SAQ Anderson et al.

What was the big picture question that motivated the 2016 PET study? [1 pts]

What is the role of dopamine in attentional biases for reward?

What was the specific research question stated and addressed in the study? [2 pts]

What is the role of dopamine in maintaining attentional capture by reward cues even when they no longer predict reward?

Describe the training task and how it was used to associate cues with reward. What aspect(s) of task performance was (were) used to measure reward-learning? [2 pts]

Participants performed a visual search task, identifying a bar’s orientation within a red or green target circle. Each color was linked to a different reward (red = high, green = low). Reward-learning was measured by response time (RT) to locate and report the target.

Describe the two different scans used in the test phase of this study. What was different about them that made it possible to detect individual differences in participants’ DA release related to attentional capture by reward? [4 pts]

• Scan A: Trials included either distractors in previously reward-associated colours (red/green) or no

• Scan B: No reward-associated distractors appeared.

• The difference was the presence/absence of reward-linked distractors. Comparing dopamine (DA) release between scans isolated how reward associations affected attentional capture.

How did the task used during the test phase measure attentional capture by reward? Please state the results they found. [2 pts]

• The task measured attentional capture by comparing response times (RTs) between trials with reward-associated distractors versus no distractors.

• Results:

  • Slower RTs occurred when high-value distractors appeared, showing involuntary attentional capture.

  • This effect was strongest early in testing but diminished over time.

Describe the relationship they observed in the test phase of the experiment between reaction time and DA availability in the dorsal striatum [2 pts].

A positive correlation was found between attentional capture (RT slowing from high-value distractors) and dopamine release in the dorsal striatum (right caudate/posterior putamen). Greater attentional capture = greater DA release.

The authors split the participants into two groups to look more closely at differences in responses. What two patterns of results did they observe? [2 pts]

high bias group

• stronger attentional capture

• released more dopamine in the scan with distractors.

low bias group

• no evidence of attentional capture

• released less dopamine in the scan with distractors

How did the authors link their results to previous findings relating DA levels measured by PET to individual differences? List 3 previous findings, their limitations, and how this study helped to address them. [6 pts]

DA links to drug-cue craving (PET).

• Limitation: Only drug rewards studied.

• This study: Showed DA also drives non-drug reward capture.

DA ties to impulsivity/reward motivation. 

• Limitation: No attention-learning link.

• This study: Linked DA to learned attentional capture.

DA involved in habit formation. 

• Limitation: No attention-bias persistence data. 

• This study: Revealed DA maintains attentional biases post-reward.

Describe the reaction time findings that were observed on average for healthy participants versus depressed patients in the depression study discussed in class. What cognitive process did they measure? How do you interpret the differences observed between groups in the depression study with reference to what was observed in the PET study [6 pts]?

• Depressed patients showed no VDAC and there was no significant difference in RT when high-value distractor was present.

• Study measured attentional bias.

• Suggests that depression is associated with reduced attentional biases toward rewarding stimuli.

What is the ONE most important take-home message from these studies regarding the role of reward-related attentional biases in motivated behaviour? [3 pts]

Dopamine signaling in the striatum plays a critical role in value-based attention, driving automatic attentional capture by reward cues and explaining individual differences in motivated behaviour.