Scientists today are using the latest imaging technologies to investigate Sigmund Freud's most fundamental tenets: that dreams represent unfulfilled wishes, that the three parts of the psyche--the ego, id and superego--have neuronal bases, and that "talk therapy" changes the physical networks of neurons in the brain. The fact that such work is happening at all represents an apparent comeback for psychoanalysis [see "Freud Returns," by Mark Solms, on page 28]. No one would be happier than Freud himself. Although his followers like to think of his work as pure psychology, the young Freud built his theories on his own detailed investigation of animal and human brains. To him, every mental illness stemmed from a physical defect in the brain.
His point of view changed, however, when he began treating women who were diagnosed as being "hysterical." They suffered from what appeared to be suppressed sexual desires. These cases and others prompted him to discard his own model of the brain as a kind of neuronal machine and replace it with a model of the mind as an entity driven by secret desires. Freud constructed his fantastic theories of dreaming, repression, and ego and id based on years of listening to troubled patients tell of their woes while lying on his office couch--a career move from the brain lab motivated primarily by Freud's need to make enough money to support his rapidly expanding family. And yet in his final writings, he acknowledged his own repressed hope that one day science would recast his maxims in neurology.