PVALB and hippocampal atrophy: Previous studies suggest that hippocampal atrophy in patients with schizophrenia may arise from an imbalance in excitatory and inhibitory transmission (Schobel et al., 2013) secondary to a reduced functioning of N-methyl-d-aspartate (NMDA) receptors and a loss of parvalbumin-containing GABAergic interneurons (Braun et al., 2007, Schobel et al., 2013, Lisman et al., 2008).