Visual field constriction and a significantly higher incidence of depression and psychosis may appear as side effects of vigabatrin treatment. Our research, using the rat hippocampal slice, revealed that VGB failed to alter the length SEADs. In contrast, VGB lowered the frequency of spontaneous discharges while increasing the excitability of CA1 cells ( Carrel et al, 1998, SFN Abstract 769.1 ). The current research examined the action of VGB on acute pyramidal cell activity, following SEADs, and after LTP-LTP-weak LTD stimulus sequence in the hippocampal CA1. Electrical stimulation through a bipolar electrode placed in the Schaffer collaterals activated CA1 pyramidal cells. Only acute treatment of CA1 cells with bicuculline ( 50uM ) caused multiple spiking . VGB ( 250 or 500uM ) failed to induce multiple spikes during the short recording time. SEADs were initiated in hippocampal slices in the CA1 region exposed to either normal ACSF or HiK Low MG ACSF. No significant differences were noted. On the other ha...