When size does matter: practicing Yoga increases brain’s volume, however which are the areas involved?
Yoga and the Brain - editorial by M. Elide
Right, now that I got your attention we can get directly into the heart of the matter. Each of us, when practicing yoga, perceives its benefits at various levels: physical, psychological, spiritual, cosmic! But what happens in practitioners' brains? Are there any differences? Well, neuroscientific research says yes: there are brain regions that show a higher volume among people who engage in this discipline. Let's begin with a foreword: the practice of yoga usually includes the triad made of asanas, that is, the various postures of the body, breathing techniques, or pranayama, and meditation (dhyana). Although there is (or hopefully there should be) a close connection between those elements, it has been shown that the effects of physical activity and meditation are associated with a change in brain volume in slightly different areas, not perfectly overlapping.
We’ll go back to meditation over the next few weeks because there is so much to deepen. However in this article, I will highlight some of the results of the research that considers practice as a whole, without distinguishing between specific effects.
Let's start with the surface: yoga practitioners have a higher brain volume in the primary somatosensory cortex, called S1. In this region the cortex receives information from all body districts related to touch, proprioception, temperature and pain. In S1 the brain is also informed of muscles and joints’ tension and of the position of the body in space. At this point it seems rather intuitive to understand the development of this area in relation to yoga, which involves, and probably develops, interoceptive awareness, that is, our sensitivity to internal information and stimuli, which in this case focuses on breathing, postures and alignments, but also on the emotional state.
Another area that is systematically noted by neuroscientific studies is the insula, a more primitive structure that is still part of the cortex, located in a lower layer than the visible, superficial layer. It is often classified as a paralimbic cortex and plays a role in a wide variety of vital functions: integration of body homeostasis, interoceptive sensitivity, regulation of laughter and crying, body self-consciousness, empathy and emotions. In fact, one of the roles of the insula, , would be to turn into conscious, the emotional reactions that derive from visceral information, and therefore to integrate cognitive and somatic aspects of emotions.
This area seems to be linked to yoga practice, especially in relation to the effects of meditation and controlled breathing and is also associated with the construct of consciousness and awareness, although we’d walk into a minefield in which neuroscientists struggle ( and rightly so) and from which they bolt with skilful dexterity.
Another protagonist of the yogic brain is the hippocampus, a small seahorse shaped area located deep within the brain, precisely in the limbic lobe: the hard core of emotional processing.
Typically, the hippocampus is associated with memory-related mechanisms, such as learning new information and establishing it into long-term memory. Another important function carried out by this area is spatial navigation: it seems, in fact, that thanks to its activity we create maps or grids that allow us to plan routes. It is no coincidence that the hippocampus is one of the first regions that deteriorate in Alzheimer's disease, where both memory and spatial orientation are compromised. With regard to its role in yoga practice, more specific hypotheses have been made: the first, compatible with the functions described above, concerns the relationship between hippocampus and brain plasticity. In fact, it seems that there is a relationship with the expression of some proteins that take care of existing neurons trying to ensure their survival, while favoring the growth and differentiation of new neurons and synapses (yes!). A second theory concerns the role of the hippocampus in the regulation of stress-related hormones.
It was noted that, in the face of stressful stimuli or events, larger hippocampus sizes are associated with lower cortisol secretion. This could indicate better efficiency in regulating negative emotional states and greater well-being.
We’ll wrap this up with some food for thought and healthy scepticism about these studies. Could it not simply be that, generally speaking, being more socially and physically active can trigger these differences? Excellent objection, however many of the studies on this topic have analyzed the brains of yoga practitioners by relating them to those of equally active people.
Furthermore, data on an increase in brain volume associate with the experience and commitment of this discipline. In a nutshell, the more hours per week are devoted to practice (and also years of experience!), the greater the effect on the volume. Finally, the observed differences seem to be concentrated above all at the level of the left hemisphere, linked to approach behaviors and positive emotions. What remains to be said? Go for it!
For the nerdiest…:
The Yoga and the Brain column is related to the practice of Yoga from the point of view of neuroscience research. We will talk about the mind-body relationship, the effects of yoga and movement on the brain, the boundaries between science and spirituality and much more, from a perspective that is anything but reductionist, but rather of research and integration. After all, "Yoga" means "Union"...
M. Elide graduated at Hari-Om in 2020. She is a trained psychologist and has been involved in neuroscientific research for years. She juggles between the study of Mind and Body, finding the true strength of practice and self-knowledge in the awareness of their encounter.