Current Members

Art Riegel

Art received his B.A. degrees in Chemistry and Biochemistry from University of Kansas in 1993/1995, his M.S. in Pharmacology in 1998 and his Ph.D. in Pharmacology & Toxicology from UA in 2001 where he worked with Edward French. He completed his postdoctoral work with Carl Lupica at NIDA/NIH and John Williams at OHSU/Vollum where he learned slice electrophysiology and 2-photon calcium imaging to study the effects of drugs of abuse on brain circuitry.


Art started the lab in 2009 in the Department of Neuroscience at MUSC. In 2019 the Riegel Lab moved to the University of Arizona to join the newly formed Comprehensive Pain and Addiction Center (CPAC) and the Departments of Pharmacology, Neuroscience and

Optical Sciences. His work focuses on the neurocircuitry underlying motivated behaviors and addiction. While not in the lab Art spends time with his family and enjoys hiking and camping.

Kayenat (Ky) Aryeh

Ky completed her B.S. in Molecular and Cellular Biology and a B.A. in Philosophy with minors in Biochemistry and Persian.  Before joining the Riegel laboratory, Ky performed cancer biology studies with Dr. Andrew Paek. She examined the role of Forkhead Box (FOX) proteins in cell apoptosis and targeted EGFR inhibitor chemotherapies, using microscopy, genomic analysis, and molecular techniques (CRISPR/cas9 and cloning). Her previous published work (PMCID: PMC6733436) examined cisplatin with and without TNF-related apoptosis-inducing ligand (TRAIL) as a form of targeted therapy. She has given over 20 talks and poster presentations. Beyond science, Ky has professional experience in marketing and graphic design and has worked in sustainability and Residence Life.  

Her current research focuses on PFC-addiction circuitry, where she uses intracranial stereotaxic surgeries in conjunction with various genetic strategies (shRNA, DREADDs, opsins) to target cocaine/heroin-related behaviors in rodents. In her free time, she is an accomplished artist, with two exhibits and six publications. She has worked as an emergency medical technician and a medical scribe and aspires to use all these different experiences to eventually study medicine and teach medicine in developing countries.

Velia Sofia Vizcarra

Sofia received her B.S. in Health Sciences-Physiology and B.S in Molecular and Cellular Biology with a minor in Spanish from the University of Arizona in 2017. Before joining the Riegel laboratory, she worked 2 years as a medical scribe in Family Medicine, Internal Medicine and Pediatrics at the El Rio Community Health Center. As an undergraduate student, she designed and conducted public health related research examining the prevalence of diabetes and metabolic disease in Ajo, Arizona.  and aided in the implementation of a community bike program called Bike Ajo. Her research focuses PFC-addiction circuitry, where she uses intracranial stereotaxic surgeries in conjunction with various genetic strategies (shRNA, DREADDs, opsins) to target cocaine/heroin-related behaviors in rodents. In her free time, Sofia is an avid reader, traveler and lover of arts and crafts. Her goal is to gain the laboratory research experience, skills and knowledge prior to pursuing a graduate degree in the area of molecular and cellular biology.

Lisa Majuta

Lisa graduated from Northern Arizona University (NAU) with a degree in Zoology. She is a versatile scientist with over 30 years of experience organizing, designing, performing, and supervising animal husbandry, rodent surgery and numerous behavioral models in both Industry and Academia. After graduating from NAU, Lisa joined Steris Laboratories Pharmaceutical company (Phoenix AZ). She later returned to academic research, performing a wide variety of studies including: oxygen consumption and weightlessness (Dr. Tipton; UA Physiology) and uterine contraction models for compounds now in stage 3 clinical trials (Dr. Porreca, UA Pharmacology, UA; Dr. Riviere; Ferring Inc.). She later pioneered new mouse models of bone cancer pain (Drs. Mantyh, Porreca, King), headache pain (Dr. Porreca), and dural-applications of anti-inflammatory agents in awake and freely moving rats (Dr. Porreca). Her recent studies of cancer-induced bone-fracture pain with Dr. Mantyh earned her 3 first author publications and the cover of PAIN, the official journal of IASP.

She recently joined the Riegel lab, to oversee the rodent self-administration and reinstatement studies investigating cocaine and heroin and intracranial surgeries.

Kara Barber

Kara graduated from West Texas A&M University (WTAMU) in Canyon, TX with a Bachelor of Science degree in Biology with a certificate in Neuroscience in 2014. She went on to earn her Ph.D. in Neuroscience at the University of Texas Medical Branch (UTMB) in Galveston, TX, in the laboratory of Yogi Wairkar. Her dissertation focused on the localization and assembly mechanisms governing the active zone, a presynaptic specialization regulating neurotransmitter release. Malfunction of these mechanisms leads to synapse loss in neurological disorders. While at UTMB, she gained experience in a host of techniques including confocal and super-resolution imaging, electron microscopy, electrophysiology, and genetic approaches of translational neuroscience.

In the Riegel Lab, she uses her expertise in synapses to investigate how altered calcium homeostasis following drug-induced persistent neuronal excitability can alter synaptic structure and strength. By learning more about these processes, she hopes to understand how addictive drugs, including opioids, can influence synaptic structure and function and how these changes can trigger relapse. Outside of the lab, she likes to spend time with her husband and her two cats. She also enjoys exploring Arizona’s deserts, mountains, and dark skies.

Ryan Ochoa

Ryan is a junior studying Physiology at the University of Arizona. Before joining the Riegel laboratory he researched pulmonary hypertension and its quantitative effects in the pulmonary vasculature of the sugen5416/hypoxia mouse model in Dr. Rebecca Vanderpool’s lab. Ryan will begin to investigate the role of microglia cells and ryanodine receptors in relation to addiction using super-resolution microscopy in the Riegel laboratory. Outside of academia he has volunteered with Americorps by tutoring underprivileged students at Amphitheater High School and helped women in need at Sister Jose Women’s Shelter through Alpha Phi Omega. Ryan is in pursuit of a PhD so he can continue contributing to the community through research. 

Braden Lopez

Braden Lopez is a UA sophomore majoring in Physiology and Medical Sciences with a minor in Business Administration. He is new to research and very excited for the opportunity to join Dr. Riegel’s pharmacology laboratory. In the lab, Braden will investigate microglia and ryandodine receptors in regards to addiction by using super-resolution microscopy and immunohistochemistry. Braden is very involved around campus in organizations like Physiology Club, Legacy Scholars, and Alpha Epsilon Delta. Recently, Braden was elected to be the Social Chair of Alpha Epsilon Delta, a premier pre-health honorary at the UA. Through the organizations, Braden partakes in many philanthropic and health focused events around the campus community, with the hope of improving individuals’ lives on an everyday basis. 

Giselle "Gigi" Ruiz

Gigi Ruiz is a sophomore in the Honor's College, majoring in Neuroscience and Cognitive Science and Pharmaceutical Sciences with a minor in Biochemistry. Before starting at the Riegel Lab, she completed an Honor's First Year Project on socioeconomic factors in the Social Risk and Resilience Factors Lab. In Dr. Riegel's Lab, she will be investigating the role that various serotonin receptors play in the development and relapse of addiction. Beyond academics, Gigi is an active volunteer for the university as an ambassador for the Neuroscience and Cognitive Science Major, the Honors College, and the College of Science. In her free time, she enjoys teaching piano, running, and taking photos of the outdoors. Gigi intends to complete a Master's in Neuropharmacology after graduation and eventually pursue an MD/Ph.D.

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Julia Ritz

Julia will complete her B.S. in Optical Sciences and Engineering and minor in mathematics in the Spring of 2021. Before joining the Riegel lab she worked as an intern at Zygo Corporation where she became experienced using laser interferometry for optical metrology and 3-D optical surface profiling using white light interferometry to perform non-contact, high precision imaging. Currently, she is leading her senior design team to develop a signal processing system for human speech, breath and heart sound signals which will be paired with NLP to give doctors a verifiable diagnostic basis.

She is a new member to the lab whose research will consist of calcium imaging in living brain slices using a two-photon laser imaging system, confocal microscopy for analyzing brain circuits and immunohistochemistry, and brain slice electrophysiology. She will also investigate the ways that light sheet microscopy can be optimized for and integrated into imaging neural circuitry relevant to motivated behaviors. She hopes to combine these research techniques with analyses of the behavioral assays associated with end-stage addiction in rodents to further uncover the neural mechanisms that drive motivated behaviors like relapse and recovery in end-stage addiction. 

Raveena Parmar

Raveena completed her B.A. in Psychology with a minor in Biology from California State University of Bakersfield in 2019. During her undergraduate tenure she was awarded the prestigious Marc U*Star fellowship and through this fellowship she worked under the guidance of Dr. Amy Gancarz for three years. In Dr. Gancarz’s lab she investigated why some people are more susceptible to becoming addicted to drugs while others are more resilient utilizing rodents as her animal model. She focused on identifying early life environmental factors that promote future drug use. Her first project focused on sugar intake in adolescence, a period of “sensation-seeking” and heightened vulnerability to substance abuse. In adolescence rats trained to voluntarily consume large amounts of sucrose, she found increased willingness (as adults) to self-administer cocaine. Moreover, cocaine consumption persisted despite co-infusion of the aversive agent histamine, suggesting that the overconsumption of sucrose during adolescence increased the sensitivity to cocaine reward and decreased the sensitivity to aversive punishments limiting drug intake. Her experiences in Dr. Gancarz’s lab later opened doors for training with Dr. Mandyam (UCSD), and Dr. Leslie (UC Irvine). She recently started her Ph.D. dissertation work with Dr. Riegel, using electrophysiology to examine neuroadaptations in the prefrontal cortex (PFC) relevant to drug abuse. Along with learning new rodent behaviors (i.e., impulsivity, morphine self-administration), she is learning patch-clamp (current/voltage clamp) electrophysiology in living brain slices. Her goal is to identify cellular adaptations in the prefrontal cortex brain circuitry underlying these behaviors. She is passionate about using science as a tool to cultivate young minds to critically examine their world and inspire younger generations towards a better society. Furthermore, she hopes to research complex health issues in drug abuse and chronic pain in order to help people make better use of health services, adopt self-care practices, and with time find an antidote that can help alleviate substance abuse for oncoming future generations.

Siera Millard

Siera Millard is a freshman at the University of Arizona with an expected B.S. in Biomedical Engineering with a minor in Spanish. Outside of academic work, she has worked with Rotary for the last two years through Interact and now the UA Rotaract club. Additionally, she is a training Hero Care Regional Family Contact Volunteer with the American Red Cross.

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Abigail "Abby" Margaret Schwarz
Hannah Renee Ortiz
Gabriela Franca

Gabriela Franca is a junior at the University of Arizona, studying Neuroscience and Cognitive Science. She has worked in Dr. Natalie Bryant’s lab, Associating Sleep and Episodic Memory Updating, where she worked with human test subjects during a control portion of the lab. This entailed using the 10-20 system to measure the head of the test subject and apply electrodes to their scalp and then ensuring validity during their resting state by monitoring their sleep activity using polysomnography recording. In Dr. Riegel’s laboratory, Gabriela will perform surgery on the rat subjects and conduct self-administration testing on them. She is a member of the pre-health honorary, Alpha Epsilon Delta, where she participates in many health and philanthropic events, serving the community and learning more about the health career field. She is also the Panhellenic Delegate on the executive board for her sorority Sigma Kappa, which is one of the Greek chapters here at the UofA. As a first-generation American, Gabriela is driven and excited for her next steps after her undergrad in hopes to achieve a PhD in Neurobiological research in order to discover new cures and treatments related to diseases such as drug addiction and Alzheimer’s.