1. Sebastien Naze and Jan Treur Presenter: Jeroen de Man
The 19th International Conference on Neural Information Processing
A Computational Model for Development of Post-Traumatic Stress Disorders By Hebbian Learning
Allright, let’s start!
I am glad to present you the work I’ve been doing during my master project with Jan. Indeed I came to amsterdam and enrolled the master in IS in order to have more freedom in the choice of my courses… and were looking early in the year for a master project in a field related to neuroscience. After several meetings and reading about mental disorders like schizophrenia and ADHD, we opted for a model of PTSD has I had much curiosity in anxiety disorders and the nature of its symptoms.
Sebastien Naze and Jan Treur
Presenter: Jeroen de Man

2. Post-Traumatic Stress
Psychological & physical trauma
PTSD is a disorder that develops during and after a very strong traumatic experience, such as a car accident, house burning or a war. The term has been created during the vietnam war as many soldier suffered from what they encompassed. It often involve psychological and physical dimensions (for example sexual abuse).
We will see after that the disorder may and usually do continue to develop even after the traumatic event itself.

3. Post-Traumatic Stress
Psychological & physical trauma
Symptoms: Flashbacks & Dissociation
Although PTSD is usually accompanied of some other psychological disorders such as depression or personality disorders; 2 types of symptoms are mainly reccorded from literature…
Flashback is defined as a enhanced arousal (excitation) and very sensible appraisal (evaluation) of sensors, that bring people to recall the memory of the trauma unexpectedly for any kind of stimuli. Visual components are recalled and the persons falls back in a state of high emotional involvement and body response.
Dissociation is another regulatory process to cope with the aversive memory recall, which consist to strongly inhibit emotional and body feelings and representation internally. It leads the patient to so-called « out-of-body » experiences, or seeing oneself as a third person.

4. PTSD and Cognitive Control
Flashback
Hypersensitivity and hypervigilance
Over-reaction and re-experiencing
Dissociation
Increased emotional regulation and intentional inhibition
Suppression of body & emotional affects and appraisals
So to sumarize cognitive aspects of the disorder, it relates much to cognitive control. Flashback results in hypersensibility to stimulis and over-reaction to emotional load.
Dissociation is rather a too strong emotional regulation and intentional inhibition of emotions and body feelings.

5. The model ω14 stimulus s2 ω0 ω1 ω17 ω9 ω10 ω16 ω15 ω7 ω8 stimulus s1
ws(s2)
ss(s2)
srs(s2)
control_state(b)
turn_away_preparation(s1)
turn_away_effector(s1)
ω16
ω15 ω7 ω8
stimulus s1
ω18 ω0 ω1 ω5
ω12
ws(s1)
ss(s1)
srs(s1)
emotional_preparation(b)
body_effector(b)
The computational agent model uses sensory representation states for external stimuli and body states, and preparation states for emotional responses and regulation actions to turn away from stimuli that lead to high, disturbing levels of arousal.
It is based on theories from Antonio Damasio regarding the role of the insula and the somatosensory cortices in processing signals regarding bodily states.
The model contains external, intermediate and internal states, delimited by the dashed line. ω6 ω3
ω11
ω13
body sensor
state for b ω2
ss(b)
srs(b) ω4

6. The model Traumatic experience ω14 stimulus s2 ω0 ω1 ω17 ω9 ω10 ω16
ws(s2)
ss(s2)
srs(s2)
control_state(b)
turn_away_preparation(s1)
turn_away_effector(s1)
ω16
ω15 ω7 ω8
stimulus s1
ω18 ω0 ω1 ω5
ω12
ws(s1)
ss(s1)
srs(s1)
emotional_preparation(b)
body_effector(b)
The computational agent model uses sensory representation states for external stimuli and body states, and preparation states for emotional responses and regulation actions to turn away from stimuli that lead to high, disturbing levels of arousal.
It is based on theories from Antonio Damasio regarding the role of the insula and the somatosensory cortices in processing signals regarding bodily states.
The model contains external, intermediate and internal states, delimited by the dashed line. ω6 ω3
ω11
ω13
body sensor
state for b ω2
ss(b)
srs(b) ω4

7. The model Flashback ω14 stimulus s2 ω0 ω1 ω17 ω9 ω10 ω16 ω15 ω7 ω8
ws(s2)
ss(s2)
srs(s2)
control_state(b)
turn_away_preparation(s1)
turn_away_effector(s1)
ω16
ω15 ω7 ω8
stimulus s1
ω18 ω0 ω1 ω5
ω12
ws(s1)
ss(s1)
srs(s1)
emotional_preparation(b)
body_effector(b)
The computational agent model uses sensory representation states for external stimuli and body states, and preparation states for emotional responses and regulation actions to turn away from stimuli that lead to high, disturbing levels of arousal.
It is based on theories from Antonio Damasio regarding the role of the insula and the somatosensory cortices in processing signals regarding bodily states.
The model contains external, intermediate and internal states, delimited by the dashed line. ω6 ω3
ω11
ω13
body sensor
state for b ω2
ss(b)
srs(b) ω4

8. The model Dissociation ω14 stimulus s2 ω0 ω1 ω17 ω9 ω10 ω16 ω15 ω7 ω8
ws(s2)
ss(s2)
srs(s2)
control_state(b)
turn_away_preparation(s1)
turn_away_effector(s1)
ω16
ω15 ω7 ω8
stimulus s1
ω18 ω0 ω1 ω5
ω12
ws(s1)
ss(s1)
srs(s1)
emotional_preparation(b)
body_effector(b)
The computational agent model uses sensory representation states for external stimuli and body states, and preparation states for emotional responses and regulation actions to turn away from stimuli that lead to high, disturbing levels of arousal.
It is based on theories from Antonio Damasio regarding the role of the insula and the somatosensory cortices in processing signals regarding bodily states.
The model contains external, intermediate and internal states, delimited by the dashed line. ω6 ω3
ω11
ω13
body sensor
state for b ω2
ss(b)
srs(b) ω4

9. Development of the disorder
From traumatic episode to chronic disorder
Learning during re-experiences (memory recalls)
Impaired fear extinction mechanism
Fear extinction: studies on animal -> haggard and the animal model

10. Hebbian Learning "neurons that fire together, wire together" ω14
stimulus s2 ω0 ω1
ω17 ω9
ω10
ws(s2)
ss(s2)
srs(s2)
control_state(b)
turn_away_preparation(s1)
turn_away_effector(s1)
ω16
ω15 ω7 ω8
stimulus s1
ω18 ω0 ω1 ω5
ω12
ws(s1)
ss(s1)
srs(s1)
emotional_preparation(b)
body_effector(b)
The computational agent model uses sensory representation states for external stimuli and body states, and preparation states for emotional responses and regulation actions to turn away from stimuli that lead to high, disturbing levels of arousal.
It is based on theories from Antonio Damasio regarding the role of the insula and the somatosensory cortices in processing signals regarding bodily states.
The model contains external, intermediate and internal states, delimited by the dashed line. ω6 ω3
ω11
ω13
body sensor
state for b ω2
ss(b)
srs(b) ω4

11. Simulation scenario Time steps : Action 0-60 : Traumatic event
: Rest period
: Neutral stimuli ("recaller")
: Rest period
: Recaller
: Rest

12. Healthy Subject

13. Sensing neutral and emotional stimuli
Emotional preparation
Learning association

14. Turn away
Control state activates

15. Emotional response ends
Stimuli end
Emotional response ends
In the trace, we see it on the bottom graph, w4, 16, 5 & 18 get back to 0 after the emotional episode.
Learned association between stimuli fades away

16. Neutral stimulus
No emotional response

17. Flashback Subject

19. Learned association between stimuli hardly fades away

20. Neutral stimulus
Emotional response
Learning during re-experience

21. Dissociative Subject

22. Lowered bodily experience
Suppress emotional response

23. Learned suppression hardly fades away

24. Neutral stimulus
Lower emotional and almost no bodily response

25. Conclusion Success in modeling the disorder at cognitive level
Possible uses:
training of therapists
rehabilitation of patients
Questions and remarks:
Sebastien Naze
Jan Treur