These studies indicate that low and medium concentrations of ethanol produce enhanced synaptic and tonic inhibition of cerebellar granule cells. These actions might be mediated through direct actions of ethanol on tonic and synaptic GABARs, but may also arise indirectly by increasing the excitability of GABAergic Golgi cells. Based on the known circuitryof the cerebellum, increased inhibition of granule cells should lead to a decrease in the synaptic activation of Purkinje cells. Purkinje cells send GABAergic projections to form synapses on the deep cerebellar nuclei, which project from the cerebellum to relay neurons of the thalamus, which in turn project to the cortex (reviewed in [17]). Thus, low and medium doses of ethanol may disrupt fine motor coordination through multiple actions in the cerebellum, which then likely impair thalamic processing of motor information.
