Figure 6

Withdrawal of cholinergic input for defined periods restores its capacity to suppress network synchrony in subsequent periods. Three multiple epoch experiments are shown using the same notations as in Figure 4. Network activity was clamped to a desynchronized activity level (Sync Ratio = 0.05 for a, b and 0.1 and 0.15 for c). Following the depletion of the ACh in the application syringe (a) or the online calculation of four consecutive IAI values <1.5 minutes (b,c), cholinergic input was removed for 12 hours. After these periods, new closed-loop epochs were initiated, using the same experimental parameters. In the first experiment (a), the syringe was refilled with freshly prepared ACh as indicated in the figure, resulting in some leakage of ACh from the open end of the application needle, and a transient desynchronization of network activity. In the other two experiments (b,c) the syringe was not refilled, and the same ACh, prepared at the beginning of the experiment, was used for the entire duration of the experiments. Firing rates for each of the multi-epoch experiments are shown in Additional file 13: Figure S9. ACh, acetylcholine.