2 - Electrophysiological Signature of Emotional Memories

Abstract

Emotional memories can be extremely robust and long lasting. Extremely unpleasant and arousing (traumatic) memories haunt some individuals throughout their entire life and sometimes lead to strong impairments. Therefore, one goal is to understand the neural mechanisms involved in encoding, consolidation, and storage of such emotional memories. This knowledge can then be used to treat psychological disorders caused by such traumatic memory, such as depression, anxiety, and posttraumatic stress disorder. The chapter focuses on the neural mechanisms of emotional memory encoding and retrieval, reviewing recent electrophysiological studies in healthy humans. This review details behavioral and pharmacological differences in the event-related potential (ERP) old/new effect , that is, an electrophysiological signature of conscious recognition in the human brain. The summarized ERP studies show that long-term recognition memory for emotional events is better than for neutral events and remains remarkably stable over time. Memory for emotional events is more accurate and associated with enhanced old/new effects in the brain potentials. This neural signature for emotional memories depends on β-adrenergic transmission in the brain during learning. Moreover, pharmacological blockade of β-adrenoreceptors selectively impairs retrieval of unpleasant arousing memories. This, of course, opens interesting, new avenues for future clinical research.