Addictive drugs such as cocaine and amphetamine disrupt the presynaptic dopamine neurotransmission, which enhances synaptic dopamine. This happens through the modulation of synaptic mechanisms involved in learning, as well as enhanced excitation or disinhibition of dopamine neuron activity and blockade of dopamine reuptake, which augment striatal dopamine neurotransmission by means that dissociate it from normal drive by environmental cues.