DEPARTMENT OF NEUROBIOLOGY

Specializations

Regions(s): Neurogenetics; Brain and Behavior; Systems Neuroscience; Cellular and Molecular Neuroscience

Research interest(s): Visual Neuroscience; Neurophysiology; Neuroanatomy; Mouse Genetics; Behavior

Research Summary

Light is an important and ever present regulator of physiology and behavior, and is involved in processes as wide ranging as daily hormonal oscillations, pattern vision, sleep, attention, and circadian photoentrainment. But how are light signals relayed to the brain to mediate these complex visual behaviors? In mammals, all light information reaches the brain via projections from the retinal ganglion cells (RGCs), of which there are ~20 subtypes in the retina. Therefore, to understand how light regulates behavior, we must understand: 1) How do RGC subtypes respond to different light stimuli? 2) What are the specific cellular targets of individual RGC subtypes in the brain? and 3) What are the functional contributions of RGC subtypes to defined visual behaviors?

We study these questions by looking at the role of RGC subtypes in specific visual functions. For example, the intrinsically photosensitive retinal ganglion cells (ipRGCs), which express the photopigment melanopsin, comprise five subtypes that drive a wide range of behaviors from circadian photoentrainment to contrast sensitivity for vision. The defined and quantitative behaviors in which these cells are involved, and the myriad available genetic tools for study of this system make it an ideal one in which to study the circuitry and role of ganglion cells in visual behavior. We do this using a range of techniques from electrophysiology, neuroanatomy, and behavioral approaches in various genetic mouse models.

Selected Publications

• Rupp AC, Ren M, Altimus C, Fernandez D, Richardson M, Turek F, Hattar S, Schmidt TM(2019) Distinct ipRGC subpopulations mediate light’s acute and circadian effects on body temperature and sleep. eLife8:e44358.
• Munteanu T, Noronha K, Leung AC, Pan S, Lucas JA, Schmidt TM(2018) Light-dependent pathways for dopaminergic amacrine cell development and function. eLife7:e39866.
•  Sonoda T, Lee SK, Birnbaumer L, Schmidt TM (2018) Melanopsin phototransduction is repurposed by ipRGC subtypes to shape the function of distinct visual circuits. Neuron99(4):754-767.
  
  • Previewed in: Pottackal J and Demb JB (2018) Melanopsin shows its contrast-sensitive side. Neuron99(4):630-632.
• Li JL, Schmidt TM(2018) Divergent projection patterns of M1 ipRGC subtypes. J Comp Neurol526(13):2010-2018.
• Lee SK, Schmidt TM(2018) Morphological identification of melanopsin-expressing ganglion cell subtypes in mice. In: Tanimoto N. (eds) Mouse Retinal Phenotyping.Methods in Molecular Biology, vol 1753. Humana Press, New York, NY.
• Laboissonniere LA, Sonoda T, Lee SK, Trimarchi JM*, Schmidt TM*(2017) Single-cell RNA-seq of defined subsets of retinal ganglion cells. J Vis Exp(123), e55229.
• Sonoda T, Schmidt TM(2016) Re-evaluating the role of intrinsically photosensitive retinal ganglion cells: New roles in image forming functions. Integrative and Comparative Biology56(5): 834-841.
• Schmidt TM,Alam NM, Chen S, Kofuji P, Li W, Prusky GT, Hattar S (2014) A role for melanopsin in alpha retinal ganglion cells and contrast detection. Neuron82(4): 781-788.
• Schmidt TM and Kofuji P (2011) An isolated retinal preparation to record light responses from genetically labeled retinal ganglion cells. J Vis Exp47.
• Schmidt TM and Kofuji P (2011) Structure and function of bistratified intrinsically photosensitive retinal ganglion cells in the mouse. J Comp Neurol519(8): 1492-1504.
• Perez-Leighton CE*, Schmidt TM*,Abramovitz J,Birnbaumer L, Kofuji P^#(2011) Intrinsic phototransduction persists in melanopsin-expressing ganglion cells lacking diacylglycerol-sensitive TRPC channel subunits. Eur J Neurosci33(5):856-867.
• Schmidt TM,Chen S-K, Hattar S (2011) Intrinsically photosensitive retinal ganglion cells: many subtypes, diverse functions. Trends Neurosci34 (11): 572-580.
• Schmidt TM, Do MT, Dacey DM, Lucas R, Hattar S, Matynia A (2011) Melanopsin-positive intrinsically photosensitive retinal ganglion cells: from form to function. J Neurosci31(45): 16094-101.
• Schmidt TM and Kofuji P (2010) Differential cone pathway influence on intrinsically photosensitive retinal ganglion cell subtypes. J Neurosci30 (48): 16262-16271.
• Schmidt TM and Kofuji P (2009) Functional and morphological differences among intrinsically photosensitive retinal ganglion cells.  J Neurosci29(2): 476-482. 
• Schmidt TM, Taniguchi K, and Kofuji P (2008) Intrinsic and extrinsic light responses in melanopsin-expressing ganglion cells during mouse development. J Neurophysiol100:371-384.

Selected Honors/Awards

• 2019  Pisart Award for Outstanding Achievements in Vision Science, The Lighthouse Guild
• 2019  Kavli Fellow, 4th Korean-American Kavli Frontiers of Science Symposium
• 2019  Brain Research Foundation Fay/Frank Seed Grant Recipient
• 2017  Sloan Research Fellowship in Neuroscience
• 2016  NIH Director's New Innovator Award
• 2016  Klingenstein-Simons Fellowship Award in the Neurosciences
• 2016  Karl Kirchgessner Foundation Vision Research Grant
• 2012-2014  Ruth L. Kirchstein Postdoctoral National Research Service Award 
• 2010  Milne and Brandenburg Research Award, University of Minnesota
• 2007  Morris Smithberg Memorial Prize, Graduate Program in Neuroscience, University of Minnesota
• 2006  Summa Cum Laude, Luther College
• 2006  Phi Beta Kappa

Centers/Institutes

• Northwestern University Interdepartmental Neuroscience (NUIN) Program