emotion and motivation - week 10 part 1 Flashcards
post traumatic stress disorder
a traumatic experience
- required to be of a serious nature involving actual or threatened death or serious injury as a victim, witness, close friends or exposure through professional duties
this episode is subsequently re experienced
- triggers often apparently meaningless stimuli that appear capable of reactivating the emotional memory
- as a consequence PTSD patients have avoidance symptoms
—-> behaviourally and cognitively
excessive fear in PTSD?
excessive amygdala activity
PFC not functioning correctly
excessive fear in PTSD?
excessive amygdala activity
2000
subliminal presentation of happy and fearful faces to PTSD patients and controls
- greater activation of amygdala in PTSD patients
- the activation of amygdala correlated with symptom severity in PTSD patients
excessive fear in PTSD?
PFC
2001
PFC important in regulating amygdala specifically the ventral PFC
if not functioning cannot regulate and amygdala generates too much emotional fear response
- amygdala is over active
excessive fear in PTSD?
PFC
script-driven imagery
2001
interview patients about their traumatic episode and they write a script about it
the script is presented to the patient and are asked to read it
reading it brings an intense visual memory of the episode
in PTSD lower activation in the vPFC compared to controls
excessive fear in PTSD?
PFC and amygdala
2005
activity in amygdala and PFC and negatively corrolated
eg. if PFC high in activity amygdala is low in activity because the PFC is inhibiting it more
what is the underlying pathology in PTSD?
is the amygdala the problem?
could be that the overactive amygdala stops the PFC from working very well
what is the underlying pathology in PTSD?
is the PFC the problem
not working properly
so allows amygdala to run out of control
abnormal stress response in PTSD?
noredrenergic system is chronically overactive in PTSD
- therefore stress response is abnormal
however cortisol levels appear lower than normal
1995 - holocaust survivours
but many findings say different, its not universal
link between PTSD and maladaptive fear memories
maladaptive fear memories in PTSD
mechanism might be the memories underpinning the emotional response are maladaptive
–> are too strong, have gone wrong
link between PTSD and maladaptive fear memories
stronger amygdala fear memories?
2002
previous studies show unconditioned activation of the amygdala
- we don’t have to learn that fearful faces are negative
- it is an innate response
might be related to arousal / hyper vigilance
link between PTSD and maladaptive fear memories
how does the enhance memory for the traumatic event come about?
physiological dysregulation may lead to enhanced memory
the brains and bodies of PTSD patients might be different before the trauma
stress system in brain and body –> hydrochloric pituitary axis
- this stress system is abnormal in PTSD patients
—> lower levels or cortisol?
link between PTSD and maladaptive fear memories
enhanced noradrenaline might potentiate traumatic memories
- uni students study
1994
cortisol and NA compete with eachother
NA impacts arousal (increases it)
- study of how video of eye surgery immediately after learning enhanced consolidation
low cortisol –> high NA
- this means emotional memories is enhanced (maybe)
this study was in university students
link between PTSD and maladaptive fear memories
enhanced noradrenaline might potentiate traumatic memories
- recalling event of emotional story
when telling emotional stories a participant will remember more of an emotional story
- this enhancement is completely wiped away if participants given a beta-blocker
—-> preventing NA from working within the brain
so emotional memories depend on NA
if too much NA in someone and they experience a traumatic episode likely that their memory will be enhanced
link between PTSD and maladaptive fear memories
attenuating NA might prevent PTSD
2002
if enhanced NA causes stronger traumatic memories a beta-blocker should prevent the such strengthening
had clinical researchers sitting in casualty wards waiting for victims of trauma to come in
they would solicit consent and give the victims a beta-blocker in order to prevent NA activity (to stop the consolidation of traumatic memory)
- not hugely convincing
- messy
- placebo participants
- tested 1 + 3 months after
still clinical score of PTSD significantly lower in the patient given propanol compared to placebo control group
NA and reconsolidation of traumatic memories
2011
enhanced NA might potentiate the reconsolidation of traumatic memories
often when we are reminded about a memory that triggers a process similar to consolidation
if you remind yourself of a memory its puts it back into a STM state
if remind a memory that memory can need further processing
–> if we interfere with that processing then the memory might go away or be disrupted
NA is important for consolidation ?
even after PTSD has developed what we know is that PTSD patients have low cortisol and high NA that may be important in terms of:
why PTSD began in the 1st place
high NA reconsolidated
- makes traumatic memory worse and worse
- traumatic memory gets stronger
the physiological changes actually cause or contribute to the cause of PTSD
also contributes to the perpetuation of the condition that the traumatic memory keeps on getting stronger and stronger
treatment for PTSD
attenuating NA might cure PTSD
2011
if NA is involved in traumatic memory a beta-blocker could create amnesia
–> beta-blocker after reminding of memory
treatment for PTSD
attenuating NA might cure PTSD
open label study
participants knew if were taking drug or not
gave the patient script to drive imagery and then have heart medication
6 weeks in a row
followed up 1 week and 6 months later
6 months later
2/3 of the patients no longer met the diagnostic criteria of PTSD
treatment for PTSD
extinction of memory
extinction is the inhibition of a previously learned memory
when the conditioned stimulus no longer predicts the unconditonal stimulus
extinction is known to depend on the PFC
impaired PFC function might result in weaker extinction and so enhanced persistence of the traumatic memory
PTSD patients are impaired at fear memory extinction 2009
- PTSD patients donot recall extinction as well as traumatised controls
- PTSD patients have less activation of the vmPFC
