Figure 5.

Grand average waveforms of rare versus common transitions for second-stage response-locked alpha power. RT differences between rare and common transitions were only significantly associated with stimulus-locked alpha power differentiation of states in the time bin before reward presentation (2000–3000 ms: β = 0.01, SE = 0.01, p = 0.04; all other time bins: p values > 0.30; Fig. 4). To complement our main result based on stimulus-locked alpha, we repeated the transition analysis with single-trial response-locked alpha estimates (measured as the mean of ±100 ms centered around each participant's averaged latency of the negative peak), which also yielded a significant association overall effect (β = 0.03, SE = 0.01, p < 0.001; Fig. 5). Similar to stimulus-locked alpha, rare transitions showed greater depression of alpha during choice selection for rare versus common transitions, suggesting that the alpha transition effect is not explained by RT.