Figure 1.

(A) The theta phase (Y axis) by position (X axis) plots which were used to determine place field location and extent. The upper panel shows the place field boundaries (vertical black lines) using the definition of a place field as the distance traversed for the cell to precess no more than 360° with respect to the theta rhythm. Each dot represents a spike and the red dots are spikes that were included in the place field. The bottom panel is the raw data presented as a phase by position density plot using a hanning window of 7cm by 70 degrees. Red areas indicate a higher density of spikes while the dark areas indicate that no spikes were fired in those positions. Note that two cycles of theta phase precession are plotted for both panels. (B) Raster plots of the place field from (A) showing a CA1 pyramidal cell recorded in an aged rat injected with 10mg/kg of memantine. The rat was running from right to left. The top panel shows the firing rate histogram, and the bottom panel shows spikes by lap.