IL6 and Tremor: In another transgenic model, IL-6 transgenic mice, over expression of IL-6 by astrocytes resulted in (depending on the level of expression) increased numbers of microglia and astrocytes in the cerebellum (i.e., gliosis), neurologic dysfunction including tremor and ataxia, cerebellar neurodegeneration in older animals, altered protein expression and altered synaptic function [15, 17, 19, 47, 83, 90].