The Generation of Phase Differences and Frequency Changes in a Network Model of Inferior Olive Subthreshold Oscillations
A: Focus on the normalized membrane potential of one neuron per cluster reveals that clusters with higher Ca2+-conductance are advanced in phase with respect to other clusters (traces have colors matching with Figure 1). In the regime of oscillatory IO neurons, higher Ca2+-density indicates a higher resting membrane potential that causes the neuron to lead in the phase. B: Phase-map color coding the phase-difference between all neurons in the network. Phase differences are given in degrees relative to the inter-peak-interval; the phase of the bottom left neuron is taken as reference (0°). Neurons within the same cluster have similar phases due to similar resting potentials, while larger phase-differences arise between clusters that are farther apart in terms of their conductances. The maximum phase-difference between two neurons was 72° in the demonstration network. C: Cross-correlation of the peak times between (one neuron from the) four clusters computed for 5 s traces confirms that the phase-differences are stable over time. D: The amplitude and phase difference is proportional to the amount of gCa-conductance a neuron contains. The y-axis denotes the peak voltage and the x-axis indicates the conductance density. The color-coding is the same as in A while the size represents the phase-difference (as measured between the neuron at the bottom left and any other neuron).