Decoupling Action Potential Bias from Cortical Local Field Potentials
Figure 5
Frequency specificity of the spike-coupled LFP signal. (a) Relative power spectrum of the LFP signal from Figure 2 after removing SUA4, SUA3, and MUA components (colors as in previous figures). This site showed a large decrease at low frequencies (1–25 Hz). (b) Relative power spectrum of the LFP signal from the site in Figure 3 after the removal of spiking components (plotted as in ). This site showed a decrease near 25 Hz and at frequencies above 75 Hz. (c) Average relative power spectrum of LFP signal averaged across recording sites. Removing coupled spike activity from the LFP signal reduced power at all frequencies. The effect was the strongest at low frequencies (1–10 Hz) but also showed a tendency to grow larger at high frequencies. Consistent with the overall changes in power reported in Figure 4, the LFP spectrum was reduced more for the more permissive definitions of spiking (). The small features around 60 Hz (most prominent for the signal with MUA components removed) reflect artifacts of line noise.
