Figure 2.

Illustration of our experimental approach with simulated data. Within the first two rows, the phase is represented by the rotational angle and the associated response time by radius (see top left item). The top row illustrates different selections of trial subsets. On the left, a complete selection encompasses all trials. On the right, five successive RT quintiles are shown. For each quintile, the red annulus indicates the range of RTs selected. The middle row displays hypothetical data with a spiral structure: each point corresponds to one trial with a particular phase value (at a given time point and frequency of interest) and an associated RT. The trials selected for each RT quintile are highlighted in red. The bottom row shows the polar phase histograms corresponding to each subset of trials. Phase is represented by the rotational angle and trial number in each bin by the corresponding radius. No apparent phase locking or ITC is expected on the left side when computed across all trials. However, each individual RT quintile shows strong phase locking (right). Within this context, our analysis relied on a statistical comparison between ITC values calculated for the left versus the right histograms. (For statistical consistency, 100 random selections of 20% of all trials were applied to the left-hand side data, and the resulting ITCs were averaged before comparison with the quintile-specific ITC values on the right).