Bilateral depth electrodes, each equipped with 10 cylindrical contacts (length: 2.5 mm, intercontact distance: 4 mm), were inserted along the longitudinal axis of the hippocampal formation using a computed tomography-based stereotactic insertion technique (Van Roost et al., 1998), with the anterior contacts located ventral to the amygdala in the anterior parahippocampal gyrus, which is covered by peri- and entorhinal cortex, and the posterior contacts located within the hippocampus (Figure 1).
