Published on December 7, 2018 | Updated on January 29, 2019

CORTEX conference by Léon Tremblay

December 13th, 2012

The relationships between Basal Ganglia and the Frontal cortex: New issues to understand the neuronal bases of behavioral disorders.

Historically, Parkinson’s disease (PD) was defined as a pure movement disorder. Cur- rently, it is widely accepted that this disease is also characterized by nonmotor signs, such as depression, apathy, and anxiety. On the other hand, the considera- tion of Gilles de la Tourette syndrome (GTS) as a neuro- psychiatric disorder has also been debated. In this review, we will focus on these two disorders, which combine both motor and behavioral features and in which dysfunction of cortical and subcortical regions was suggested. Anatomical, experimental, and clinical data are reported to support the involvement of basal ganglia (BG) in cognitive and motivational functions in addition to motor control. In PD, the nonmotor signs could result from the heterogeneity of dopaminergic lesions and excessive activation of the dopamine receptors, particularly within the limbic neuronal net- works. Experimental results obtained on nonhuman pri- mates using local disinhibition within functional territories of BG allowed the precise mapping of their motor and nonmotor functions. Thus, impairment of inhibitory control inside specific striatal territories induced behavioral disorders and abnormal movements, which had striking similarities to clinical expressions of GTS. Establishing such a relationship between BG sub- territories and motor and behavioral disorders could potentially be helpful for future target choices for DBS in many neuropsychiatric disorders. Furthermore, it is also of great interest for therapeutic research and for the efficient targeting of symptom relief to determine the precise pharmacological effects of the two main modulators of BG function, which are dopamine and serotonin.