Joel Geerling, MD PhD

As a physician-scientist, I divide my time between clinical practice and basic research. I run a subspecialty clinic in Cognitive Neurology and dedicate most of my effort to running a basic neuroscience laboratory. Our laboratory combines molecular neuroanatomy with physiological and behavioral assays to identify the specific neurons and circuits that control vital functions — from wakefulness and sleep to appetite and autonomic control. These homeostatic functions depend on interconnected neural networks spanning the brainstem, hypothalamus, and limbic forebrain. By mapping and understanding interoceptive circuits, we aim to develop better treatments for patients with disorders affecting these fundamental systems.

Current Lab Members

  • Postdoc - University of Iowa Geerling Laboratory (2017 - 2022)

    Research Associate Scientist (2022 - present)

    • Silvia joined the Geerling at the end of 2017 and finished a series of studies on the neurons, hormones, and neurotransmitters that control sodium appetite.

    • She accepted a promotion to Research Assistant Scientist in 2022, then Research Associate Scientist in 2023, and continues investigating the circuitry and physiology of sodium appetite.

  • Postdoctorate Researcher - University of Iowa Geerling Laboratory (2024 - present)

    • Gislaine joined the Geerling lab in mid-2024.

    • She is contributing to research focused on the nucleus of the solitary tract, parabrachial nucleus, and Kolliker-Fuse nucleus.

  • Lab Manager - (2023 - present)

    • Mya joined the laboratory after completing her B.S. in neuroscience at the University of Iowa in 2023.

    • She manages mouse breeding and genotyping, compliance, histologic analysis, and a variety of other lab managerial tasks.

  • PhD Student - University of Iowa Interdisciplinary Program in Neuroscience (2024 - present)

    • Haidong completed a Master’s degree at the Florey Institute in Melbourne.

    • He is identifying novel neuronal subtypes and functions in the nucleus of the solitary tract.

  • M1-4 Medical Student, University of Iowa Carver College of Medicine (2019- Present)

    • Richie began working in the lab before his M1 year and obtained Summer Research Fellowship support for his pre-M1 summer.

    • He obtained a second SRF in 2023, joined the Research Distinction Track, and published two first-author papers, with a third in preparation.

  • M4 medical student (2021–2022), University of Iowa, Carver College of Medicine.

    Neurology Resident (2022–present)

    • Ben published (2023) a case report describing a remarkable patient with selective destruction of the Left frontoinsular cortex, who underwent a striking and sustained change in appetite.

    • He graduated in 2022 and began Neurology residency training here, while continuing collaborative work on brain lesions that impair consciousness.

Biographies

  • Haidong Zhu- PhD Student - University of Iowa Interdisciplinary Program in Neuroscience (2024 - Present)

    • Haidong joined the lab after he completed his Master’s degree at the Florey Institute in Melbourne.

    • He is currently working on identifying novel neuronal subtypes and functions in the nucleus of the solitary tract.

    Margaret Tish - PhD Student - University of Iowa Interdisciplinary Program in Neuroscience (2018 - 2023)

    • Maggie won the “Student Presentation of the Year" award in 2018, the Post-Comprehensive Research Fellowship award in 2019, an NIH F31/NRSA fellowship award from NINDS (2020–2023), and the Kwak-Ferguson prize from the Iowa Neuroscience Institute in 2020.

    • Maggie published three first-author papers, a clinical case report, and an invited book chapter on Barrington's nucleus (2023).

    • After defending her thesis and graduating in 2023, Maggie started a Postdoctoral Fellowship at Emory University.

    Fillan Grady - MD-PhD Student - University of Iowa Medical Scientist Training Program (2017 - 2022)

    • Fillan received the Post-Comprehensive Fellowship Award in 2019 and the Graduate Student Publication Award from our Neuroscience program in 2020.

    • Fillan developed a novel machine learning algorithm that identifies presynaptic boutons (Brain Structure and Function 2022) and published five first-author papers and three as middle co-author.

    • After completing medical school in 2024, Fillan started a combined PSTP Medicine residency and Endocrine fellowship in the University of Washington in Seattle.

  • Silvia Gasparini - Postdoc - University of Iowa Geerling Laboratory (2017 - 2022) | Research Associate Scientist (2022 - Present)

    • Silvia joined the Geerling at the end of 2017 and finished a series of studies on the neurons, hormones, and neurotransmitters that control sodium appetite.

    • She accepted a promotion to Research Assistant Scientist in 2022, then Research Associate Scientist in 2023, and continues investigating the circuitry and physiology of sodium appetite.

    Gislaine De Almeida Pereira - Posdoc - University of Iowa Geerling Laboratory (2024 - Present)

    • Gislaine joined the Geerling lab in mid-2024.

    • She is contributing to research focused on the nucleus of the solitary tract, parabrachial nucleus, and Kolliker-Fuse nucleus.

  • Frederico Fazan - Visiting Master’s Student - São Paulo / University of Iowa (2019 - 2020)

    • Fred spent 6 months of his Master’s thesis work in the Geerling lab, funded by a FAPESP fellowship from the University of Sao Paolo in Brazil; Dr. Geerling served on his dissertation committee.

    • Fred completed one first-author and one middle-author paper in the lab.

    • After defending his Master’s thesis, Fred worked for an additional year in the Ahern lab and Dr. Geerling helped support his successful application to graduate school. He moved to New York and began his PhD thesis work in Molecular Biophysics at Weill-Cornell Medical College 2022.

  • Richie Zhang - M1-2 Medical Student, University of Iowa Carver College of Medicine (2019- Present)

    • Richie began working in the lab before his M1 year and obtained Summer Research Fellowship support for his pre-M1 summer.

    • He obtained a second SRF in 2023, joined the Research Distinction Track, and published two first-author papers, with a third in preparation.

    Benjamin Reasoner – M4 medical student (2021–2022), University of Iowa, Carver College of Medicine. Neurology Resident (2022–present)

    • Ben published (2023) a case report describing a remarkable patient with selective destruction of the Left frontoinsular cortex, who underwent a striking and sustained change in appetite.

    • He graduated in 2022 and began Neurology residency training here, while continuing collaborative work on brain lesions that impair consciousness.

    Dake Huang - M1-M4 Medical Student, Research Dissertation Track - University of Iowa Carver College of Medicine - (2019 - 2023)

    • Dake joined the lab in 2019, before his M1 year, with support from a Summer Research Fellowship award from the Carver College of Medicine. He continued working in the lab during his M1 year and returned the following summer. Dake was extremely productive, publishing three neuroanatomy papers as first author and another as middle co-author. He received the CCOM "Excellence in Basic Neuroscience Research" award (2020) and was invited to give a talk at the American Neurologic Association meeting in 2021.

    • Dake graduated and started an Anesthesiology residency Washington University School of Medicine in Saint Louis in 2023.

    Benjamin Kreitlow - M2 Medical Student Summer Research Fellowship, University of Iowa Carver College of Medicine (2019)

    • Ben examined cell-type-specific markers in the human parabrachial region. I helped support his successful application to the Iowa MSTP, where he began his Neuroscience PhD work in 2020.

  • Anuradha Gore - Post-Baccalaureate - (2017-2018)

    • Anu worked as a part-time RA and co-authored a paper on the pre-locus coeruleus (Gasparini et al 2020 AJP-Reg), then left for a post-bac program at UC Irvine and returned to begin medical school here at the Carver College of Medicine in 2020.

    Gabrielle Iverson - Post-Baccalaureate - University of Iowa Center for Research by Undergraduates (ICRU) - (2017-2018)

    • Gabby worked as a part-time RA for two years in the laboratory, before moving to Minnesota in 2018 to work with the genetic counseling group at Mayo, then a genetic counseling training program in 2021. Gabby is a middle co-author on four papers from the lab.

    Lila Peltekian - Post-Baccalaureate - (2017-2019)

    • Lila was the first RA and a key ingredient for success in starting the lab. She completed an outstanding first-author, primary research study (published in J Physiol 2023) and contributed as co-author on seven other papers. We supported her successful application to medical school in 2019. Lila presented her work at the Society for Neuroscience convention in 2023 and intends to pursue residency training in Neurology.

    Yaritza Delgado Deida - Post-Baccalaureate - (2018-2019)

    • Yaritza worked part-time in the lab for a year after finishing college, helping with cell counts for fate-mapping and gene/protein co-localization experiments across hundreds of thousands of neurons in hundreds of tissue sections in triple-labeling material.

    • She moved to Colorado in 2019, and we supported her application to medical school.

  • Samyukta Karthik - University of Iowa - (2019-2022)

    • After working in my lab in high school (summer, 2018), Samy enrolled at Uiowa and returned to work in my lab her freshman year to begin an undergraduate honors thesis project involving the genetic expression patterns and molecular-genetic ontology of the parabrachial nucleus. Her contributions helped finish a longstanding project, published in 2022 in the Journal of Comparative Neurology. She graduated early (2022) to pursue an MPH at Cambridge, then began medical school the following year, at Penn State.

    Marco Nino - University of Iowa - Biomedical Engineering - (2018-2019)

    • After transferring from California to our BME program, Marco joined my lab to help part-time with circuit design, 3D printing, mouse EEG, and other tasks. After graduation, Marco gained acceptance to Iowa BME graduate program to pursue a PhD in Biomedical Engineering.

    Sowmya Narayan - University of Minnesota - (2017 - Summer)

    • Sowmya worked in my lab in the summer of 2017 and helped trace the output projections of aldosterone-sensitive HSD2 neurons. Her work was a key part of my lab's first paper on this project (Gasparini et al 2019 Brain Struct Funct). After graduating from U of Minnesota, Sowmya began graduate school at the Max Planck Institute in Germany, where she is pursuing a PhD in Neuroscience.

    Jacob Howland - University of Iowa - Microbiology - (2017-2018)

    • Jacob helped plot retrogradely labeled neurons (whole-brain mapping) to complete a neuroanatomical study of inputs to the NTS in rats and mice and served as a co-author on the resulting publication (Gasparini et al. J Comp Neurol 2020). He graduated in 2018.

    Alison Hsu - University of Iowa - (2018-2019)

    • In the summer of 2018, Alison helped plot more than 100,000 presynaptic boutons in mouse brain tissue sections. These data helped calibrate a machine-learning algorithm that detects boutons in whole-brain microscopy datasets, which allowed several published articles in my lab. Alison returned to help with 3D plotting and analysis of electrolytic lesions in the mouse midbrain in summer 2019.

    Andrew Thatcher - University of Iowa - Biomedical Engineering - (2018-2020)

    • As an undergraduate Biomedical Enginnering student, Andrew helped with a variety of technical and animal care tasks (roughly 10 hours per week 2018-19-20). He received an ICRU fellowship for the 2019-2020 academic year and assisted Dr. Gasparini analyze behavioral experimental data related to the aldosterone-sensitive HSD2 neurons and their output targets.

    • He graduated with a bachelor’s degree in BME (2021) and began full-time work at a nearby engineering firm.

    Natalie Voss - University of Iowa - Premedical - (2019-2022)

    • Natalie joined the lab in 2019 and helped us analyze micturition video thermography (MVT) data, Rotarod results, 3D brain lesion analysis, DigiGait, and other behavioral tests in hydrocephalic mice, to support Maggie Tish's PhD thesis work. She also tested male-female differences in micturition behavior. Natalie received an ICRU award to support her work in the 2020-2021 academic year, and we supported her successful application to medical school.

    • In 2022, she began as an M1 medical student here at CCOM.

    Rulan Zhang - University of Chicago - (2022 - Summer)

    • Rulan joined the lab for one summer and assisted Maggie Tish with Rotarod analysis, micturition video thermography, and 3D brain lesion mapping. She plans to pursue Political Science coursework at the University of Chicago.

    McKenna Warnock - University of Iowa - (2022-2023)

    • McKenna helped with mouse perfusions and immunohistology to assist with Fillan Grady's PhD thesis work. Her work on this project merited co-authorship on a paper that is in revision at Cell Reports.

    • We supported her successful application to dental school in 2023, where she now studies.

    Shantelle Graff - University of Iowa - Premedical - (2019-2023)

    • Shantelle joined the lab at the end of 2019. She helped score 48h video-EEG recordings and plotted lesions onto a 3D mouse brain atlas, assisting Fillan Grady's PhD thesis work. She was accepted into the MSTP (SUMR) program in 2022. She graduated in 2023 and began a postbacc at the NIH (Neurosurgery/Neuro-oncology), with plans to apply to medical school in 2024. She will be first author on a large study of insular cortex molecular markers and connectivity and co-author on a paper we are revising for Cell Reports.

    Chidera Mitchell - University of Iowa - Premedical - (2022-2023)

    • Under the auspices of the Iowa Sciences Academy (ISA), CJ joined the lab and worked part-time, approximately 10 hours per week, throughout her Freshman year and the first semester of her Junior year. She helped Drs. Gasparini and Geerling by counting populations of immunolabeled neurons after cell-type-specific ablation experiments and quantifying Fos-activated neurons. CJ also helped with brain cutting and immunofluorescence staining.

    Ana Sofia Peraza Muñuzuri - University of Iowa - Biomedical Engineering - (2022- 2023)

    • Sofia conducted groundbreaking research in our lab on the output connections of neuronal subpopulations in the nucleus of the solitary tract. This work earned her second place at the 2023 Iowa Illinois Nebraska STEM Partnership for Innovation in Research & Education (IINSPIRE) through the NSF Louis Stokes Alliance for Minority Participation (LSAMP). After earning her undergraduate degree, she completed a post-baccalaureate program at the University of Michigan.

    • She is now pursuing a PhD in Biomedical Engineering at the University of Wisconsin–Madison.

  • Mya Leuang - Lab Manager - (2023 - Present)

    • Mya joined the laboratory after completing her B.S. in neuroscience at the University of Iowa in 2023.

    • She manages mouse breeding and genotyping, compliance, histologic analysis, and a variety of other lab managerial tasks.

    Justin Liang - Lab Manager - (2020-2021)

    • Justin was our lab manager from 2020-2021, after which he moved to Colorado to be closer to his wife’s family. He now works as a lab manager for a neuroscience laboratory in Colorado.

    Lila Peltekian - Post-Baccalaureate - (2017-2019)

    • Lila was the first RA and a key ingredient for success in starting the lab. She completed an outstanding first-author, primary research study (published in J Physiol 2023) and contributed as co-author on seven other papers. We supported her successful application to medical school in 2019. Lila presented her work at the Society for Neuroscience convention in 2023 and intends to pursue residency training in Neurology.