Figure 4.
Option-Generation Task Performance in Healthy Elderly People (n = 29) on Cabergoline and Placebo (Study 3)
(A–C) Healthy people generated significantly more path options when they have taken cabergoline (dopamine D2 agonist) compared to placebo (p < 0.001) (A). Yet they were more unique (p < 0.05) (B) and explored a larger area in the 2-dimensional path subspace (p < 0.05) (C) when they were on placebo.
(D) A scatterplot of each individual’s mean uniqueness of paths against their number of paths generated. The same individual when on cabergoline and placebo are connected by green lines.
(E) A mixed model applied to account for the correlation between fluency and uniqueness found that dopamine increases the uniqueness of paths for a given fluency (p < 0.001), which is consistent with what we have found from Parkinson’s disease patients in study 2. This increase is stronger in apathetic individuals.
Error bars refer to one SE. See also Figures S2, S3, S4, and S7.