The marriage of neuroscience and psychoanalysis will eventually place the mind on an equal scientific footing with other physical processes.

As Eric Kandel points out, the insights of psychoanalysis can inform neuroscience, whose hard research findings can check the validity of psychoanalytic theory. Freud’s dream was to create a scientific foundation for psychoanalysis in his "Project for a Scientific Psychology," published in 1950. Not having the technology to integrate the brain and the mind, he was limited to studying the mind by clinical case material. Even though clinical case material proved to be a good source for developing hypotheses, it was criticized by many as being too observer biased.

Efforts to provide an empirical basis for psychoanalysis first involved the laboratory dream studies, as well as studies of the unconscious in subliminal stimulation. In recent years there has been an explosion of knowledge in brain science, with the development of brain imaging, neurosurgery, and animal laboratory experiments. Now we do have the technology to fulfill Freud’s dream of psychoanalysis being a science and silencing its critics.

The American Academy of Psychoanalysis and the American Psychoanalytic Association are engaged in integrating the roles of the brain and the mind, and a new journal, "Neuro-Psychoanalysis," is publishing articles to stimulate dialogue between psychoanalysis and neuroscience.

In addition, this summer, the Journal of the American Academy of Psychoanalysis published a special issue, for which I was the editor, devoted to integrating psychoanalysis and neuroscience. This issue of the journal contains articles that bridge the artificial boundary between social and biological determinants of behavior and psychopathology, with the goal of increasing our knowledge and the effectiveness of our work with patients.

So what has neuroscience taught us about psychoanalysis so far? We now know that in the first three years of life the right hemisphere and amygdala are dominant, during which time attachment, the ability to regulate affect, and a model for relationships are established. This corresponds to psychoanalytic theory of the importance of early childhood experiences in personality formation.

We also know from neuroscience that there are at least two memory systems in the brain, which correspond to the Freudian topographic model of the unconscious and conscious. Cognitive neuropsychologists have also noted a similar mental duality. One form is implicit memory, which stores unconscious perceptions, and the other is explicit memory, which encodes conscious memories. The groundbreaking laboratory research by Joseph LeDoux has traced the pathways for each of these two forms of memory. The unconscious, emotional (implicit) memory involves perceptions going directly from the thalamus to the amygdala. The amygdala then signals the hypothalamus, which controls the autonomic nervous system, releasing stress hormones and resulting in unconscious behavioral and bodily responses. This pathway is "fast and dirty," serving basic survival. The conscious, declarative (explicit) memory traverses a longer pathway, with perceptions going from the thalamus, through the hippocampus to the neocortex, and then to the amygdala. Here the perception is matched in the cortex to recent and past experiences, which can then modulate the emotional response to facilitate adaptation that is more realistic. Both of these systems, which operate in a parallel fashion, have also been explored in humans through brain-imaging techniques.

In summary, Freud’s topographic model of the conscious and unconscious is validated by these brain studies. In addition, Freud’s discovery reported in 1914 that traumatic memories are stored in the unconscious and are expressed repeatedly through behavior outside of conscious awareness also is confirmed. Unconscious behavior also includes transference, projective identification, splitting, and nonverbal communication, which stimulate countertransference reactions.

We now know that the brain is plastic and that new synaptic connections can occur. In addition, new stem cells are being generated, so that the brain can learn and develop throughout life. In this way, new structural pathways can gradually be established from the cortex to the amygdala to achieve greater control of behavior. Thus the goal of long-term dynamic therapy to make unconscious memories conscious becomes meaningful. The findings of dream research reveal that dreams do have meaning, even more than being the royal road to the unconscious.

Not only psychoanalysis but also the entire field of psychiatry will become enriched and more scientifically based by these findings. Our diagnoses may no longer be based on collections of symptoms but on neuroscientific and genetic findings, especially now that the human genome is mapped.

Our medical knowledge, together with our training in psychotherapy, will therefore provide our patients with the most effective treatment. 

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Dr. Slipp is a clinical professor of psychiatry at New York University School of Medicine, a training and supervising analyst at the Psychoanalytic Institute of New York Medical College, and a past president of the American Academy of Psychoanalysis.