Neuronal Dynamics of The Basal Ganglia and Related Systems

Ohio State University Research Foundation -Do Not Use, Columbus OH

Investigators

Abstract

Terman 0103822 The investigator and his colleague develop geometric, dynamical systems tools for analyzing biophysical, conductance-based models for a broad class of neuronal networks. These systems arise in numerous applications including motor activity, sensory processing and learning. They also develop computational models for the generation of sleep rhythms, epilepsy and parkinsonian tremor. The investigators also construct and refine a mathematical and computational model for electrical activity in the subthalamic nucleus and external segment of the globus pallidus. These are two nuclei in the basal ganglia, a part of the brain involved in motor activity. Dysfunction of the basal ganglia is associated with movement disorders such as Parkinson's disease and Huntington's disease. The model is used to test hypotheses on the role of the basal ganglia in both normal and pathological movement. Numerous experiments have demonstrated that neurons within the basal ganglia display a rich variety of dynamic behavior; moreover, patterns of neuronal activity, both spatial and temporal, are different between a normal and a pathological state. The investigators characterize the possible patterns of neuronal activity that arise in the model and determine how these patterns change with respect to modulations of network parameters and structure. A long term goal is to develop a model realistic enough so that it can shed light upon the key parameters and mechanisms responsible for the generation and modulation of observed activity patterns. A mathematical theory for the analysis of neuronal dynamics helps illuminate the role played by various components of a model in generating a particular population rhythm. These components may correspond to some intrinsic property of individual cells, or to some network property such as the strength and type of synaptic coupling or the probability that two cells communicate with each other. Clarification of the mechanisms underlying different activity patterns may lead to a classification of all possible rhythms that can emerge from a given network, and enable us to determine how complicated a model should be in order to display some observed behavior. It also helps predict transitions of the network behavior as parameters in the model are varied. The investigators develop models for neuronal dynamics, and in particular of electrical activity in the subthalamic nucleus and external segment of the globus pallidus. These are two nuclei in the basal ganglia, a part of the brain involved in motor activity. Dysfunction of the basal ganglia is associated with movement disorders such as Parkinson's disease and Huntington's disease. The model is used to test hypotheses on the role of the basal ganglia in both normal and pathological movement. Such models may help illuminate both fundamental neuroscience questions and clinical issues about how the brain and central nervous system work.