Figure 8.

Basket cell EAPs contributed little to simulated ripple LFPs. A, Locations of pyramidal cell (PYR) and basket cell (BC) somata within stratum pyramidale in a 1-mm-diameter simulated population. The small circles represent subthreshold cells, and the larger triangles and diamonds represent cells spiking within one 5 ms period. B, Spiking histograms and extracellular potentials from populations of pyramidal cells (red) and basket cells (blue) during 200 Hz rhythmic spiking with all synaptic driving currents removed, as well as the extracellular potential when both signals are combined (black). Here, basket cells are less numerous (5% of pyramids) but have five times higher average firing rates than pyramidal cells. Peak basket cell firing lags that of pyramidal cells by 90° (1.25 ms at 200 Hz) (Sullivan et al., 2011). C, Spectral peaks of 25-trial-average FFTs of stratum pyramidale potentials from the separate (color) and combined (black) populations during rhythms from 50 to 400 Hz. D, Mean ± SD for the potentials in B over 25 trials.