Figure 6.

Synchronization of Multi-Unit Activities Increases before and Decreases after Corresponding Changes in Discharge Rates and Behavioral Seizures

(A) Top: Corresponding to the recordings, behavioral seizure stages are gradually increased to reach the maximum (S5) and then gradually attenuated. Note that at low-stage (S0.5 – S1) seizures, the behaviors are coded into different colored segments if the rat has a large-enough movement to change its posture (probably implicating a significant change in electrophysiological activities) but remains in the same seizure stage according to Racines criteria. Lower: Sample multi-unit spikes (MU) and the rasters from the ADs in bilateral BLA after a ±270 μA stimulus (the ninth session of kindling procedure). The dissimilarity profiles are calculated from SPIKY (see Methods). S is the dissimilarity score, with 0 for complete synchrony and 1 for complete asynchrony between the two spike trains.

(B) A closer view of the data in (A) at the highest-stage (S5) and the adjacent segments shows that the dissimilarity profile also oscillates roughly at the delta frequency range around a mean level of ∼0.178.

(C) The mean similarity score (S′, derived from 1-S to have a more straightforward correlation with the level of synchronization) is plotted on top of the simultaneous mean multi-unit firing rates (spike frequency) in bilateral BLA and the seizure stage in each segment of behavioral seizures. Note the close correlation between the firing rate and seizure stage. The level of synchronization, however, increases before and decreases after the corresponding changes in firing rates and behavioral seizures.

Data are shown as means ± SEM.