Our work has been funded through numerous sources, most prominently from the National Institute on Deafness and Other Communication Disorders. Our longstanding grant (NIH R01 DC004391), has been funded continuously since 1999. In 2020, we started a second grant (R01 DC018214) in collaboration with Dr. Michael Roberts at the University of Michigan. Below is a summary of the major questions we are addressing in these projects.
Modulatory Circuits in the Auditory System
What are the sources of cholinergic input to the cochlear nucleus?
In the photos on the left, cholinergic axons are filled with a red fluorescent protein. Cholinergic axons with associated boutons can be seen in the dorsal cochlear nucleus (DCN), granule cell area, and ventral cochlear nucleus (VCN). We are currently using viral tract tracing in a newly developed mouse model to determine the sources of this cholinergic input.
Which subtypes of GABAergic cells in the inferior colliculus receive cholinergic input?
The photos on the left show four subtypes of GABAergic cells in the inferior colliculus (GAD, green). Each of them can be contacted by cholinergic boutons (red). We are currently preparing a manuscript with these results.
What are the projection patterns of inferior colliculus cells that receive cholinergic input?
In the photos on the left, cells in the inferior colliculus have been retrogradely filled via injections into the cochlear nucleus (upper) or medial geniculate nucleus (lower). Cells within both pathways (IC-CN and IC-MG) can be contacted by cholinergic boutons (magenta). Contacted IC-MG neurons could be GABAergic (stained in green and marked G+) or nonGABAergic (not shown).
Circuit Mechanisms for Auditory Processing in the Inferior Colliculus
What are the inputs and outputs of two subclasses of cells in the inferior colliculus?
In the photo above, inferior colliculus cells that express neuropeptide Y (NPY, green) are retrogradely labeled after an injection of retrograde tracer into the medial geniculate nucleus (magenta), meaning that NPY cells can send projections to the medial geniculate nucleus. We have also shown projections from NPY cells within the ipsilateral inferior colliculus and to the contralateral inferior colliculus. We are currently working to address the possibility that NPY cell may also project to the nucleus of the brachium of the inferior colliculus. This project also addresses the circuitry of inferior colliculus cells that express vasoactive intestinal peptide, which we’ve shown have widespread projections.
Past and Present Funding
National Institutes of Health
1999–present R01 DC004391 Modulatory Circuits in the Auditory System
2020–present R01 DC018214 Circuit Mechanisms for Auditory Processing in the Inferior Colliculus
2019–present R01 DC016918 Neuronal Hyperactivity: Tinnitus and Distress (PI: A. Galazyuk)
2016–2019 R01 EY026662 Metabolic Vulnerability as a Disease Target for Glaucoma (PI: D. Inman)
2012–2017 R01 EY 022358 Axonopathy in Glaucoma (PI: S. Crish)
1998–1999 R55 DC003790 Functional Anatomy of the Auditory Pathways
NIH National Research Service Awards to lab trainees
2014-2016 F31 DC014228 Predoctoral NRSA (PI: Nichole Foster Beebe)
2012–2015 F32 DC012450. Postdoctoral NRSA (PI: Jeffrey Mellott)
2010–2012 F32 DC010958. Postdoctoral NRSA (PI: Kyle Nakamoto)
2007–2009 F31 DC08463. Predoctoral NRSA (PI: Susan Motts)
2001–2004 F31 DC05277. Predoctoral NRSA (PI: Diana Coomes Peterson)
NEOMED Research Incentive Program
2006–2007 Physiology and Morphology of Guinea Pig Auditory Cortex Neurons (Co-investigator: Y. Lu)
2009–2010 Modulation of Synaptic Transmission in the Prefrontal Cortex by the Tachykinin NK3 Receptor (Co-investigator: M. Simmons)
Deafness Research Foundation 1997–1998 Research Grant