The relationship between neuroscience and psychoanalysis is studied by taking “the new mechanism of neuroscience” under scrutiny. That new trend stresses that neuroscientific explanations are mechanistic explanations in particular. Since the issue of psychological mechanisms lies at the core of psychoanalysis, it is crucial to study the relationship between neural and psychological mechanisms. The authors argue that neuroscience cannot verify psychoanalytic theories. However, by combining neuroscientific and psychoanalytic (psychological) viewpoints, it will be possible to approach a more holistic picture of psychological phenomena, here suggested by a new conception of defense mechanisms.