POST TRAUMATIC STRESS DISORDER AND THE THALAMIC/CORTICAL PAUSE.

ROD GIBSON [*]

AS A COUNSELOR and trainee psychotherapist, I've found Korzybski's thalamic/cortical model an excellent introduction to the subject of brain functions, and have used variants on the "thalamic/cortical pause" for treating stress and phobic symptoms.

I ask clients when dealing with a phobic panic to pause and become aware of their physiological responses to their experience. Conscious awareness of an increase in heartbeat, sweating palms, shallow breathing, etc., then paves the way for the question "is my reaction appropriate to the stimulus," or "do I need to become so frightened because I can see a spider in the bath?" The effects of introducing a pause and becoming aware of one's s immediate process can sometimes yield immediate and most impressive results, and I have increasingly become interested in the mechanics of why this should happen.

From "Implicit" to "Explicit" Memory

While studying the effects and treatment of Post Traumatic Stress Disorder (PTSD), I've encountered models of brain function which seem to me to owe something of their origins to Korzybski's original model. Willem Lammers of the Institute for the Application of the Social Sciences (I.A.S.) in Switzerland has for some years been treating PTSD with therapeutic techniques intended to process patients' experiences from "implicit" to "explicit" memory. In PTSD, Lammers found, sufferers experience the full impact of the original traumatic event in the "here and now." A case of PTSD resulting from a patient's experience of a car crash resulted in her constant re-experiencing of the force and sound of the impact. After therapy the patient could clearly remember the sound and fury of the original event, but no longer experienced it in her "here and now." Lammers describes this shift in memory as being from "implicit" (currently experienced) to "explicit" (remembered events). [1]

"Re-living" the Event

Current psychotherapy practice with PTSD clients frequently involves a "re-living" of the traumatic event which allows the patient to process the event into a narrative. PTSD treatment as a whole frequently focuses on some method of processing these memories from the implicit to the explicit memory system. Daniel Goleman quotes the example of child survivors of a playground shooting at a school in Stockton, California, who developed a playground game named after Patrick Purdy, the gunman.

"In ensuing months, the Purdy game spontaneously appeared in the play of (the) boys and girls ... one of the many signs that those seven minutes and their aftermath were seared into the children's memory. ... These games, played over and over again, let children relive a trauma safely, as play. This allows two avenues for healing; on the one hand, the memory repeats in a context of low anxiety, desensitizing it and allowing a non-traumatized set of responses to become associated with it. Another route to healing is that, in their minds, children can magically give the tragedy another, better, outcome: sometimes in playing Purdy, the children kill him, boosting their sense of mastery over that traumatic moment of helplessness." [2]

The physical brain substrates involved in trauma are neatly described by Joseph LeDoux [3], whose extensive research has identified key brain structures used in information processing. In LeDoux's model, incoming stimuli are received by the amygdala (in the thalamus, a phylogenetically older part of the brain), and the cortex, and are processed by both. However, as the senses are effectively "hard wired" to the thalamus, and signals travel at a finite speed, there is a slight time delay before the cortex has full access to the incoming stimuli. So an archaic fear response is triggered in the thalamus by the presence of something in the bath before the cortex has been able to evaluate the level of actual danger from the spider.

In Danger, "Low Road" Takes Control

LeDoux calls these two processing routes the "high road" and the "low road," and indicates the actual time lag involved could be as little as 20 milliseconds. Charles Darwin described his attempts to suppress his response to a lion behind glass at the Zoo and found that, even with advance knowledge of his safety, he was unable to stop himself starting back in fear when the lion lunged at him.

It seems that the "low road" takes executive control when potential danger threatens. (See Figure 1.)

The hippocampus, key organ of the limbic system, plays a role in this process and appears to act as a link between the amygdala and cortex. Stimuli first processed by the amygdala pass through the hippocampus to the frontal cortex for long-term storage, and as such it appears to play a major role in the processing of memories from "implicit" (amygdala) to "explicit" (cortical). (See Figure 2.)

The amygdala appears to be responsible for generating adrenaline and other stress hormones in the brain. When these hormone levels rise under stress, the executive shifts toward the amygdala which can make faster ("instinctive") responses essential for survival (the "fight or flight" response). At a certain hormonal threshold, the hippocampus is excluded entirely as all resources are commandeered by the amygdala for use in the crisis. Under these circumstances memories become lodged in the implicit system and are not stored in the explicit memory of the frontal cortex. As language is so closely associated with cortical functions, these implicit memories will be pre-verbal in nature and may be re-called only as emotional responses which may be irrational or inappropriate to the "here and now" situation. [4]

This gives us a useful model of the mechanics of trauma, and explains why traumatic experiences are lodged in the implicit, pre-verbal memory. Traditional psychotherapy techniques which process implicit memories into a narrative correlate to the hippocampus acting as the agent of transfer of memories from the amygdala to the frontal cortex, and by "talking through" a patient's experiences use language to facilitate the process. (See Figure 3.)

Recent revolutionary techniques such as EMDR (Eye Movement Desensitization and Reprocessing, see Note 1) are thought to work by direct stimulation of the hippocampal system which is "kick-started" to deal with previously un-processed implicit memories. One of the principle properties of sleep may be to allow the brain a period free from external stimuli so that the day's events stored in the amygdala can be "uploaded" to long-term memory storage in the cortex. It is possible that the eye movements observed in REM (see Note 2) sleep have some correlation to this processing of memories from implicit to explicit systems, and may give us clues as to when the hippocampal system is working at its peak. EMDR uses rapid eye movement techniques in a reversal of this process. By inducing eye movements of a certain type and frequency the hippocampus can appear to access previously inaccessible implicit memories and process them to long-term memory. As this process is essentially non-verbal it bears a closer relationshi p to the original memory storage procedure, and allows patients to deal with trauma without reference to a verbal level.

Korzybski's "thalamic/cortical pause" seems to me to be the father of all these models of brain function, and the illustration on page 193 of Science and Sanity bears an almost spooky structural resemblance to LeDoux's much later model. [5] Korzybski's technique strikes me as a useful method for allowing the cortex access to incoming stimuli under stress, resulting in much lower levels of trauma. LeDoux concedes that the frontal cortex and hippocampus are engaged in some kind of "feedback loop" which can influence events at the amygdala, (and even suggests that further evolution may strengthen cortical control over the amygdala), thus giving scientific support to the idea that a "thalamic/cortical" pause could be an effective way of lowering stress hormone levels in the brain.

(*.) Rod Gibson lives in the North of England and teaches at an Adult Training Centre in Bradford. He is currently in advanced training as a Transactional Analyst and has a small private therapy practice. A member of ISGS since March 1995, he is keen to develop g.s. concepts in the fields of training and psychotherapy, and runs one day introductions to g.s. at Yorkshire Training Centre in Halifax. His e-mail address is: [less than][e-mail][greater than].

NOTES

1. EMDR stands for Eye Movement Desensitization and Reprocessing. It is a complex treatment methodology which combines various aspects of the major theoretical orientations (e.g., psychodynamic, behavioral, cognitive, physiological, interactional and client-centered) in addition to a dual attention stimulus. EMDR is best conceptualized as a method that helps to reprocess dysfunctionally stored experiences. The most recent four rigorously controlled studies demonstrate that 84-90% of single-trauma victims no longer retain the PTSD diagnosis after only three sessions.

"In EMDR sessions the eye movements, or other forms of rhythmical stimulation appear to move information at a rapid rate. Both REM state and EMDR rapidly cause emotional processing and learning to take place. There are a variety of similarities between EMDR and REM-sleep effects and it may be that the deliberate activation of similar eye movement activities link into the same processing mechanisms."

Francine Shapiro, originator and developer of EMDR.

Shapiro, F. (1995). Eye Movement Desensitization and Reprocessing: Basic Principles, Protocols, and Procedures. New York: Guilford Press.

Shapiro, F. & Forrest, M. (1997) EMDR. New York: Basic Books.

2. REM (Rapid Eye Movement) sleep is the name given to the stage of sleep associated with increased brain activity and dreaming. It was discovered by Aserinsky and Kleitman in 1955. The physiological actions that take place during REM sleep induce the sensation of dreaming, and it is believed that REM in fetuses acts as sensory substitutions to stimulate and aid the development of the brain. Jonathan Winson proposed that, "at the age of two when the hippocampus becomes functional," REM sleep no longer aids in nerve growth, it "takes on its interpretive memory function." Dr. Avi Karni also performed studies in which he explored the possibility that REM sleep played a role in the formation of memory. Karni tested whether REM deprivation had any effects upon the learning of a perceptual skill. Results of this experimentation also hint that REM sleep is somehow involved in processing memory.

from [less than]www.wesleyan.edu/synthesis/FRIDAY/frifinal/artsr.htm[greater than]

Shailesh Rao

Jonathan Winson, "The Meaning Of Dreams." Scientific American, vol. 263, November, 1990; p.88.

Karni, Avi. "Dependence on REM Sleep of Overnight Improvement of a Perceptual Skill." Science, vol. 265, July 29, 1994; pp. 679-8.

[The lay reader seeking a contemporary introduction to neurophysiology may find such a presentation in Rita Carter, Mapping the Mind, University of California Press, 1998. -- Ed.]

REFERENCES

(1.) Lammers, Willem. Conference presentation, Institute of Transactional Analysis. Edinburgh, 1999.

(2.) Goleman, Daniel. Emotional Intelligence. Bloomsbury, 1996.

(3.) LeDoux, Joseph. The Emotional Brain. Weidenfeld & Nicolson, 1998.

(4.) Bukovics-Heiller, Birgit. Ego states and the brain; elements of the puzzle. ITA conference papers. Edinburgh, 1999.

(5.) Korzybski, Alfred. Science and Sanity. First Edition, 1933, Fourth Edition, 1958, The International Non-Aristotelian Library Publishing Company.