Figure 2.

Two examples of neurons specialized for either attention (a) or working memory (c). Correct brightening and dimming trials were grouped into a 4 × 4 matrix according to the remembered location (rows) and attended location (columns). Neuronal activity in each trial was aligned on the go signal (vertical line in spike raster), and firing rates were assessed for the preceding 800 ms of the variable delay period. The 16 spike density functions show average activity across like trials in spikes per second (sp/s). a, A cell most active when the monkey attended to the right (blue rectangle). b, For the cell in a, polar tuning curves for attention (blue, solid line) and memory (red, dashed line), and the attention PD (blue arrow). c, A working-memory neuron most active for holding the upward location in memory (red rectangles). d, For the cell in c, polar tuning curves for attention (blue, dashed line) and memory (red, solid line), and the working-memory PD (red arrow). Both example neurons were recorded in the left hemisphere of monkey Z.