Types of trauma are discussed, also discussed are the nature of traumatic memories from a neuroscience-based microscopic view as well as a macroscopic view. Details of neuronal firings and spikes as well as action potentials are discussed. Everything is finally tied together to provide ways of treating trauma.

1. Traumatic Memories – A Neuroscience Perspective
Homayoun Shahri, PhD, MA, LMFT
http://www.ravonkavi.com
Homayoun.shahri@ravonkavi.com

2. Trauma and Traumatic Memories
● Shock Trauma vs Developmental Trauma.
● Shock trauma is sudden, massive, and may be chronic. It affects individuals
in their core, and may alter the functioning of the brain including the frontal
cortex, limbic system, parietal lobe, insula cortex, and visual cortex, etc.
● Developmental trauma, is usually chronic, happens during developmental
stages, and is mostly due to non-optimality of caretakers’ responses to the
developing child.
● Developmental trauma can and does affect brain functioning but generally
not in the same way as shock trauma.
● Developmental trauma is also referred to as complex trauma.
● At the core of understanding trauma and healing trauma, is the nature of
traumatic memories and their activation.

3. Neurons
● At the core of the brain are the neurons.
● There are about 100 billion neurons in our brain, and each
neuron can have thousands of connections with other
neurons.
● Neurons communicate via their axons (transmitters) and
dendrites (receivers).
● A neuron can have thousands of dendrites, thus receiving
input from thousands of other neurons.
● Neurons however, usually have one axon, but axons can
have many branches

4. Neurons

5. Synapses
● The junction where an axon meets a dendrite is called a synapse.
● The neurons transmit information by their axon to other neurons through synaptic
space.
● When an electrical signal reaches the end of the axon it releases neurotransmitters
contained in Vesicles.
● These neurotransmitters travel through the synaptic space and bind to dendrites of
other neurons, resulting in electro-chemical changes in the body of receiving neurons.
● There are two general types of neurotransmitters
– Inhibitory and excitatory neurotransmitters.
– Excitatory neurotransmitters stimulate the brain (increase the potential buildup in the
receiving neuron)
– Inhibitory neurons calm the brain (reduce the probability of potential buildup in the
receiving neuron).

6. Synapses

7. Neurons and Electro-Chemical Reactions
● The main inhibitory and excitatory neurotransmitters in the brain are
Gaba (Gamma-Amino Butyric Acid), and Glutamate respectively.
● Other neurotransmitters also play a significant role in brain information
processing and memory.
● When the receptors on the receiving dendrites bond with the
neurotransmitters, and electro-chemical change inside the neuronal cell
takes place, this results in increase of the internal potential of the neuron
from a resting voltage of -70 mV to possibly a voltage of +40mV. At this
point the charge rapidly decreases to -90 mV, which results in release of
neurotransmitters into the synaptic space of the receiving neuron through
its axon.
● This event is called action potential and the rise and fall of potential is
called a spike.

8. Action Potentials - Spikes

9. Spike Trains
● A neuron usually releases a sequence of spikes called a
spike train, or a train of action potentials.
● Neurons do not function in isolation.
● The axon of one neuron may form synapses with dendrites
of many other neurons.
● Many neurons may fire action potentials at the same time.
● The question is, what happens when many neurons are
involved in generating action potentials?

10. Spike Trains

11. Neuronal Firing
● Reconstruction of image with one ganglion cell of
salamander using relative latency and spike count

12. Mathematics of Synaptic Firings
● What is the mathematics of synapses? (Joseph LeDoux)
● Exuberance – that is more synapses are made than are
preserved.
● Use – that is the synapses that are preserved are the ones
that are active.
● Subtraction – that the synaptic connections that are not used
are destroyed.
● This points to synaptic plasticity.
● It means the brain is constantly in the process of rewiring
itself, thus forming new synapses, and destroying others.

13. Neural Networks
● Neural networks and memory are associative.
● Associative memory is defined as the ability to learn and
remember the relationship between unrelated items.
● In 1949, Donald Hebb suggested that if the axon of neuron A
is close enough to the dendrite of neuron B to excite it and
result in action potential, and if the process occurs repeatedly
and consistently, then the connection between neurons A and
B will be strengthened, and will result in higher likelihood that
neuron B fires an action potential in response to neuron A.
● Hebbian Axiom: Neurons that fire together wire together.

14. Neuroscience of Memory (A microscopic view)
● Memories are represented by associative neural networks which are
separate but linked together.
● For associative networks to form, constituent networks must have reached a
certain degree of activation.
● This activation is dependent on the constituent components of memory, as
well as the weight of each component.
● The weight of the components is dependent on the cues that were present
during the learning process, and are also present during recall.
● These cues in many cases are emotions associated with the components of
memory.
● The cues in this case may be signals from brain and the body (emotions) that
indicate that we may be in the same emotional state as during the time of
formation of memory.

15. Neuroscience of Memory (Cont)
● It is also very important to emphasize that memories are a
reconstruction of events at the time of recall.
● Our emotional state can influence the way the recalled memory is
remembered.
● The converse is also true in that memories are recalled and
remembered best when one is in the same situation or emotional
state.
● Emotions may affect the recall of certain aspects of memory more
than others.
● In general, the memory of the more emotionally significant aspects of
an experience is remembered better than the more emotionally
benign aspects of memory.

16. Neuronal Firings and Emotional Significance
● Look at checkered patterns.
● Which do you notice?

17. Thalamus and Amygdala
● All the sensory nerves (except for olfactory nerves) end up in
the thalamus and are then relayed to various parts of the
brain including Amygdala.
● The thalamus (which has two halves) can be thought of as
brain’s switchboard or information hub.
● The amygdala is an almond size structure (one on each side
of the brain, deep within the limbic system), which is
responsible for appraisal of stimuli and evaluation of
emotional significance of the stimuli.
● Amygdala has also been named “The Smoke Detector of the
Brain”.

18. Amygdala – Brain’s Smoke Detector

19. The Low Road and the High Road
● High road runs through the hippocampus and anterior
cingulate to the prefrontal cortex, and then is sent to
Amygdala.
● Low road runs directly from Sensory Thalamus to
Amygdala.
● It takes 30 ~ 50 mSec for information to travel Amygdala
via the low road.
● It takes 400 ~ 500 mSec for information to travel to
Amygdala via the high road.

20. The Low Road and the High Road

21. Memory – A macroscopic view
● Memory, in its most general sense, can be defined as what we
consciously recall from past events.
● But memory is more than what we consciously recall from the past.
● If a certain neural pattern has been activated in the past (in response
to external or internal stimuli) then the probability of activating a
similar pattern in the future is enhanced. This is how we remember
and learn from the past.
● The increased probability of firing a similar pattern is how the neural
network remembers.
● Memory storage is the change in probability of activating a particular
neural network pattern in the future.

22. Memory (Cont)
● Memories can be categorized in two broad categories: implicit and explicit.
● Implicit (procedural) memory can exist early in development and can be
present at birth.
● Implicit memory is not subject to recall whether of self or of time (timeless).
● Emotional, somatosensory, and perceptual memories can be encoded as
implicit memories.
● Generally attention is not required for encoding of implicit memories.
● Recall of implicit memories is independent of the hippocampus and medial
temporal lobes, and thus not under conscious control.

23. Memory (Cont)
● Encoding of explicit (declarative) memories begins near
the second year of life, and includes semantic (factual),
and episodic (autobiographical) memories.
● Explicit memories require conscious awareness for
encoding.
● Explicit memories involve a subjective sense of recall and
are not timeless, that is there is the notion of time in
encoding of explicit memories.
● The hippocampus, and the temporal lobes and cortices are
involved in processing and encoding of explicit memories.

24. Memory (Cont)
● Our brain generally does not encode and save every
experience as explicit memory.
● It seems that the more emotionally intense an experience is,
the higher the probability of its encoding and recall. The event
is simply labeled as important (by the amygdalae).
● Events that are filled with fear, terror or are just overwhelming
may not be encoded by the hippocampus.
● Several factors such as amygdala discharge and various
neuroendocrines including noradrenaline and corticosteroids
may inhibit the functioning of the hippocampus, thus blocking
the encoding of the event and later recall.

25. Memory (Cont)
● Fear or terror filled events may be stored in implicit memory as
fragments, while explicit memory is impaired.
● When implicit memory is reactivated, it is not associated with a sense of
time, place, and sense of self in time, nor is there a sense that something
is being recalled. Implicit memory stores emotional dynamics of events,
and not their contents.
● The brain can have implicit memory (mainly stored in the limbic system)
from very early in an infant's life (even prenatally).
● It is only after roughly the second year of life that the hippocampus is
developed enough to encode explicit memory.

26. Memory and Stress
● Stress also mediates encoding and storing of explicit memory.
– Small amounts of stress generally do not have a significant effect on
encoding events into memory.
– Moderate amounts of stress help to encode events into memory for
later recall.
– Large amounts of stress impair memory encoding and recall.
● Chronic Stress affects the size and functioning of the hippocampus,
which mediates encoding of explicit memory.
● Chronic elevated levels of the stress hormone cortisol results in atrophy
of the hippocampus.

27. Traumatic Memories
● In shock trauma, the signals from afferent neurons
(sensory neurons) may not fully reach the cortex to be
processed.
● Hippocampus cannot categorize, organize, and encode
the memories.
● These memories may not be recalled as a complete
whole, but only are recalled as fragments and tend to be
associated with sensory inputs, and certain body states,
which may include sounds, imagery, touch, and certain
body positions.

28. Traumatic Memories (Cont)
● Emotional aspects of the traumatic memories are stored
as implicit memories in the limbic system.
● There is a splitting off or dissociation of contents of the
painful experiences from the emotional aspects and
dynamics of the experiences.
● The painful contents are repressed while the emotional
dynamics are retained as implicit memories.
● Traumatic memories may be repressed, dissociated or
both.

29. Repression vs Dissociation
● Repression is both motivated and defensive.
● Dissociation does not have to be motivated or psychologically defensive.
● Repression refers to formulated experience, and dissociation generally
refers to unformulated experience.
● Repression usually refers to a piece of information that was accessible at
one time but not at another.
● Dissociation usually refers to divisions of experience in which the parts
are side by side, contrasting, and may be concurrent in time.
Dissociation refers to states and systems of states, which are often
mutually exclusive.
● Dissociated memories are especially context-dependent.

30. Recall of Traumatic Memories
● The recall of (degraded) past memories recovers some parts of
these memories but may further augment these memories for
meaning (elaborative repression), in an effort to reduce the
uncertainty, and increase predictability in order to reduce
arousal.
● In dissociation this same process may not occur, as these
memories are highly state dependent and typically are not
amenable to augmentation the way repressed memories may be.
● This is partially due to the nature of the dissociated memories
that overwhelm various neuronal circuits and block the normal
processing of these memories.

31. Gluing of Dissociated Memories and Healing
● It may still be possible to “glue” the dissociated memories together to make
some sense of them, and to reduce arousal.
● For this gluing of dissociated memories to be possible, clients must be able
to tolerate high arousal and not be overwhelmed, while the narrative is
being reconstructed.
● It is understood that the presence of an empathic, supportive, and attuned
therapist is a crucial stem in this process.
● This form of client-therapist connection allows clients to make left
hemisphere centric sense of their right hemisphere representations,
resulting in the capacity to regulate strong emotional states.
● The presence of an empathically attuned therapist may keep the clients
arousal within a tolerable level, causing the integration of traumatic
memories.

32. Case Studies
● My own experiences
● Case of Elizabeth
● Case of Jane
● In both cases, we were able to glue the fragmented and dissociated
memories of the abuse with new memories that were empowering,
reduced their arousal and lowered the activation of their amygdalae.
● It might be possible to trigger synaptic plasticity and reconsolidation of
aversive memory in the lateral amygdala (LA) by introducing new
information at the time of recall and reactivation (Díaz-Mataix, Ruiz
Martinez, Schafe, LeDoux, & Doyère, 2013).