Figure 3. Cognition-related responses to placebo.

(A) Changes in verbal learning performance differed for cognitive responders (PL_R; n = 7) and nonresponders (PL_NR; n = 5) to placebo (p = 0.003; 2 × 2 repeated-measures analysis of variance [RMANOVA], interaction effect). (B) Treatment-mediated changes in Parkinson disease–related cognitive pattern (PDCP) expression did not differ for cognitive responders and nonresponders to placebo (p = 0.11; 2 × 2 RMANOVA, interaction effect). Network activity did not change with placebo in either response subgroup (p ≥ 0.19). (C) There was also no change in Parkinson disease–related motor pattern (PDRP) expression with placebo treatment (p ≥ 0.14) in either response subgroup. *p < 0.05, **p < 0.01, ***p < 0.001, Student t tests for comparisons of network expression in each subgroup to healthy control values.