A selective effect of dopamine on information-seeking
- Affective Brain Lab, Department of Experimental Psychology, University College London, United Kingdom
- The Max Planck UCL Centre for Computational Psychiatry and Ageing Research, University College London, United Kingdom
Figures
Figure 1
Stock market task.
(A) Participants observed the evolution of a financial market after investing in two of its five companies. They then indicated whether they believed their portfolio value likely went up or down relative to the previous trial and indicated their confidence in their answer. They then indicated how much they were willing to pay to receive or avoid information about their portfolio value. Next, their portfolio value in points was presented on screen or hidden (‘XX points’ was shown).
Figure 2
L-DOPA does not alter general aspects of information-seeking.
There were no differences in general information-seeking between those who received Placebo and those who were administered L-DOPA. In particular, there were no differences in the average number of trials on which the participants decided to receive or to avoid information or were indifferent (i.e. paid 0). Furthermore, there was no difference across groups in the number of trials participants missed (that is trials in which they were too slow in responding). Error bars SEM.
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Figure 2—source data 1
Source data for Figure 2.
- https://cdn.elifesciences.org/articles/59152/elife-59152-fig2-data1-v1.xlsx
Figure 3
L-DOPA reduces the effect of valence on information-seeking.
(a) A mixed linear regression predicting Willingness To Pay (WTP) for information revealed an interaction between group (Placebo/L-DOPA) and valence (the amount by which the market went up or down), with no interaction between group and absolute market change. To tease apart the interaction, we ran linear mixed models separately for the L-DOPA and Placebo groups. Plotted are the fixed effects of those models. As observed, this revealed a significant effect of valence on information-seeking in the Placebo group but lack thereof in the L-DOPA group. Absolute change was a significant predictor in both groups. This indicates a reduction in the influence of valence on information-seeking under L-DOPA. (b) To further characterize the effect of valence and drug on information-seeking, we run separate mixed linear models for each group and polarity predicting WTP from market change, trial number and the interaction of the two. Plotted are the fixed effects of market change for each. As can be observed under L-DOPA market change was a significant predictor of information-seeking about potential losses and gains - the greater the expected gain/loss the more participants were willing to pay for information. In contrast, under Placebo market change was a significant predictor of information-seeking about potential gains, but not losses. These results show that L-DOPA selectively alters information-seeking about losses. (c) Plotted is the effect of market change on WTP for information controlling for any effects of trial number. As can be observed the slopes are significantly positive for all groups/conditions except for the Placebo group in the loss domain. Clouds are based on Standard Errors of the fixed effect. Error bars SEM, * p <0.05, ** p < 0.01, *** p < 0.001.
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Figure 3—source data 1
Source data for Figure 3.
- https://cdn.elifesciences.org/articles/59152/elife-59152-fig3-data1-v1.xlsx
Tables
Table 1
Demographics.
| Demographics | Placebo mean (SD) | L-DOPA mean (SD) | p-Value |
|---|---|---|---|
| Age (years) | 24.36 (7.91) | 25.44 (7.92) | 0.301 |
| Gender | Females N= 72 | Females N= 71 | 0.893 |
| Income (1-9) | 4.85 (2.38) | 4.61 (2.54) | 0.462 |
| Education Level (1-10) | 7.09 (1.72) | 7.39 (1.50) | 0.157 |
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There were no differences between groups in terms of demographics. p-Value is of independent sample t-test , or in the case of gender of X2. Education was measured on a scale ranging from 1 (no formal education) to 10 (Doctoral degree ). Annual household income was measured on a scale from 1 (less than 10K) to 10 (more than 100K).
Table 2
Subjective State Questionnaire.
Subjective State Questionnaire (Joint Formulary Committee, 2009) revealed no differences in subjective state between groups. p-Value relates to independent sample t-test.
| Subjective State Questionnaire | Before the task | After the task | ||||
|---|---|---|---|---|---|---|
| Placebo mean (SD) | L-DOPA mean (SD) | p-Value | Placebo mean (SD) | L-DOPA mean (SD) | p-Value | |
| Alert to drowsy | 2.68 (1.19) | 2.62 (1.08) | 0.687 | 3.60 (1.41) | 3.85 (1.57) | 0.208 |
| Calm to excited | 2.33 (1.11) | 2.29 (1.03) | 0.808 | 2.34 (1.09) | 2.27 (1.22) | 0.632 |
| Strong to feeble | 2.68 (1.01) | 2.63 (1.01) | 0.699 | 2.97 (1.13) | 3.15 (1.35) | 0.264 |
| Muzzy to clear headed | 4.47 (1.26) | 4.48 (1.11) | 0.956 | 3.70 (1.23) | 3.41 (1.39) | 0.099 |
| Coordinated to clumsy | 2.28 (1.14) | 2.22 (1.06) | 0.722 | 2.80 (1.16) | 3.02 (1.31) | 0.187 |
| Lethargic to energetic | 3.89 (1.14) | 3.94 (1.18) | 0.736 | 3.20 (1.24) | 3.00 (1.43) | 0.263 |
| Contented to discontented | 2.18 (1.01) | 2.12 (0.83) | 0.620 | 2.58 (1.16) | 2.65 (1.19) | 0.644 |
| Troubled to tranquil | 4.83 (1.02) | 4.66 (1.02) | 0.201 | 4.52 (1.13) | 4.55 (1.13) | 0.858 |
| Slow to quick witted | 4.32 (1.11) | 4.28 (1.04) | 0.761 | 3.63 (1.30) | 3.31 (1.30) | 0.069 |
| Tense to relaxed | 4.64 (1.11) | 4.67 (0.98) | 0.803 | 4.47 (1.14) | 4.42 (1.23) | 0.733 |
| Attentive to dreamy | 2.78 (1.26) | 2.73 (1.10) | 0.740 | 3.47 (1.34) | 3.42 (1.38) | 0.804 |
| Incompetent to proficient | 4.56 (0.98) | 4.70 (0.86) | 0.260 | 4.14 (1.16) | 4.02 (1.26) | 0.450 |
| Happy to sad | 2.43 (1.06) | 2.34 (0.84) | 0.453 | 2.62 (1.12) | 2.57 (0.95) | 0.712 |
| Antagonistic to friendly | 5.08 (0.97) | 5.07 (0.81) | 0.942 | 4.65 (0.95) | 4.60 (1.04) | 0.703 |
| Interested to bored | 2.35 (1.21) | 2.28 (1.02) | 0.639 | 3.52 (1.45) | 3.63 (1.50) | 0.587 |
| Withdrawn to sociable | 4.34 (1.17) | 4.36 (1.18) | 0.868 | 3.90 (1.17) | 3.83 (1.39) | 0.672 |
Key resources table
| Reagent type (species) or resource | Designation | Source or reference | Identifiers | Additional information |
|---|---|---|---|---|
| Software, algorithm | SPSS | SPSS | RRID:SCR 002865 | Version 25 |
| Software, algorithm | MATLAB | MATLAB | RRID:SCR_001622 | Version R2020a |
| Software, algorithm | R | R | RRID:SCR_001905 | R-4.0.1 |
| Chemical compound, drug | levodopa | Orion Pharma (UK) Limited | PubChem CID:6047 | 150 mg |
| Chemical compound, drug | carbidopa | Orion Pharma (UK) Limited | PubChem CID: 34359 | 37.5 mg |
| Chemical compound, drug | entacapone | Orion Pharma (UK) Limited | PubChem CID: 5281081 | 200 mg |
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A selective effect of dopamine on information-seeking
eLife 9:e59152.
https://doi.org/10.7554/eLife.59152
