Dopamine deficiency is associated with risk aversion but not loss aversion in Parkinson’s disease
Bibliographic record
Abstract
ABSTRACT Background Clinical evidence suggests that Parkinson’s Disease (PD) patients are risk-averse, but clear experimental evidence of this is surprisingly lacking. Anti-parkinsonian therapy has been reported to increase tolerance for risk, though findings have been mixed, and it has remained unclear whether this results from altered attitudes towards potential rewards, potential punishments or both. In some cases, alterations in reinforcement learning may have also been responsible for the findings. Objective To disambiguate the effects of PD and its therapy on attitudes towards rewards vs. losses in the context of risky decision making unconfounded by reinforcement learning. Method 36 patients with idiopathic PD receiving levodopa monotherapy and 36 healthy age-matched controls performed two behavioural economic tasks aimed at quantifying 1) risk tolerance/ aversion in the gain frame and 2) valuation of gains relative to losses. PD patients performed the tasks on and off their usual dose of levodopa in randomized order; the healthy controls performed the same tasks twice. Results Relative to the healthy controls, unmedicated PD patients showed significant risk aversion in the gain frame, which was normalized by levodopa. There was no difference between PD patients and controls in valuation of gains relative to losses. In addition, across both tasks and regardless of medication state, choices of the PD patients were more driven by expected values of the prospects than were the choices made by controls. Conclusion Dopamine deficiency in PD was associated with risk aversion but not with an altered valuation of gains relative to losses. Financial disclosure/conflict of interest: This work was supported by operating grant MOP-130566 from the Canadian Institutes of Health Research. JB was supported by Canada Research Chair 950-228984 and the Marianne Koerner Chair in Brain Diseases. AJS is supported by the Canada Research Chairs program. Authors declare no competing interests.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.006 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; both teacher heads agree on what is shown here.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".