About

Dr. David Krantz is Professor in Residence in the Department of Psychiatry and Biobehavioral Sciences at the David Geffen School of Medicine at UCLA. He completed his undergraduate studies at Brown University and earned an MD/PhD through the Medical Scientist Training Program at UCLA in 1991, where he performed his dissertation on Drosophila eye development with Larry Zipursky. Following a residency in psychiatry at UCLA, he was awarded a Howard Hughes Postdoctoral Fellowship for Physicians to investigate the regulation of vesicular neurotransmitter transporters in Robert Edwards’ laboratory at UCSF. Since returning to UCLA in 2000, Dr. Krantz has been using Drosophila as a model organism to study how changes in the function of neurotransmitter transporters influence synaptic transmission and behavior.

Research topics

• Medicine
• Psychology
• Psychiatry
• Audiology
• Neuroscience
• Internal medicine
• Physical medicine and rehabilitation
• Biology
• Physics

Selected publications

• Differential neural responses to rhythmic and patterned TMS protocols: Insights from EEG spectral analysis

  Neuropsychopharmacology · 2026-01-07

  articleOpen access

  Repetitive Transcranial Magnetic Stimulation (rTMS) engages brain networks for the treatment of Major Depressive Disorder (MDD), using either rhythmic (e.g., 10 Hz) or patterned (e.g., intermittent Theta Burst, or iTBS) stimulation protocols. The distinct effects of these protocols on brain function are not well understood. Sixteen subjects with MDD underwent a TMS-electroencephalography (TMS-EEG) "interrogation" paradigm, in which a broad range of rhythmic and patterned stimulation frequencies were administered in a randomized order to the left dorsolateral prefrontal cortex (L-DLPFC). rTMS-induced changes in oscillatory activity and effective connectivity to the DLPFC were examined at each frequency. Linear mixed-effects models revealed widespread changes in power and connectivity, with magnitude and regional distribution of change dependent upon both protocol and frequency of stimulation. Increases in beta band power were most prominent with patterned stimulation, while rhythmic stimulation increased both alpha and beta power at stimulation frequencies greater than 7 Hz (p < 0.05). Source localization showed that patterned and rhythmic stimulation elicited activation in distinct subregions of the cingulate. Rhythmic and patterned stimulation also had distinct effects on connectivity: notably, only rhythmic stimulation increased connectivity with regions near the stimulation site, while only patterned stimulation decreased connectivity to the left precuneus. Both protocols increased the effective connectivity to the orbitofrontal cortex in the theta and beta response bands (p < 0.05). These results indicate that rhythmic and patterned rTMS engage distinct brain regions in a protocol- and frequency-dependent manner. Future studies should examine how these mechanistic differences may relate to clinical outcomes.

  PublisherOA PDFDOI

• The relationship between individual alpha-band activity and cognitive outcomes from repetitive Transcranial Magnetic Stimulation (rTMS) treatment for Major Depressive Disorder (MDD)

  Journal of Affective Disorders · 2026-02-18

  article
  PublisherDOI

• Trajectories of patient-rated baseline-severe depressive symptoms during repetitive transcranial magnetic stimulation (rTMS) for major depressive disorder

  Transcranial magnetic stimulation . · 2026-02-14

  articleOpen access

  <h2>Abstract</h2> Major Depressive Disorder (MDD) presents with heterogeneous symptom profiles. While repetitive Transcranial Magnetic Stimulation (rTMS) treatment is known to improve depressive symptoms overall, it remains unclear how rapidly individual symptoms that are rated as severe at baseline improve during a clinical course. We analyzed Inventory of Depressive Symptomatology Self-Rated (IDS-SR) data collected every five sessions during rTMS treatment of 741 patients with treatment-refractory depression (TRD). Symptoms were grouped into Somatic-Vegetative (S-V) or Affective-Cognitive (A-C) domains, and analyses were restricted to baseline-severe items (IDS-SR item score ≥2) on a within-patient basis to reduce floor effects. Linear mixed-effects models examined symptom trajectories across domains, and we quantified time to 50% sustained improvement for individual symptoms. S-V symptoms improved slightly faster than A-C symptoms early in treatment (sessions 5 and 10; p < 0.01), but differences between symptom domains were small in comparison to overall change over time and symptom domains converged by the end of treatment. Symptoms that improved earlier were more likely to achieve 50% sustained improvement throughout the course. These real-world data primarily inform expectation-setting: patients can anticipate generalized improvement across baseline-severe symptoms during a full rTMS course, with at most modest early differences between symptom domains.

  PublisherDOI

• Efficacy of 5x5 accelerated versus conventional repetitive transcranial magnetic stimulation (rTMS) for treatment-resistant depression

  Research Square · 2025-08-19

  preprintOpen access
  PublisherOA PDFDOI

• The effect of older age on outcomes of rTMS treatment for treatment-resistant depression

  International Psychogeriatrics · 2024-03-25 · 17 citations

  articleOpen access

  Clinical outcomes of repetitive transcranial magnetic stimulation (rTMS) for treatment of treatment-resistant depression (TRD) vary widely and there is no mood rating scale that is standard for assessing rTMS outcome. It remains unclear whether TMS is as efficacious in older adults with late-life depression (LLD) compared to younger adults with major depressive disorder (MDD). This study examined the effect of age on outcomes of rTMS treatment of adults with TRD. Self-report and observer mood ratings were measured weekly in 687 subjects ages 16-100 years undergoing rTMS treatment using the Inventory of Depressive Symptomatology 30-item Self-Report (IDS-SR), Patient Health Questionnaire 9-item (PHQ), Profile of Mood States 30-item, and Hamilton Depression Rating Scale 17-item (HDRS). All rating scales detected significant improvement with treatment; response and remission rates varied by scale but not by age (response/remission ≥ 60: 38%-57%/25%-33%; <60: 32%-49%/18%-25%). Proportional hazards models showed early improvement predicted later improvement across ages, though early improvements in PHQ and HDRS were more predictive of remission in those < 60 years (relative to those ≥ 60) and greater baseline IDS burden was more predictive of non-remission in those ≥ 60 years (relative to those < 60). These results indicate there is no significant effect of age on treatment outcomes in rTMS for TRD, though rating instruments may differ in assessment of symptom burden between younger and older adults during treatment.

  PublisherOA PDFDOI

• Review for "Microdosing ketamine in &lt;i&gt;Drosophila&lt;/i&gt; does not block serotonin reuptake, but causes complex behavioral changes mediated by glutamate and serotonin receptors"

  2024-01-10

  peer-review1st authorCorresponding
  PublisherDOI

• Expression and potential regulatory functions of <i>Drosophila</i> octopamine receptors in the female reproductive tract

  G3 Genes Genomes Genetics · 2024-01-19 · 9 citations

  articleOpen accessSenior author

  Aminergic signaling is known to play a critical role in regulating female reproductive processes in both mammals and insects. In Drosophila, the ortholog of noradrenaline, octopamine, is required for ovulation as well as several other female reproductive processes. Two octopamine receptors have already been shown to be expressed in the Drosophila reproductive tract and to be required for egg-laying: OAMB and Octβ2R. The Drosophila genome contains 4 additional octopamine receptors-Octα2R, Octβ1R, Octβ3R, and Oct-TyrR-but their cellular patterns of expression in the reproductive tract and potential contribution(s) to egg-laying are not known. In addition, the mechanisms by which OAMB and Octβ2R regulate reproduction are incompletely understood. Using a panel of MiMIC Gal4 lines, we show that Octα2R, Octβ1R, Octβ3R, and Oct-TyrR receptors are not detectable in either epithelium or muscle but are clearly expressed in neurons within the female fly reproductive tract. Optogenetic activation of neurons that express at least 3 types of octopamine receptors stimulates contractions in the lateral oviduct. We also find that octopamine stimulates calcium transients in the sperm storage organs and that its effects in spermathecal, secretory cells, can be blocked by knock-down of OAMB. These data extend our understanding of the pathways by which octopamine regulates egg-laying in Drosophila and raise the possibility that multiple octopamine receptor subtypes could play a role in this process.

  PublisherOA PDFDOI

• Constitutive and Conditional Epitope Tagging of Endogenous G-Protein–Coupled Receptors in <i>Drosophila</i>

  Journal of Neuroscience · 2024-06-27 · 16 citations

  articleOpen accessSenior author

  To visualize the cellular and subcellular localization of neuromodulatory G-protein–coupled receptors in Drosophila , we implement a molecular strategy recently used to add epitope tags to ionotropic receptors at their endogenous loci. Leveraging evolutionary conservation to identify sites more likely to permit insertion of a tag, we generated constitutive and conditional tagged alleles for Drosophila 5-HT1A , 5-HT2A , 5-HT2B , Oct β 1R , Oct β 2R , two isoforms of OAMB , and mGluR . The conditional alleles allow for the restricted expression of tagged receptor in specific cell types, an option not available for any previous reagents to label these proteins. We show expression patterns for these receptors in female brains and that 5-HT1A and 5-HT2B localize to the mushroom bodies (MBs) and central complex, respectively, as predicted by their roles in sleep. By contrast, the unexpected enrichment of Octβ1R in the central complex and of 5-HT1A and 5-HT2A to nerve terminals in lobular columnar cells in the visual system suggest new hypotheses about their functions at these sites. Using an additional tagged allele of the serotonin transporter, a marker of serotonergic tracts, we demonstrate diverse spatial relationships between postsynaptic 5-HT receptors and presynaptic 5-HT neurons, consistent with the importance of both synaptic and volume transmission. Finally, we use the conditional allele of 5-HT1A to show that it localizes to distinct sites within the MBs as both a postsynaptic receptor in Kenyon cells and a presynaptic autoreceptor.

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• Safety and efficacy of targeting the supplementary motor area with double-cone deep transcranial magnetic stimulation vs figure-eight coil in treatment of obsessive-compulsive disorder with comorbid major depressive disorder

  Journal of Psychiatric Research · 2024-09-21 · 4 citations

  article
  PublisherDOI

• Heterogeneity in the projections and excitability of tyraminergic/octopaminergic neurons that innervate the Drosophila reproductive tract

  Frontiers in Molecular Neuroscience · 2024-08-02 · 7 citations

  articleOpen accessSenior authorCorresponding

  Aminergic nuclei in mammals are generally composed of relatively small numbers of cells with broad projection patterns. Despite the gross similarity of many individual neurons, recent transcriptomic, anatomic and behavioral studies suggest previously unsuspected diversity. Smaller clusters of aminergic neurons in the model organism Drosophila melanogaster provide an opportunity to explore the ramifications of neuronal diversity at the level of individual cells. A group of approximately 10 tyraminergic/octopaminergic neurons innervates the female reproductive tract in flies and has been proposed to regulate multiple activities required for fertility. The projection patterns of individual neurons within the cluster are not known and it remains unclear whether they are functionally heterogenous. Using a single cell labeling technique, we show that each region of the reproductive tract is innervated by a distinct subset of tyraminergic/octopaminergic cells. Optogenetic activation of one subset stimulates oviduct contractions, indicating that the cluster as a whole is not required for this activity, and underscoring the potential for functional diversity across individual cells. Using whole cell patch clamp, we show that two adjacent and morphologically similar cells are tonically inhibited, but each responds differently to injection of current or activation of the inhibitory GluCl receptor. GluCl appears to be expressed at relatively low levels in tyraminergic/octopaminergic neurons within the cluster, suggesting that it may regulate their excitability via indirect pathways. Together, our data indicate that specific tyraminergic/octopaminergic cells within a relatively homogenous cluster have heterogenous properties and provide a platform for further studies to determine the function of each cell.

  PublisherOA PDFDOI

Recent grants

• NIH Grant K08MH001709

  NIH · $644k · 2005

• Models of Neuromodulatory Circuits in Drosophila

  NIH · $2.1M · 2018–2025

• Identification of the Kenyon Cell Neurotransmitter

  NIH · $424k · 2016–2018

• The Influence of Neurotransmitter Transport on Aminergic Neuromodulation

  NIH · $1.9M · 2015–2020

• Training in Molecular Toxicology

  NIH · $4.0M · 2008–2026

Frequent coauthors

• Andrew F. Leuchter

  48 shared

• Nathaniel D. Ginder

  Neurobehavioral Systems

  38 shared

• Robert H. Edwards

  University of California, San Francisco

  34 shared

• Ian A. Cook

  The Master's Seminary

  32 shared

• Reza Tadayonnejad

  Neurobehavioral Systems

  27 shared

• Jennifer G. Levitt

  27 shared

• Andrew C. Wilson

  University of Colorado Boulder

  22 shared

• Nikita Vince-Cruz

  22 shared

Awards & honors

• H.W. Magoun Distinguished Lectureship
• Samuel Eiduson Student Lectureship
• Arnold Scheibel Distinguished Fellow in Neuroscience Lecture
• Community Scholars Awards
• Eva Kavan Prize