L8 Intrusive Thoughts and Sleep Flashcards
(20 cards)
What are intrusive memories?
When you are reminded of past experiences and it triggers memories to spring to mind
May not always be positive
What 3 options do you have if a song comes on that reminds you of a bad experience?
- Skip the song, have nothing more to do with the song or triggered memory
- Leave song on and relive the experience in detail in the mind
- Continue to listen to the song but actively avoid thinking about the negative experience
What are the methods of the Think/No-Think task?
People first trained to make associations between face and scene - so when shown the face can vividly recall the associated scene and get up to 100% on recognition performance
A third of faces are presented in a green frame and the PPs are asked to visualise the scene and keep the scene in mind for entire time face is on the screen
A third of faces presented in red frame - have to actively avoid the scene its associated with and make mind go blank, pushing the image out of mind
The last third of faces don’t appear to serve as a baseline e.g. skipping a song
What happens after every trial on the TNT task?
They give an intrusion rating, ranging from never to often
What are the results from the TNT task?
People are generally good at the task, can push image out of mine more than 50% of the time
Can practice it and improve avoiding the scenes
People are equally good at avoiding negative scenes as neutral scenes
BUT huge variability in performance, unknown why but important to understand for psychiatric disorders like PTSD and MDD
What is the ‘executive deficit’ hypothesis?
Variability might come from IDs in executive control ability
Suppression ability should be diminished whenever people are in experimental conditions that tax their executive control abilities
Sleep has a big effect on this
Hypothesised that SD may be an important factor underlying the IDs surrounding suppression ability
What is top down suppression?
Retrieval suppression engages the PFC which down-regulates recollection-related activity in the medial temporal love (HPC) via inhibitory top-down mechanisms
How is top down suppression related to SD?
SD reduces functional connectivity between the PFC and MTL resulting in elevated amygdala reactivity to emotional images
Can link to emotion regulation and lack of suppression
SD also impairs the ability to inhibit a motor response during go/no go tasks - loss of suppression ability
What are some findings surround mental fatigue?
Memory suppression ability is compromised under conditions of mental fatigue using a TNT task
Used longer trials for some PPs
Half way through the PPs got progressively worse - mental fatigue
Implications for fatigue from SD
How are memory intrusions related to psychiatry?
They are commonplace in PTSD and MDD
They may increase susceptibility to PTSD and MDD
Sleep disturbance is a recognised symptom of these conditions and may contribute to their onset and maintenance
What is the relationship between memory control and emotion?
Suppressing the retrieval of emotionally negative memories in the face of reminder cues renders them less subjectively aversive
Greater intrusion control is associated with a more positive change in affective evaluation of scenes - helps to reduce affective charge
What were the research questions of Harrington et al.’s study?
- Does SD influence memory suppression ability?
2. Does SD influence the affective benefits of memory suppression?
What methods were used in Harrington et al.?
UG students completed affective evaluation task, rated images on how they felt
Did face-picture learning until 100% performance
Half of PPs slept in lab with full PSG
Other half stayed awake all night - without caffeine
In morning reminded of face-picture pairs
Completed TNT task in 5 blocks and took HRV recordings
Completed another identical affective evaluation task
What were the specific hypotheses of Harrington et al.?
- SD group will report more memory intrusions than the sleep group
- Suppressing emotionally negative memories will render them less aversive
- Affective suppression for negative ‘no-think’ scenes will be greater in the sleep group relative to the SD group
What was the TST of the sleep group?
almost 7 hours, slept very well
What was seen on the ‘think’ trials?
Think trials elicited more intrusions than no think trials, so did the task they were supposed to do and were effective in doing so
What were the results of relapse?
The SD group reported more memory intrusions
The intrusions became less frequent with repeated suppression, but the sleep group get better faster than SD group
The SD group reported more intrusion relapses, the relapses became less frequent with repeated suppression
What were the results of intrusion control and affect suppression?
Greater intrusion control predicted a shift towards more positive affective evaluations of negative no think scenes
This replicated previous studies’ effects
Significant interaction between TNT instruction and group on the change in affect ratings toward negative images
This is specific to memory suppression as wasn’t seen in baseline pairings
What conclusions can be made from Harrington et al.’s study?
SD impairs memory suppression ability due to reduced connectivity between PFC and MTL
Poor intrusion control following SD undermines the affective benefit of suppressing negative memories
What are the implications for psychiatry from this study?
SD could contribute to MDD/PTSD but don’t know why?
Poor intrusion control and reduced positive appraisal may play a part
It is important for interventions as they might target intrusion control to prevent the development of PTSD and MDD in poor sleepers
Treating underlying sleep disturbances could improve symptoms by improving the intrusion control and promote positive reappraisal
