Steven Barnes, PhD

When we peer into the eye’s black pupil, we are literally looking at the neurons of the retina. But they are too small, dark and non-reflective to be seen without special instruments. The retina is an extremely complex, thin film of brain tissue that has the critical task of capturing visual images with its rod and cone photoreceptors, and nearly instantly turning the images into electrical and chemical signals that are processed by intricate neural circuits formed by the many interacting types of retinal neurons. The analyzed images are sent in real time via the ganglion cell axons in the optic nerve to the brain centers responsible for visual perception.

The neurons and their connections in the retina are the parts of the eye that my laboratory studies. We investigate how the photoreceptors, horizontal cells, bipolar cells, amacrine cells and ganglion cells shape and tune their electrical signals using membrane ion channels, and how they transfer these signals to one another at synapses with chemical neurotransmitters. We analyze how individual retinal neurons detect spatial and color contrast in visual space, how they respond to changes in light intensity, how the different metabolic environments in the retina affect the signaling and health of the neurons, and how newly generated neurons develop the correct retinal properties when grown from stem cells in a dish. Our current work is undertaken in collaboration with other laboratories at Doheny Eye Institute and UCLA Stein Eye Institute, along with the Departments of Ophthalmology, Neurobiology, and Chemistry. Funding for these investigations comes the from National Institutes of Health, other agencies, private charities and donations, and these funding sources also support the training of new scientists, students, trainees and fellows.

Fuller JT, Barnes S, Sadun LA, Ajmera P, Alexandrova AN, Sadun AA (2023).  Coenzyme Q10 trapping in mitochondrial complex I underlies Leber’s hereditary optic neuropathy. Proceedings of the National Academy of Science (U.S.A.) 120(39):e2304884120. doi: 10.1073/pnas.2304884120

Smith BJ, McHugh CF, Hirano AA, Brecha NC, Barnes S (2023). Transient and Sustained Ganglion Cell Light Responses Are Differentially Modulated by Intrinsically Produced Reactive Oxygen Species Acting upon Specific Voltage-Gated Na⁺ Channel Isoforms. Journal of Neuroscience 43:2291–2304.   doi: 10.1523/JNEUROSCI.1723-22.2023

Barnes S (2022). Visual processing: When two synaptic strata are better than one.  Current Biology 32 (3): R129-R131. doi: 10.1016/j.cub.2021.12.044. PMID: 35134361

Zhang X, Mandric I, Nguyen KH, Nguyen TTT, Pellegrini M, Grove JCR, Barnes S and Yang X-J (2021). Single Cell Transcriptomic Analyses Reveal the Impact of bHLH Factors on Human Retinal Organoid Development. Frontiers in Cell Developmental Biology 9:653305. doi: 10.3389/fcell.2021.653305. PMCID: PMC8155690

Hirano AA, Vuong HE, Kornmann HL, Schietroma C, Stella SL Jr, Barnes S, Brecha NC (2020). Vesicular release of GABA by mammalian horizontal cells mediates inhibitory output to photoreceptors. Frontiers in Cellular Neuroscience 14:600777. doi: 10.3389/fncel.2020.600777

Barnes S, Grove JCR, McHugh CF, Hirano AA, Brecha NC (2020). Horizontal cell feedback to cone photoreceptors in mammalian retina: Novel insights from the GABA-pH hybrid. Frontiers in Cellular Neuroscience 14:595064. doi: 10.3389/fncel.2020.595064.

Grove JCR, Hirano AA, de los Santos J, McHugh CF, Purohit S, Field GD, Brecha NC, Barnes S (2019). Novel hybrid action of GABA mediates inhibitory feedback in the mammalian retina. PLOS Biology 13(12):e1002322. doi:10.1371/journal.pbio.1002322. PMCID: PMC6459543.

2023 Steven Barnes, PhD, Selected to Receive Five-Year NIH
2018 Shaffer Award, Glaucoma Research Foundation Research Grant
1997 Picchione Visiting Professor, Dalhousie University
1995-1998 Roy Allen Investigator in Ophthalmological Research, University of Calgary