Basal Ganglia Modeling in Healthy and Parkinson's Disease State. I. Isolated Neurons Activity

Parkinson's disease (PD) is a neuro-degenerative pathology affecting the basal ganglia, a set of small subcortical nervous system nuclei. It induces a progressive necrosis of dopaminergic (i.e., releasing dopamine, a neurotransmitter) cells and, as a consequence, produces altered information patterns along movement-related ganglia-mediated pathways in the brain, thus inducing motor disorders like tremor at rest and postural instability. While pharmacological and electrical therapies are currently available for PD treatment, the mechanisms according to which such disease operates are still partly unclear, due to the lack of knowledge about the basal ganglia role in motor tasks execution. For that reason, in order to shed some light on the inner dynamics of the basal ganglia and investigate how PD alters their electric patterns, we develop a two-stages modeling study: in the present paper we focus on those nuclei involved in the genesis of PD motor symptoms and, for them, develop a conductance-based electrical model able to mimic quantitative data from different in vitro physiological analyses. Such models show how several highly nonlinear electrical behaviors can stem from the interaction between specific ionic currents as particular parameters change. In [1], then, cellular models are inserted in a network scheme to reproduce the main actual anatomical connections and the resulting macroscopic behaviors reported in literature for normal and Parkinsonian conditions.