a, Mice display equal performance across trial types (n = 4 mice, P = 0.52, Wilcoxon rank-sum test). b, Multi-electrode implant used for PFC neural recordings. Inset, magnification showing electrodes. c, Post-mortem histology in an example brain showing electrode tip locations (arrowheads). d, Example of spike sorting in energy space to identify single units. Two identified clusters reflect two single units. Inset, corresponding spike-waveforms. e, In 17% of rule-tuned cells, tuning is observed for both task rules (example PSTHs shown), albeit with distinct temporal offsets during the delay. f, Schematic showing electrode locations from which rule-tuned neurons (dots) were recorded, illustrating that they are most frequently found in deeper layers. Dot sizes are scaled in proportion to the number of tuned neurons found at that location (n = 594 cells from four mice). g, Fast-spiking (FS) and regular-spiking (RS) neurons are identified on the basis of the peak to trough time of their spike waveform (left, example waveforms; right, peak to through time histogram, dashed line represents cut off for fast-spiking to regular-spiking classification21,43). h, Example rasters and PSTHs for two cells during delay periods of either 400 or 800 ms, randomized within the same recording session. In the first, an early peak is present in both conditions (left), while in the other a late peak is only evident in the 800-ms condition (right). i, Task-variable information for each mouse of our first cohort (manipulation free). Task-variable information is based on the PCA from the divergence of population activity of task-modulated PFC neurons on the axis associated with each variable (see Methods) and is highly informative for task rule (green), but contains no information about movement (side selection, grey). Shaded areas indicate the bootstrapped 95% CI.