Fig 4. Theta/gamma band rhythms generated with a double peaked spatial distribution of g_Ks.

A, Example of double peaked spatial mapping of g_Ks values for corresponding neurons on the 20×20 E cell lattice for hotspot radius r = 4.6 and distance between hotspot centers d = 8. B, Dominant rhythmic activity of individual E cells (dark blue = none, light blue = theta band, green = gamma band and yellow = mixed, both gamma and theta) plotted at cell position on the E cell lattice due to double peaked g_Ks spatial distribution shown in A. C, D and E, Numbers of neurons exhibiting dominant theta (C), dominant gamma (D), or theta-gamma coupled activity (E) as a function of radius of g_Ks hotspots r and the distance between hotspot centers d for a double peaked g_Ks spatial distribution. F, G and H, Spike raster plots (top panels) and histograms for the dominant rhythmic activity exhibited by neurons based on their individual g_Ks values (bottom panels) for networks with double peaked g_Ks distributions with r and d values indicated by labels in C, D, E. In the raster plots, E cells are numbered 1 to 400, and I cells are numbered 401 to 500. Color indicates g_Ks values of cells with the scale in A. I, Snapshots of E cell firing rates from 4500–4800 ms during the simulation in H (shaded area in H; r and d values indicated by label H in C). Cells inside the orange contour lines have $g_{K_s}$ values less than 0.6 mS/cm².