Dopaminergic neurons in the ventral tegmental area play a key role in signalling motivational information. Modulation of this signalling by drugs is also key to the development of addiction. These neurons have several firing modes ranging from periodic low frequency activity to higher frequency bursts. In vitro, intrinsically generated bursts are seen, while in vivo irregular high frequency alternates with periodic activity. Addictive drugs alter this firing patter towards high frequency bursting. In this talk i will discuss analysis of the mechanisms that lead to the various firing modes of the dopamine neurons and how addictive drugs alter them. Notably, I will present recent results on modelling effects of alcohol on dopaminergic dynamics and dopamine outflow. Here i will show how changes in the inhibitory input synchrony to the dopamine neurons may promote high frequency firing. Time permitting, I will show how inout structure to the dopamine neurons may control their excitabilty type and what that may imply for their ability to encode reward related signals.