Neural basis of operant behaviors maintained on the differential-reinforcement-of-low-rate (DRL) schedule in rodents

Various schedules of reinforcement have long been used in experimental psychology to establish and maintain operant behaviors. These reinforcement contingencies have also been widely applied in preclinical psycho- and neurobiology research. However, the differential reinforcement of low-rate response (DRL) schedule has received less attention than other schedules based on response ratios or different types of intervals. Hence, little is known about the neural basis of DRL schedule-controlled behavior. Herein, we review early and recent reports of rodent experiments utilizing brain lesions and intracranial drug infusions to respectively elucidate the neural substrates and neuropharmacological basis of DRL behavior. Overall, the available evidence implies that 1) certain cortical and subcortical areas are differentially involved in the DRL behavior and 2) disruption of dopamine or serotonin neurotransmission alters DRL behavior. We further identify remaining challenges in the field and suggest future work that will be helpful for understanding the neurobehavioral mechanisms of the DRL schedule of reinforcement.