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. 2020 Sep 8;9:e60692. doi: 10.7554/eLife.60692

Figure 4. Effect of cell and network properties on high-frequency oscillations.

(A) Low cellular firing rates decorrelate the network output in the forms of reduced peaks of power spectrums (left) and CCGs (right). CV ISI is ~0.45. Synaptic conductance is 1 nS and radius is 5. (B) Irregular spiking (high CV of ISIs) also decorrelates network. The cellular firing rate is ~141 Hz. Same layout and network properties as in A. (C) Small conductance (cond) of inhibitory synapses decorrelates network output. Same layout and network properties as in A with cellular firing rate ~151 Hz and CV ISI ~ 0.45. (D) Short connection radius also decorrelates network output. Same layout and cellular firing properties as C.

Figure 4.

Figure 4—figure supplement 1 . Formation of High-frequency Oscillations at High Rates.

Figure 4—figure supplement 1 .

(A and B) Raster plots of random PC spikes when they fire regularly (CV ISI ~ 0.07) and irregularly (CV ISI ~ 0.4) at low rates (here,~2 Hz in the network, but 12 Hz in isolated cells). In the right plot of (B), average CCG is shown. (C) PCs show spike-to-spike synchrony when they fire regularly (CV ISI ~ 0.02) at high rates (154 Hz). (D) PC spikes show high-frequency oscillations when they fire irregularly (CV ISI ~ 0.44) at high rates (153 Hz). The right plot of (D) shows the average CCG with a significant central peak and side peaks.
Figure 4—figure supplement 2 . Decreased PRC at high firing rates can weaken oscillations.

Figure 4—figure supplement 2 .

(A) PRCs for negative synaptic stimulus when PCs fire at 95 Hz (blue) and 106 Hz (purple) driven by OU process with basal values of synaptic conductance. Reduced PRC at 106 Hz was achieved by 50% of basal synaptic conductance (black). (B) The power spectrum of spike trains with the cellular rate of 95 Hz (blue, basal conductance), 106 Hz (purple, basal conductance) and 113 Hz (black, 50% of basal conductance, firing rate increased to 113 Hz due to the reduced inhibition, with other conditions the same as 106 Hz with basal conductance). In all cases, the CV of ISI is 0.45. The power spectrum at high firing rates gets flatter with lower amplitude when the PRC amplitude is reduced (black trace). (C) The CCGs of spike trains with the same condition as in B. Central and side peaks reduce at high firing rates when the phase response is smaller.