Figure 9.

Examples of anomalous place cells. The layout is the same as Figures 2 and 3. A, Control group examples. The cells in A1 and A2 show spatially selective firing patterns emerging from initial near silence in S1. For the cell in A1, the firing field is present in sessions 2 and 4. The cell in A3 has a stable firing field in sessions 1–3 that disappears in session 4. B, Seizure group examples. A new field develops for the cell in B1 in session 4 that could be due either to seizure-induced synaptic plasticity or the intrinsically dynamic nature of the place representation, as seen also in control rats. The frequency of such occurrences is not noticeably different from the control group. The cell in B2 shows a transient remapping in S3 before returning to its preseizure state in S4. This instability may be a seizure effect but again is rare. The cell in B3 exhibits both reduced firing rate and disintegration of its firing field in S4.