Pre-clinical research projects
TMS effects on circuit plasticity and drug seeking in rodents
The TN² lab studies the neurobiological effects of Transcranial Magnetic Stimulation (TMS) on brain circuits distal to the site of TMS stimulation by taking advantage of the olfactory circuit anatomy. This project allows us to answer fundamental questions about the neurobiological effects of TMS. For example, it is not clear 1) whether TMS of the brain surface can induce lasting synaptic and intrinsic changes in downstream cortical and subcortical circuits, 2) how different TMS parameters affect downstream circuits, and 3) whether TMS can reverse established circuit pathologies in models of disease. Answering these questions will allow the development of more effective and safer clinical TMS protocols tailored to specific circuit pathologies. We recently developed and validated a non-invasive opioid self-administration model using vaporized fentanyl (Moussawi et al., Science Advances 2020), which we use for the TMS investigations.
Opioid-induced changes in midbrain dopamine neurons
The TN² lab investigates opioid-induced neuroadaptations in dopamine neurons that could underly the persistent vulnerability to relapse after prolonged abstinence. We identify the drug-induced changes using patch-clamp electrophysiology techniques and then test their physiological relevance and effect on cue reactivity using multi-array single unit recordings in awake behaving rats.
Role of the olfactory tubercle in reward and motivation
The olfactory tubercle is an anatomical and functional extension of the ventral striatum. However, the role of the olfactory tubercle in drug reward and vulnerability to relapse has not been investigated. Studies from the TN² lab show profound drug-induced changes in the olfactory tubercle medium spiny neurons.
Clinical research projects
Identifying new neuromodulation targets for drug addiction
The TN² lab is interested in exploring the use of limbic GPi DBS for the treatment of severe cases of drug addiction. Further, in a recent collaboration with Dr. Michael Fox at the Laboratory for Brain Network Imaging and Modulation, we used lesion network mapping to identify an ‘addiction remission network’, which highlights specific targets for neuromodulation for the treatment of drug addiction. We will conduct clinical studies to test the efficacy of non-invasive neuromodulation of some of these targets.
The effects of Globus pallidus DBS on impulsivity and motivation
In Parkinson’s patients implanted with DBS in the GPi, and in collaboration with Dr. Kelly Mills at Johns Hopkins, we examine the effects of GPi DBS on addiction related behavioral measures (e.g., impulsivity and motivation).