By Alia Nurmohamed
Introduction
The vagus nerve, also known as the “wandering nerve” (Breit, Kupferberg, Rogler and Hasler, 2018: 2), represents the chief component of the “rest and digest” parasympathetic nervous system. The tenth (X) cranial nerve, the vagus nerve, is the longest cranial nerve and is both efferent and afferent (Breit et al., 2018). Efferent fibres send messages from the brain to regulate multiple organs such as the heart, throat, stomach and intestines, and lungs for homeostasis or equilibrium (Kenny and Bordoni, 2021; Breit et al., 2018). In addition to performing this regulatory function, the bulk of the vagus nerve is composed of afferent fibres that receive messages from the organs it regulates. Approximately 80-90% of these fibres communicate between the stomach, intestines, and the brain in what is known as the “brain-gut” axis (Breit et al., 2018). As such, the vagus nerve is a sensory nerve involved in interoception (sensations felt from within the body) and a motor nerve involved in smooth muscle and vascular contraction and dilation (Feldman Barret, 2017; Breit et al., 2018; Kenny and Bordoni, 2021). More specifically, the X-cranial nerve controls the respiratory rate, heart rate, digestion, and blood pressure, among others. As a sensory nerve, the vagus nerve’s regulatory and equilibrium functions are closely associated with the brain’s emotional areas (Breit et al., 2018).
A Brief History
The history of cranial nerves goes back to the Ancient Greeks. Herophilus of Chalcedon, followed by Galen of Pergamum, identified seven of the twelve cranial nerves (Pearce, 2017). Galen’s work, conducted on animals, was highly influential for 1,500 years (Pearce, 2017). These ancient anatomists had to rely on nerves visible to the naked eye. It was not until 1778 that German anatomist Samuel Thomas Soemmerring classified the twelve cranial nerves (some of which are below the threshold of visibility) accepted today (Pearce, 2017). Additionally, Soemmerring subscribed to the medieval tradition and believed cerebrospinal fluid was part of the “organ of the soul” (Riese, 1946; Pearce, 2017).
Soemmerring’s belief that cerebrospinal fluid was part of the soul meant he located cranial nerves, including the vagus nerve, as part of the sensorium commune, the area of the brain that gathered together all the nerves and was considered to be the locus of sensation (Riese, 1946). The sensorium commune was the operating center of Aristotle’s sensus communis, where the senses are unified and integrated into a singular awareness (Howes, 2009). However, it is uncertain that Soemmerring was aware of Aristotle’s conception (Riese, 1946). Influenced by Romantic nature philosophers (Riese, 1946), Soemmerring’s conception of the cranial nerves speaks to a generalized and diffuse understanding of multiple senses operating as one. What is more, Soemmerring considered cerebral structures necessary for the “power” of cerebrospinal fluid to “enhance the conditions of life” (Reise, 1946: 313). During Soemmerring’s lifetime, Romanticism strongly influenced the pursuit of scientific knowledge, believing that understanding nature also meant understanding the self and humanity (Poggi, 1994). Echoes of Soemmerring’s Romantic understanding of cranial nerves can be seen in contemporary understandings of the vagus nerve’s impact on sociality, as understood by Steven Porges.
The Vagus Nerve and Social Connection
According to Porges’ (2011) polyvagal theory, the vagus nerve acts as a damper on the body’s stress response from the “fight or flight” sympathetic nervous system and enables sociality (van der Kolk, 2011). In short, “when the environment is appraised as being safe, the defensive limbic structures are inhibited. This makes it possible to be socially engaged with calm visceral states” (van der Kolk, 2011: xiv). The safety and well-being associated with the “rest and digest” system, activated by the vagus nerve, seems to confer an “ontological security” upon persons, rooted in feelings of trust while circumventing an existential anxiety (Giddens, 1991: 37).
The vagus nerve’s interoceptive function is critical in understanding one’s own emotions and being receptive towards others (Feldman Barrett, 2017; Porges, 2011). The physical sensation of slow breathing may be associated with calm, feeling dazed, euphoria. Internal emotions associated with sensation are socially constructed concepts understood through language, which is grounded in and reflective of culture (Feldman Barrett, 2017). By the same token, the sense of calm from an activated vagus nerve opens individuals to connect with others. Vagal nerve activation enables individuals to become attuned to another’s tone of voice, speech rhythms and patterns, and facial expressions (van der Kolk, 2011). Thus, the vagus nerve creates a two-way street of sensual perception promoting shared connection and meaning. Linking mind, body, and culture, the vagus nerve enables individuals to become aware of their calm bodily sensations and concomitant emotions. The mind-body link from vagal nerve activation fosters a sensually driven self-understanding and awareness. In turn, self-awareness primes individuals to offer this openness to others, leading to relational receptivity and understanding.
The link between the multiple senses associated with the vagus nerve and sociality exemplifies the plurality of the sensorium anchored in Laplantaine’s “multiplicity of the body’s modalities of perception – the senses” (Laplantaine in Howes, 2015: xii). What is more, it harks back to an ancient understanding of the senses as a give-and-take form of communication (Howes, 2009). In this way, the vagus nerve “walks” around the body, navigating multiple sensations simultaneously; it does not isolate one sense from another. Rather, it is a multisensory nerve vital to cultural and emotional connection; and, ultimately, meaning-making.
Howes (2019) notes that meaning is shared with others through the social, which is inherently sensory. Through “sharing in the sensible” (le partage du sensible), one can “feel along with others what they experience” (Laplantaine in Howes, 2015: xii). In this way, the senses are made, understood, and mediated through culture (Howes, 2019). The X-cranial nerve’s multiple functions open individuals towards social engagement through a state of calm. Thus, the vagus nerve facilitates sensual sociality. The vagus nerve acts as a sensory bridge, linking people together and creating a space for openness across and within cultures.
The interoceptive functions of the vagus nerve are not confined to the body. Rather, they are mediated through and by the outside world. In other words, external sensations are felt internally. When the parasympathetic nervous system is activated, visceral sensations are understood as safe, enabling joint meaning-making. The five primary senses of touch, taste, smell, sight, and hearing can all elicit changes in heart rate, respiratory rate, blood pressure, even the flutter of butterflies in one’s stomach. As Wacquant (in Buckingham and Degen, 2012) notes, the body is a “vector”, a pathway that drives both individual and shared experience and meaning. This is how culture is shared, through “sensory interaction” (Howes, 2019: 22). Through the relationship between the brain and the body, sensory interaction creates a space between persons, generating a sensual communication that opens a place for connection and relationality (Howes, 2009; Buckingham and Degen, 2012).
Vagal Sensory Security: A Virtuous Social Circle
The vagus nerve is the principal constituent element of the “rest and digest system” and is associated with feelings of safety (Breit et al., 2018). On the other hand, the “fight and flight” response is associated with anxiety (Harvard Health Publishing, 2020). The two systems dialogue with one another, assessing if one is in a dangerous or secure environment. Feelings of sensory safety are essential to enable individuals to engage with an “Other” and foster social connection with other bodies, other beings (van der Kolk, 2011). In this way, activating the vagus nerve yields a virtuous circle for social connection through feelings of safety that are driven through body sensation. In other words, the X-cranial nerve generates a sense of safety that gets written into the body. In turn, physical vagal sensory security held in the body is transferred into perception and emotion producing an ontological security (Giddens, 1991). The calm from physical and emotional safety promotes sociality. An openness to engage with others lays the groundwork for shared social experiences which generates space for shared meaning-making and social belonging.
Anxiety, on the other hand, creates a sense of sensory danger and unleashes a vicious circle, cutting persons off from one another. Activating the fight or flight system blocks engagement with an “Other”, limiting empathetic connection. Anxious individuals tend to have trouble regulating their heart rate, find it difficult to achieve a sense of calm, and have less animated facial expressions (Porges, 2011). Rather than creating a porous sensory space between persons that fosters empathy, anxiety erects an impermeable wall forcing individuals to dissociate from their own experiences, and others, as they flee a pervasive sense of threat. However, sensually mediated safety and anxiety are not only individual concerns; they are relation, impact and are impacted by culture. In this way, anxiety and safety are collective and political concerns.
Sensory Safety: The Bridge to Social Belonging
Depression is known to be one of the main contemporary mental health concerns causing feelings of hopelessness and extreme sadness (Breit et al., 2018). Post-traumatic stress disorder (PTSD) is an anxiety disorder rooted in traumatic experience causing sufferers to “to live as though under a permanent threat. They exhibit fight and flight behavior or a perpetual behavioral shutdown and dissociation, with no possibility of reaching a calm state and developing positive social interactions.” (Breit et al., 2018: 7). Depression and PTSD both negatively impact social well-being and inhibit connection between persons.
Loving-kindness meditation, rooted in yoga-based breathing techniques, stimulates the vagus nerve and leads to increased vagal tone among depressed individuals. Among depressed persons, improved vagal tone from meditation is linked with an increase in positive emotions. Consequently, depressed individuals who took up meditation reported an increase in social connectedness, better mood, and reduced stress (Breit et al., 2018). What is more, yoga also improved symptoms in PTSD sufferers, particularly dissociative symptoms that obstruct positive social interactions (Breit et al., 2018). The diminished stress response induced by stimulating the vagal nerve, through yogic practices, and the corresponding dampening of the “fight and flight” system improved positive emotion, sociality, and connection among persons and reduced suffering. In this way, yoga itself is a sensory interaction that prepares the body, through activation of the vagus nerve, for social connection. What can the embodied social drive of the vagus nerve tell us about developing a sense of belonging and acceptance? Can it be leveraged to foster self-acceptance and collective compassion and connection?
Buckingham and Degen’s (2012) study on yoga as a reasearch method to foster connection with abused, vulnerable, and highly marginalized women at an East London women’s centre demonstrates the power of the vagus nerve’s social drive to facilitate connection. The researchers hosted a weekly drop-in yoga class at the centre to develop a relationship with at-risk participants. Yoga is an ancient spiritual practice dating to 2,700 BCE and linked to the Indus Saraswati Valley in India. The root of the word “yoga” comes from the ancient Sanskrit root “Yuj”, meaning “to unite”. With yoga’s emphasis on harmony between mind and body, this unison is seen as the fusion of nature and nurture (Basavaraddi, 2015). Understood in this way, yoga strives to bring together the body, sensation, with the mind, emotion, and its interaction through culture.
Buckingham and Degen (2012) note that yoga’s intent is to balance the body, mind, and spirit making it an inherently holistic practice. As such, yoga is rooted in a basic acceptance that the physical metabolizes the emotional and vice versa. At the East London women’s centre, Buckingham and Degen (2012) found that after yoga sessions, participants were more willing to share their personal experiences. The authors also found themselves reciprocating, sharing experiences they may have ordinarily kept private with more conventional research methods (Buckingham and Degen, 2012). The act of doing yoga together created a shared space of collective feeling through a collective sensuality felt in individual bodies. As yoga instructors, the authors touched the women’s bodies and both participants and researchers became more aware of their own and each other’s bodies (Buckingham and Degen, 2012). Thus, the embodied experience of doing yoga together fostered a sensuous intimacy, creating a safe space between participant and researcher, cultivating a shared vulnerability that led to meaning-making for women from vastly different backgrounds and experiences.
In Western countries, people typically cite health and physical fitness as reasons for starting yoga (Wei, 2016). Yet, the social values of kindness, community, and purpose tend to keep people practicing (Wei, 2016). Yoga’s core principles are mindfulness, being in the moment, and letting go of judgement (Wei, 2016). Just as Buckingham and Degen (2012) demonstrate, these social values are practiced through the body and sensually felt. Yogic activation of the vagus nerve creates a cascade of sensations that foster a calm state of mind. Sensual security allows individuals to create connection through vulnerability. This can be seen in high rates of community involvement and volunteering among yoga practitioners (Wei, 2016), forging relationships among diverse groups of people. As yoga’s popularity spreads, increasing numbers of individuals may experience the multiple sensations of vagus nerve activation as a soothing tranquility. Together these persons may foster collective well-being, non-judgement, and eventually a sense of belonging. In this way, the vagus nerve remains a promising area of sensory inquiry towards social inclusion and acceptance. The vagus nerve may be regarded as a prime embodiment of the “sociality of sensation” (Howes, 2019)
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