Figure 6: Effect of removing spike-correlated activity on the frequency tuning of LFP in A1. (a) Frequency tuning curves for site shown in Figure 2. Gaussian fits are plotted with dashed lines and best frequency (peak of the Gaussian fits) is indicated by arrows. The raw LFP tuning curve was centered at a higher best frequency than the SUA4 curve (0.92 octaves above SUA4, , jackknifed -test). After the SUA4-coupled component was removed, the LFP tuning curve was shifted to even higher frequencies (1.63 octaves above SUA4, , jackknifed -test). Similar curves to this last case are observed for the LFP signals with SUA3 and MUA components removed. (b) Tuning curves for site shown in Figure 3 (plotted as in ). For this site, there was no significant difference between the SUA and LFP tuning curves ( 0.1 octave difference), even after the spike-coupled component was removed from the LFP.