Correcting the Cognitive Map with
EMDR: A Possible Neurobiological Mechanism
David Lister MB, BChir. EMDR (Level I and II)
February 2003
The experience of life is commonly likened to a journey through a landscape. This
cannot be an accident; it must be based on neurobiological activity in the brain.
If one is fortunate the journey is made through a pleasant landscape, with occasional
mild adventures to vary the monotony. Travelling is an ancient evolutionary feature
of all animals, and all animal brains have developed fairly uniform methods of
recording the body’s motion through the environment, in different degrees
of complexity (O'Keefe & Nadel, 1978; Stickgold, 2002). Occasionally, a traumatic
disaster upsets an otherwise placid journey.
The hippocampus plays a major role in mapping the journey, and I suggest that
EMDR enables the hippocampus to redraw the map, following a traumatic incident,
which disturbs the geographical or corporeal map, like a volcano becoming active.
I will outline my reason for this in the following short essay.
EMDR alters the nature of traumatic memories. Many patients describe this process
by such phrases, as “It’s getting smaller”, “It is more distant”,
“I am able to look down on it and see it in perspective”. Even if they
describe the change in other ways it often seems to imply an alteration in a cognitive
map. O’Keefe and Nadel, in their book “The Hippocampus as a Cognitive
Map”, make a good case for the theory that this map is built up and indexed
so to speak by the hippocampus. In the rat the hippocampal formation comprises
a surprisingly large part of the brain. As the rat moves about its environment
its position in space is translated into a neuronal code built up by the midbrain,
cerebellum and cortical association areas, and indexed in the hippocampus. Stickgold,
p. 72, also suggests this.
Rats are, so to speak, physical animals. Although Panksepp (1998) has recorded
the ultrasonic giggles of young rats when he tickled them, one cannot imagine
much cognitive insight taking place in a rat brain. Similarly, experimental stress,
although producing visible change in a rats behaviour, is a feeble mirror for
the rich cognitive reaction which we find in humans. The geographical space registered
by the rat’s hippocampus is transformed by the human brain in corresponding
circumstances into a rich geographical and cognitive map. Humans use spatial,
geographical, and temporal terms to describe psychological experience, mirroring
and building on their evolutionary history, (see the Borrelli Column, Chapter
6 – March 2002, EMDR Practitioner).
One could also suggest that not only is there a map of the external environment
indexed by the hippocampus, but the body image is also registered and ordered
there, in association, say, with Penfield’s homunculus. Torture in humans,
using sensory deprivation, rapidly leads to mental disintegration, as the cognitive
map of their body and surroundings breaks up. In the condition known as anosognosia,
the awareness of the left side of the body disappears due to destruction of part
of the left parietal lobe.
I have been impressed by four cases in my practice that have led me to believe
that EMDR alters the body image. I have two female patients who have been cured
of “eczema” following EMDR on the PTSD following their respective mother’s
deaths. Both eczema cures were examples of serendipity after curing the PTSD.
A male patient has been cured of a blistering skin condition, produced by sunlight
on his arms, following a second degree burn to both forearms in a petrol bomb
attack. Lastly, I have a female patient with lower leg paralysis following Guillain
Barre’s disease. She is experiencing improvement in the strength of her limbs
with bilateral hand tapping while she focuses her attention on her lower limbs.
Intense images of “normal” feet and movement of those feet accompany
this while I hand tap. There is no special emotional trauma associated with her
condition. I imagine that her brain still retains a map of her normal body image,
and EMDR facilitates an attempt at reconstruction. This suggests that EMDR does
more than correct emotional dysplasia.
Francine Shapiro discovered the power of eye movement while walking in the park.
Her genius then led her to construct the wonderfully useful therapy that we call
EMDR, theoretically based on what she describes as “reprocessing” neural
networks. If, say, she had been a neurophysiologist interested in the hippocampus
and its role in memory and had experienced the effect of EMDR on her Guillain
Barre’s syndrome, her paradigm would have been quite different, and she would
have constructed a different protocol and theoretical framework for EMDR. I think
that the success of EMDR is based on altering the neuronal synaptic networks of
the brain, especially the hippocampal cognitive map system. I would like to further
suggest that a great deal of the discussion as to the effectiveness of other forms
of therapy compared with EMDR would become superfluous if there was a clearer
understanding of the neurobiological basis for EMDR. I end with the time-honoured
phrase – this needs further neurobiological research.
References
O’Keefe, J and Nadel L. (1978). The Hippocampus
as a Cognitive Map. Oxford University Press.
Panksepp, J. (1998). Affective Neuroscience. The Foundations of Human and
Animal Emotions. Oxford University Press. New York.
Stickgold R. (2002). EMDR: A Putative Neurobiological Mechanism of Action. Journal
of Clinical Psychology. 58.1, 61-75.
©2003 The EMDR Practitioner - All Rights Reserved Worldwide