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| Name | Class |
|---|---|
| Emory University | OTHER |
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The purpose of this study is to establish the dose-response curve for therapeutic doses of d-amphetamine on tasks of motivation and reward learning in the same participants and to use d-amphetamine as a dopaminergic probe to test newer theories about the role of dopamine in reward-related decision-making.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Placebo, then 10 mg d-amphetamine, then 20mg d-amphetamine | Experimental |
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| Placebo, then 20 mg d-amphetamine, then 10mg d-amphetamine | Experimental |
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| 10 mg d-amphetamine, then placebo, then 20mg d-amphetamine | Experimental |
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| 10 mg d-amphetamine, then 20mg d-amphetamine, then placebo | Experimental |
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| 20 mg d-amphetamine, then 10mg d-amphetamine, then placebo | Experimental |
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| 20 mg d-amphetamine, then placebo, then 10mg d-amphetamine | Experimental |
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| 10 mg d-amphetamine | Drug | 10 mg d-amphetamine dose given (double-blind) and behavioral tasks (EEfRT, PRT, ELT, CGT) administered. |
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| Measure | Description | Time Frame |
|---|---|---|
| Reward motivation as assessed by the Effort Expenditure for Reward Task (EEfRT) | A measure of effort-based decision-making in humans, the Effort Expenditure for Reward Task (EEfRT), will be used. The EEfRT requires participants to choose between a low-effort, low reward task vs a high-effort, high reward task. Willingness to exert effort, or reward motivation, is measured by taking the average number of hard task choices from the first 50 trials. | about 100 minutes to 140 minutes after receiving drug at 1st, 2nd, and 3rd study session |
| Reward learning as assessed by the Probabilistic Reward Task (PRT) | The Probabilistic Reward Task (PRT), which uses a signal detection paradigm, will be used to measure response bias towards rewarded stimuli. | about 100 minutes to 140 minutes after receiving drug at 1st, 2nd, and 3rd study session |
| Measure | Description | Time Frame |
|---|---|---|
| Reward learning as assessed by the Effort Learning Task (ELT) | The novel Effort Learning Task (ELT) will be used, in which participants learn to associate abstract shapes with reward, loss, high effort and low effort outcomes, to examine the effect of dopaminergic stimulation on reward learning. Learning rates are determined for each symbol, and trial-wise learning curves are calculated as metrics of reward learning. |
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Inclusion Criteria:
- Healthy individuals
Exclusion Criteria:
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| Name | Affiliation | Role |
|---|---|---|
| Scott D Lane, PhD | The University of Texas Health Science Center, Houston | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| The University of Texas Health Science Center at Houston | Houston | Texas | 77030 | United States |
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| ID | Term |
|---|---|
| D059445 | Anhedonia |
| ID | Term |
|---|---|
| D019954 | Neurobehavioral Manifestations |
| D009461 | Neurologic Manifestations |
| D009422 | Nervous System Diseases |
| D012816 | Signs and Symptoms |
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| ID | Term |
|---|---|
| D003913 | Dextroamphetamine |
| ID | Term |
|---|---|
| D000661 | Amphetamine |
| D000662 | Amphetamines |
| D010627 | Phenethylamines |
| D005021 | Ethylamines |
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| 20mg d-amphetamine | Drug | 20 mg d-amphetamine dose given (double-blind) and behavioral tasks (EEfRT, PRT, ELT, CGT) administered. |
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| Placebo | Drug | Placebo dose given (double-blind) and behavioral tasks (EEfRT, PRT, ELT, CGT) administered. |
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| about 100 minutes to 140 minutes after receiving drug at 1st, 2nd, and 3rd study sessions |
| Level of influence of counterfactual information on later decision-making, as measured by the Counterfactual Gambling Task (CGT) | Striatal dopamine is involved in signalling counterfactual information, i.e. encoding differences between the value of actual outcomes and hypothetical outcomes of alternative choices. The CGT is a gambling task used to assess the relationship between choice factors (available options, expected value, and outcomes) on self-reported measures of momentary happiness and regret. Participants complete a gambling task and are informed of their outcome and of the counterfactual outcome (i.e. hypothetical outcome had the participant selected another option). With this task, the degree to which participants make choices to avoid potential regret can be estimated. | about 100 minutes to 140 minutes after receiving drug at 1st, 2nd, and 3rd study session |
| Mood state as assessed by the Profile of Mood States (POMS) | The effect of d-amphetamine on mood state will be assessed throughout sessions and will be used as a manipulation check. | 15 minutes before receiving drug and 30, 90, 180, and 210 minutes after receiving drug at 1st, 2nd, and 3rd study sessions |
| Subjective effects of drug as assessed by the Drug Effects Questionnaire (DEQ) | The pharmacodynamics of d-amphetamine will be assessed throughout the study and will be used as a manipulation check. | 15 minutes before receiving drug and 30, 90, 180, and 210 minutes after receiving drug at 1st, 2nd, and 3rd study sessions |
| D013568 | Pathological Conditions, Signs and Symptoms |
| D000588 |
| Amines |
| D009930 | Organic Chemicals |