Research demonstrates that acute and chronic stress can both reduce as well as potentiate an animal's drive to seek reward. In humans, anxiety disorders are also highly comorbid with substance-use disorders. A better understanding of the underlying circuitry connecting these behaviors is necessary for developing better treatment strategies. Neuropeptide S (NPS) acts to reduce anxiety-like behavior and drives drug-seeking through activation of its cognate Gq-coupled protein receptor, NPSR1. The peri locus coeruleus (periLC) produces NPS and sends projections to the orbitofrontal cortex (OFC), a region dense with expression of NPSR1. Although we know the NPS population is involved in cue-reward processing, the elucidation of specific NPS/NPSR1 neuronal circuits correlated to observed behaviors have yet to be documented. In preliminary studies, my mentor, Dr. Kasey Girven, successfully identified a projection from NPS neurons in the periLC to the OFCNPSR1 neuron population. Currently I am investigating the role of the OFCNPSR1 population in drug-seeking behaviors. In my preliminary work I utilized NPSR1-cre mice that expressed a cre-inducibleGCaMP6s in the OFC and a photometry fiber implant above the expressing population to examine the OFCNPSR1 activity during a fixed ratio one task constructed to incentivize an active nose poke with 10 seconds of access to a 10ug/ml fentanyl solution. Using this paradigm combined with fiber photometry, I was able to test the effects of oral fentanyl self-administration on OFCNPSR1 neurons and I uncovered a bidirectional response to delivery of the conditioned stimulus (enhanced activity), and fentanyl reward (quiescence). This experimentation seeks to further our findings on the role of NPS transmission in the OFC and its involvement in drug-seeking behaviors.

Substance use disorders (SUDs) have a significant impact on global health and are experienced by over one third of individuals in the United States. Maladaptive, hypersensitive reward processing and hypersensitivity to aversive stimuli are well established behaviors associated with SUDs that are modulated by the hippocampus and basolateral amygdala by way of norepinephrine and dopamine signaling. The primary source of norepinephrine is the locus coeruleus (LC) and the primary source of dopamine is the ventral tegmental area (VTA). LC-sourced norepinephrine in the basolateral amygdala promotes anxiety-like behaviors. Recent studies suggest both norepinephrine and dopamine in the dorsal hippocampus promote spatial learning and memory. The dynamics of these neuromodulators in the ventral hippocampus in response to salient stimuli is not understood. In the ventral hippocampus, we found norepinephrine release is observed during both aversive and appetitive behaviors, and both norepinephrine and dopamine are released upon LC terminal stimulation. While the role the LC and ventral hippocampus play in these behaviors is established, we lack an understanding of LC dopamine sourcing and the role of receptors in monoamine release dynamics. Here, we employ biosensors and optogenetic approaches to determine monoamine release dynamics both endogenously and following photo-stimulation. Pharmacological agents are used to activate D₂ and α₂ receptors on downstream LC targets, and Gi-DREADDs are used to silence the VTA for dopamine source discrimination. Our preliminary findings show that inhibiting the VTA results in decreased dopamine transmission in the ventral hippocampus – but not complete abolition of dopamine release. These studies provide new insights into the neural mechanisms underlying reward seeking and aversive behaviors, and further our understanding of the LC’s potential role in dopamine signaling reward. (Funded by NIMH-R01MH112355 and NIDA-F31DA056148)

The opioid epidemic is a growing challenge facing the US, and adolescents are an under-researched population susceptible to opioid addiction and overdose. After surgery, many adolescents are prescribed pain medicines such as opioids to treat severe pain, but this exposes teens to opioids which have strong addictive properties. The aim of this study is to 1) understand teens’ perceptions and attitudes about prescription pain medicines that influence opioid use decisions and behaviors, and 2) develop a measure assessing perceptions and beliefs as risk factors for adolescent opioid misuse. I conducted semi-structured brief phone interviews about their perspectives on decision making about using opioids with 21 adolescents aged 12-18 years, who either had recent surgery/ICU admission or were healthy, from 3 existing studies at Seattle Children’s Hospital. After consent, we recorded, transcribed, and coded the interviews to identify themes across the interviews. Themes were: “opioids reduce extreme pain and facilitate recovery after teens’ surgery,” “teens are familiar with the risks and negative effects of opioids,” “teens carefully consider risks, benefits, and symptoms when taking opioids,” “trusted adults are important for teen opioid management,” and “teens think a variety of factors influence opioid risk.” Guided by these five themes, we are developing a new measure to assess adolescents’ perceptions and beliefs of prescription opioids. We will conduct pilot testing of the measure in existing longitudinal studies examining pediatric postoperative pain. Understanding perceptions about prescription pain medicines will allow researchers to develop interventions for youth requiring opioid treatment, for example in the context of surgery. Additionally, a validated measure assessing these perceptions and beliefs of prescription pain medicines will allow researchers to measure factors which place youth at higher risk for opioid addiction and assess the efficacy of new interventions.

The focus of psychedelic research has been on psilocybin during the last decade, revealing positive implications for the future of psychiatry. Psilocybin has recently emerged as a potential therapeutic breakthrough for major depressive disorder, with a favorable profile of rapid-acting, long-lasting effects, and non-addictive properties. Given the high comorbidity and overlapping symptoms betweeen depression and opiate withdrawal, this recent advancement in depression treatment can be utilized to gain new insights into opiate withdrawal and its potential treatment. Recent research has also assessed psilocybin for treatment of nicotine and alcohol cessation, which showed promising results. The present study hypothesizes that psilocybin treatment alleviates anhedonic behaviors related to naloxone-induced morphine withdrawal and restores baseline behavior in rats. We examine morphine withdrawal symptoms and the efficacy of psilocybin using the open field test and sucrose preference test. Behavioral markers for anhedonic morphine withdrawal symptoms are extracted and quantified using DeepLabCut, a novel deep machine learning algorithm. Our preliminary data showed that psilocybin attenuated the overall effects of morphine withdrawal on locomotor activities, in support of our hypothesis. Since hundreds of thousands of lives are lost and affected by addiction every year in the U.S, there is an urgent call for new, effective treatments for substance use disorders. This study aids our understanding of opiate withdrawal and its untapped potential therapeutic treatment.

Δ⁹-tetrahydrocannabinol (THC) is the primary psychoactive compound found in Cannabis sativa and acts on the cannabinoid-1 receptor (CB₁R). Given its well-documented analgesic effects, THC’s therapeutic value in treating pain such as those associated with motor neuron disease states, muscle spasticity-related pain, chronic pain, and muscular sclerosis has gained traction. THC’s psychotomimetic locomotor impairing effects causes patients to cease treatment. However, this relationship between THC and locomotor control is poorly understood. To address this, we are investigating THC’s effects on Pre-Frontal Cortex (PFC) neural activity during natural, unprompted movement behavior in mice. The PFC historically is known for its role in executive function but is also a target for THC’s psychotomimetic effects. We expressed GRAB_eCB2.0, an endocannabinoid biosensor, or GCaMP6f, a Ca²⁺ biosensor, in the PFC and recorded neural activity through fiber photometry during uninhibited movement behavior. We found a novel, THC- and locomotion-dependent transient of Ca²⁺ and endocannabinoid activity in the PFC at the initiation of movement. I investigated the activity of glutamatergic and GABAergic neuron activity in the PFC by utilizing genetic mouse lines and found the Ca²⁺ activity transients were primarily driven by the GABAergic interneurons that constitute 20% of the anatomical population. I hypothesized that this is due to THC-dependent activation of the CB1R on distinct GABAergic interneuron subpopulations in the PFC, which would disinhibit glutamatergic activity and in turn promote spontaneous movement. I utilized in situ hybridization to examine colocalization of CB₁R with distinct GABAergic interneuron subpopulations. We found that while CB₁R does, in fact, colocalize with GABAergic interneurons, there was no differential localization between subpopulations. Overall, this project furthers our understanding of the ways in which THC modulates neuronal activity and locomotive behaviors.

Cannabis use has dramatically increased in response to legalization in the U.S., with total sales in the U.S. jumping 46% from 2019 to 2020. ᐃ9-tetrahydrocannabinol (THC) is the primary psychotomimetic compound in Cannabis and has been shown to modify memory and motivation, processes mediated by the prefrontal cortex (PFC) brain region. I sought to test the effects of THC on PFC activity during appetitive Pavlovian conditioning in mice- a behavior in which a subject learns to associate a non-rewarding stimuli to a reward. THC acts on the endocannabinoid (eCB) CB1 receptor (CB1R), a presynaptic signaling protein responsible for modulating neural activity throughout the brain, with robust expression in the PFC. To monitor neural activity during behavioral trials, we implanted optic fibers into the PFC and virally expressed biological sensors: GCaMP6f to track Calcium activity, and the novel GRABeCB2.0 to measure eCB activity. VGAT-Cre and VGLUT1-Cre animals were presented with a house light prior to a sucrose reward to observe the neuronal GABAergic and glutamatergic activity during the conditioning, respectively. After 5 days of conditioning, I administered vehicle or THC (i.p., 5 mg/kg) to observe behavioral and neural effects of THC. We observed neural activity that transferred from the sucrose reward to the house light cue suggesting these neurons encode for this learning. Endocannabinoid activity also transitioned from sucrose reward to the house light cue suggesting cannabinoid involvement in regulating this association. THC pre-treatment reduced licking and motivation for sucrose while modifying neural activity without eliminating it. This provided much needed insight into the formation of memory during learning and reward motivation under the effect of THC.