Fig. S4.

Inspecting the role of ISI on our dataset: A There are two groups of trials, those with $\mathrm{ISI}<2.35$ s (top), and the rest (bottom). In the short-ISI trials, the first stPLV (timing marked in orange) that was computed after the enforced minimum ISI (grayed out area) already matched the awaited next condition (here: high condition). In these trials, it is possible that there was a sustained high FC for longer than 100 ms before the pulse. In the long-ISI trials (bottom), there was at least one stPLV (blue mark) before the deciding stPLV (orange mark), which did not match the awaited condition. Here, the stPLV at the blue mark was below the high-condition threshold. This means that in the long-ISI trials, there cannot be a period of sustained high FC longer than 100 ms before the deciding stPLV. B Pre-stimulus FC timecourses (population average) for the high and low conditions, and short ($\mathrm{ISI}<2.35$ s) vs. long ($\mathrm{ISI}>2.35$ s) ISI trials. The stPLVs were estimated post hoc from 500 ms windows. The distance of the right edge of that window and the stimulus is shown on the $x$-axis. The approximate range of the time of the decisive stPLV is indicated by the dotted gray lines. C The logged decisive real-time stPLVs were compared between short (early) and long (late) ISI-groups within condition. For both conditions, there is a significant difference between the short-ISI and long-ISI trials in real-time stPLV (tested with two-sided Wilcoxon rank sum tests).