Lecture 2: Drug Habits, Cognitive Contol And Neural Basis

Question 1

What are the two criteria of goal-directed action and explain them

Answer 1

• the (cognitive) belief criterion = performance is mediated by a representation of the causal relationship between the action and its outcome
• the (motivational) desire criterion = performance is mediated by a representation of the current goal or incentive value of the outcome

Question 2

Habit

Answer 2

= instrumental response that is triggered by a stimulus and that does not depend on the current motivation for the outcome of the behavior

Question 3

Explain the law of effect and how it related to habits

Answer 3

The experience of reward following an instrumental response leads to the strengthening of a mental association between contextual stimuli (S) and the response (R), so in the future the context will directly activate the response through the S-R association. This will also happen with the omission of an aversive event. In contrast, the occurrence of an aversive outcome (or cancellation of a reward) should weaken the S-R association.

Question 4

What is the difference between habits and goal-directed behavior

Answer 4

Only in goal-directed behavior is performance mediated by knowledge of the response-outcome relationship and an evaluation of the anticipated outcome in light of one’s current motivation. Habits are mediated by S-R links and are therefore “behaviorally autonomous” of the current desirability of the outcome (the behavior is under external stimulus control), it is stimulus dependent and goal independent.

Question 5

What two people are associated with the Dual-Processes Instrumental Action (the habit account)

Answer 5

Everitt and Robbins

Question 6

Explain the dual-process instrumental action

Answer 6

= automatic inflexible behavior may result from strong S-R habit formation and/or from disrupted goal-directed action

Question 7

What areas (according to Everitt & Robbins) are involved in initial drug use, drug habits and drug abuse/addiction

Answer 7

Initial use: craving and goal-directed drug-seeking = PFC, mesolimbic dopamine pathway
Drug habits: nigrostriatal dopamine pathway (substantial nigra —> posterior putamen)
Drug abuse/addiction: compulsive behavior = PFC dysfunction/damage + mesocortical dopamine pathway (ventral steam entail area —> PFC)

Question 8

Explain the outcome devaluation paradigm

Answer 8

Phase 1: instrumental learning phase —> a hungry rat is trained to press a lever to obtain food (in a Skinner box)
Phase 2: outcome devaluation phase —> rat is removed from the box and receives unlimited access to food in a separate cage (saturation), or gets injected with something that will make him nauseous; the outcome (food) is devalued
Phase 3: critical test phase —> rat is returned to skinner box and has the opportunity to press the lever again. If pressing the lever is goal-directed, this should be adjusted after devaluation. If the behavior has become a habit, it should not be adjusted.

Question 9

What was the outcome of the outcome devaluation test in rats at moderate and extensive training and was this replicated in humans?

Answer 9

Moderate: lever presses at valued outcome was significantly higher than at devalued outcome
Extensive: lever presses at valued outcome was not significantly different from devalued outcome
—> this was replicated in humans

Question 10

What 2 areas in humans have been implicated in goal-directed action and what is this connected to

Answer 10

• ventromedial prefrontal cortex (cortical)
• caudate (subcortical)
  —> dorsomedial striatum

Question 11

What 2 areas in humans have been implicated in habits and what is this connected to

Answer 11

• premotor cortex (PMC)
• posterior putamen
  —> dorsolateral striatum

Question 12

Explain cue reactivity as indirect evidence for habits

Answer 12

Several cue reactivity fMRI studies show that pictures of substances activate the striatal habit region (dorsal striatum) which could indicate the activation of a habit

Question 13

Do substances have an acute effect on goal-directed action (explain with example)?

Answer 13

Yes. Subjects were given either alcohol or placebo and then trained to press a button for either chocolate or water. They were then satiated on chocolate, and there was a strong outcome devaluation effect in the placebo group but this was reduced in the group that had alcohol —> acute alcohol shifted the general balance from goal-directed control towards reliance on habits

Question 14

Does drug seeking become habitual with repetition?

Answer 14

Yes. Rats were assigned to a short or long training group and trained to press a lever for alcohol. Alcohol was then devalued by satiation and the animals were tested in extinction. Within each training group, half got an implant in the dorsomedial striatum (goal-directed behavior) and the other half in the dorsolateral striatum (habits) —> supports the idea that there is a transition from goal-directed alcohol-seeking behavior to a habit that is insensitive to devaluation

Question 15

Is habit formation accelerated for drug rewards relative to neutral rewards (example)?

Answer 15

Yes. Rats were trained to press a lever for either food or alcohol and these were then devaluated. Devaluation of food reduced lever pressing more than devaluation of alcohol.

Question 16

Does substance abuse lead to a general tendency to rely on rigid habits (example)?

Answer 16

Yes. Fabulous fruits game; humans are taught to press left or right at presentation of a certain fruit to get another fruit (which gets them point that can be turned into money). Then some of the fruits are devalued, which means you have to refrain from pressing upon seeing it. Showed that people with history with abuse performed worse.

Question 17

Are drug habits compulsive (example)?

Answer 17

Not certain. Rats were trained to self-administer cocaine and at a later stage sometimes a lever press would lead to an electric shock. After moderate training, punishment suppressed drug seeking. After extensive training, a subgroup of rats continued to work for cocaine even when they received electric shocks. As in humans, this addictive-like behavior was only present in a small portion of subjects using cocaine (just like in humans, only a small portion of people that use gets addicted).

Question 18

What are changes in brain volume in addicts compared to healthy individuals

Answer 18

• PFC gray matter volume has been shown to decrease gradually but can be attenuated after periods of abstinence. Nonabusing individuals with a family history of substance abuse have also been shown to have gray-matter reduction
  —> may be more of a risk factor
• frontal white matter is affected by substance abuse and to some degree also appears to constitute a vulnerability factor

Question 19

What 3 executive functions seem to be impaired in individuals with substance abuse

Answer 19

• cognitive flexibility
• decision making —> more risk taking and perseverating on bad choices
• inhibitory control

Question 20

What is the clinical relevance of findings regarding impaired decision making

Answer 20

In order to take into account an inability to forego immediate gratification (and focus on long-term goals instead), it can be chosen in treatment to attach immediate positive consequences to the desired behavior (eg. contingency management)

Question 21

What are the areas are responsible for the following things; habits, craving/goal-directed behavior, cognitive control functions

Answer 21

Craving/goal-directed behavior = mesolimbic
Habits = nigrostriatal
Cognitive control functions = mesocortical

Question 22

What are 3 areas in which the most gray matter reductions are found

Answer 22

• PFC
• cingulate cortex
• insula

Question 23

What 3 areas have neuroimaging studies most consistently related executive control deficits/dysfunction to

Answer 23

• prefrontal cortex
• anterior cingulate cortex
• orbitofrontal cortex