Are the same, or different, putative FSIs phase-modulated by gamma-50 and gamma-80? To address this, we computed spike-field coherograms for each neuron with its associated LFP recorded from the same tetrode. Spike-field coherence for a given frequency ranges from 0 to 1, where 0 indicates there is no relationship between spike times and the phase of the LFP component at that frequency, and 1 indicates perfect phase locking. The average coherence for all FSIs is shown in Figure 14A (red line); because coherence depends on firing rate in realistic situations (Curtis et al., 2009) we compared the observed coherence to that obtained from ISI shuffled spike trains, where the temporal alignment between spike times and LFP is disturbed but first- and second-order spiking statistics are preserved (black line). This plot shows that while much of the structure of the average coherence was also present in the shuffled control data, the observed coherence was increased at a range of frequencies, prominently so in the gamma range. To assess the contribution of individual FSIs, we plotted each cell's coherence z- score against
