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Barnes Lab

Investigating retinal neurons and glia

Over the course of his 35 years in vision research and neuroscience, Dr. Barnes has developed expertise in patch clamp electrophysiology and calcium imaging. Dr. Barnes has brought these biophysical tools to bear on the membrane mechanisms responsible for visual function in the retina using living retinal slice, cultured cells, eyecup, acutely isolated cells and flat-mount retina.

Dr. Barnes' work investigates the roles of voltage- and ligand-gated ion channels in visual function in the retina. He specializes in the bidirectional neural signaling between photoreceptors and horizontal cells, showing that many critical features of these synaptic interactions, which underlie the formation of center-surround antagonistic receptive fields, involve ion channel modulation by neural messengers.

His experience investigating the electrophysiological properties of retinal neurons and glia contributes substantially to the biophysical aspects of the research programs on retinal signaling in the Retina and Optic Nerve Research Laboratory.

Selected publications

  • Liu X, Hirano A, Sun XP, Brecha N, Barnes S (2013) Voltage-gated calcium channels in horizontal cells regulate inhibitory signalling to rat photoreceptors. Journal of Physiology 591:3309-3324.
  • Vessey JP, Stratis AK, Daniels BA, Da Silva N, Jonz MG, Lalonde MR, Baldridge WH, Barnes S (2005) Proton-mediated feedback inhibition of presynaptic calcium channels at the cone photoreceptor synapse. Journal of  Neuroscience 25:4108-4117.
  • Sargoy A, Sun XP, Barnes S, Brecha N (2014) Differential calcium signaling mediated by voltage-gated calcium channels in rat retinal ganglion cells and their unmyelinated axons. PLoS ONE 9:e84507.
  • Farrell SR, Rankin DR, Brecha NC, Barnes S (2014) Somatostatin receptor subtype 4 modulates L-type calcium channels via Gbg and PKC signaling in rat retinal ganglion cells. Channels 8:519-527.  [Featured in News and Views: Hildebrand ME, Snutch TP (2015) The Unusual Suspects: Regulation of retinal calcium channels by somatostatin. Channels 9(2):61-62] 
  • Lalonde MR, Jollimore CAB, Stevens K, Barnes S, Kelly MEM (2006) Cannabinoid receptor-mediated inhibition of calcium signaling in rat retinal ganglion cells.  Molecular Vision 12:1160-1166.

See more publications


A large part of the funding for the Barnes Lab comes from:


Dr. Barnes is a professor in the Departments of Physiology & Biophysics and Ophthalmology & Visual Science at Dalhousie University. He has been a faculty member at Dalhousie University since 1998.

Dr. Barnes was previously a faculty member at the University of Calgary from 1989-1998. In 1985, he completed his PhD training with Frank Werblin at the University of California at Berkeley, and in 1989, he completed his PDF with Bertil Hille at the University of Washington in Seattle.