Figure 4. Spikes become repetitive.
(A) An EEG sample is shown from a rat that initially developed isolated spikes. By the second week, ‘doublets’ were seen, and by the third week, spikes (indicated by *) occurred repetitively with 3–6 in a row. (B) Quantifying this increase by calculating the percent of spikes that were clustered with other spikes shows a progressive increase in clustering with time (n=11; R2=0.492; Linear regression slope=0.75%/day, p=0.0025).