Memories are Made of This

Eric R. Kandel, Howard Hughes Medical Institute Investigator, examines whether the brain's two major memory systems, implicit and explicit, have any common features. Implicit and explicit memory both have a short-term component lasting minutes, such as remembering the telephone number you just looked up, and a long-term component that lasts days, weeks, or a lifetime, such as remembering your mother's birthday. Short-term memory is mediated by modifications of existing proteins, leading to temporary changes in the strength of communication between nerve cells. In contrast, long-term memory involves alterations of gene expression, synthesis of new proteins and growth of new synaptic connections.