Circuits frontaux sous-corticaux et applications psychiatriques

The frontal-subcortical circuits are central to psychiatric disorders. These are parallel neuronal circuits linking specific regions of the prefrontal association cortex with various subcortical structures. Rye circuits are known. Two are related to motor and three to cognitive functions, emotions and motivation. Each circuit comprises a closed loop and open afferents and efferents. The frontal-subcortical circuits have multiple connections with limbic structures which place them in a position of key importance in psychiatric disorders. This article is a didactic review. We first describe the common anatomical, neurophysiological and cytoarchitectomic structures of the five circuits. We next discuss the functions and clinical deficits of each. The circuits that mediate motor and oculomotor functions seem to be implicated, in part, in disorders of smooth visual pursuit and saccadic eye movements and also in the programming and control of complex movement. Those concerning behaviour are responsible for alterations of executive functions, disturbances of emotional control and apathy These symptoms can appear in various pathologies such as schizophrenia, mood disorders, obsessive-compulsive disorder, attention deficit/hyperactivity disorder and catatonia. These clinical pathologies seem to reflect, in part, electrochemical disturbances in the frontal-subcortical circuits. Finally, we discuss the clinical approach to investigation and treatment.