Figure 4.

Single-neuron activity during DPX task performance. Each row of panels illustrates the activity of a single neuron in PFC (A–C) or MD (D–F). Individual panels indicate activity on a single trial type defined by cue-probe sequence. Rasters indicate timing of action potentials, spike density functions (solid gray; σ = 40 ms; 10 Hz/div) show modulations in average firing rate. Red tick marks indicate the time of the response in each trial. A, Early B-cue neuron: PFC cell 4623 is an example of a neuron whose firing rate during the cue period is greater on B-cue trials than A-cue trials. B, Early B-cue and Late A-cue neuron: PFC cell 5175 is an example of a switch neuron that switches its cue preference from B-cues during the cue period to A-cues during the probe period. C, Early B-cue and NT-response neuron: PFC cell 5445 is an example of a neuron whose firing rate is greater on B-cue than A-cue trials during the cue period and is also greater on invalid NT-response than T-response trials during the response period. D, Early B-cue and Late A-cue neuron: MD cell 4488 is an example of a 'switch' neuron that switches its cue preference from B-cues during the cue period to A-cues during the probe period. E, X-probe neuron: MD cell 5486 is an example of a neuron whose firing rate during the probe period is greater on X-probe than Y-probe trials. F, Early B-cue and Y-probe neuron: MD Cell 5372 is an example of a neuron whose firing rate during the cue period is greater on B-cue than A-cue trials, and during the probe period is greater on Y-probe than X-probe trials.