My research is generally concerned with understanding brain systems that contribute to appetitively motivated behaviors. It is well established that the dopamine system is important in motivation and reward, but much remains to be learned about how the dopamine system is activated. Most rewards, including several drugs of abuse, activate the dopamine system indirectly.  Environmental stimuli, which through experience predict the availability of rewards, also come to activate the dopamine system, and almost certainly do so indirectly. Thus, understanding the source, type, and nature of afferent inputs to the dopamine system is critical. My interests have been particularly focused on the pedunculopontine tegmental nucleus (PPTg) and the laterodorsal tegmental nucleus (LDTg), two closely related brainstem nuclei that excite the dopamine system through both cholinergic and glutamatergic inputs. My laboratory uses a combination of experimental approaches (in-vivo pharmacology, cell-specific lesions techniques, and optogenetics) to understand the role of PPTg and LDTg cholinergic and glutamatergic inputs to the dopamine system in rat and mouse reward-seeking and reward-taking behaviors.