Module 10: OCD and the role of habits Flashcards
Explain how symptom provocation studies can provide insight into the neural basis of OCD [paraphrasing] Demonstrate how studies using the 'outcome revaluation' paradigm show that the balance between habits and targeted control is disrupted in OCD [analyzing] Take a critical position on the role of habits in OCD based on behavioral and neuroscientific research [evaluating] Define 'cognitive dissonance' and explain how this could cause obsessions to result from compulsions, rather than the other w
How does the C-O-D view oppose the classical view of OCD?
Classical view argues that compulsive actions are a response to obsessive thoughts, but COD argues that obsessions are a form of post-hoc rationalization that reduces cognitive dissonance due to compulsions
How do habits manifest in OCD?
- those with OCD recognize that concerns are unrealistic but they continue to repeat the compulsion (ego-dystonic)
- bias towards appetitive habit formation at the expense of goal-directed behaviour
- avoidant rather than appetitive
- conditioned fear and anxiety are also important for OCD
What was the method used in this study?
Shock avoidance paradigm was used by avoiding receiving electric shocks by pressing correct foot pedal. Some stimuli were warning stimuli that predicted shock to the left and right wrists and a third CS never predicted shocks. Correct responses cancelled the shock but did not stop the CS+. Habit formation was tested using outcome devaluation paradigm, with one wrist being connected from stimulator and other wrist disconnected. Then the task was to avoid the shock given to one wrist
Measured the avoidance responses to the devalued stimulus to explore role of habits
How are compulsions viewed?
As rational avoidance responses triggered by irrational beliefs rather than habits. These are the product of cognitive bias like overestimation of threat, increased personal responsibility and thought-action fusion which form the basis of obsession. Seen as a goal-directed avoidance response. Recorded levels of the shock expectancy to determine if responding was habitual (low expectancy of shock)
What did results find?
No difference in proficiency of task in response to warning stimuli. Before over-training, both groups responded more to valued stimulus than the devalued stimulus. So those with OCD were unimpaired to learn about safety of devalued stimulus. But with OCD patients showed S-R habit learning than control due to greater evidence. Responses to valued stimulus did not differ. No difference in response between medicated and non-medicated responses to the devalued stimuli. No difference in skin conductance found between OCD and controls to warning or safe stimuli. OCD patients reported experiencing a more intense urge to perform unnecessary presses
Points of discussion
- avoidance habits the result of measurable differences in contingency knowledge
- stress responses alone do not create compulsive responses
- no differences between medicated and unmedicated OCD individuals-> limitation
- SCRs not predictive of habit responses
- difficult to separate irrational beliefs from habit behaviour
What does the cognitive school of thought explain compulsivity?
That there is a dysfunction in how the individual assigns value to behavioural alternatives, with stopping having higher costs than benefits. The choice to continue the behaviour is goal-directed and has purpose. So a cognitive bias could be present in individuals giving more responsibility to behaviour than thoughts
What is the alternative proposition?
Goal-directed dysfunction interacts with anxiety and irrational beliefs. so those with OCD do not take control over their actions despite realistic expectations towards value of the outcome
What are the neurobiological parallels in habits and obsessive-compulsive disorder?
Habits and goal-directed actions are two separate systems (reflexive and reflective respectively). Goal directed actions can be less likely due to stress or if behaviour is habitual. Shift from associative to sensorimotor fronto-striatal circuits mediates transition from goal-directed to habitual control of behaviour. DMS linked to goal directed action, DLS to habitual action control, infralimbic linked to both and OFC for goal-directed control for both humans and rodents. vmPFC in goal-directed behaviour for humans, anterior caudate, medial OFC, medial PFC track contingency between actions and outcomes. Increased putamen for habitual control and more white matter connectivity between vmPFC and caudate predicted goal-directed action
Key neurobiological areas in OCD
- increased grey matter volumes in putamen compared to healthy controls
- caudate nucleus and orbital gyrus function abnormally
- fronto-strital loops (network from frontal lobes to striatum through thalamus back to frontal)
What has evidence found about goal-directed dysfunction in OCD?
- dependence on white matter tract connectivity
- bias towards stimulus-response learning and deficits in refraining from responding to stimuli in extinction
- potential regret to operationalize goal-directed behaviour which finds the decision with least regret. Goal-directed behaviour found to be attenuated in OCD
What are the potential explanations for reduced goal-directed responding for those with OCD?
- deficit in action-outcome associative learning and rely on stimulus-response links-> deficiency in explicit knowledge about action-outcome associations
- excessive stimulus-response learning leads to lost sensitivity to action-outcome leads so deficiency in knowledge )activation of ventral striatum during reward anticipation task, learning schema distinguishes between model-free behaviour to habitual and model-based to goal-directed actions)
- problem in OCD is distinguishing between controllers of model-free and model-based learning
What is a problem with the classic OCD model?
Obsessions are thought to drive compulsions, but compulsive behaviors can develop in OCD individuals without obsessions
→ indicative of OCD having a purely behavioral disturbance + it being an egodystonic disorder (despite insight into impossibility of compulsion helping, still performing behavior). This could also be helpful in determining an OCD diagnosis
How can habits explain obsessional thinking?
Could be related to urge to respond in context of cognitive dissonance, conflict arising through this is due to a mismatch of beliefs and behaviours, and obsession being a trigger for it
What evidence provides support for irrational thinking after behaviour?
- shock has been found to play a role in responding to devalued stimuli, but since these behaviours are avoidant then can be difficult to disconfirm these through experience
- higher activation of amygdala when OCD individuals see disorder-relevant stimuli
- trouble recalling extinction memories and show reduced activation in mOFC during extinction learning
