Fig. 7.

Neuronal activity in the superior colliculus (SC) predicts decisions independent of confidence. A. schematic of the spatial arrangement of the task used to assess opt-out (OO) choices (low confidence) and OO-waived choices (high confidence) when the OO choice target was in RF of recorded neurons. The arrangement of the task is the same as that shown in Fig. 1, B and C. OO-available and OO-unavailable trial types and the location of the OO choice target (in the RF or away from the RF) occurred randomly across trials. The choice targets appeared in either the upper or lower hemifield corresponding to either upward or downward motion (see materials and methods). B: comparison of spike density functions (SDFs) (σ = 10 ms) plotted over time for the same 253 neurons recorded singly or in multiples simultaneously as shown in Fig. 2 while monkeys performed the confidence tasks shown in A (A and B for the data shown in Fig. 2). Iconography shows the different trial types. Solid black lines show SDFs from the high-confidence, OO-waived trials (same as shown in Fig. 2C), and the dotted black lines show SDFs for low-confidence trials, when the monkeys chose the OO choice target, placed in the RF of the recorded neurons. If decision neurons of the SC also signal confidence, they should show different activity in high- versus low-confidence trials. Vertical scale bars indicate 10 sp/s and horizontal scale bars indicate 200 ms. The filled gray bars on the abscissas in B indicate the interval of discharge that was quantified (P > 0.05). C–F: same layout as shown in B for the single and multiple neurons shown separately for each monkey. MUA, multiunit activity; SU, single-unit activity.