The neuronal correlate of mentalization and a shortcut in the route to satisfaction and “self” awareness: addiction
Jacques van Hoof and Wim Schouten
In investigating addiction there is a great problem: the lack of an adequate physiological model. An attempt is made to bridge this gap between biological and psychological phenomenons. In the presented dual process model, it is assumed that the relevant psychological problems are the manifestation of an imbalance between two mechanisms in the brain: drive and guidance. Both mechanisms are used to control movements. The core of this model’s thesis is that during the normal development of the human brain both of these mechanisms are implemented in a repetitive way from the “how to do” motor domain into the “what to do” limbic domain. The first, striatal mechanism (reactive orientation) is necessary to initiate and calibrate movements and intentions, such as intimidation or affiliation. This mechanism is organized in the ventral parts of the brain. The second, cerebellar mechanism (proactive orientation) is necessary for guidance. The intentional variant of the representational guidance mechanism is organized in the dorsal parts of the brain. The repetitive application and training of both mechanisms during brain development allow the possibility to mentalize; viz. the ability to create (meta) representations, language and consciousness, but also an increased capacity to deal with conflicting demands and emotions. This development creates the possibility for satisfaction and “ self ” awareness. Evidence is accumulating that in addiction, patients show an imbalance: they excessively rely on the ventral drive mechanism. Therefore they show a comparatively increased reactive orientation: the repeated use of the addictive substance further increases this imbalance and the risk on tipping of the scale: a higher reactivity of this ventral circuit and consequently the irresistible desire for the addictive substance.