Figure 2A shows examples of bandpass-filtered theta activity from a patient in whom the anterior four contacts were located in the entorhinal cortex, while the posterior six contacts were located in the hippocampus. The two entorhinal traces (channels 3 and 4) exhibit an oscillatory pattern that differs from the hippocampal traces (channels 5 and 6), particularly in the first and last third of the displayed traces. Accordingly, the average degree of synchrony between the adjacent entorhinal and hippocampal channels (R = 0.18) is substantially lower than the degree of synchrony between the two entorhinal channels (R = 0.85) and the two hippocampal channels (R = 0.60), respectively.
