Pontine tegmental lesions can eliminate the atonia of rapid eye movement sleep (REM) and allow animals to exhibit overt behavior at the same time that other electrophysiological signs of REM are intact. We produced electrolytic lesions in the reticularis pontis oralis (RPO) and reticularis pontis caudalis (RPC) in rats and observed them for behavior during REM without atonia (REM-A) and for alterations in sleep and waking compared to normal rats. Relatively small unilateral lesions were sufficient to remove the atonia of REM, whereas larger, bilateral lesions were required to release overt behavior during REM-A. Lesions in both RPO and RPC were capable of releasing elaborate behaviors, including full locomotion, during REM-A. The results are discussed with respect to their importance for understanding the neural activity of REM and with respect to REM-A being a model for REM behavior disorder (RBD) in humans.