This script contains the standard implementation of the
activation model, in which the drop in dopamine efflux
after administration of TC-7020 is caused by activation
of the a7 receptors under the influence of TC-7020.

Characteristics of the model are the predominant (or total)
expression of a7 receptors on the GABA neurons (or their
glutamatergic afferents), and the absence of a too strong 
cholinergic tone.