Page numbers listed correspond to the print edition of this book. You can use your device's search function to locate particular terms in the text.
Adaptive behavior. Polyvagal Theory emphasizes the adaptive function of spontaneous behaviors by focusing on the impact that behavior has on regulating physiological state. This perspective is based on an evolutionary model in which behavior is interpreted as adaptive if it enhances survival, minimizes distress, or influences physiological state in a manner that would optimize health, growth, and restoration. At times behaviors that are initially adaptive may become maladaptive. For example, this would occur if an acute behavior that initially enhanced survival or minimized distress during threat is chronically recruited when there is no threat. Such a behavior would be maladaptive, since it would not optimize survival and may compromise physiological function and amplify distress. Trauma may result in reactions that are initially adaptive in a life threat situation (e.g., immobilizing and passing out), which if repeated or slightly modified (e.g., dissociation) in less threatening situations will be maladaptive.
See pages : 43, 45, 55-56, 61, 67, 73, 99, 122, 139, 141-142, 156, 176-178, 195, 200, 202, 205, 209, 212, 229, 241-242
Afferent nerves. Polyvagal Theory focuses on a subset of afferent fibers that send information from the visceral organs to brain structures. These pathways are also called sensory nerves, because they send signals from organs informing brainstem regulatory structures of the status of the organs.
See: throughout
Anxiety. Anxiety is frequently defined from a psychological (emotional feelings of fear or uneasiness) or psychiatric (e.g., anxiety disorders) perspective. Polyvagal Theory emphasizes the autonomic state that underlies the psychological feelings that define anxiety. Polyvagal Theory assumes that anxiety is dependent on an autonomic state characterized by concurrent activation of the sympathetic nervous system with a down-regulation of the ‘ventral’ vagal circuit (see ventral vagal complex) and the social engagement system (see social engagement system).
See pages : 97, 153, 160, 191-193, 200, 216
Attachment. Attachment is a psychological construct reflecting a strong emotional bond between two individuals, such as the relationship between a mother and her child. Polyvagal Theory focuses on the features of safety manifested in the social engagement system (see social engagement system) that enable attachment to occur. Prosodic voices, positive facial expressions, and welcoming gestures trigger through neuroception (see neuroception) feelings of safety and trust that spontaneously emerge when the social engagement system is activated.
See pages : 72-73, 99, 122-123, 183, 230
Autism. Autism spectrum disorder (ASD) is a complex psychiatric diagnosis that includes communication problems and difficulties relating to people. Polyvagal Theory focuses on the observation that a diagnosis of ASD involves features that reflect a depressed social engagement system (see social engagement system). Thus, many individuals with ASD have voices without prosody, have auditory hypersensitivities, have auditory processing difficulties, do not make good eye contact, have flat facial expressivity especially in the upper part of their faces, and have severe behavioral state regulation difficulties that are frequently manifested in tantrums. Polyvagal Theory is not focused on the antecedent cause of these problems, but takes an optimistic perspective and assumes that many of the features of the depressed social engagement system observed in ASD may be reversed through an understanding of how the nervous system, via neuroception, responds to cues of safety. Intervention strategies based on the Polyvagal Theory emphasize re-engagement of the social engagement system. Polyvagal Theory does not make any assumptions regarding features in ASD other than a depressed social engagement system.
See pages : 74-76, 79-80, 87-88, 97, 116, 119, 127, 136, 206-211, 221
Autonomic balance. Autonomic balance is a construct that represents the balance between the sympathetic and parasympathetic branches of the autonomic nervous system. Although several organs receive innervation from both branches of the autonomic nervous system, autonomic balance assumes a linear additive model in which both branches have similar magnitudes of influence. For example, since the sympathetic nervous system increases heart rate and the parasympathetic nervous system decreases heart rate through the vagus (the major neural component of the parasympathetic nervous system), a high heart rate would be interpreted as a manifestation of an autonomic balance biased towards sympathetic excitation. In contrast, a slow heart rate would be interpreted as a bias towards parasympathetic excitation.
Although autonomic balance is a frequently used term, it is often used to indicate dysfunction in the autonomic nervous system (e.g., atypical autonomic balance). From a Polyvagal perspective, a focus on autonomic balance obfuscates the importance of the phylogenetically-ordered response hierarchy of how the autonomic nervous system reacts to challenges. According to Polyvagal Theory, when the social engagement system with the myelinated ventral vagal pathways is engaged, a unique autonomic state emerges that supports an optimal autonomic balance in the regulation of subdiaphragmatic organs. This optimal autonomic balance to subdiaphragmatic organs, via sympathetic and unmyelinated dorsal vagal pathways, is the emergent product of the activation of the ventral vagal pathways. Due to the hierarchical nature of autonomic reactivity, activation of ventral vagal pathways enables both branches of the autonomic nervous system regulating subdiaphragmatic organs from being engaged in defense.
Autonomic nervous system [traditional view]. The autonomic nervous system is the part of the nervous system that regulates the internal organs in the body without conscious awareness. The name reflects that the regulation occurs in an “automatic” manner. Traditional definitions partition the autonomic nervous system into two subsystems: the sympathetic nervous system and the parasympathetic nervous system. Traditional views emphasize the antagonistic influence of the motor pathways of the sympathetic and parasympathetic nervous systems traveling to the target organs and do not emphasize the sensory pathways traveling from the organs to the brain or the brainstem areas regulating both sensory and motor pathways that provide the bidirectional communication between the internal organs and the brain.
See pages : 58-59, 171, 223-224
Autonomic nervous system [Polyvagal Theory]. Polyvagal Theory focuses on the vagus, the primary component of the parasympathetic nervous system. The vagus is the tenth cranial nerve, which connects brainstem areas to several visceral organs. The theory emphasizes the difference between two motor (efferent) pathways that travel through the vagus; each pathway originates in a different area of the brainstem (i.e., dorsal nucleus of the vagus and nucleus ambiguus). The primary motor pathways from the dorsal motor nucleus of the vagus (i.e. dorsal vagus) are unmyelinated and terminate in visceral organs located below the diaphragm (i.e., subdiaphragmatic vagus). The primary motor pathways from the nucleus ambiguus (i.e., ventral vagus) are myelinated and terminate in in visceral organs located above the diaphragm (i.e. supradiaphragmatic vagus).
Polyvagal Theory uses a more inclusive definition of the autonomic nervous system that includes sensory pathways and emphasizes the brainstem areas regulating autonomic function. The theory links the brainstem regulation of the ventral vagus to the regulation of the striated muscles of the face and head to produce an integrated social engagement system (see Figure 1, ventral vagal complex and social engagement system).
In contrast to the traditional model that focuses on chronic influences on visceral organs, Polyvagal Theory emphasizes autonomic reactivity. Polyvagal Theory accepts the traditional model of interpreting chronic autonomic influences on visceral organs as the sum of a paired antagonism between vagal and sympathetic pathways. However, Polyvagal Theory proposes a phylogenetically ordered hierarchy in which autonomic subsystems react to challenges in the reverse of their evolutionary history consistent with the principle of dissolution (see dissolution).
The theory postulates that when the ventral vagus and the associated social engagement system are optimally functioning, the autonomic nervous system supports health, growth, and restoration. During this ventral vagal state, there is an optimal ‘autonomic balance’ between the sympathetic nervous system and the dorsal vagal pathways to subdiaphragmatic organs. When the function of the ventral vagus is dampened or withdrawn the autonomic nervous system is optimized to support defense and not health. According to the Polyvagal Theory, these defense reactions may be manifested as either an increase in sympathetic activity that would inhibit the function of the dorsal vagus to promote mobilization strategies such as fight and flight behaviors or as a biobehavioral shutdown manifested as depressed sympathetic activation and a surge of dorsal vagal influences that would result in fainting, defecation, and an inhibition of motor behavior often seen in mammals feigning death.
See pages : 40, 48-49, 51, 62-65, 68-69, 99, 101-102, 104, 107, 127-131, 141, 157, 164-165, 171-174, 184, 223-228
Autonomic state. Within Polyvagal Theory autonomic state and physiological state are interchangeable constructs. Polyvagal Theory describes three primary circuits that provide neural regulation of autonomic state; these states are selectively regulated by ventral vagal, dorsal vagal, and sympathetic pathways. Autonomic state reflects activation of these pathways. In general, there is a focus on each circuit providing the primary neural regulation for a specific state. This would result in the ventral vagal circuit supporting social engagement behaviors, the sympathetic nervous system supporting mobilized defensive (fight/flight) behaviors, and the dorsal vagal circuit supporting immobilized defensive behaviors. However, autonomic state can support mobilization and immobilization behaviors that are not defensive when coupled with activation of the ventral vagal circuit and the social engagement system (see autonomic balance and social engagement system). Thus, by coupling the social engagement system with the sympathetic nervous system there is an opportunity to mobilize without moving into defense. This is observed in play in which aggressive movements are contained by social engagement behaviors. Similarly, when the social engagement system is coupled with the dorsal vagal circuit, cues of safety (e.g., prosodic voice, facial expression) enable immobilization to occur without recruiting defense (e.g., shutdown, behavioral collapse, dissociation). This is observed during intimacy and in trusting relationships. Thus, through the coupling of social engagement with mobilization and immobilization, the three autonomic circuits support five states associated with different classes of behavior: social engagement, fight/flight, play, shutdown, and intimacy.
See pages : 39, 41, 44-45, 50-51, 68, 75, 83, 105, 117, 156, 164, 219
Biological imperative. Biological imperatives are the needs of living organisms required to perpetuate their existence. This list frequently includes survival, territorialism, fitness, and reproduction. Polyvagal Theory emphasizes that the need to connect with others is a primary biological imperative for humans. The theory emphasizes that through connectedness, physiology is co-regulated to optimize mental and physical health. The theory focuses on the role that the social engagement system plays in initiating and maintaining connectedness and co-regulation.
Biological rudeness. Our nervous system evolved to anticipate reciprocal interactions from others when the social engagement system down regulates autonomic nervous system defenses via the ventral vagus. When this neural expectancy is violated, by either a neglect of the engagement cues or a hostile reaction, there is an immediate and massive shift in the autonomic nervous system to a state that supports defense. This violation frequently promotes an emotional response of being hurt and a personal narrative of being offended. Biological rudeness is a cascade, which starts with a lack reciprocity to a spontaneous social engagement that triggers an autonomic state of defense and ends with an emotional response of being offended that may lead to an aggressive reaction.
See pages : 232-234
Borderline Personality Disorder. Borderline personality disorder (BPD) is a psychiatric diagnosis including features of mood instability and difficulties in regulating emotion. From a Polyvagal perspective, the regulation of mood and emotion involves the neural regulation of the autonomic nervous system. Thus, the theory would lead to hypotheses that borderline personality distorder would be associated with a challenged social engagement system and especially the efficiency of ventral vagal pathways in downregulating sympathetic activation. This hypothesis has been tested and supported (Austin, Riniolo, & Porges, 2007).
Connectedness. Polyvagal Theory refers to the social connectedness that define trusting relationships that humans have with others as a biological imperative. Humans can also feel connected to their pets, which are usually other mammals with reciprocal social engagement systems.
See pages : 51, 180-182, 192, 230
Co-regulation. Within Polyvagal Theory co-regulation involves the mutual regulation of physiological state between individuals. For example, within the mother-infant dyad the mother not only is calming her infant, but the infant’s response of relaxing and calming to the mother’s vocalizations, facial expressions, and gestures has the reciprocal effect of calming the mother. If the mother is unsuccessful in calming her infant, the mother’s physiological state also becomes dysregulated. Co-regulation can also extend to groups such as families. For example, following the death of a family member, frequently the presence of others support the biobehavoral state of grieving person.
See pages : 48-51, 80, 118-120, 195
Cranial nerves. Cranial nerves emerge directly from the brain, in contrast to spinal nerves that emerge from segments of the spinal cord. Cranial nerves are functionally conduits that contain both motor and sensory pathways. Humans have twelve pairs of cranial nerves (I–XII). They are: the olfactory nerve (I), the optic nerve (II), oculomotor nerve (III), trochlear nerve (IV), trigeminal nerve (V), abducens nerve (VI), facial nerve (VII), vestibulocochlear nerve (VIII), glossopharyngeal nerve (IX), vagus nerve (X), accessory nerve (XI), and hypoglossal nerve (XII). Other than the vagus, which provides pathways for both sensory and motor communication with several visceral organs, cranial nerves primarily relay information to and from regions of the head and neck.
See pages : 134-135
Cybernetics. MIT mathematician Norbert Wiener (1948)coined the term cybernetics to define a science of control and communication in animals and machines. Polyvagal Theory uses concepts from cybernetics to emphasize the feedback loops within the body and between individuals that regulate physiological state.
Similar concepts discussed throughout.
Death feigning/shutdown system. In mammals under certain conditions the nervous system reverts to a primitive defense response characterized by appearing to be inanimate. This defense pattern is frequently observed in vertebrates, such as reptiles and amphibians, that evolved prior to the phylogenetic emergence of mammals. However, mammals are great consumers of oxygen and the immobilization required in feigning death is associated with a decrease in the capacity to oxygenate the blood and an inability to deliver sufficient oxygenated blood to the brain to support consciousness. This massive depression of autonomic function is due to activation of the dorsal vagal circuit, which depresses respiration (apnea) and slows heart rate (bradycardia). Polyvagal Theory proposes that death feigning is an adaptive response to life threat when options for fight/flight behaviors are minimized, such as during restraint or when there is an inability to escape. During conditions of life threat, the nervous system through neuroception may revert to the ancient immobilization defense system. Polyvagal Theory emphasizes aspects of this life threat response in understanding trauma reactions. The theory functionally operationalizes a trauma response as the body’s physiological response to life threat that would include features of death feigning such as fainting (vasovagal syncope), defecation, and dissociation.
See pages : 50, 55, 61, 103, 131
Depression. Depression is a common and serious mood disorder that influences feelings, thoughts, and behavior. Polyvagal Theory assumes that depression has a physiological state profile that could be explained by the Polyvagal Theory. Hypothetically, the profile would include a down regulation of the social engagement system and atypical coordination between sympathetic and dorsal vagal pathways. The latter point may lead to behavior oscillating between high levels of motor activity coincident with sympathetic activation and lethargy coincident with depressed sympathetic activity and increased dorsal vagal activity.
See pages : 75, 135, 138, 75">75, 135, 138, 153, 200, 206
Dissociation. Dissociation is a process of losing a sense of presence resulting in experiencing a disconnection and a lack of continuity between thoughts, memories, surroundings, and actions. For many people dissociation is within the range of normal psychological experiences and is manifested as daydreaming. For others dissociation is sufficiently disruptive that it results in a loss of personal identity and creates severe difficulties in relationships and in functioning in everyday life. Trauma history is frequently associated with the severe disruptive effects of dissociation and may result in a psychiatric diagnosis.
Polyvagal Theory interprets dissociation in response to life threat as a component of an immobilization or death feigning defense response. Polyvagal Theory interprets dissociation as an adaptive reaction to life threat challenges, which unlike the effects of a prolonged death feigning response would not compromise the neurobiological needs for oxygen and blood flow. Based on Polyvagal Theory, one could speculate that there may be gradations in reactions to life threat from total shutdown and collapse mimicking the death feigning responses of small mammals to an immobilization of the body during which muscles lose tension and the mind dissociates from the physical event.
See pages : 54-55, 62, 161-162, 168, 174, 176, 200, 235
Dissolution. Dissolution is a construct introduced by the philosopher Herbert Spencer (1820–1903) to describe evolution in reverse. It was adapted by John Hughlings Jackson (1835–1911) to describe how brain damage and brain disease function similarly to a process of “de-evolution” in which evolutionarily older circuits become disinhibited (Jackson, 1884). Polyvagal Theory adapts dissolution to explain the phylogenetically ordered hierarchy in which the autonomic nervous system responds with progressively evolutionarily older circuits.
See pages : 64, 172; see phylogenetically order hierarchy
Dorsal vagal complex. The dorsal vagal complex is located in the brainstem and consists primarily of two nuclei, the dorsal nucleus of the vagus and the nucleus of the solitary tract. This area integrates and coordinates sensory information from visceral organs via sensory pathways in the vagus that terminate in the nucleus of the solitary track with the motor outflow originating in the dorsal nucleus of the vagus that terminate on visceral organs. Both the nucleus of the solitary tract and the dorsal nucleus of the vagus have a viscerotopic organization in which specific areas of each nucleus are associated with specific visceral organs. The motor pathways from this nucleus provide the unmyelinated vagal pathways that travel through the vagus and primarily terminate in subdiaphragmatic organs. Note that a few of the unmyelinated vagal pathways may also terminate on supradiaphragmatic organs such as the heart and bronchi. This is the likely mechanism for bradycardia in preterm infants and is potentially related to asthma. The vagal pathways originating in the dorsal nucleus of the vagus have been referred to in various publications as the dorsal vagus, the subdiaphragmatic vagus, the unmyelinated vagus, and the vegetative vagus.
See pages : 111, 133, 173, 226, 243
Efferent nerves. Efferent nerves are the neural pathways that send information from the central nervous system (i.e., brain and spinal cord) to a target organ. They are also called motor fibers because they send signals to organs that influence how the organs function.
See: throughout
Enteric nervous system. The enteric nervous system consists of a mesh-like system of neurons that governs the function of the gastrointestinal system. The enteric nervous system is embedded in the lining of the gastrointestinal system, beginning in the esophagus and extending down to the anus. The enteric nervous system is capable of autonomous functions, although it receives considerable innervation from the autonomic nervous system. Polyvagal Theory assumes that optimal functioning of the enteric nervous system is dependent on the ventral vagal circuit (see ventral vagal complex) being activated by the dorsal vagal circuit (see dorsal vagal complex) not being recruited in defense, which occurs when the ventral vagal circuit is activated.
Fight/flight defense system. Fight and flight behaviors are the predominant mobilized defense behaviors of mammals. Activation of the sympathetic nervous system is necessary to support the metabolic demands required to flee or fight. Withdrawal the ventral vagal circuit and a dampening of the integrated social engagement system facilitate efficient and effective activation of the sympathetic nervous system in supporting the metabolic demands for fight and flight behaviors.
See pages : 50, 54-56, 61, 66-69, 72, 80-84, 101-103, 108, 111-112, 128-129, 137-138, 144, 156-157, 171-173, 174, 178, 194, 199, 202, 224-229, 234, 236, 243
Heart rate variability. Heart rate variability reflects the variation in the time between heartbeats. A healthy heart does not beat with a constant rate. Only a heart without neural innervation would beat at a relatively constant rate. Much of the variability in heart rate is determined by vagal influences especially through the myelinated ventral vagus (see ventral vagal complex), which is manifested in respiratory sinus arrhythmia (see respiratory sinus arrhythmia). Other contributions to heart rate variability may come through the dorsal vagus. Blocking vagal influences to the heart with atropine will remove virtually all heart rate variability.
See pages : 36-42, 59, 97-98, 106, 144
Homeostasis. Homeostasis reflects the neural and neurochemical processes through which our body regulates visceral organs to optimize health, growth, and restoration. Although the word is derived from the Greek word meaning same or steady, homeostasis is better understood as the product of a negative feedback system that oscillates around a “set” point. In some physiological systems, greater amplitude of the oscillations (i.e., rhythmic deviations from the set point) is a positive indicator of health (e.g., respiratory sinus arrhythmia), and in other situations it is a negative indicator of health (e.g., blood pressure variability). Oscillations in physiological systems are primarily a reflection of neural and neurochemical feedback mechanisms.
Interoception. Interception is the process describing both conscious feelings and unconscious monitoring of bodily processes by the nervous system. Interoception, similar to other sensory systems, has four components: 1) Sensors located in internal organs to evaluate internal conditions; 2) Sensory pathways conveying information from the organs to the brain; 3) Brain structures to interpret sensory information and to regulate the organs response to the changing internal conditions; and 4) Motor pathways that communicate information from the brain to the organs and to change the state of the organs. In Polyvagal Theory interoception is the process providing the signal to the brain of changes in physiological state (see Porges, 1993). In contexts in which there are cues of risk or safety, interoception would occur after the process of neuroception. Interoception may result in a conscious awareness of a bodily response. In contrast, neuroception occurs outside conscious awareness.
See pages : 142-143
Listening. Listening is an active process to understand the acoustic information being presented. In contrast to listening, hearing is the detection of acoustic information. Polyvagal Theory emphasizes the role of middle ear structures in enhancing the ability to listen and understand human voice.
See pages : 48-49, 71-72, 75, 87-96, 100, 103, 108-109, 114-116, 118, 134, 170, 186, 189, 191
Listening Project Protocol. The Listening Project Protocol (LPP) is a listening intervention designed to reduce auditory hypersensitivities, improve auditory processing, calm physiological state, and support spontaneous social engagement. The intervention is currently known as the Safe and Sound Protocol (SSP). The SSP is available to professionals only through Integrated Listening Systems (http://integratedlistening.com/ssp-safe-sound-protocol/).
The LPP/SSP is a theoretical departure from the disciplines frequently involved in the treatment of auditory processing disorders, which emphasize the role of central structures in the processing of speech. LPP/SSP was theoretically designed to reduce auditory hypersensitivities by recruiting the anti-masking functions of the middle ear muscles to optimize the transfer function of the middle ear for the processing of human speech. LPP/SSP is based on an “exercise” model that uses computer altered acoustic stimulation to modulate the frequency band passed to the participant. The frequency characteristics of the acoustic stimulation are theoretically selected based on the documented frequency band and weights associated with contemporary techniques used to extract human voice from background sounds. During normal listening to human speech, via descending central mechanisms, the middle ear muscles contract and stiffen the ossicular chain. This process changes the middle ear transfer function and effectively removes most of the “masking” low frequency background sounds from the acoustic environment and allows human voice to be more effectively processed by higher brain structures. Modulation of the acoustic energy within the frequencies of human voice, similar to exaggerated vocal prosody, is hypothesized to recruit and modulate the neural regulation of the middle ear muscles, functionally reduce auditory hypersensitivities, stimulate spontaneous social engagement, and calm physiological state by increasing the influence of ventral vagal pathways on the heart.
Theoretically, the vocal music has been processed to “exercise” the neural regulation of the middle ear muscles to improve the auditory processing of human vocalizations. The acoustic stimuli, which represent the range of normal human speech, are modulated and presented to both ears. The intervention stimuli are delivered through headphones. The protocol consists of 60 minutes of listening on five sequential days and is delivered via a MP3 or iPod device in a quiet room without major distractors, while the clinician, parent, or researcher provide social support to insure that the participant remains calm. For additional information see Porges et al. (2013, 2014) and Porges & Lewis (2010).
See pages : 87-96, 114-116, 208, 211
Middle ear muscles. The two smallest striated muscles in the body, the tensor tympani and the stapedius, are located in the middle ear. The middle ear is the portion of the auditory system between the eardrum and the cochlea (inner ear). Middle ear structures include the ossicles and the muscles regulating the stiffness of the ossicle chain. When these muscles are tense, they stiffen the ossicle chain and increase the tension of the eardrum. This process changes the characteristics of sound that reaches the inner ear. The inner ear transduces sound into a neural code that is transmitted to the brain. The tensing of the middle ear muscles reduces the influence of low-frequency sounds and functionally improves the ability to process the human voice. The middle ear muscles are regulated by special visceral efferent pathways (see Figure 1 and special viceral efferent pathways).
See pages : 76-79, 87-89, 91, 94-95, 109, 114-117, 137-138, 186, 207
Middle ear transfer function. As middle ear muscle tone changes there is a change in the transfer of acoustic energy through the middle ear structures to the inner ear. Borg and Counter (1989) described a role of the middle ear muscles in facilitating the extraction of human speech by dampening the transmission of low frequency noise from the external environment to the inner ear. The Borg and Counter model explains why auditory hypersensitivity is a symptom of Bell’s palsy, a condition characterized by a lateralized paralysis of the facial nerve including the pathway regulating the stapedius muscle in the middle ear. Borg and Counter (1989) provide a scientific basis to investigate whether improvements in auditory processing would occur if neural regulation of the middle ear muscles were rehabilitated through the exercises embedded in LPP/SSP (see Listening Project Protocol). The extrapolation from normalizing the middle ear transfer function to improved vagal regulation of the heart is based on the theoretical model elaborated in Porges and Lewis (2010) and linked to the social engagement system described in the Polyvagal Theory (Porges, 2011).
Neural expectancy. Within Polyvagal Theory, neural expectancy refers to the predisposition wired into our nervous system that anticipates a reciprocal response to a spontaneous social engagement behavior. Neural expectancies promote social interactions, bonding, and trust. When neural expectancies are met calm states are supported, while violations of these expectancies may trigger physiological states of defense.
See: play and neural exercise
Neural exercise. Polyvagal Theory focuses on specific neural exercises that provide opportunities to optimize the regulation of physiological state. According to the theory, neural exercises consisting of transitory disruptions and repairs of physiological state through social interactions would promote greater resilience. Play, such as peek-a-boo, is an example of a neural exercise that parents frequently employ with their children.
See pages : 45, 80, 82-84, 91, 118, 121, 155-156, 187, 191, 208
Neuroception. Neuroception is the process through which the nervous system evaluates risk without requiring awareness. This automatic process involves brain areas that evaluate cues of safety, danger, and life threat. Once these are detected via neuroception, physiological state automatically shifts to optimize survival. Although we are usually not aware of cues that trigger neuroception, we tend to be aware of the physiological shift (i.e., interoception). Sometimes we experience this as feelings in our gut or heart or as an intuition that the context is dangerous. Alternatively, this system also triggers physiological states that support trust, social engagement behaviors, and the building of strong relationships. Neuroception is not always accurate. Faulty neuroception might detect risk when there is no risk or identify cues of safety when there is risk.
See pages : 43, 65-73, 83-87, 91-94, 107, 113, 143, 147-150, 153, 171, 175, 177-178, 186, 197, 230, 238
Nucleus ambiguus. The nucleus ambiguus is located in the brainstem ventral to the dorsal motor nucleus of the vagus. Cells in the nucleus ambiguus contain motor neurons associated with three cranial nerves (glossopharyngeal, vagus, and accessory), which control striated muscles of pharynx, larynx, esophagus, and neck through somatomotor pathways and the bronchi and heart through myelinated ventral vagal pathways.
Nucleus of the solitary track. The nucleus of the solitary track is located in the brainstem and serves as the primary sensory nucleus of the vagus.
Oxytocin. Oxytocin is a mammalian hormone that also acts as a neurotransmitter in the brain. Oxytocin is primarily produced within the brain and released by the pituitary gland. In women oxytocin acts to regulate reproductive functions including childbirth and breast-feeding. However, oxytocin is released in both sexes. In the brain, oxytocin is involved in social cognition and social recognition. The social functions of oxytocin are related to the influence of oxytocin on the brainstem areas involved in the ventral vagal complex and the dorsal vagal complex. Since both vagal complexes have abundant oxytocin receptors, many of the positive features attributed to oxytocin overlap with the positive features described in the Polyvagal Theory as social engagement and immobilization without fear.
Parasympathetic nervous system. The parasympathetic nervous system is one of the two main divisions of the autonomic nervous system. The primary neural pathways of this system are vagal and primarily support health, growth, and restoration. However, Polyvagal Theory emphasizes that under certain life-threatening conditions, specific vagal pathways, which would normally support homeostasis and health, can respond defensively and inhibit health-related functions.
See pages : 58-59, 62-63, 130-131, 169, 171-172, 212, 223-225
Physiological state. See autonomic state.
See: throughout
Phylogenetically ordered hierarchy. Polyvagal Theory proposes that the components of the autonomic nervous system react to challenges following a hierarchy in which the phylogenetically newer circuits react first. This pattern of evolution in reverse is consistent with the Jacksonian principle of dissolution (see dissolution). Functionally, the order of reactivity proceeds through the following sequence: myelinated ventral vagus, sympathetic nervous system, unmyelinated dorsal vagus.
See pages : 64, 128, 225; see dissolution
Phylogeny. Phylogeny is the science that describes the evolutionary history of a species. As a science, it provides evolution-based methods for taxonomic grouping of organisms. Within Polyvagal Theory there is an interest in the phylogenetic transitions in autonomic function among vertebrates with a focus on the transition from primitive extinct reptiles to mammals.
See pages : 46, 61-63, 76, 82, 99, 101, 107-108, 128, 130-131, 161, 225-226, 229, 244
Play. Polyvagal Theory defines interactive play as a “neural exercise” that enhances the co-regulation of physiological state to promote the neural mechanisms involved in supporting mental and physical health. Interactive play as a neural exercise requires synchronous and reciprocal behaviors between individuals and necessitates an awareness of each other’s social engagement system. Access to the social engagement system insures that the sympathetic activation involved in the mobilization does not hijack the nervous system, resulting in playful movements transitioning into aggressive behavior.
See pages : 61, 80-83, 129, 154-157, 243-244
Post-Traumatic Stress Disorder (PTSD). PTSD is a psychiatric diagnosis reflecting the consequences of experiencing a traumatic event such as sexual assault, severe injury, war, earthquake, hurricane, or a bad accident. Polyvagal Theory focuses on the response to the event and not the qualities of the event. This focus on the response is consistent with the observation that there are great variations in individual reactions to a common ‘traumatic’ event. A common ‘traumatic’ event may be devastating to an individual and disrupt their life, while others may be more resilient and less affected. Because of the range of reactivity and recovery trajectories, Polyvagal Theory focuses on the profile of the reaction to infer shifts in neural regulation of autonomic state and emphasizes the mediated via dorsal vagal pathways life threat response. Based on Polyvagal Theory, many of the problems associated with PTSD are emergent features following a life threat response that are manifested as a dysfunctional social engagement system and a low threshold for either the sympathetic nervous system or the dorsal vagal circuit to respond in defense.
See pages : 56, 70, 76, 79-80, 85, 90, 165, 202
Prosody. Prosody is the intonation in voice that conveys emotion. Polyvagal Theory emphasizes that prosody is mediated by vagal mechanisms and, similar to heart rate variability (i.e., respiratory sinus arrhythmia), conveys information about physiological state.
See pages : 50, 64-65, 75, 91-92, 104, 109, 114, 134, 137, 139-140, 143, 147, 186
Respiratory sinus arrhythmia. Respiratory sinus arrhythmia (RSA) is characterized by rhythmic increases and decreases in heart rate occurring at the frequency of spontaneous breathing. The amplitude of this periodic heart rate process is a valid index of the influence of the ventral vagus on the heart (see Lewis et. al. 2012).
See pages : 38, 41, 59-60, 87, 98, 144
Safety. Polyvagal Theory proposes a neurophysiological model of safety and trust. The model emphasizes that safety is defined by feeling safe and not by the removal of threat. Feeling safe is dependent on three conditions: 1) the autonomic nervous system cannot be in a state that supports defense; 2) the social engagement system needs to be activated to down regulate sympathetic activation and functionally contain the sympathetic nervous system and the dorsal vagal circuit within an optimal range (homeostasis) that would support health, growth, and restoration; and 3) to detect cues of safety (e.g., prosodic vocalizations, positive facial expressions and gestures) via neuroception. In everyday situations, the cues of safety may initiate the sequence by triggering the social engagement system via the process of neuroception, which will contain autonomic state within a homeostatic range and restrict the autonomic nervous system from reacting in defense. This constrained range of autonomic state has been referred to as the window of tolerance (see Ogden et. al. 2006; Siegel, 1999) and can be expanded through neural exercises embedded in therapy.
See: throughout
Safety in therapeutic settings. From a Polyvagal perspective feeling safe is an important moderator influencing the effectiveness of many therapeutic manipulations including medical procedures, psychotherapy, and psychoeducation. The theory assumes that physiological (autonomic) state functions as an intervening variable influencing the effectiveness of treatment. More specifically the theory assumes that for treatments to be effective and efficient it is necessary to keep the autonomic nervous system out of states of defense. Activating the social engagement system with its ventral vagal pathways (see ventral vagal complex) enable the autonomic nervous system to support health, growth, and restoration. In this state of safety, the autonomic nervous system is not easily recruited in defense. Note that this principle of ‘feeling safe’ as the precursor of treatment is not well integrated into educational, medical, and mental health treatment models. In addition, the physical environments in which therapy is delivered are seldom vetted for cues (e.g., low frequency background sounds, street noises, ventilation system sounds, vibrations from elevators and escalators) that would trigger, via neuroception, defensive states of the autonomic nervous system, which would interfere with the effectiveness of the treatment.
See pages : 86, 94, 202, 222, 231, 237, 242
Self-regulation. Self-regulation is a term frequently used to describe an individual’s ability to regulate their own behavior without the aid of another person. Self-regulation is often a defining feature of a child’s ability to deal in the classroom or in a novel situation. Polyvagal Theory does not treat self-regulation as a learned skill, but interprets self-regulation skills as a product of the nervous system that can maintain feelings of safety in the absence of receiving cues of safety from another person. The theory emphasizes that through processes of co-regulation, an individual develops a capacity to self-regulate. The theory emphasizes that the mutual, synchronous, and reciprocal interactions between individuals that define co-regulation function as a neural exercise enhancing the ability to self-regulate in the absence of opportunities to co-regulate.
See pages : 97-125
Singing. Polvagal Theory interprets singing as a neural exercise of the social engagement system. Singing requires slow exhalations, while controlling the muscles of the face and head to produce the modulated vocalizations that we recognize as vocal music. The slow exhalations calm autonomic state by increasing the impact of ventral vagal pathways on the heart. During the exhalation phase of breathing, vagal motor fibers send an inhibitory signal (i.e., vagal brake) to the heart’s pacemaker that slows heart rate. During the inhalation phase of breathing the vagal influence to the heart is diminished and heart rate increases. Singing requires longer exhalations relative to inhalations, which promotes a vagal mediated calm physiological state. The process of singing couples the exercise of turning on and off the ‘vagal brake’ with the exercise of the neural regulation of the muscles of the face and head, including facial muscles, middle ear muscles for listening, and muscles of the larynx and pharynx for vocal intonation. Thus, singing provides an opportunity to exercise the entire integrated social engagement system. Chants, oral readings, and playing a musical instrument would also provide opportunities to exercise the system.
See pages : 71, 92-93, 117-118, 185-186, 189
Single trial learning. Single trial learning is a specific type of learning which occurs in a single pairing of a response and stimulus and is not strengthened over time by repeated exposures. Polyvagal Theory proposes that most cases of single trial learning occur when the response includes features of the dorsal vagal circuit. Moreover, Polyvagal Theory suggests that the profound shutdown reactions to life threat, which are often antecedent to PTSD, are a manifestation of single trial learning. Thus, single trial learning paradigms in which the conditioned responses include defecation, death feigning, fainting, and nausea may provide insights into the treatment of survivors of trauma.
See pages : 162-167
Social engagement system. As illustrated in Figure 1, he social engagement system consists of a somatomotor component and a visceromotor component. The somatomotor component involves special visceral efferent pathways (see special visceral efferent pathways) that regulate the striated muscles of the face and head. The visceromotor component involves the myelinated supradiaphragmatic vagus that regulates the heart and bronchi. Functionally, the social engagement system emerges from a heart–face connection that coordinates the heart with the muscles of the face and head. The initial function of the system is to coordinate sucking-swallowing-breathing-vocalizing. Atypical coordination of this system early in life is an indicator of subsequent difficulties in social behavior and emotional regulation.
See pages : 47-51, 68-69, 72-73, 76-77, 80-87, 91-92, 96, 111-123, 129, 138, 147, 151, 157, 166, 175, 185-186, 188, 190, 194, 210, 234-236, 242-243
Figure 1 The Social Engagement System
The social engagement system consists of a somatomotor component (solid blocks) and a visceromotor component (dashed blocks). The somatomotor component involves special visceral efferent pathways that regulate the striated muscles of the face and head, while the visceromotor component involves the myelinated vagus that regulates the heart and bronchi.
Somatomotor. Somatomotor pathways are motor pathways regulating striated muscle. The pathways regulating the striated muslces of the face and head travel through cranial nerves and those regulating the muscles of the limbs and trunk travel through spinal nerves.
Special visceral efferent pathways. Special visceral efferent fibers originate from motor nuclei in the brainstem (ambiguus, facial, and trigeminal) that develop from the branchiomotor column (i.e., ancient gill arches) of the embryo and innervate striated muscle fibers (muscles of mastication involved in ingestion, facial musculature involved in emotional expression, muscles of the pharynx and larynx involved in vocalizations, and muscles of the middle ear involved in listening) associated with the pharyngeal arches. Special visceral efferent pathways compose the somatomotor component of the social engagement system (see Figure 1).
Subdiaphragmatic vagus. The subdiaphragmatic vagus is the branch of the vagus that connects brainstem areas with organs located below the diaphragm. The motor fibers in this branch of the vagus originate primarily in the dorsal nucleus of the vagus. These motor fibers are predominantly unmyelinated.
See pages : 111, 132, 158-163, 167, 170, 172-174, 226
Supradiapragmatic vagus. The supradiaphragmatic vagus is the branch of the vagus that connects brainstem areas with organs (e.g. bronchi, heart) located above the diaphragm (see Figure 1). The motor fibers in this branch of the vagus originate primarily in the nucleus ambiguus, the source nucleus in the brainstem for the ventral vagus. These motor fibers are predominantly myelinated.
See pages : 110, 132, 162, 173-174
Sympathetic nervous system. The sympathetic nervous system is one of the two main divisions of the autonomic nervous system. The sympathetic nervous system functions to increase blood flow throughout the body to support movement. Polyvagal Theory focuses on the role that sympathetic nervous system has in increasing cardiac output to support movement and fight-flight behaviors.
See pages : 51, 54-55, 58-59, 63, 69, 80, 82-83, 101-105, 108, 111-112, 128-132, 138, 145-146, 157, 160-161, 171-174, 185, 194, 199, 212, 223-228, 236
Taste aversion. Taste aversion is an example of single trial learning (see single trial learning). Generally, taste aversion develops after ingestion of a food that causes nausea or vomiting. Patients receiving nausea inducing chemotherapy have been found to develop aversions to normal dietary items consumed in close temporal relation to treatment administrations. Polyvagal Theory proposes that the neural process underlying the perseverance of taste aversion may lead to a better understanding on how trauma gets encoded in the nervous system and why trauma is difficult to treat.
Vagal afferents. Approximately 80 percent of the neural fibers in the vagus are afferent (sensory). Most vagal sensory fibers travel from the internal organs to an area of the brainstem known as the nucleus of the solitary track. Of note, medical training provides a very limited understanding of vagal afferents. Thus, medical treatments seldom acknowledge possible influences due to feedback from the treated organ to the brain. Changing sensory feedback has the potential to influence mental and physical health.
Vagal brake. The vagal brake reflects the inhibitory influence of vagal pathways on the heart, which slow the intrinsic rate of the heart’s pacemaker. If the vagus no longer influences the heart, heart rate spontaneously increases without any change in sympathetic excitation. The intrinsic heart rate of young healthy adults is about 90 beats per minute. However, baseline heart rate is noticeably slower due to the influence of the vagus functioning as a “vagal brake.” The vagal brake represents the actions of engaging and disengaging the vagal influences to the heart’s pacemaker. It has been assumed that the vagal brake is mediated through the myelinated ventral vagus. Although the unmyelinated vagal fibers appear to mediate clinical bradycardia in preterm neonates, this process has not been conceptualized in the vagal brake construct. Thus, discussing clinical bradycardia as a product of a vagal brake should be clarified by emphasizing that it is through a vagal mechanism different from the protective ventral vagal influence.
See pages : 57-68, 111, 146, 149
Vagal paradox. Vagal influences to visceral organs have been assumed to be protective. However, vagal influences can be lethal by stopping the heart or disruptive by triggering fainting or defecation. These responses, often linked to fear, are mediated by the vagus. The vagal paradox was initially observed in research with preterm infants in which respiratory sinus arrhythmia was protective and bradycardia was potentially lethal. This created a paradox, since both respiratory sinus arrhythmia and bradycardia were both mediated by vagal mechanisms. The contradiction was solved by the introduction of the Polyvagal Theory, which linked these responses to different vagal pathways.
See pages : 57, 60, 106-107, 130-131, 163
Vagal tone. The construct of vagal tone, or more accurately cardiac vagal tone, is usually associated with the more tonic influence of the myelinated ventral vagal pathways on the heart and is frequently indexed by the amplitude of respiratory sinus arrhythmia.
See pages : 38-39, 58-59, 143-145, 157, 174
Vagus. The vagus is the tenth cranial nerve. The vagus is the primary nerve in the parasympathetic division of the autonomic nervous system. The vagus functions as a conduit containing motor pathways originating in nucleus ambiguus and the dorsal nucleus of the vagus and sensory fibers terminating in the nucleus of the solitary tract. The vagus connects brainstem areas with structures throughout the body including the neck, thorax, and abdomen. Polyvagal Theory emphasizes the phylogenetic changes in the autonomic nervous system in vertebrates and focuses on the unique change in the vagal motor pathways that occurred with the emergence of mammals.
See: throughout
Vegetative vagus. See dorsal vagal complex.
Ventral vagal complex. The ventral vagal complex is an area of the brainstem involved in the regulation of the heart, bronchi, and the striated muscles of the face and head (see Figure 1). Specifically, this complex consists of nucleus ambiguus and the nuclei of the trigeminal and facial nerves regulating the heart and bronchi through visceromotor pathways and the muscles of mastication, middle ear, face, larynx, pharynx, and neck through special visceral efferent pathways.
Visceromotor. Visceromotor nerves are motor nerves, within the autonomic nervous system, that regulate smooth and cardiac muscles and glands.
Yoga and the social engagement system. Polyvagal Theory deconstructs yoga practices involving breath into specific neural exercises of the vagal brake (see vagal brake). Pranayama yoga is functionally a yoga of the social engagement system, since it involves neural exercises of both breath and the striated muscles of the face and head (see Figure 1).
See pages : 118