internal signals of the body and our mental well-being is very interesting. It suggests that not only does a calm mind generate a greater ability to understand the inner body, but it generates a more positive orientation to said experience. Additionally, it may be possible that this positive outlook spills over into other aspects of life beyond the interpretation of the self. Perhaps the calmer mind generates an accurate and positive outlook on all information received. This is perhaps why those who are expert meditators seem to be so peaceful, loving, and have a feeling of unity amongst everything.
The way we interpret information influences our experience of both ourselves and the world. Being aware of the body and its sensations in a non-judgmental way, creates a general sense of well-being. This may be indicative of a deeper philosophical idea: that the calmer the mind, the more capable the brain can interpret and understand information. This would not only provide a more accurate depiction of reality but provide a more profound understanding of it. Leading to a perspective of the world that is more positive, and potentially more oriented around the idea that we are all one. I cannot claim this is true. Nonetheless, it will be a concept that I will continue to explore. Regardless, it does seem to be the case that mindfulness meditation is capable of increasing interoception and therefore well-being. This being the case, I highly recommend that anyone interested in this topic incorporates mindfulness practice into their life. Reading and thinking about these ideas are all well and good, but to achieve full understanding, one must practice and experience it for themselves.
References
Bishop, S. R., Lau, M., Shapiro, S., Carlson, L., Anderson, N. D., Carmody, J., Segal, Z. v., Abbey, S., Speca, M., Velting, D., & Devins, G. (2004). Mindfulness: A Proposed Operational Definition. Clinical Psychology: Science and Practice, 11(3), 230–241. https://doi.org/10.1093/clipsy.bph077
Craig, A. D. (2002). How do you feel? Nature Review. https://doi.org/10.1177/1359105308095062
Craig, A. D. (2003). Interoception: The sense of the physiological condition of the body. Current Opinion in Neurobiology, 13(4), 500–505. https://doi.org/10.1016/S0959-4388(03)00090-4
Craig, A. D. (2009). How do you feel — now? The anterior insula and human awareness. 10(January).
de Jong, M., Lazar, S. W., Hug, K., Mehling, W. E., Hölzel, B. K., Sack, A. T., Peeters, F., Ashih, H., Mischoulon, D., & Gard, T. (2016). Effects of mindfulness-based cognitive therapy on body awareness in patients with chronic pain and comorbid depression. Frontiers in Psychology, 7(JUN). https://doi.org/10.3389/fpsyg.2016.00967
Farb, N. A. S., Anderson, A. K., Mayberg, H., Bean, J., McKeon, D., & Segal, Z. v. (2010). Minding One’s Emotions: Mindfulness Training Alters the Neural Expression of Sadness. Emotion, 10(1), 25–33. https://doi.org/10.1037/a0017151
Fox, K. C. R., Nijeboer, S., Dixon, M. L., Floman, J. L., Ellamil, M., Rumak, S. P., Sedlmeier, P., & Christoff, K. (2014). Is meditation associated with altered brain structure? A systematic review and meta-analysis of morphometric neuroimaging in meditation practitioners. Neuroscience and Biobehavioral Reviews, 43, 48–73. https://doi.org/10.1016/j.neubiorev.2014.03.016
Garfinkel, S. N., Seth, A. K., Barrett, A. B., Suzuki, K., & Critchley, H. D. (2015). Knowing your own heart: Distinguishing interoceptive accuracy from interoceptive awareness. Biological Psychology, 104, 65–74. https://doi.org/10.1016/j.biopsycho.2014.11.004
Giuliani, N. R., Drabant, E. M., Bhatnagar, R., & Gross, J. J. (2011). Emotion regulation and brain plasticity: Expressive suppression use predicts anterior insula volume. NeuroImage, 58(1), 10–15. https://doi.org/10.1016/J.NEUROIMAGE.2011.06.028
Grant, J. A., Courtemanche, J., & Rainville, P. (2011). A non-elaborative mental stance and decoupling of executive and pain-related cortices predicts low pain sensitivity in Zen meditators. Pain, 152(1), 150–156. https://doi.org/10.1016/j.pain.2010.10.006
Hanley, A. W., Mehling, W. E., & Garland, E. L. (2017). Holding the body in mind: Interoceptive awareness, dispositional mindfulness and psychological well-being. Journal of Psychosomatic Research, 99, 13–20. https://doi.org/10.1016/j.jpsychores.2017.05.014
Mehling, W E, Price, C., Daubenmier, J. J., Acree, M., & Bartmess, E. (2012). The Multidimensional Assessment of Interoceptive Awareness (MAIA). PLoS ONE, 7(11), 48230. https://doi.org/10.1371/journal.pone.0048230
Mehling, Wolf E., Price, C., Daubenmier, J. J., Acree, M., Bartmess, E., & Stewart, A. (2012). The Multidimensional Assessment of Interoceptive Awareness (MAIA). PLoS ONE, 7(11). https://doi.org/10.1371/journal.pone.0048230
Seth, A. K. (2013). Interoceptive inference, emotion, and the embodied self. Trends in Cognitive Sciences, 17(11), 565–573. https://doi.org/10.1016/j.tics.2013.09.007