Comparison of LFP, CSD, and MUA spreads from an example electrode recorded from Monkey 1. A–C: evoked LFP, CSD, and MUA responses, respectively, averaged across trials for 6 recording sessions (shown in gray; not all traces are visible due to a high degree of overlap) at each of the 81 stimulus positions (9 × 9 rectangular grid spanning 2 × 2° of visual space). Mean responses across recording sessions are plotted in black traces. The duration for which stimulus was presented (200 ms) is shown in light gray. D: estimated RF sizes and centers for each recording session (gray traces), as well as the mean across sessions (black), estimated by fitting a 2D Gaussian on the data (see text for details). The mean responses (black traces) are replotted in the plot on the bottom right in dotted (LFP), dashed (CSD), and solid (MUA) traces for comparison. Note that the estimated RF sizes follow the order: LFP > CSD > MUA.