Modulation of phase-to-rate mapping by beta amplitude.

<p>Beta phase has a stronger impact on spike rate when beta amplitude is large, but gain modulation is not uniform across neurons. A–D show the phase-to-rate mappings for 9 example neurons, where instantaneous phases and spike times were pre-sorted into one of four bins based on beta amplitude (see <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1002809#s2" target="_blank">Materials and Methods</a>). Phase-to-rate modulation depth (difference between maximum and baseline rates) is largest for bin with largest amplitudes (c.f. scale of y-axis of A–D), but some modulation depth increases faster for some neurons than others; sig045a (black) has highest rate in smallest amplitude bin but ranks third in the largest amplitude bin, while sig043c (cyan) moves from rank 4 to 2. Differential changes can shift the beta phase where two neurons exchange spike rate rank order, even if the preferred phases do not change (note shift in phase of crossover of sig043c (cyan) with sig029a (blue), indicated by vertical lines. E) Phase-to-rate modulation depth as a function of mean beta amplitude. F) Amplitude modulation of phase-to-rate mapping can be expressed as a product of two terms, one of which is a quadratic weight factor (see <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1002809#s2" target="_blank">Materials and Methods</a>).