Response-locked CSD waveforms (−700 to 300 ms, 100 ms baseline preceding stimulus onset) at selected midline (Fz, Cz, Pz) and adjacent medial (F3/4, C3/4, P3/4) sites (indicated by black dots in inset) comparing new and old items for each group and modality. A distinct mid-frontal response-related negativity (FRN) terminated the preceding P3 source in all conditions, giving rise to a late inverted old/new effect (LN sink) over mid-posterior sites. However, the focal Fz sink was markedly reduced in patients.