Figure 3.

Blocking axonal electrical coupling between pyramidal cells abolishes γ oscillations in the model. (A) Simulation with axon gap junctions present (and dendritic gap junctions, 1.05 nS). Signals are the average (inverted) somatic potential of 224 nearby pyramidal cells, the average somatic potential of 28 nearby interneurons, and the somatic potential of a single pyramidal cell (hyperpolarized with −1.0 nA current). (B) The simulation of A was repeated, but with axonal gap junctions blocked. (C) Superimposed power spectra (10–100 Hz) of the local average pyramidal signals from A and B. The power spectrum of A (thin line, axon gap junctions present) reveals a clear peak at 44 Hz. The power spectrum of B (thick line, axon gap junctions blocked) plotted on the same scale shows virtually no γ power.