p603fig16.38 Role of hippocampal feedback in maintaining grid fields.  (a) Data showing the effect of hippocampal inactivation before and during muscimol inhibition of hippocampal cells, as in Figure 16.37.  (b) Model simulation with normal grid fields.  (c) Model simulation that emulates the effect of hippocampal inhibition on grid fields.<BR>||  (a) Data: hippocampal inactivation [before, after] cart [spikes on trajectory (p: [18.6, 6.7] Hz), spatial autocorrelogram (g= [1.12, 0.09])].  (b) Model: noise-free path integration, [spikes on trajectory (p: 14.56 Hz), rate map, spatial autocorrelogram (g= 1.41), dynamic autocorrelogram (g=0.6)].  (c) Model: noisy path integration + non-specific tonic inhibition, [spikes on trajectory (p: 11.33 Hz), rate map, spatial autocorrelogram (g= 0.05), dynamic autocorrelogram (g=0.047)].