Fig. 1.

A: basis functions. B: correlation between R² and firing rates in all principal neurons (PNs; blue, n = 420) and presumed interneurons (red; n = 45). C–E: impact of sequentially adding different classes of variables on R² in all cells (C; n = 465), only PNs (D: n = 420), or only PNs responsive to task events (E; n = 89). Prior trial (S/F) indicates prior trial success and failure. The increases in R² values caused by adding the various classes of variables were all significant. Friedman one-way ANOVAs revealed χ² ranging between 1,110 and 1,637, with P values <3.4e10⁻²³⁹. Dunn’s tests revealed that all differences were significant at P < 0.01 for the 3 sets of cells.