Dopamine and serotonin modulation of motor and non-motor functions of the non-human primate striato-pallidal circuits in normal and pathological states.

Thanks to the non-human primate (NHP), we have shown that the pharmacological disturbance of the anterior striatum or of external globus pallidus triggers a set of motivation and movement disorders, depending on the functional subterritory involved. One can, therefore, assume that the aberrant activity of the different subterritories of basal ganglia (BG) could lead to different behavioral disorders in neuropsychiatric disorders as Tourette's syndrome and Parkinson's disease. We are now addressing in the NHP the impact of modulating dopamine or serotonin within the BG on behavioral disorders. Indeed, we have shown a prominent role of serotonergic degeneration within the ventral striatum and caudate nucleus in neuropsychiatric symptoms in de novo PD patients. Of note, the serotonergic modulation of these BG regions in the NHP plays also a critical role in the induction or treatment of behavioral disorders. Given that both dopamine and serotonin are targeted to treat neuropsychiatric disorders, we are studying the effects of modulating dopamine and serotonin transporters in the different territories of the striatum, and more particularly within the ventral striatum on decision-making processing at both behavioral and neuronal levels. Finally, we evidence the need to extend the pharmacological approach to the receptors of these two neuromodulator systems as the use of substances targeting receptor subtypes preferentially localized in the associative and limbic territories of BG could be very effective to specifically improve the behavioral disorders in Parkinson's disease, Gilles de la Tourette syndrome but also in several psychiatric disorders such as depression, anxiety, anorexia, or impulse control disorders.