Relationship between LFP PSD ratios and contrast response changes of V1. MUA Rmax changes (Δ Rmax) were significantly correlated with both (a) low and (c) high frequency changes. Semi-saturation contrast changes (ΔC50) were (b) uncorrelated with low frequency changes but (d) showed a strong negative correlation with γ-band changes. The large symbols in (c) and (d) denote the recording locations showing either a 70 Hz peak (square), a 40 Hz peak (diamond), both peaks (star) or no peaks (dot). Correlation coefficients (r) and p-values are given on top of each plot.