The following information is from an extensive pre-session questionnaire Simon was asked to complete before his first meeting with me: Simon is 43 years old man, married with two adult children; he is a middle-level manager at a supermarket chain, normally a competent and well-organized man. Four months ago he was in a car accident: he was driving home from work in the late afternoon at 75 mph on an Interstate highway when a tractor trailer went out of control just ahead of him, colliding with several other cars. He was convinced that he was going to die; but after sideswiping a couple of cars he ended up in the breakdown lane. Apart from a few minor bruises he reported being unhurt; his air-bag went off and he was wearing his seat belt. He was, however, taken to a local emergency room for an examination.
On arriving home that evening, he felt very shaken and teary, but pushed away the impulse to cry and told himself that he should "pull himself together." The next morning he woke up feeling depressed and anxious, and was unable to organize himself to rent a car and get to work. He became angry with himself. The following day he managed to rent a car and as he began driving to work, he had a panic attack before getting onto the Interstate. He was able to get to work by the back roads, but found himself unable to concentrate at work.
Over the following 4 months he continued to feel "not himself"; he alternated periods of depression and anxiety with bouts of extreme irritability and outbursts of anger, all of which had a negative impact on his work and his marriage. He describes having chronically cold hands and feet, a pounding heart, a knot in his stomach and a fuzzy feeling in his head. Also he notes that whenever he is outside, he has a tendency to be hyper-focused on passing traffic to the point of being distracted from what he is doing. After 2 months, at his wife's urging, he went to see a therapist, but got extremely angry at what he described as the therapist's implication that it was "all in his head." He says that he knows he should not be reacting this way, that it is not rational, that after all "nothing really happened to him," but feels completely powerless to change how he feels. Through a friend he heard about Somatic Experiencing, and on being assured it was "not talk therapy," he decided to give it a try.
When discussing the autonomic nervous system (ANS), pioneering researcher and Nobel prize winner in physiology and medicine, Hess as well as early researcher Gellhorn used the terms "ergotropic" (energy seeking) and "trophotropic" (nutrition seeking) to point out that the two principal branches of the ANS cannot be isolated from the somatic and central nervous systems and the neuroendocrine system. The ergotropic system includes activation of the sympathetic nervous system as well as the motor and premotor system (increased muscle tension and preparedness to act), the endocrine system (increased secretions of a number of stress hormones), and the central nervous system (increased sensory alertness), in a coordinated preparation for strong energy expenditure ("fight or flight"). In contrast, the trophotropic system involves these same systems in a preparation for rest, feeding and recuperation. This recognition of an integrated response of the whole nervous system, especially the integration of the autonomic and somatic systems, is central to our thesis.
Unlike conventional psychotherapy which focuses largely on verbal cognitive processes, the focus of SE is on the functioning of the deeper, regulatory, levels of the nervous system, in particular the autonomic nervous system (ANS); the emotional motor system (EMS) (Holstege et al.,); the reticular arousal systems (RAS) (Krout et al.,; Strominger et al.,); and the limbic system (LS) (Heimer and Van Hoesen,); these four subcortical structures form what we term the core response network; see Figure 1.
There is extensive evidence that these four networks interact strongly (Gellhorn,; Weinberg and Hunt,; Hamm et al.,; Critchley,; Thompson,; Coombes et al.,; Hajcak et al.,; Sze et al.,; Kim et al.,; Herbert and Pollatos,; Price et al.,; Norman et al.,). The ANS can intensify or calm the activity of the viscera, alter blood circulation, trigger hormonal and endocrine activity, change muscle tone, increase or decrease cognitive arousal, and contribute to emotional experience (Norman et al.,).
The LS, including amygdala, hippocampus, and septal regions, is central to fear- and pleasure-based experience and to the recall of emotional significance (Heimer and Van Hoesen,). This network has strong bi-directional links to the ANS (Uylings et al.,), and the RAS (Strominger et al.,), and triggers emotion-specific movement and posture via the EMS (De Gelder,). The RAS involves multiple networks which trigger arousal through several different pathways. It controls alertness and orientation in different contexts, and interfaces strongly with LS, ANS and EMS (Krout et al.,; Berntson and Cacioppo,). The EMS involves multiple subcortical motor centers [striatum, red nucleus, periaqueductal gray (PAG)] which are involved in emotion-specific movements and postures which can occur outside voluntary cortical control. It is primarily extra-pyramidal. It is strongly influenced by ANS, LS and RAS, and provides important kinesthetic and proprioceptive feedback to them (Holstege et al.,; Holstege,). The CRN responds very quickly to arousing or threatening stimuli, with little input from higher cortical evaluative processes (Porges' "neuroception" Porges,).
This view is very similar to Panksepp's concept of the core self (Panksepp,): a network of largely subcortical structures, centered on the PAG, which are responsible for primal affective experiences and their concomitant motor response organization. We also note the similarity to Damasio's concept of the "proto-self" (Damasio,) and Schore's "implicit self" (Schore,). SE views this core system as the primary target for the treatment of stress and trauma.
We suggest that SE works by restoring optimal function to this network by way of the interoceptive (insula/anterior cingulate) and premotor cortices (Critchley et al.,; Craig,). Although words are used in the process of SE therapy, they are used to point to and elicit non-verbal experiences of internal bodily sensation (interoception), sense of position and orientation (proprioception), sensations of movement (kinesthesis), and spatial sense. These are mediated respectively by the insular and anterior cingulate gyrus (Critchley et al.,), the premotor cortex (Desmurget and Sirigu,), the parietal cortex (Bartolomeo,; Briscoe,), as well as by the orbitofrontal cortex (Roy et al.,). All these areas have very rich and direct communication with the subcortical networks mentioned above, and SE views them as the basis for voluntary intervention on the dysregulated subcortical networks; see Figure 2.
Since its first use in physiology, the word "stress" has been subject to multiple definitions and interpretations and the word is often used imprecisely. Hans Selye acknowledged his poor command of English as responsible for a use at odds with that of physics, where "stress" refers to the force acting on an object and "strain" to the resulting distortion; Selye used the word to refer to the response of the organism, and the word "stressor" came to be used for the impacting situation (Rosch,). Stressors may broadly be divided into biological, where the stressor has an unambiguous physical and physiological effect on the organism; and psycho-social, where the effect of the stressor is determined by the interpretation the organism makes of the external situation (Everly and Lating,). Using the same word "stress" to describe the organism's response to these very different categories of events is justified by Walter Cannon's concept of the "stress response" (Cannon,), a supposedly unitary response of the organism to any stressor regardless of its nature.
This early approach led to several difficulties, which have been pointed out by many authors (Levine,; Lupien et al.,; Berntson and Cacioppo,; McEwen and Wingfield,; McVicar,): first, although certain psycho-social situations may be referred to as "stressors," the event can only be so defined in relation to the response of a specific organism, rendering the definition meaningless (it no longer makes sense to assert that a certain situation "is a stressor" in any absolute or generalized sense). Second, the division into physical and psycho-social stressors neglects the fact that the general state of the organism influences its response to every kind of event, not merely psycho-social events (Vosselman et al.,). Some individuals have conclusively demonstrated voluntary (Kox,) and teachable (Kox et al.,) control over functions usually believed to be purely "physiological," such as sympathetic thermogenesis and inflammatory immune responses. The division into physiological and psycho-social is a legacy of the now outmoded Cartesian mind-body separation. Third, current research demonstrates that even the response of the autonomic nervous system to simple physical stressors (pain, temperature, thirst...) is extremely nuanced and individually variable (Saper,), and cannot be summed up as unitary "stress response." In an effort to resolve these issues, attempts were made to define "good stress" and "bad stress" (Selye,), adding awkward and unwieldy concepts to the mix (Levine,).
Although current views of stress emphasize the role of cognitive appraisal of the stress-inducing situation, recent writers (Porges,; Cohen,) have pointed out that emotionally charged and sudden situations are responded to very rapidly at a sub-cortical level, involving the amygdalar complex and the hippocampus, and not initially engaging the complex associative cortex with its capacity for reasoned decision. In fact much psychological research (Bargh and Chartrand,; Chaiken and Trope,; Cohen,) demonstrates that even apparently rational thought processes are strongly influenced by emotional states. Conscious thought and unconscious emotional processes influence each other reciprocally, it is not a one-way street. Emotional processes equally influence the physical state at the pre-motor level; reciprocally, the state of the body frames the emotional response.
Since the 1920s, ideas about the functioning of the ANS have evolved from a simple homeostatic linear reciprocal system (Cannon,; Selye,), through concepts of homeodynamics and allostasis (McEwen and Wingfield,; Berntson and Cacioppo,) to the current framework of an allodynamic system, capable of very complex self-regulatory behavior involving feed-back and feed-forward loops and integration with rostral brain centers (Berntson and Cacioppo,). Predating many of these developments, Levine, in his 1977 Ph.D. thesis (Levine,), suggests that the ANS (and related subcortical structures) form a complex dynamical system (CDS) (Abraham et al.,). He acknowledges Gellhorn's seminal discovery that, although under normal circumstances the sympathetic and parasympathetic (or ergotropic and trophotropic) systems maintain a reciprocal relationship and return to baseline after disturbance (see Figure 3) following even moderately intense disturbance they can become "tuned" (Gellhorn,), chronically biased in one direction, and can fail to return to baseline; see Figure 4. In Gellhorn's experiments, rats subjected to stressful stimuli below a certain threshold demonstrated temporary elevation in sympathetic activation and diminished parasympathetic tone, followed by a spontaneous return to baseline levels; however if the stimulus exceeded a certain level of intensity or duration, the ANS did not return to baseline and the rats remained in a chronic state of elevated sympathetic and depressed parasympathetic activity (Gellhorn,).
Under extreme and inescapable stress, the ANS may start to respond in paradoxical ways, and even manifest simultaneous extreme activation of both sympathetic and parasympathetic branches (Gellhorn,). Working with anesthetized cats, Gellhorn clamped the trachea, inducing suffocation. There was an initial extreme rise in sympathetic arousal, followed by an even greater co-activation of the parasympathetic system. This phenomenon has been verified by other researchers (Paton et al.,), and is believed to underlie the well-recognized phenomenon of "tonic immobility" (Nijenhuis et al.,; Marx et al.,), which is known to occur in both animals and humans under conditions of extreme stress. Gellhorn's animal experiments clearly demonstrate this unexpected behavior of the ANS (Gellhorn,), and Levine clarifies the clinical implications of this phenomenon (Levine,). Levine demonstrates the use of the mathematics of catastrophe theory (Thom,) to explicate and predict the behavior of the ANS under extreme conditions, and relates this model to clinical approaches to treating PTSD and related conditions.
"Stress," in the sense of an undesirable state, is defined by Levine as the inability of the complex dynamical system of the ANS to recover to normal functionality (Levine,). This is distinct from the current concept of allostatic load in describing stress. Allostatic load refers to the complex neurological and endocrine changes ("wear and tear") that result from having to make continual adaptations to environmental challenges (McEwen and Wingfield,), but leave the exact nature of the stress response itself still undefined. The "wear and tear" is the effect of the stressed condition, and it may lead to circular patterns of perpetuated disruption of normal functioning (Juster et al.,). However Levine's approach suggests that to be "stuck" in a "stressed-out" or traumatized state is for the CRN to be stuck in a dysfunctional dynamic mode which is, in principle, fully reversible, and is not determined by the external situation (Levine,). This suggests that (again, in principle) someone whose CRN is fully functional will not accumulate allostatic load in response to challenging environmental circumstances and will thus manifest extraordinary resilience.
As with "stress," the term "trauma" is used in different ways in different contexts. In SE, a traumatic event is defined as an event that causes a long-term dysregulation in the autonomic and core extrapyramidal nervous system (Levine,). The implication of this is that trauma is in the nervous system and body, and not in the event; an event that is very traumatic to one person may not be traumatic to another, as people differ very widely in their ability to handle various kinds of challenging situations due to different genetic makeup, early environmental challenges, and specific trauma and attachment histories.
This view implies a continuum of stress conditions; a chronic but mild elevation of sympathetic response at one end, and chronic extreme activation of both sympathetic and parasympathetic (or more exactly, ergotropic and trophotropic) systems at the other. At precisely what point the stress should be regarded as "traumatic" is less important than the understanding of the nature of the dysregulation of the nervous system; however, the phenomenon (demonstrated in cats by Gellhorn,) of extreme co-activation of sympathetic and parasympathetic systems under life-threatening conditions offers a compelling model for the freeze, collapse, and dissociation often observed in PTSD (Nijenhuis et al.,; Halvorsen,); see Figure 5.
The medical term in common use, post-traumatic stress disorder (PTSD), implies pathology; however SE, (which was developed several years before the definition of PTSD in the DSM III) views the trauma response as part of a natural, non-pathological process that has been interrupted, and therefore prefers the term post-traumatic stress syndrome (PTSS) (Levine,). The criteria laid out in DSM IV and V for the diagnosis of PTSD have been challenged by several authors (Shin and Handwerger,; Bovin and Marx,; Scaglione and Lockwood,) and impose limitations not relevant to the theory of SE; most importantly, the DSM V requires exposure to a situation which is threatening to life or body, and limits the range of peri-traumatic emotion acceptable for this diagnosis. Recent authors have pointed to the diversity of various kinds of trauma, suggesting that a unitary diagnosis of PTSD should be replaced by a spectrum of trauma-related disorders (Bovin and Marx,). The theories of SE might provide a framework for such future classification.