Electrophysiological correlates of recognition memory for faces

Most ERP studies on long-term memory retrieval show the potential power of ERP components in discriminating correctly identified old and new items: the well-known old-new effect. Recently, such discoveries have become very important in the field of forensic neuroscience, in which the memory contents of the accused is of fundamental interest. However, although these effects have been studied and validated in paradigms using old and new words, results for non-linguistic matter are still not univocal. Therefore, the present study used ERPs to explore long-term memory, and in particular recognition memory, in response to 300 Caucasian faces belonging to 30 characters, 15 women and 15 men, each presented in 10 different perspectives. 100 belonged to 10 famous Hollywood actors or showmen, 100 belonged to 10 characters familiarized during the week preceding the experimental session, and 100 to 10 unknown characters. ERPs were recorded from 128 scalp sites in volunteer students. ERP results showed that the memory recognition processes strongly affected brain activity over fronto-central sites, with increased negativity for new faces between 200 and 400 ms post-stimulus, possibly related to encoding processes of new material, and an increased positivity between 600 and 800 ms post-stimulus to old faces, with larger potentials for better-known faces.