Fig. 2.

Examples of parahippocampal neurons with activity related to different trial events. For the present figure and all subsequent figures of this format, each panel includes a raster display of representative trials and a summary histogram of peri-event activity accumulated across all trials in 100 msec bins and displayed in a continuous line showing average spikes/second for each bin during the 2 sec period before and after the synchronization event. Then shown on each panel refers to the number of cDNMS trials over which unit activity was averaged. A, A perirhinal cue-sampling cell that began firing during trial initiation and fired maximally during odor sampling. Vertical tic marks to the right of the synchronization point indicate the unpoke. B, A perirhinal reward-approach cell that fired maximally just before the water port response.Vertical tic marks to the left of the synchronization point indicate the unpoke. C, A subiculum trial-initiation cell whose firing decreased during trial initiation (the poke). D, An entorhinal delay cell that fired maximally during the intertrial (delay) interval.