Fig. 2. Depicts rodent and human paradigms and outcome measurement for the acquisition of operant self-administration and progressive ratio self-administration.

Rodents acquire operant self-administration through the pairing of an active level press with access to an ethanol solution. Over time, rodents learn to acquire this self-administration behavior. Currently, there is no human paradigm which parallels the acquisition of self-administration. In the rodent and human progressive self-administration, the response requirement to obtain an alcohol delivery gradually increases during the operant session. The maximum number of responses the rodent/human makes in order to receive alcohol is referred to as the break point. This type of schedule reflects an animal’s motivation to obtain an alcohol delivery.