Disconnected pyramidal cells show theta spiking oscillations.

<p>A) Schematic of this experiment with isolated pyramidal cells each receiving a unique train of Poisson spikes with base rates derived from a lognormal distribution (mean 50 Hz SD 40 Hz, chosen to reproduce place cells firing rates). B1) Spike raster plot of pyramidal cells showing grossly random firing. B2) Population firing rate calculated using a 20 ms sliding window. B3, 4) Example membrane voltage traces from two neurons. C1) The power spectrum of the spiking activity of pyramidal cells as a population showing a peak at 8 Hz. C2) the spike-triggered average of the ‘u’ current of the Izhikevich model that captures the spike-frequency adaptation of the cells. C3) The inter-spike interval distribution of pyramidal cells. D) Same as in C, but with the time-constant of adaptation lowered from 100 ms to 25 ms, resulting in a power spectrum peak at 17 Hz, to demonstrate the relationship between the spiking oscillations, adaptation current, and the spiking dynamics of pyramidal cells.