The HPA axis & Memory Function In Humans

1. The HPA axis & Memory Function In Humans Meeting Accident

2. Impact of stress on memory 2 principal effects Forget something due to stress e.g. wedding anniversary Vivid memory of an emotional situation e.g., car accident

3. Differences between STRESS and EMOTION Similarity --> Stress : Always cause an emotion --> Emotion : Can cause a stress In both cases: --> Can identify the source --> Lasts for a brief moment --> Creates physical reactions - Cardiac rhythm perspiration

4. Difference between STRESS and EMOTION Differences : --> Stress always causes an emotion --> Emotion is not always stressful Laboratory : --> Emotion : Images, words, etc. --> Stress : public speaking

5. Impact of EMOTION on Memory

6. MEMORY is a processus that develops in time -Vigilance -Attention consolidation RECALL ENCODING -Attention : Permits elaboration …more elaborate…better recalled

7. Attention, Emotion and Memory.... The amount of attention allowed to an event will depend on the VALENCE of this event

8. A question ….. --> Which one would you remember best? --> the traumatic ones. --> High Valence: Increased Attention --> Better encoding … --> Better encoding… Better recall later A demonstration….

9. The ‘ Flashbulb Memory ’ Phenomenon … February 26, 1997 ... A certain day Explication Emotion Attention Attention = Elaboration

10. Memory of an emotional event First particularity: -Memory for details vs periphery Study of trauma victims --> Excellent memory of traumatic event --> Poor recall of surrounding events ‘Weapon Focus Phenomenon’

11. Weapon Focus Phenomenon

12. Memory of an emotional event Study by Christianson : -Series of Slides: 2 groups Group 1 : Neutral slides through the series Group 2 : One slide depicts a traumatic events In both series : the background is the same (e.g. bicycle/house) Results : Group 1 remember more background information than Group 2 --> Trauma : Focussing on central details

13. Memory of an emotional event -Trauma : Can lead to Post-Traumatic Stress disorder --> Dissociation (might be related to high focus on central) --> Depersonalization (Detachment from self) --> Derealization (Everything seems unfamiliar) --> Flashback (Intrusive Flashbulb memory phenomenon) --> Hyperarousal (Red Flags everywhere) --> Intrusive Symptoms (« Reliving » of the trauma)

14. Acute Stress Disorder vs Post-Traumatic Stress Disorder Acute PTSD Acute Stress Disorder Chronic PTSD Months 1 month 3 months 6 months TRAUMA

15. Memory of an emotional event Focus on Central Details : Memory Bias in ANXIETY Feelings of Lack Of control over « threatening » Situations

16. Anxiety Symptoms Panic Attacks Generalized Anxiety Disorder

17. Anxiety & Memory In anxiety, there is an attentional bias for threat Anxious patients (and also PTSD patients) have a tendency To systematically attend to threatening informations and to Avoid processing non-threatening information Problem in SELECTIVE ATTENTION: --> Capacity to discriminate between RELEVANT and IRRELEVANT information In anxious patients : RELEVANT = THREATENING

18. Anxiety & Memory Study 1 : Eysenck et al., (1987) --> 2 groups Anxious Non-Anxious Task : Listen to words and write them down later --> 2 types of words : Neutral vs Homophones with threat e.g. Die vs Dye --> Results : Anxious patients remember all the negative homophones Conclusion : Memory bias for threatening information

19. Anxiety & Memory Study #2 : Eysenck et al., 1993 2 groups : Phobics for spiders vs controls Task : Stroop neutral vs emotional words RedBlue Yellow JeansHouseSpider GreenBlackPinkCatWebDog Results : Phobics have longer Reaction times to name the color of phobic words Conclusion : Attentional bias against threatening information

20. Memory of an emotional event Second particularity : -Immediate vs Delayed memory Emotional Events : --> Immediate Recall : Poor --> 2 weeks after : Excellent

21. Memory of an emotional event Immediate vs Delayed Memory of emotional events Study by Cahill et al., 1998: 2 groups of controls Task 1 : 12 slides all neutral Task 2 : 12 slides, those 4 in the middle (5-8) are emotional Recall : performed 2 weeks after encoding Emotional Group Neutral group Slide number 1-4 5-8 9-12

22. Memory of an emotional event Biological Explanation Release of Adrenaline Cardiac Rhythm Perspiration Tremors Consciousness of state : Implication : « False-Feedback » Memory

23. Memory of an emotional event Study #2 Cahill et al., (1998) : --> 2 Groups : Placebo vs Propanolol (antagonist adrenaline) --> Both groups received the emotional story with 12 slides Results : Placebo Group Propanolol group Slide number 1-4 5-8 9-12 Conclusion : if you block adrenaline secretion, you block the enhancing effects of emotion on memory

24. Memory of an emotional event Antagonist adrenaline block memory enhancing effects of emotion Application to traumatic syndrome --> New York Scientists : Clinical trial in ASD victims --> Administer propanolol very close to the time of trauma Rationale : By blocking adrenaline surge induced by trauma (with administration of antagonist adrenaline) one might prevent the induction of the traumatic flashbulb phenomenon

25. Hormonal dysfunctions in PTSD Other hormonal dysfunction in relation to trauma Cortisol levels in PTSD patients : --> DECREASED basal cortisol levels --> ENHANCED negative feedback inhibition

26. Hormonal dysfunctions in PTSD 1. Decreased Basal cortisol secretion Yehuda et al., 1992 : Women with a prior history of rape had significantly lower cortisol levels in the immediate aftermath of a rape Conclusion : First trauma : decreased cortisol levels These decreased cortisol levels prevent further stress-related « normal » cortisol response

27. Hormonal dysfunctions in PTSD 2. Enhanced negative feedback sensitivity - CRF Dex : 0.5 mg (usual dose = 1 or 2 mg) PTSD : Suppress cortisol levels faster and with a stronger response Hyper-suppressor to DEX - ACTH GCs Remember : Depressed are non-suppressor to DEX so this is a major difference between PTSD and depression

28. Hormonal dysfunctions in PTSD Yehuda 1999 : Personal communication The children of Holocaust survivors Suffering from PTSD also present The hormonal dysfunction of PTSD Possibility of a Genetic component

29. Impact of STRESS on Memory

30. Impact of STRESS on Memory HORMONES GLUCOCORTICOIDS CRF - + Stress Response Recovery ACTH - + GCs

31. Circadian Rhythm Krieger, 1978 GCs 8 12 16 20 24 4 8 Time

32. HORMONES CRF - + ACTH - + GC Receptors -Type I : High Affinity -Type II : Low Affinity GCs Stress Response

33. Memory Performance Circulating Concentrations GCs Stress & Memory Inverted-U Shape Important implications For the effects of Glucocorticoids on Memory function

34. Memory Performance Circulating Concentrations GCs Stress & Memory Inverted-U Shape Stress/GCs Stress/GCs

35. Stress & Memory Inverted-U Shape & Time of Day GCs AM Levels Placebo : Memory > Memory Performance GCs PM Levels Placebo : Memory < Circulating Concentrations GCs Fehm-Wolfsdorf et al., 1993:

36. Stress & Memory Inverted-U Shape & Time of Day AM Memory Stress/GCs Stress/GCs Memory Performance Memory PM Circulating Concentrations GCs Lupien et al., 2002

37. Stress & Memory Inverted-U Shape & Population -Young -Normal Adults -30% Elderlies -Alzheimer -Depressed Memory Performance -PTSD -Burn-Out Circulating Concentrations GCs

38. Stress & Memory Inverted-U Shape & Population Stress/GCs -Young -Normal Adults -30% Elderlies -Alzheimer -Depressed Stress/GCs Memory Performance Stress/GCs -PTSD -Burn-Out Circulating Concentrations GCs Lupien & McEwen, 1997

39. Memory Performance Circulating Concentrations GCs Stress & Memory Inverted-U Shape Hormone Replacement Protocol Young Metyrapone Lupien et al., 2001

40. Memory Performance Circulating Concentrations GCs Stress & Memory Inverted-U Shape Hormone Replacement Protocol Hydrocortisone Replacement Young Metyrapone Lupien et al., 2001

41. Stress & Memory Conclusion : --> The impact of stress hormones (glucocorticoids) on memory function are RELATIVE, I.e. They depend on --> Time of day --> Population --> Dose