Part II starts with a systemic model of the basal ganglia to evaluate
the position of the STN in the direct, indirect and hyperdirect
pathways. A summary of in vitro studies is given, describing STN
spontaneous activity as well as responses to depolarizing and
hyperpolarizing inputs, and high frequency stimulation. STN bursting
activity and the underlying ionic mechanisms are investigated. Deep
brain stimulation used for symptomatic treatment of Parkinson's disease
is discussed in terms of the elements that are influenced and its
hypothesized mechanisms. This part of the monograph pays attention to
the pedunculopontine-subthalamic connections and tries in cell cultures
to mimic neurotransmitter actions of the pedunculopontine nucleus and
high frequency stimulation on cultured dissociated rat subthalamic
neurons. STN cell models: single and multi compartment, and system level
models are discussed in relation to subthalamic function and
dysfunction. Part I and II are mutually compared.