Xiaojie Liu, PhD

Dr. Liu received her Master of Science degree in Physiology, specializing in the role of melatonin in Alzheimer’s disease. She earned her PhD in Neuroscience at the Medical College of Wisconsin, where she continued her postdoctoral training. During this period, her research focused on the molecular mechanisms of cocaine addiction and the circuit‑level regulation of endocannabinoid signaling. Dr. Liu joined the Medical College of Wisconsin as an Assistant Professor in the Department of Pharmacology and Toxicology in July 2026, where her laboratory investigates the neural, molecular, and circuit mechanisms underlying reward, reinforcement, addiction, and affective regulation.

• Addiction and Substance Use Disorders
• Endocannabinoid Signaling
• Neural Circuits and Synaptic Plasticity
• Neuropharmacology
• Behavioral Neuroscience

My research centers on two major goals:

1. Defining the molecular and circuit mechanisms that govern reward and reinforcement, with a particular emphasis on adaptations that drive drug taking and drug seeking.
2. Elucidating the cell type–specific and circuit level mechanisms through which endocannabinoid signaling regulates anxiety and depression like behaviors.

To address these questions, our lab integrates slice and in vivo electrophysiology, fast scan cyclic voltammetry, optogenetics, chemogenetics, in vivo calcium imaging, fiber photometry, and sophisticated behavioral paradigms. We apply these approaches both to dissect the neural substrates underlying the addictive properties of abused drugs and to uncover how endocannabinoid signaling shapes emotional behaviors. Together, these methods allow us to identify molecular and circuit adaptations and to manipulate them in vivo to prevent pathological drug seeking and maladaptive affective states.