CA2 and epilepsy: Similarly, the density of PV+ cells is considerably reduced in CA2 during epilepsy (Andrioli et al., 2007), and physiological recordings in the hippocampi of human epileptic patients revealed an important decrease in inhibition of (Wittner et al., 2009) or a complete loss of inhibition of CA2 PNs (Williamson and Spencer, 1994).