Ganglion Cell Function

Green ring of cells

Fluorescent ring of ganglion cells serving the foveal cones. These cells are expressing the calcium indicator GCaMP, which allows cell responses to be monitored optically.

This research examines the role of retinal ganglion cells in the visual perception of primate (human and macaque) and mouse. Although the retina contains more than 17 types of ganglion cells and each type forms a complete mosaic across the retina, little is known about what role each type plays in seeing. ARIA is studying the role of different ganglion cell types using adaptive optics imaging of their calcium response.

Left: Rainbow pattern over ganglion cell array. Right: Black and white bar stimulus

Phase map of ganglion cell responses to a 0.2Hz drifting grating visual stimulus presented to the foveal cones.

  • Imaging the physiological activity of retinal ganglion cells with G-CaMP, a calcium indicator.
  • Restoration of vision to blind retina by inserting channel rhodopsin into retinal ganglion cells. Determines how perception can be mediated by light-gated channels used to restore vision to blind subjects.
  • Identification and classification of retinal ganglion cells using response characteristics to chromatic and spatio-temporal stimuli.

Funding Sources

  • NIH RO1 RO1EY021166 Title: Functional Imaging of Ganglion Cells in the Living Mammalian Eye
  • PN2EY018241 Title: Develop improved method for viral vector insertion of channel rhodopsin in primate retina. Collaborator Ehud Isacoff, PI, Nanomedicine Developmental Center
  • NIH EY014375-05 Title: Adaptive Optics Instrumentation for Advanced Ophthalmic Imaging, Collaborator David Williams, PI
  • NIH grant Title: Retinal Mechanisms, Collaborator David Williams, PI


  • McGregor JE, Godat T, Dhakal KR, Parkins K, Strazzeri JM, Bateman BA, Fischer WS, Williams DR, Merigan WH (2020). Optogenetic restoration of retinal ganglion cell activity in the living primate. Nature Communications 11(1), 1703. PDF
  • McGregor, J.E. (2019). Restoring vision at the fovea. Current Opinion in Behavioral Sciences 30, 210-216. PDF
  • McGregor JE, Yin L, Yang Q, Godat T, Huynh KT, Zhang J, Williams DR, Merigan WH (2018). Functional architecture of the foveola revealed in the living primate. PLoS One 13(11):e0207102. PDF
  • Yin L, Masella B, Dalkara D, Zhang J, Flannery JG, Schaffer DV, Williams DR, Merigan WH (2014). Imaging light responses of foveal ganglion cells in the living macaque eye. J Neurosci. ;34(19):6596-605. doi: 10.1523/JNEUROSCI.4438-13.2014. PDF
  • Yin L, Geng Y, Osakada F, Sharma R, Cetin AH, Callaway EM, Williams DR, Merigan WH (2013). Imaging light responses of retinal ganglion cells in the living mouse eye. J Neurophysiol. 2013 Feb 13. PDF
  • Dalkara D, Byrne LC, Klimczak RR, Visel M, Yin L, Merigan WH, Flannery JG, Schaffer DV (2013). In vivo-directed evolution of a new adeno-associated virus for therapeutic outer retinal gene delivery from the vitreous. Sci Transl Med. 5(189):189ra76. PDF
  • Geng, Y., Dubra, A., Yin, L., Merigan, W.H., Sharma, R., Libby, R.T., and Williams, D.R. (2012). Adaptive optics retinal imaging in the living mouse eye. Biomed Opt Express 3(4), 715-734. PDF
  • Yin, L., Greenberg, K., Hunter, J.J., Dalkara, D., Kolstad, K.D., Masella, B.D., Wolfe, R., Visel, M., Stone, D., Libby, R.T., DiLoreto, Jr., D., Schaffer, D.V., Flannery, J., Williams, D.R., Merigan, W.H. (2011). Intravitreal injection of AAV2 transduces macaque inner retina. IOVS. 52(5):2775-2783. PDF
  • Scoles, D., Gray, D.C., Hunter, J.J., Wolfe, R., Gee, B.P., Geng, Y., Masella, B.D., Libby, R.T., Russell, S., Williams, D.R., Merigan, W.H. (2009). In vivo imaging of retinal nerve fiber layer vasculature: imaging – histology comparison. BMC Ophthalmology, 9:9 doi:10.1186/1471-2415-9-9. PDF
  • Gray, D.C., Wolfe, R., Gee, B.P., Scoles, D., Geng, Y., Masella, B.D., Dubra, A., Luque, S., Williams, D.R., Merigan, W.H. (2008). In vivo imaging of the fine structure of rhodamine labeled macaque retinal ganglion cells. IOVS, 49(1), 467-73. PDF
  • Merigan, W.H, Freeman, A., Meyers, S. (1997). Parallel processing streams in human visual cortex. Neuroreport, 8, 3985-3991.
  • Merigan, W.H. and Maunsell, J.H.R. (1993). How parallel are the primate visual pathways. Annual Review of Neuroscience, 16, 369-402.