The Brain That Changes Itself: Stories of Personal Triumph from the Frontiers of Brain Science

by Norman Doidge

Freud stated that when two neurons fire simultaneously, this firing facilitates their ongoing association. Freud emphasized that what linked neurons was their firing together in time, and he called this phenomenon the law of association by simultaneity. The law of association explains the importance of Freud’s idea of “free association,” in which psychoanalytic patients lie on the couch and “free-associate,” or say everything that comes into their minds, regardless of how uncomfortable or trivial it seems. The analyst sits behind the patient, out of the patient’s sight, and usually says little. Freud found that if he didn’t interfere, many wardedoff feelings and interesting connections emerged in the patient’s associations—thoughts and feelings the patient normally pushed away. Free association is based on the understanding that all our mental associations, even seemingly “random” ones that appear to make no sense, are expressions of links formed in our memory networks. His law of association by simultaneity implicitly links changes in neuronal networks with changes in our memory networks, so that neurons that fired together years before wired together, and these original connections are often still in place and show up in a patient’s free associations.