2.13.0
A Polyvagal Theory of Emotions
This chapter presents various theories of emotion. This is very important because the entire PVT is based on the belief that it is the peripheral activity of the "smart vagus" and not the higher cortical brain that creates feelings of safety, social interaction, true love, and so much more. Does it?
2.13.1
What are emotions?
Look at this woman! Her eyes are wide open and her mouth is open. She is holding her head with her right hand, and her left shoulder is bent forward. Is she afraid? Has she found an incredible deal on the Internet? Or did she just catch her co-worker flirting with the boss? Did her boyfriend or husband say something offensive or exciting? Or is she overwhelmed when she looks at you? We don't know. Without context, we can't tell. But the emotion is there!
For two and a half centuries, philosophers have debated the nature of emotions. Plato saw emotions as part of the soul, often at odds with reason. Aristotle saw emotions as essential to virtue and moral reasoning. Stoic philosophers (e.g., Seneca or Marcus Aurelius) focused on controlling emotions through reason.
René Descartes, a prominent 17th-century philosopher, made a significant contribution to the understanding of emotions. In his work “Les Passions de l'âme” (The Passions of the Soul), Descartes described emotions (which he called “passions”) as fundamentally connected to the body and mind. He identified six basic passions: wonder, love, hate, desire, joy, and sadness. However, he maintained a distinction between soul and body, unite
Emotions and the Vagal Nerve
Claude Bernard, a French scientist (1813-1878), is frequently cited as a founding figure of modern experimental physiology. He was the first to note the intimate connection between the brain and the heart. He identified the vagus nerve as the primary route for this two-way communication (Thayer, 2009).
In The Expression of the Emotions in Man and Animals (1872), Darwin quoted Claude Bernard's description of the two-way vagal nerve involved in emotional physiological responses.
The Polyvagal Theory postulates that activation of the ventral branch of the parasympathetic produces a sense of psychological security. As Porges puts it, “Psychophysiology as a discipline has been interested in using physiological variables to infer information about specific psychological processes.’’ Berntson, Cacioppo, and Grossman (2003) oppose this statement, writing that we can’t say: “if “φ (physiology) then ψ (psychology).“
What, now?
This question is fundamental as we review the PVT, a theory based on a bottom-up concept of emotion.
Bottom-up vs. Top-down
We can broadly classify the theories of emotions into two groups. In the first group, authors think emotions are born in the brain and create physical reactions (body). The second group feels that external events (e.g., confronting a tiger) trigger instant physical responses (e.g., trembling or heart palpitations), which higher centers then perceive. However, this schema is too simplistic, as the two leading theories (James-Lange and Cannon-Bard) see a double explanation (see below).
2.13.2
James-Lange vs. Cannon-Bard
James-Lange and Cannon-Bard's Theories of Emotions
Historically, there have been two fundamental approaches to emotions—the James-Lange and the Cannon-Bard theories—which are two different ways to explaining the physiological and psychological processes underlying emotions.
The James-Lange Theory, developed by psychologists William James and Carl Lange (James, 1922) in the late 19th century, posits that emotions result from physiological responses to external stimuli. The body's reactions (e.g., trembling or accelerated heart rate) are then interpreted by higher centers in the brain. Accordingly, different physiological responses produce different emotions.
The Cannon-Bard Theory, developed by psychologists Walter Cannon (Cannon, 1915) and Philip Bard in the early 20th century as an alternative to the James-Lange theory, it proposes the following sequence: stimulus →, simultaneous physiological response, and emotion. One does not cause the other, but both originate from the thalamus.
In essence, the James-Lange theory emphasizes the role of physiological responses as the source of emotions. In contrast, the Cannon-Bard theory suggests that emotions and physiological responses occur simultaneously and independently.
2.13.3
Bottom-up vs. Top-down: Who is Right?
While opponents of the James-Lange theory criticize its naive bottom-up view (bodily reactions create an emotional state), we must not forget that the theory implies a subsequent top-down phase, as the cortical centers evaluate the bodily reactions. The Cannon-Bard theory shows simultaneous top-down (thalamus to body) and bottom-up (thalamus to higher centers) actions, starting from a subcortical center (thalamus).
Interoception, the ability to perceive internal bodily states such as hunger, thirst, pain, and muscular and visceral sensations has historically been viewed as a purely bottom-up, sensory-driven phenomenon. It's a fundamental basis for embodied selfhood. Recent accounts, however, have expanded this view to include a robust top-down component.
According to Gentsch et al. (2019), visceral signals, such as one's heartbeat, are determined by top-down predictions about the expected interoceptive state of the body (interoceptive inference). You get what you expect. Visceral predictions are generated to adjust how the body organizes internal resources (e.g., heart acceleration or energy release) to respond; not to the present, but to the immediate future. The optimization of energy use in the body is triggered by allostasis, finding stability by anticipating stress.
Current Scientific Approaches
While James-Lang's theory has long been discarded as Cannon-Bard's theory seemed more accurate, current research sees both.
In a recent article published in Nature (Bo, 2023), researchers describe how cognitive reappraisal is fundamental to everyday emotion regulation and cognitive therapies. This process, identified with fMRI, involves multiple networks distributed throughout the brain, including cortical and subcortical areas.
Further Reading
Brain Mechanisms of Emotion in Neuroscience (Bear, Connors, and Paradiso, 2016, Chapter 18, p. 616-643).
The brain basis of emotion: A meta-analytic review (Lindquist, 2012, p. 121-202).
In How Emotions Are Made (Feldman Barrett, 2017), a fascinating 425-page book, Barrett gives an insightful analysis of the evolution of emotion and its role in our daily lives. In Seven and a Half Lessons about the Brain (2020), she elaborates further on her description of emotions.
Therapists working with body-centered approaches may prefer bottom-up theories of emotion because these approaches emphasize the role of physiological processes and somatic experiences in emotional regulation and healing. Bottom-up theories are consistent with their practical professional training, which often focuses on the connection between the body and emotions. In contrast, academically trained therapists, such as psychiatrists and psychologists, may have a more extensive background in cognitive and behavioral theories, which tend to lean toward top-down approaches to emotion processing and regulation.
Here are some reasons why body-centered therapists may prefer bottom-up theories:
Emphasis on the body: Body-centered therapists emphasize the body's role in emotional experience, making bottom-up theories more compatible with their practice. These therapists work directly with the body, using touch, movement, or other somatic interventions to influence emotional states and promote healing.
They focus on physiological processes: Bottom-up theories of emotion emphasize the importance of physiological responses in shaping emotional experiences. Body-centered therapists seek to regulate and balance these physiological processes, making the bottom-up perspective more relevant to their practice.
Trauma and stress: Many body-centered therapies, such as Somatic Experiencing, are designed to address the effects of trauma and stress on the body. Bottom-up theories can help explain how unresolved physiological responses to traumatic events can contribute to emotional and psychological distress, making them a helpful framework for these practitioners.
Holistic approach: Body-centered therapists often take a holistic approach to wellness, emphasizing the interconnectedness of the body, mind, and emotions. Bottom-up theories provide a framework for understanding how changes in the body can influence emotions and mental states, which is consistent with this holistic perspective.
Therapists need to recognize the value of integrating both bottom-up and top-down approaches into their practice, regardless of their background. Emotions are complex and multifaceted, and understanding the interplay between physiological, cognitive, and contextual factors can lead to more effective therapeutic interventions.
Further bottom-up and top-down models
In this view, it seems accurate to position the ideas of Jaak Panksepp, Paul McLean (Triune Brain), and Stephen Porges as a bottom-up perspective, giving more importance to the lower parts of the brain (brain stem and hypothalamus). In contrast, other neuroscientists (e.g., Joseph Ledoux) prioritize cortical processes.
Jaak Panksepp focuses on the neurobiological basis of emotions and the role of subcortical brain structures, thus taking a bottom-up perspective. He identified seven primary emotions — seeking, anger, fear, lust, care, panic/grief, and play — rooted in subcortical brain structures and fundamental to all mammals.
Paul MacLean's Triune Brain is a model that divides the brain into three evolutionary layers: the reptilian complex (brainstem and basal ganglia), the paleo-mammalian complex (limbic system), and the neo-mammalian complex (neocortex). The limbic system, which plays a vital role in emotion processing, is considered an older, more primitive part of the brain, leading to a bottom-up approach.
Porges' polyvagal theory focuses on the role of the vagus nerve and the autonomic nervous system in emotional regulation and social behavior. In this perspective, the interaction of the heart and the branchiomotor nerves (V, VII, IX-XI) creates a sense of security unique to mammals. Although Porges (2024) presents PVT as fundamentally bidirectional, isn't it a bottom-up perspective?
Joseph LeDoux (1996. 2023) emphasizes the role of cognitive processes and higher brain functions in interpreting emotional experience, presenting a top-down perspective.
As illustrated above, these differences parallel the antagonism between the James-Lange and Cannon-Bard theories. While the perspectives of Panksepp, MacLean, and Porges represent a bottom-up approach and contrast with LeDoux's top-down emphasis, it's essential to understand that contemporary emotion research incorporates both bottom-up and top-down processes. This approach recognizes the complex interplay between physiological responses, cognitive processes, and context in shaping emotional experiences.
2.13.4
Somatic and Visceral Systems are Two Things!
The Polyvagal Theory (PVT) focuses primarily on the visceral organs and the autonomic nervous system (ANS), mainly ignoring the somatic system, which includes the skeletal (striated) muscles, skin, and sensory receptors (skin, muscles, and joints). However, the somatic system plays a vital role beyond initiating and regulating voluntary movements (e.g., writing, running, or catching) and maintaining postures (e.g., standing or sitting). It is instrumental in creating a bodily sense of self (self-image) and promoting a pleasant or unpleasant perception of life.
This somatic feedback manifests itself in numerous expressions, both positive and negative, such as “breaking one's back,” “being tense vs. relaxed,” “a weight lifted off one's shoulders vs. carrying the world on one's shoulders,” “feeling heavy vs. feather-light,” and “a heavy heart. These expressions highlight the profound impact of somatic experiences on our overall well-being and emotional state.
2.13.5
The Soldier and the Cook
The somatic and visceral systems can be compared to the two parts of an army.
Soldiers who fight on the front lines (operational units)
Logistics or support units responsible for various critical functions such as supply, transportation, medical care, communications, and maintenance (e.g., the cook). They ensure that frontline soldiers have the resources and support they need to perform their missions effectively.
Heart and respiratory rates covary with specific somatic states (e.g., exercise vs. rest). The visceral system serves the somatic system, constantly adapting to oxygen and caloric needs. As fish evolved their predatory system (jaws and strong facial muscles), their cardiovascular system improved to allow for rapid acceleration and deceleration of the heart. ANS-driven regulation maintains ergotropic engagement and post-chase disengagement, conserving energy. Similarly, the DVC vagal loop (up to the NTS, down through the dorsal parasympathetic) provides the necessary calories (sugars and fats) for the fight.
Both systems are complementary and work together through successive phases of action and pause. However, the cook often works while the soldiers rest and digest. So does the digestive system.
2.13.6
How Exercise and Effort Improve Your Mood
Yoga asanas, stretching sessions, or Pilates classes all work to release chronic muscle contractions. But they also strengthen the muscles. As a result, the body is better able to adapt to its needs, alternating between contraction and relaxation. Depending on the situation, we feel safer with a strong and responsive body or, on the contrary, we let it go and indulge in laziness. This feeling of strength and security is directly related to our somatic system (somatomotor and somatosensory). As civilization has dramatically reduced our somatic efforts, the need to move has increased exponentially. We have escalators, elevators, electric bicycles, automobiles, blenders, and washing machines. So we have to buy home exercise machines, Pilates classes, and fitness sessions. Exercise is not only about losing weight, but also about feeling strong and alive. We can't stop moving!
2.13.7
Does Slowing the Heartbeat Calm Our Anxiety?
How does the Polyvagal Theory answer to this question?
Porges (2024, p. 6) states, “The synergistic effect of slowing heart rate and reducing contractility is experienced as a calm state.” However, this brings us back to the ambiguity of Polyvagal Theory: Is a decrease in ventricular contractility a response to threat or a sign of relaxation? Moreover, there is no clear evidence linking heart contractility to mood regulation.
He also posits that tachycardia (rapid heartbeat) generates anxiety, reducing the complexity of emotional experiences to a simple dichotomy of feeling safe vs. unsafe, depending on the autonomic state—sympathetic vs. parasympathetic. The theory becomes more perplexing when the “dorsal vagal complex” causes neurogenic bradycardia in response to an inescapable threat. In this case, bradycardia is no longer positive, and Heart Rate Variability (HRV) or Respiratory Sinus Arrhythmia (RSA) becomes dangerously reduced.
This raises further confusion: does HRV, merely an index, induce calm? Is there some sensor, an “HRV meter,” signaling this change directly to the brain?
In the discussion about psychopathology and HRV, we observed a recurring fallacy of cause and effect (see polyvagal fallacies). It was unclear whether the HRV was the cause, the effect, or associated with anxiety and depression – cause or correlation.
What is the scientific evidence?
A recent study (HSUEH, 2021) described Cardiogenic control of affective behavioural state. The researchers accelerated the heart of a mouse for a short time (optogenetic stimulation). In a neutral situation, they observed no significantly different behavior. In a context of risk (e.g., mild electric shock), mice with increased heart rate tended to take less risk. The authors suggested that “higher-order brain functions are involved in the processing of interoceptive cues.” They observed specific activation of the NTS (nucleus tractus solitarius) in the spinal cord and posterior insular cortex (pIC) that produced this avoidance. Inhibiting the pIC suppressed this “anxious” behavior. See a summary in The cardiac origin of anxiety (Martini, 2023). The authors didn’t observe an association with the change in HRV.
Gorman and Sloan (2000), in Heart rate variability in depressive and anxiety disorders, describe how depressed patients are more at risk of sudden death. Anxiety Disorders are Associated with Reduced Heart Rate Variability: A Meta-Analysis (Chalmers, 2014) couldn’t observe a consistent change of HRV (or RSA) after a treatment: “Clearly, there is considerable heterogeneity in treatment studies with respect to treatment type and the specific disorder being treated. Thus, it is unsurprising that there is considerable variation in reports on HRV outcomes in response to treatment.”
A recent article, A top-down slow breathing circuit that alleviates negative affect in mice (Jhang, 2024), shows a top-down (cortex to the brainstem) circuit that induces slower breathing and calming anxiety.
2.13.8
Polyvagal Theory and Emotions
Polyvagal Theory is problematic for two reasons:
It focuses far too much on one part of the brainstem, ignoring the rest of the brain (subcortical and cortical parts).
Porges swears by MacLean's triune brain theory, which is odd. MacLean places the siege of emotions in the “limbic system” (paleomammalian) in the subcortical front brain. Porges limits the discussion of emotions to the brainstem: “intelligent vagal,” sympathetic, and “dorsal.” Doesn't he see the conflict, or does the PVT have a cognitive bias?
The PVT doesn't take the somatic system into account properly. It suggests that the DVC is responsible for immobilization, depression, or dissociation. There is a huge lack of information about the neurobiology of these disorders or reactions.
The first diagram shows the triune brain. The limbic system, the siege of emotions for MacLean, is located in a subcortical part of the frontal brain. The second diagram (background image from Sobotta, 1922) shows (yellow square) where most of the polyvagal narrative takes place.
2.13.9
Inconsistency of the Polyvagal Model of Emotions
It is fundamentally problematic to discuss the polyvagal theory of emotions because Porges' account is not sufficiently consistent. It's unclear whether “smart vagal systems” or “social engagement systems” talk directly to each other, as an Open Hearts Assets poster suggests, or — as Porges (2024) vaguely suggests — whether the cortex is involved.
Can two speakers talk together?
Every phone, regardless of its age, is equipped with a microphone and a speaker. Similarly, the motor and sensory nervous systems can be likened to these components at the human level. The motor system enables mimics and vocalization, while the sensory system (e.g., smell, sight, hearing, and taste) receives information. There is an IN, and there is an OUT. Just as two microphones or speakers cannot converse, communication between two “smart vagal systems” – without sensory and cortical involvement – doesn’t make sense.
The Ventral Vagal Complex (VVC)
The polyvagal Ventral Vagal Complex (VVC) is just a microphone–an output. To exchange and connect, humans need a sensory system:
Somatic sensory system (muscles, articulation, and skin).
Special sensory system: CN I (smell), II (vision), VIII (audition and balance), and taste.
Visceral afferent system through the slow sensory fibers of the IX and X, connecting to the NTS (part of the “dorsal).”
The PVT presents neuroception as a unique mammalian property. However, the interoception, which, in the PVT perspective, allows neuroception, relies mainly on the “dorsal vagal” and the somatic tone (relaxed vs. tense). Remember: the VVC is only an output–it doesn’t feel anything.
Cortical participation
The PVT describes the “smart vagal” as it would be the central actor in neuroception. However, screening information happens in the front brain. So, the amygdala constantly scans information for novelty and danger. Higher in the brain, the Anterior Cingulate Cortex (ACC) scans information for “fake news” vs. “true news.” With further centers (e.g., insula or prefrontal areas), they create emotions or cognitive processes and initiate actions. Van der Kolk explains his perspective in The Body Keeps the Score (2014). LeDoux (2023) ceaselessly explains how the cortex participates in making emotions. Human emotions are complex: reducing them to safe vs. non-safe is problematic.
Whether a stranger or a familiar person smiles at you, your higher brain instantly starts making sense of what you see: “She/he likes me” or “She/he wants something from me.” According to the Machiavellian Intelligence Hypothesis theory, the human brain has developed so much that it can deal with the complexity of social life in large groups. There was not only friendship and feelings of safety. There were also lies, competition, and trickery.
Porges likes repeating (2017, p.99) that we “reciprocally regulate each other’s physiological state, and basically create relationships to enable individuals to feel safe.” Later (p. 101): “The phylogenetically newest vagal circuit is available only when the body detects features of safety. In addition to calming our visceral state, this circuit enables the face to work; our face can be expressive and our voice can be prosodic. When these features are projected from others, our body calms and our voice and face express positive affect.”
The Angry Face Paradox
The Angry Face Paradox: if, as Porges suggests, the 'phylogenetically newest vagal circuit (VVC) is only available when the body detects features of safety ', then what about instances when we are angry, unhappy, or unfriendly? Do we not also use the motor facial nerve (CN VII) to express these emotions? And do predators not use their trigeminal nerve to bite their prey? Does a wolf wait until it feels safe to use the so-called ventral vagal complex–and bite? This contradiction highlights the potential limitations of reducing a group of motor nuclei that existed since the first vertebrates to a Social Engagement System.
Making sense
When we meet a person we trust, with a friendly expression and a pleasant voice, we feel better: is this not obvious? But does the VVC do the magic here, and what does “the body detects features of safety” mean? The VVC does not rule the visceral and somatic sensory systems. The cortex commands the smile, and the motor facial nerve pulls the muscles. Similarly, the cortex designs the soft tone, expressed by the larynx AND a softer expiratory action (respiratory muscles). Similarly, what is that “the body calms?” The PVT plays with generic and ambiguous terms. Who knows what “the body” means?
We argue that human communication is a highly complex process that goes far beyond the basic functions of the brain stem. In its focus on the ventral vagal complex, the PVT framework overlooks critical elements such as culture, symbolism, context, and social cues. A broader framework is needed to understand the complexity of human communication fully.
Isn’t it a form of logical fallacy called ad hoc reasoning? This fallacy occurs when an author repeatedly adds new justifications or exceptions to a theory to explain away any evidence that contradicts it, rather than revising or discarding the theory itself. In this case, the person is trying to “patch up” the theory to protect it from falsification, making it more and more convoluted and less credible.
Of course, as the French do, we could say, “L'exception confirme la règle” (the exception confirms the rule). The idea that exceptions confirm a rule is indeed absurd if it means that exceptions strengthen a theory that they contradict. In everyday life, exceptions are not that important. In science, exceptions are critical red flags: one exception can ruin an entire theory. Regularly adding exceptions that contradict a theory weakens rather than strengthens its validity. See the last section on polyvagal fallacies for more.
>> to the next chapter Polyvagal Perspectives