Figure 3.

The source-projection coherence and its effect on inter-areal coherence

(A) Illustration of different factors contributing to coherence. Inset plots show a simulation where the subset of area-1-to-2 projecting neurons is most coherent with the area-1 LFP at the oscillation frequency.

(B) LFP signals were generated as an oscillatory AR(2) process and modulated the activity of neurons according to inhomogeneous Poisson processes. 1,500/5,000 neurons were projection neurons. The activity of the projecting neurons (“projection”) and the entire population (“source”) were summed up. The resulting signals were used to calculate the source-projection coherence.

(C) Dependence of source-projection coherence on the number (Np) and phase locking (PPC) of projection neurons. Dashed: analytical fits. Solid: simulations, in which an AR(2) signal modulated spiking probability in 10,000 neurons according to inhomogeneous Poisson processes.

(D) Increases in coupling weight and SOS cause a narrow-band increase in inter-areal coherence.

(E) Coherence between two areas that have identical power spectra.

(F and G) Power and Granger-causality spectra for two bidirectionally coupled areas oscillating at gamma and beta frequencies.

See also Figures S2 and S3.