“…Pharmacological, physiological, and anatomical analysis in the En revealed recurrent excitatory synaptic activity within the dominant multipolar cell population, suggesting that the hypothesis of synaptically mediated positive feedback, developed as a mechanism for the latent period in hippocampus (Ayala et al, 1973;Johnston and Brown, 1986;Traub et al, 1989;Traub and Miles, 1991), also may be applicable to the PC (Hoffman and Haberly, 1993). Using voltage imaging techniques (Grinvald et al, 1988;Wu and Cohen, 1993), we examined the spatiotemporal pattern of electrical activity in slices of PC and observed the accelerating build-up of activity at the onset site described previously (Hoffman and Haberly, 1993;Demir et al, 1998). In addition, a second form of abnormal activity was observed during the latent period, which has not been described previously.…”